Food Technology
Massoumeh Mehraban Sangatash; Maryam Dadras-Moghadam; Seyed Ali Mortazavi; Hanieh Yarabbi
Abstract
The increasing growth of cardiovascular diseases, high blood pressure, and hardening of the vessel walls as well as obesity in many countries has made low-fat and low sodium pizza cheese one of the subjects of study all over the world. The effects of four important independent variables including inulin ...
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The increasing growth of cardiovascular diseases, high blood pressure, and hardening of the vessel walls as well as obesity in many countries has made low-fat and low sodium pizza cheese one of the subjects of study all over the world. The effects of four important independent variables including inulin (0-0.025 %), pre-gelatinized starch (0-0.5 %), NaCl (0.35-1%), and KCl (0.35-1%) were studied. The fat content of imitation pizza cheese was significantly decreased to 11.91% with the increased levels of inulin and starch substitution (p<0.05). Also, its moisture and pH values were significantly different (p < 0.05). The increased levels of pre-gelatinized starch and inulin reduced hardness (from 5.04 to 3.55) and adhesiveness (from 4368.89% to 1640.54%), however, increased cohesiveness (from 0.365 to 0.43) and springiness (from 0.456 to 0.545). NaCl and KCl increased the hardness of the product. Inulin and starch led to decrease the a* value. The b* value decreases with the increase of inulin and increases with the increase of modified starch. The formulation containing 0.19% inulin, 0.4% pre-gelatinized starch, 0.35% NaCl, and 0.50% KCl was found as the optimal formulation for low-fat imitation cheese. Results of scanning electron microscope (SEM) images revealed that inulin crystals were accumulated in the continuous phase, which this can lead to important changes in the sensory and textural properties. The study concludes that inulin or starch can be used to replace up to 3.6% of fat in the imitation pizza cheese and 0.35% NaCl-0.50% KCl to lower the sodium content of the product.
Food Biotechnology
Hossein Zanganeh; Fakhri Shahidi; Seyed Ali Mortazavi; Behrooz Alizadeh Behbahani
Abstract
IntroductionOxidation reactions and microorganisms’ activity are considered as the most important factors affecting the quality of food products. Recently, in the light of the inefficiency of some chemical preservatives against microorganisms and the presence of toxic residues in food products, ...
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IntroductionOxidation reactions and microorganisms’ activity are considered as the most important factors affecting the quality of food products. Recently, in the light of the inefficiency of some chemical preservatives against microorganisms and the presence of toxic residues in food products, the use of natural antimicrobials and antioxidants has been increased. Natural antimicrobial compounds have the potential to control microbial contamination and reduce the use of antibiotics. Plant essential oils are natural compounds with the potential to be used as active ingredients in the food, pharmaceutical, and cosmetic industries. Various studies have shown that essential oils have antifungal, antibacterial, antiviral, and antioxidant activity. The essential oils are considered as superb preservatives with various biological functions. Essential oils are generally recognized as safe product (GRAS) which can be used as an alternative to synthetic additives.Grapefruit (Citrus paradisi) peel and fruit contain active ingredients such as acids, flavonoids, vitamin C, and potassium, and its essential oil is composed of terpenic hydrocarbons, such as citral, limonene, citronelal, and geraniol. Although plant essential oils have antimicrobial and antioxidant properties, one of the main problems of these natural compounds is their high volatility and instability. In this context, nanoemulsion formulations are frequently used to increase the stability and efficiency of these biologically active compounds. This study is therefore aimed to nanoemulsifying the grapefruit essential oil and evaluate its antioxidant and antimicrobial properties. Materials and Methodsβ-carotene, linoleic acid, ABTS (2,2’-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt), and DPPH (2,2-diphenly-1-picrylhydrazyl) were purchased from Sigma-Aldrich Co. (USA). Mueller Hinton Broth (MHB) and Mueller Hinton Agar (MHA) were supplied from Merck Co. (Darmstadt, Germany). Grapefruit peel was dried at ambient temperature and then powdered. The obtained powder was then transferred to a Clevenger device containing 750 ml of distilled water to perform the distillation extraction (3 h). The resulting grapefruit essential oil was stored at 4 °C until use. Grapefruit essential oil was prepared using the hydrodistillation method, and then nanoemulsified. The antioxidant activity of the nanoemulsified essential oil was investigated by DPPH and ABTS radical scavenging activity and beta-carotene/linoleic bleaching test. The nanoemulsified essential oil or methanolic (control) was mixed with DPPH solution and the mixture was then stored at ambient temperature for 30 min, in a dark place. The control sample was prepared by methanol. The absorbance of the samples was measured at 517 nm. To determine the ABTS-RS activity, the nanoemulsified essential oil was briefly charged with methanolic ABTS radical cation solution and the resulting mixture was left at room temperature for 30 min. Afterward, the absorbance was read at 734 nm. A spectrophotometric method was applied to monitor β-carotene/linoleate solution bleaching in the presence of the nanoemulsified essential oil. To do this, the absorbance of the solution was recorded at 490 nm after 120 min against the control sample at time zero and after 120 min. Antibacterial effect of the grapefruit essential oil nanoemulsion was also evaluated against Escherichia coli ATCC 25922, Salmonella typhi ATCC 6539, Pseudomonas aeruginosa ATCC 27853, Listeria innocua ATCC 33090, Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 14579, Bacillus subtilis ATCC 23857, Streptococcus pyogenes ATCC 19615, and Staphylococcus epidermidis ATCC 12228, based on disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration. Results and DiscussionsThe results showed that the nanoemulsion of grapefruit essential oil had a remarkable antioxidant effect of 42.27 mg/ml, 33.27 mg/ml and 54.54%, respectively, based on DPPH, ABTS, and beta-carotene-linoleic acid bleaching tests. According to disk diffusion agar and well diffusion agar results, the lowest inhibition zone was related to E. coli and the highest inhibition zone was observed in L. innocua. The minimum inhibitory concentration for L. innocua and S. aureus (the most sensitive bacteria) was 25 mg/ml, and E. coli, S. typhi, and P. aeruginosa had the highest inhibitory concentration. Also, the lowest bactericidal concentration was related to L. innocua and S. aureus bacteria and the highest concentration was observed for E. coli, S. typhi and P. aeruginosa. The nanoemulsified essential oil generally exhibited greater antibacterial activity against Gram-positive species. This could be mainly due to the difference in the cell wall composition of Gram-positive bacteria in comparison to Gram-negative; Gram-positive bacteria have a thicker mucopeptide layer in their cell wall, while Gram-negative bacteria have only a thin layer of mucopeptide and the wall structure is mainly composed of lipoprotein and lipopolysaccharide, thereby leading to a higher resistant to antibacterial agents According to the results, grapefruit essential oil nanoemulsion can be used as a natural antioxidant and antimicrobial agent to control oxidation reactions and the growth of spoilage and pathogenic microorganisms.
Food Biotechnology
Kobra Tajik Toughan; Mohammad Reza Edalatian Dovom; Seyed Ali Mortazavi; Ali Javadmanesh
Abstract
[1]Introduction: Poultry and meat products are the largest sources of non-typhoid salmonella infections in most countries. Studies have shown that raw foods of animal origin, especially poultry and its products, are the main source of contamination of kitchens and restaurants. In terms of growth conditions, ...
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[1]Introduction: Poultry and meat products are the largest sources of non-typhoid salmonella infections in most countries. Studies have shown that raw foods of animal origin, especially poultry and its products, are the main source of contamination of kitchens and restaurants. In terms of growth conditions, these microorganisms are resilient bacteria and easily adapt to their environmental conditions. Salmonella has been known to cause intestinal disease for many years and has been reported as the most important cause of food poisoning. According to Iranian and international standards, there should be no S. enteritidis or S. typhimurium in 25 grams of food. DNA-based methods for the identification and differentiation of Salmonella serovars have been designed and applied using specific primers at the genus and serovar levels. Therefore, they can be used as useful and rapid screening tests, as well as to supplement or replace conventional biochemical and serological tests. Real-time PCR, with the most accurate and reliable results using a fluorescence probe, which of course has a high cost. In this method, sequence specific fluorescence probes are used, and as a result, in the target molecule, screening and determination the presence or even the concentration of specific sequences is possible. Therefore, even in the presence of other types of nucleic acid molecules, the results are obtained quickly and have a high level of specificity. Under these conditions, if specific probes with different florescence dyes are used, even multiple targets can be detected in a single PCR reaction. The aim of this study was to identify S. enteritidis or S. typhimurium by PCR and Salmonella spp. by real time PCR method in poultry products. Material and Method: In total, 45 samples of poultry products, including chicken breast, liver and gizzard (15 samples each) were purchased from different regions of Mashhad and from various companies and transferred to the laboratory in accordance with hygienic standards. For each sample, 25 g of tissue was isolated and homogenized under sterile conditions and DNA extraction was then performed using a DNA extraction kit. The extracted DNA was evaluated by agarose gel electrophoresis. The purity and quantity of DNA extracted from each sample was examined by spectrophotometry method. In the next step, in order to identify the genus Salmonella, the samples were examined by real time PCR. In this method we used an internal control to ensure that negative results are not false negative due to inhibitors. The results of real time PCR showed that out of 45 samples, nine samples were infected with Salmonella. Then, these nine samples were evaluated for Salmonella typhimurium and Salmonella enteritidis infection by conventional PCR method. Result and Discussion: The results showed that out of nine samples that were positive in real time PCR test, seven samples were contaminated with Salmonella typhimurium, of which five samples were related to chicken breast and two to liver. Regarding Salmonella enteritidis infection, out of nine samples, only one sample was contaminated, which was related to chicken breast. Conventional methods have been traditionally used to enumerate target bacteria in food. However, these methods have some limitations and require considerable time and labor. Previous studies have already shown that real time PCR is more effective than conventional bacteriological methods for the detection of Salmonella spp. In a study by Whyte et al. (2002) The presence of Salmonella was assessed by traditional culture methods and by a Salmonella-specific polymerase chain reaction (PCR) test. Salmonella was recovered from 16% of samples using traditional culture methods. In contrast, the PCR assay proved to be more sensitive and detected Salmonella DNA in 19% of the examined samples (Whyte et al. 2002). Results of PCR with specific primers showed that reactions in real time PCR with general primers of Salmonella spp. were done correctly. Despite of accuracy and speed of real time PCR to detect DNA of microorganisms, further studies are developed to have more advantages. Loop-mediated isothermal amplification (LAMP) showed a higher sensitivity of Salmonella detection in compare to qPCR (Vichaibun & Kanchanaphum, 2020). Although LAMP could detect trace amount of Salmonella DNA but primer design for this reaction is very difficult. However, it is important to highlight that non-viable cells can be detected by real time PCR or other DNA-based methods, which does not occur in traditional methods of culture and isolation that require viable cells for quantification (Zeng et al., 2016).
Food Biotechnology
Negin Ghazanfari; Seyed Ali Mortazavi; Farideh Tabatabaei Yazdi; Morteza Mohammadi
Abstract
Introduction: One of the most important challenges facing medical science is infectious diseases and poisoning, which in turn increases the production and consumption of new and common antibiotics. With theover use of common antibiotics, we are witnessing the spread of antibiotic-resistant microbial ...
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Introduction: One of the most important challenges facing medical science is infectious diseases and poisoning, which in turn increases the production and consumption of new and common antibiotics. With theover use of common antibiotics, we are witnessing the spread of antibiotic-resistant microbial species, which makes the treatment of infectious diseases long and costly. Natural compounds of plant origin (essential oils and extracts) have been used to kill or at least prevent the growth of pathogenic microorganisms. These compounds, which are naturally present in plant tissues, are probably produced as part of their defense mechanisms against microbial invasion. Plant-based antimicrobials have therapeutic potential and are not only effective in treating infectious diseases, but also reduce the large number of side effects that are often associated with synthetic antimicrobials. Essential oils are complex mixtures of volatile, aromatic, low molecular weight and hydrophobic compounds present in various parts of aromatic plants, including leaves, flowers, seeds, sprouts and shoots. Among these plants, we can mention the coriander plant. Coriander (Coriandrum sativum L.) is an annual, herbaceous, aromatic plant belonging to the Apiaceae family. Coriander has a long history of nutritional and therapeutic use. This plant is a rich source of aromatic compounds and essential oils that have antibacterial, antifungal and antioxidant effects and is used in the preparation of various foods as a spice. Materials and Methods: The tested coriander seeds were obtained from Khorasan Razavi province, Mashhad city. Antioxidant-free soybean oil was obtained from the Seh Gol Khorasan vegetable oil factory. Total phenolic content (TPC), Radical scavenging ability (DPPH assay), Oxidative stability index (OSI), Peroxide value (PV), Minimum inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) of essential oil were measured on a number of bacteria causing infection and food poisoning. The compositions of essential oils were identified by Gas Chromatography-Mass Spectrometry (GC-MS). Results and Discussion: Most of the constituents of coriander seed essential oil were oxygen monoterpene compounds. Essential oils that have a higher percentage of oxygenated compounds are more important than other compounds in terms of aroma, strong odor, as well as antimicrobial and antioxidant power, so they are considered more valuable essential oils. Analysis of microbial test results showed that coriander seed essential oil had a relatively strong and good effect against the studied Gram-positive bacteria, so that the essential oil inhibited the growth of Staphylococcus aureus even at low concentrations. This essential oil had good antioxidant activity in the thermal stability of soybean oil. Coriander seed essential oil as an antioxidant compound was able to increase the oxidative stability of soybean oil under oxidative acceleration conditions. The results showed that total phenolic compounds were 0.161 mg GAE/100g, IC50 for essential oil was 30.981 mg/ml and thermal stability of soybean oil treated with coriander seed essential oil was 5.17 h. The results of microbial tests showed that Gram-positive bacteria was more sensitive to Coriander seed oil than Gram-negative bacteria. The most important constituents of coriander seed essential oil were Linalool (49%), Terpinolene (7%) and α-Pinene (6.8%).
Sahar Sabahi; Seyed Ali Mortazavi; Mohammad Reza Nassiri; Arash Ghazvini; Fakhri Shahidi
Abstract
Introduction: Immunoglobin Y (IgY) or egg yolk antibodies have captured attention as substitutes for antibiotics against the presence of disease-causing organisms (Thomsen et al., 2016; Li et al., 2015; Pereira et al., 2019). Compared to mammalian IgG, IgY has several advantages including high yield, ...
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Introduction: Immunoglobin Y (IgY) or egg yolk antibodies have captured attention as substitutes for antibiotics against the presence of disease-causing organisms (Thomsen et al., 2016; Li et al., 2015; Pereira et al., 2019). Compared to mammalian IgG, IgY has several advantages including high yield, cost-effectiveness, and convenience (Li et al., 2015). It has been reported that the use of IgY against Helicobacter pylori can be particularly useful for prevention and treatment of diseases (Najdi et al., 2016). The growth inhibitory effect of IgY antibody is one of its crucial features (Alfarouk et al., 2019), meaning that IgY antibody could be consumed daily with no health risks. Therefore, daily consumption of IgY requires a suitable host. The ice cream is the best choice for this proposed, because this product is maintained at -18 C and ice cream composition has positive effect on the function of IgY. Therefore, we develop a new product for the prevention and treatment of Helicobacter pylori. Material and Methods: The Mueller-Hinton media was used for H. pylori growth. Then, 109 colonies of bacterium were inactivated by formaldehyde methods. The 3 white leghorn chickens (Animal Science Department of Ferdowsi University of Mashhad) of 16 weeks old were immunized by H. pylori and Freund’s complete adjuvant with an equal volume. The reminder immunization was done two weeks later and using of Freund’s incomplete adjuvant for stage 2. One week after the chickens received their last injection, their eggs were collected on a daily basis for eight weeks, labeled and kept at 4 °C (Pauly et al., 2011). Extraction and purification of IgY antibody from egg yolk was done using polyethylene glycol 6000 (PEG 6000) powder (Merck, Germany) according to Polson’s method (Pauly et al., 2011). The IgY production wasverified by the SDS-PAGE and Bradford methods. The specific activity of IgY antibody against H. pylori was examined by ELISA. The absorbance of each well was measured at 492 nm (Nasiri et al., 2016). The egg yolk ice cream preparation contains IgY was prepared according to the method of Herald et al (2008). For estimation of IgY shelf life in ice cream, the residual activity of IgY after freezing was measured by ELISA. The Sensory evaluation of the egg yolk ice creams was conducted by 5-point hedonic scale through surveys to assess consumers’ level of acceptance. Results and Discussion: The purification of IgY using the SDS-PAGE method was verified correctly and the size of heavy and light chains of IgY was estimated about 65 and 27 kDa. The IgY yield in samples was 11.46 mg/ml, therefore, the high purity and yield of IgY, it could be effectively used as an ideal antibody in the food industry. The purification of IgY from egg yolk by PEG method is remarkably cost effective. The ELISA assay indicated binding of IgY to H. pylori antigen that was fixed on plates. Also, the results revealed significant differences between the control and treatment groups (P-value <0.001). The shelf life of IgY in ice cream showed that this product could be most certainly used as bio-food. ELISA analysis confirmed that IgY could remain effective in ice cream for 3 months. The activity of IgY during this period decreased about 6%, which is insignificant. The sensory features of ice cream using hedonic scale revealed that this product could be suitable for marketing, as no significant difference was found between egg yolk and vanilla ice creams. Ice cream is considered as the best candidate for production of IgY bio-foods, as it possesses the features needed to protect IgY and to increase efficiency of IgY activity. The optimum temperature for protection of ice cream was -18 °C that is utterly suitable for IgY protection. Furthermore, ice cream is consumed while cold and studies showed that IgY can remain active at temperatures of up to 80 °C and pasteurization process had no effect on IgY activity (Horie et al., 2004). Jaradat et al (2000) reported that, IgY activity was inhibited in presence of carbohydrates (sucrose, lactose and trehalose). Therefore, here, we used freeze dried egg yolk to protect IgY. Consequently, ice-cream is an ideal candidate for transferring antibodies into human body, as the particular composition of ice cream can properly protect IgY antibodies.
Reza Mobasserfar; Seyed Ali Mortazavi
Abstract
Introduction: Doogh is one of the most important and most widely consuming fermented traditional Iranian milk products, which is being prepared from the healthy milk by using the activity of certain lactic acid bacteria and molds under the especial conditions. Streptococcus thermophilus and Lactobacillus ...
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Introduction: Doogh is one of the most important and most widely consuming fermented traditional Iranian milk products, which is being prepared from the healthy milk by using the activity of certain lactic acid bacteria and molds under the especial conditions. Streptococcus thermophilus and Lactobacillus bulgaricus are used as starter culture for milk fermentation. The fermented dairy products have long storage life and constitute an important part of the milk's per capita consumption. For this reason, studying the different methods in order to improve the quality of these products is crucial. By considering the fact that the strong thermal treatments damage some components of milk such as protein and vitamins, using the membrane filterations decrease the need to impose the intense thermal conditions which result into the relative loss of nutrients. On the other hand, using the membrane filters not only increase SNF (solid non-fat) and the percentage of protein but also lead into the production of less-lactose milk as well, the production of less-lactose products, in addition to their nutritional value for some people, have especial benefits for improving the quality. As follows, UF filters in 10-2-10-1 diameter separate the bacteria, fats and protein when milk is passing with a pressure about 1-10 bar but also they pass the minerals such as salts and water which are being removed as permeate and the concentrated milk is called “Retentate”. Materials and methods: Materials provided in this study were including: Starter culture (No: 505 form Danisco, USA), Lactic acid (1.00366) with a degree of purity level more than 95%, NaH2PO4*2H2O (1.06345) plus the cultures' environment and the chemical substances from MERCK Company. HPLC system (Agilent, 1100 series, USA), Rheometer (Anton, MCR300, Austria), Milk analyzer bar (Azmalaban, MCC, Iran), pH meter (Knick,766, Germany), Digital scale 0.001 (AND,GF4000, Japan), Psychrometer (Sartorius, MA45, Germany), Oven (memmert, UM400, Germany), Centrifuge (Funke Gerber, Nova safety, Germany), Kjeldahl (Gerhardt, KB, Germany), Refrigerated incubator (WTW,TS606-6/2-i, Austria), Incubator (memmert, BM400, Germany), Autoclave (RT-2, Reyhan Teb, Iran). In the present study the effect of a decrease in lactose percentage on the durability, flavor and sensory (organoleptic) properties of produced doogh on the 1st, 23rd and 46th day’s after production time in comparison to control ones, was investigated. The changes of acetaldehyde levels were measured using Gas chromatography mass spectroscopy. In this study, milk was passed through UF filters in three consecutive days and its lactose level was decreased by about 2%. After that fermentation and standardization of doogh based on the amount of fat and solid-nonfat has been done. All tests were repeated 3 times and the comparison of averages has been done by using LSD test (p= 0.05 %). Results were expressed as mean ± SE. Values were the average of triplicate experiments. Significant differences between the results were calculated by analysis of variance (ANOVA) with the help of SPSS software version 20. Differences at P<0.05 were considered to be significant. Also the obtained data for the rheological experiments was processed using software such as Excel 2010 and SPSS software version 20 to determine an appropriate mathematical model. And in this case, the linear and nonlinear regressions were used. Results & discussion: Results showed that by increasing the storage time, the acidity and pH changes and the acetaldehyde amount of produced doogh was less than those of the control samples. Additionally flavor and sensory properties improved considerably. Based on the findings of this research, it seems that the reduction of lactose and the decrease of lactic acid bacterial activity can play an important role in increasing the durability time, improving the sensory properties and enhancing the quality of doogh. It was determined that the decrease of lactose using ultrafiltration to the control sample not only indicates the significant changes in most considered variables but also there are these kinds of changes during the durability time. In addition, the significant and slow changes of pH to the control sample due to the decrease of lactic bacteria activities show the least qualitative and flavor changes over the durability time. And also it was specified that by increasing the activities of lactic bacteria, the amount of acetaldehyde will increase but by decreasing this activity, the level of acetaldehyde will decline. This issue has a direct relationship with the changes of lactose's amount. The post-filtration doogh due to its high amount of proteins shows high viscosity and concentration and for this reason, the attention of panelists in the sensory evaluation was directed toward choosing the post-filtration doogh instead of the pre-filtration one. Therefore, it can be concluded that the decrease of lactose using ultrafiltration has a main role in improving the quality of the product and also the tendency of the consumers.
Soheila Ahmadian Mask; Farideh Tabatabaei Yazdi; Seyed Ali Mortazavi; Arash Koocheki
Abstract
Introduction: Kefir is a traditional beverage produced by fermented milk with kefir grains, which is becoming increasingly popular throughout the world due to its health benefits and disease prevention properties beyond its basic nutritional value. The grains contain a mixture of complex microflora such ...
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Introduction: Kefir is a traditional beverage produced by fermented milk with kefir grains, which is becoming increasingly popular throughout the world due to its health benefits and disease prevention properties beyond its basic nutritional value. The grains contain a mixture of complex microflora such as lactic acid bacteria, yeast and sometimes acetic acid bacteria which are lodged by a polysaccharide matrix calls “kefiran”. Kefir is a self-carbonated beverage that owes its distinctive flavor to a mixture of lactic acid, ethanol, carbon dioxide and other flavor products such as acetaldehyde and acetone. Kefir has been recommended for the treatment of several clinical conditions such as gastrointestinal problems, hypertension, allergies, and ischemic heart disease. Kefir grain fermentations from various substrates have been evaluated and a wide variety of bioactive compounds have been observed, such as organic acids, CO2, H2O2, ethanol, bioactive peptides, exopolysaccharides (kefiran), and bacteriocins. These compounds may act independently or together to produce the various health benefits attributed to kefir consumption. Nowadays, its popularity has been expanded worldwide and it is considered as a healthy product with high nutritional value in Europe, Asia, and South and North America. Wheat germ, corresponding to 2–3% of the total weight of wheat kernel, is almost systematically removed during milling since it adversely affects the keeping and processing quality of the flour. Wheat germ (WG) is widely recognized as a nutritious raw material for incorporation into food product formulations or as an independent food product. Wheat germ, containing about 8% - 14% oil (average 10%), is mainly used in food, medical and cosmetic industries as a source of oil. Unfortunately, the whole quantity of the germ produced in Iran is currently utilized in the production of animal fodder. According to chemical analyses, wheat germ contains magnesium, zinc, calcium, selenium, sodium, potassium, phosphorus, chromium, antioxidants including beta-carotene (for vitamin A), vitamin E, vitamin C, vitamin B12, vitamin B6, thiamin, riboflavin, niacin, folic acid, iron, amino acids, and enzymes, and has a high dietary and medicinal value. The purpose of this study was to investigate the effects of various concentrations of wheat germ powder on physicochemical, microbial and sensory properties of kefir beverage. Materials and methods: A commercial freeze-dried Kefir starter culture (ABT_2) was purchased from Chr. Hansen (Denmark) also Saccharomyces cerevisiae was supplied from Saf-Levure (France). Cow milk were obtained from the Department of Food Engineering, Ferdowsi University of Iran. Wheat germ was supplied from Isar Qaynat Co. All chemicals were from Merck Co.Steam stabilized wheat germ powder at 1, 2 and 3% levels with DVS starter and Saccharomyces cerevisiae at 25 ° C were transferred to full fat cow’s milk and the fermentation was ended at pH 4.6. Microbial, physicochemical and sensory tests were performed at 24, 48 and 72 hours after inoculation. The pH and acidity of kefir were determined according to National Iranian Standard Number 2852. The viscosity was also determined using a Brookfield viscometer (spindle 3, USA) at the temperature of 5°C and a shear rate of 80.0 1/s. Spectroscopic measurement of alcohol was performed according to Sayyad et al. (2015). Lactobacilli counts were performed on MRS medium at an incubation temperature of 37°C for 3 days. Yeasts counts were carried out on YGC at an incubation temperature of 25°C for 5 days. Total counts were performed on PCA at an incubation temperature of 30°C for 2 days. All statistical calculations were completed using the Minitab Version 16. Analysis of variance (ANOVA) was carried out using the general linear model (glm) procedure and Tukey test was used to determine the differences among means. Results and discussion: Wheat germ is a by-product derived from the wheat milling industry and is a rich source of vitamins, proteins, dietary fiber and minerals. Due to its antioxidant, sterol and essential amino acids contents, it has a lot of health effects and is known as a nutritious raw material for its composition in food formulations. Therefore, in this study it was used to produce kefir beverage to produce a high-nutritional product. Based on the obtained results, increasing the percentage of wheat germ powder concentration on the physicochemical, microbial and sensory properties of kefir beverage has a significant effect. The sample containing 3% wheat germ powder showed the highest acidity, ethanol, yeast and total microbial count, during the storage period, acidity, ethanol and yeasts increased in all samples, while pH, Lactobacilli, total microbial count and apparent viscosity had decreasing trend and samples of kefir containing wheat germ powder showed non-Newtonian flow behavior according to the power law model. On the other hand, the apparent viscosity of the samples significantly decreased with increasing wheat germ concentration. According to the sensory evaluation results, kefir produced with one percent wheat germ received the highest overall score within 72 hours after inoculation.
Fatemeh Pourhaji; Farideh Tabatabaei Yazdi; Seyed Ali Mortazavi; Mohebbat Mohebbi; Mostafa Mazaheri Tehrani
Abstract
Introduction: Banana is one of the most consumed fruit in the world and is cultivated almost in all tropical countries. This fruit has a high nutritional value and is a suitable source of energy due to the presence of high amount of starch, sugar, vitamin A and C, potassium, sodium, and magnesium. Banana ...
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Introduction: Banana is one of the most consumed fruit in the world and is cultivated almost in all tropical countries. This fruit has a high nutritional value and is a suitable source of energy due to the presence of high amount of starch, sugar, vitamin A and C, potassium, sodium, and magnesium. Banana is highly vulnerable after harvesting and is subject to the microbial spoilage due to the high moisture content which makes difficult its sales and exports. Therefore, several methods have been used to overcome these problems. Drying and dehydration are methods to extend the shelf life of banana which usually carries out by hot air. This method can prevent some degree of microbial spoilage, but it has some disadvantages such as changing color, taste, flavor and reducing the nutritional value.
Foam-mat drying as a substitute for hot air drying introduces some advantages such as using the microwave energy. In this method, food products are whipped to form stable form and then dehydrated by thermal means. Due to the larger surface area and accelerated moisture transfer from foam, food products can be dried at lower temperature and time by this method of drying. Moreover, the porous structure of dried foam results in a faster rehydration and solubility of dried food samples. Additionally, microwave-assisted drying results in a product with better quality because of faster rate and saving energy.
Materials and methods: The fresh banana was cut into small pieces with a diameter of 1.0 mm after peeling. To prevent the enzymatic browning of samples, blanching was carried out by boiling water (100 °C) for 3 min. After that, the banana cuts were placed in a container containing 10°C water in order to cool. To produce pulps, the homemade Bosch mixer (model w600, CNSM, 30EW, Slovenia) at a speed of 1500 rpm and 1.0 min was used. Then, the pulps were mixed with skim milk at different concentrations (3-6 % w/w) and homogenized by ultra-turrax (IKA® Labortechnik) at 10000 rpm for 5.0 min. Moreover; the prepared xanthan gum was added to the mixture at concentrations of 0.15 and 0.25%. Xanthan gum was prepared by adding 1.0 g gum into 100 mL water and mixing by magnet stirrer. Afterwards, the gum solution was kept overnight at 4 °C for complete hydration. Finally, the sample transferred into the foam-maker device which was connected to a nitrogen gas tank with different flow rate (0.2-2 L min-1). The speed and time were adjusted to 16000 rpm and 5.0 min, respectively. After the producing of banana milk foam and selecting optimum sample based on the lowest density and the highest stability, the drying kinetic of this sample was studied. Then the banana milk foam was dried using microwave (360, 660 and 900 V) in a glass plate with diameter of 3.0 and 5.0 mm. Foam density and stability were determined by the methods of Xian-Zheetal (2010), Stauffer (1999) and Bag et al. (2010). The color of samples was studied by hunterlab. Moisture content also was measured based on the AACC standard method (AACC, 2000). Glass transition temperature also was determined by differential scanning calorimetry (DSC, model OIT-500 Sanaf Electronics Co, Iran).
Results and Discussion: In the present study, foam-mat method and microwave drying were used to reduce the drying damages. Nitrogen gas and xanthan gum also were used respectively to control foam generation and improve the stability of foams. Optimization of the banana milk production was carried out using response surface methodology based on three variables including the rate of nitrogen gas (0.2-2 L min-1), concentration of xanthan gum (0.15-0.25 %) and milk to banana ratio (1:6 and 1:3). Optimization was done based on the highest stability and lowest foam density. The optimum condition was proposed as the nitrogen gas rate of 0.2 L min-1, xanthan gum of 0.22 % and 3% banana which showed the density of 0.39 and the highest stability (0 mL after 1.0 h). After that, the optimum sample was dried by microwave. The effects of three levels of microwave voltage (360, 660 and 900 V) and two diameters (3 and 5 mm) were evaluated for drying of optimum sample. The results showed that the sample dried with diameter of 3 mm and voltage of 900 V had the highest L*, highest glass transition temperature and the lowest moisture content.
Esmail Khazaei; Fakhri Shahidi; Seyed Ali Mortazavi; Mohebbat Mohebbi
Abstract
Introduction: Kiwifruit (Actinidia sp.) has many appealing properties for consumers such as flavor, color, and nutritional content, especially vitamin C. Kiwi seems to be used as one of the major ingredients within the formulation of this category of foods.Microalgae are nutritional and innovative natural ...
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Introduction: Kiwifruit (Actinidia sp.) has many appealing properties for consumers such as flavor, color, and nutritional content, especially vitamin C. Kiwi seems to be used as one of the major ingredients within the formulation of this category of foods.Microalgae are nutritional and innovative natural sources that can be used in the development of novel foods. Among the known species of algae, Chlorella vulgaris and Spirulinaplatensis are common edible microalgae that have no side effects on health of human. The amino acid, carbohydrate, and fatty acid profiles of these microalgae are very similar to those of other food materials. Spirulina is a multicellular filamentous blue-green microalga, which was introduced as generally recognized as safe (GRAS) after being approved by food and drug administration (FDA). Spirulina can also be incorporated into common food preparations such as pastas, biscuit, bread, snack,pastille, candy, yoghurt, soft drink, causing health-promotion that are associated with microalgae biomass.The aim of this study was to investigate the possibility of producing new product based on kiwifruit and its enrichment with Spirulinaplatensis microalgae so that this product could replace common snacks, especially the pastilles containing synthetic colors and flavors, which have increasingly been used day by day despite having a low nutritional value and causing a variety of side effects. The role of pHysicochemical and sensory properties is very important in producing new products which can help producers design the products suitably. Therefore, some of the pHysicochemical properties of the kiwi base pastille were examined in this study, as well as the formulation and enrichment of it with Spirulinaplatensis. Material and methods: The ingredients of the formulations consist of 65% w/w kiwifruit puree, 30% w/w sweeteners (sugar, powdered glucose, invert syrup and sorbitol), 0.25% w/w high methoxyl pectin, 0.5% Agar, 0.5% Guar and Spirulinaplatensis(0, 0.25, 0.5, 1 and 2% w/w) as well.In order to produce fruit pastille based on kiwifruit puree, the kiwifruits were fist washed up, peeled and cut into pieces. Then the pieces were grinded. The prepared puree was mixed with Spirulinaplatensis, hydrocolloids and sweeteners at 70°C with specific ratios. Agar was dissolved in distilled water at 90°C and added to the concerned mixture. Finally, after moderating pH to 3.4 by adding 40 M citric acid and controlling the Brix degree in constant Brix of 45, the mixture was prepared. The mixture was then poured into stainless steel mesh molds with cavity dimensions of 1.2 cm × 2 cm × 2 cm and the molds were kept at 4°C for 2 hours to form the gel. Then the obtained gel was taken out of the mold cavities and the samples were dried at 70°Cfor 6 hours in a hot air drier with 1.5 m/s airflow rate. Then the regarded tests were performed on the dehydrated samples. To measure pH, pH meter (Hana, Portugal) was used. The measurement of mixture Brix was performed by an optical refract meter (Carlze, Germany). The drying process of the samples was conducted in a hot air drier (Soroush Medicine Co. Iran).Moisture, protein, fiber, lipid, ash, vitamin C, calcium and iron elements were measured according to the Iran national standard.Texture profile analyzer (QTS25 CNS Farnell England) equipped with a software was used to determine the textural properties of the samples. Samples were compressed and decompressed in two reciprocating cycles by a round plate cylindrical probe with 3.5 cm diameter, 1 mm/s probe speed and 5 g force to 30% initial height.Histological properties obtained from force-deformation curve are as follows: Hardness, Cohesiveness, Elasticity, Adhesiveness and Chewiness.Sensory test was performed with the judgment of 10 trained panelists. In order to evaluate the samples. A 9-point Hedonic method (1: very undesirable - 9: very desirable) was used. 5 sensory attributes (color, texture, flavor, odor and overall acceptance) were evaluated.SPSS software was used for the statistical analysis of the parameters. Mean of the replicates were compared via the multi-range Duncan`s test at 95% confidence level.In order to pHotograpHy with Scanning electron microscope, initial preparation should perform on all of samples.The obtained sampleswas removed from the templates and were sectioned on a scale of 2×1×1mm. samples were dehydrated in ethanol solution and then dried in a critical point. Then samples with 30 nm of gold/palladium coated and were tested using SEM (model LEQ1450VP) in the maximum voltage of 15 kv. At least four images with magnification of 500, 1000, 2000 and 5000 were prepared in several different areas of the samples.Results and discussion: The obtained results indicated that the effect of Spirulinawas significant on the moisture content and increasing Spirulinaconcentration led to increased moisture content of the product.The results of texture profile analysis indicated that the hardness and chewness was increased, but the cohesivness of samples was decreased when the amount of Spirulina is increased. The amount of protein, vitamin C, total ash, iron and calcium was increased by increasing the amount of Spirulina. SEM microscopic results showed that adding up Spirulina is led to the reduction of the uniformity of sample’s structure and then the gel matrix will be created with a larger pore. Results of sensory analysis indicate that samples containing 0.25% Spirulina have sensory characteristics (color, aroma, flavor and overall acceptability) than other samples.
Amin Rangriz; Seyed Ali Mortazavi; Morteza Khomeiri; Soheil Amiri
Abstract
IntroductionTraditional mayonnaise is probably one of the oldest and most widely used sauces in all over the world. Mayonnaise is a product with particular consistency and is classified as a type of oil in water emulsions. Vegetable oil, acetic acid, and egg yolk are main components of mayonnaise. In ...
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IntroductionTraditional mayonnaise is probably one of the oldest and most widely used sauces in all over the world. Mayonnaise is a product with particular consistency and is classified as a type of oil in water emulsions. Vegetable oil, acetic acid, and egg yolk are main components of mayonnaise. In addition, mayonnaise may contain salt, sweeteners, spices, effective flavor materials, preservatives and stabilizers. It must contain at least 78.5 % of total fat and 6 % pureegg yolk. Due tohigh levels of oil present in mayonnaise, continuous usageof this product may result in diseases such as obesity,arteriosclerosis, hypertension and cardiovascular diseases.Therefore, consumers tend to consume low-fat products.Yoghurt is a very useful fermented milk products in terms of lactic acid bacteria that have beneficial effects on human health and Because of the similarity between this productand mayonnaise in terms of rheological properties, Yoghurt have been selected as a fat mimetic in mayonnaise.Therefore, the objective of present study was to investigate the effects of partial fat substitutionby yoghurt on physicochemical, rheological and sensory properties of low fat mayonnaise.Materials and methodsMayonnaise preparationOne kilogram of each mayonnaise sample was prepared.Different recipes of mayonnaise contained yoghurt asfat mimetic (as % of oil and yoghurt) including (49.5 % & 25%), (33% & 50%), (16.5% & 75%). All formulations contained 13 % Egg yolk, 10 % Vinegar, 1 %Mustard, 1 % common salt ,4 % sugar , sodium benzoate 0.07 % , Xanthan gum 0.2%.Mayonnaise preparation procedure was as follows; firstlyegg and vinegar were mixed together and then all otherIngredients(including Yoghurt for the low fatmayonnaise recipes) except oil were added and mixed well. The oil was finally poured insidethe mixer very slowly and homogenized for 1 min. Subsamples (250 g) of mayonnaise were aseptically transferredto sterile 250 ml, Duran glass bottles withpolypropylenescrew caps and left for one-day at 5 °C.Proximate composition analysisMoisture, protein, and ash contents were determined accordingto AOAC (2005) official methods. Fat content wasmeasured by Bligh and Dyer (1959) method, and totalcarbohydrate content was calculated by difference.Rheological measurementsRheological measurements were performed after 24 hstorage using a Brookfield viscometer Model RVDV-IIwith aspindle no.6 at 5 °C and 25 °C. Shear stress data wereplotted versus shear rate for each mayonnaise sample ata range of spindle speed (10–200 rpm). Plots of Lnshear stress versus Ln shear rate (for each sample) werethen used to calculate values including flow behaviorindex (n) andconsistency coefficient (K).Texture analysisMayonnaise samples were stored in refrigerator for 24 huntil texture analysis. The measurements were carriedout using a Brookfield texture analyzer (BrookfieldLFRA texture analyzer model number 4500 texture prolite) equipped with a 38 mm diameter cylindrical probeat 25 °C.The condition of the analysis was as follows; one cyclewas applied, at a constant crosshead velocity of 1 mm/s to asample depth of 30 mm, and then returned. From the resultingforce-time curve, the values for texture attributes, i.e.firmness, adhesiveness, and consistency were obtained usingtexture pro lit software.pH measurement and stability testpH was determined using AOAC standard method at 25 °C. The samples were assessed for the stabilitytest after 24 h storage at 35 °C. Mayonnaise stability wasdetermined after centrifugation (10 min, 2,500 rpm), andwas expressed as the volume of separated phase to the totalemulsion volume.Color measurementMayonnaise samples were measured for color in the L*, a*,b* system using a Lovibond Colorimeter.Sensory analysisAfter 1 day storage Sensory characteristics including appearance,color, odor, texture, taste, and overall acceptabilitywere evaluated by 14 semi-trained panel on 5-point hedonicscale (1 = the least or the lowest; 5 = the most or thehighest).Statistical analysisAll the tests were performed in triplicate. The data collectedwere analyzed by one-way analysis of variance (ANOVA),and significant differences of means were compared usingDuncan test at 5 % significance level using SAS softwareprogram.Results and Discussion: In present study, physicochemical, texture, sensory and rheological properties were evaluated in mayonnaise formulation with dairy-based. Fat was partially substituted by yoghurt at levels of 25, 50 and 75% which were referred respectively as SM1 (25% fat substitution level), SM2 (50% fat substitution level) and SM3 (75% fat substitution level) and the full fat mayonnaise (S) with 66 % oil was used as control sample. Results indicated that low-fat mayonnaise samples had considerably lower energy content compared with control sample, but higher water content than it. In terms of texture, SM3 had lower hardness compared with control sample. The samples exhibited thixotropic and shear thinning behavior through rheological studies and all samples were classified in the group of solid viscoelastic materials because, in all samples, storage modulus was greater than loss modulus. Also, the loss tangent of low-fat mayonnaise samples were higher than the control sample which reflects the tendency of these samples behavior to pseudo-liquid behavior. Results of sensory evaluation demonstrated that SM2 and SM3samples, were more acceptable. It was concluded that yoghurt can be used as a suitable fat replacer in mayonnaise formulation.
Behzad Nasehi; Seyed Mohammad Ali Razavi; Seyed Ali Mortazavi; Mostafa Mazaheri Tehrani
Abstract
The influence of 0-27 g/100g of full-fat soy flour (FFSF), 31-35g/100g of water content and extrusion conditions on the textural characteristics of spaghetti were evaluated. Process was performed with screw speed of 10-40 rpm and water circulating temperature of 35-70°C. This enrichment resulted ...
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The influence of 0-27 g/100g of full-fat soy flour (FFSF), 31-35g/100g of water content and extrusion conditions on the textural characteristics of spaghetti were evaluated. Process was performed with screw speed of 10-40 rpm and water circulating temperature of 35-70°C. This enrichment resulted in significant differences in mechanical strength and cutting parameter. Based on the mixture surface and contour plots, it was found that the optimum textural characteristic of spaghetti could be obtained by addition of 20.6 g/100g FFSF and 35.0 g/100g water and process in screw speed of 40 rpm and temperature of 35oC.
Seyed Ali Mortazavi; Zahra Sheikholeslami; Mehdi GhiafeDavoodi
Abstract
Introduction: Bread stales and unfortunately it is a certainty and causes significant product waste all over the world.Staling results in loss of important sensory parameters of bread, like flavor and texture, and it is a consequence of a group of several physical–chemical changes occurring during ...
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Introduction: Bread stales and unfortunately it is a certainty and causes significant product waste all over the world.Staling results in loss of important sensory parameters of bread, like flavor and texture, and it is a consequence of a group of several physical–chemical changes occurring during bread storage that lead mainly to an increase of crumb firmness and loss of freshness (Gray and Bemiller 2003). At 21th century freezing technology introduced to bakery industry in order to increase bread shelf life, access fresh bread with a minimum need for equipment and skilled personal at any time.The current trend in the baking industry is to use frozen dough to manufacture quality products because it can be quickly transformed into fresh baked product. However, the use of frozen dough has certain disadvantages such as its variable performance and loss of stability over long-term frozen storage (Ribotta and Le Bail 2007). Research has shown that ice crystallization and recrystallization causes physical damage to the gluten network, leading to changes in the rheological properties of the frozen dough. Water available for freezing forms ice crystals that injure yeast cells (Mazur 1968). Gums trap free water and control moisture migration.Furthermore, Ward and Andon (1993) mentioned that gums such as carboxymethyl cellulose, carrageenan, gum arabic, and locust bean gum may be used to alleviate the problems associated with frozen dough. Numerous studies report that enzymes play key roles in bread making such as increasing loaf volume, producing finer crumb cells, and extending shelf-life. Amylase improved frozen dough bread quality; the enzyme allowed us to obtain breads from frozen dough with high specific volume and low crumb firmness(Ribotta and Le Bail 2007). Therefore, the aim of this work was to study the effect of guar gum and alpha amylase on frozen dough and the influence of them on the minimization of the damage caused by frozen storage. Materials and methods: Wheat flour sample (cvs, Pishgam) with 10.52% moisture, 10.8% proteins ,79% ash, 26.7% wet gluten, was obtained from silo No.3, Mashhad, Iran. Bread recipes also contained active dry yeast (Razavi Co., Mashhad, Iran), vegetable oil( Ladan Co. Behshahr, Iran), salt and sugar (Local market). Amylase enzyme (25 klu/g) and guar gum afforded from Novozyme and Rodhia CO respectively. The bread formula used for Barbari bread consisted of flour (100 parts), compressed yeast (2 parts), salts (2 parts), sugars (1parts), vegetable oil (1 part) and water (based on water absorption at 500 BU). Guar and amylase replaced in bread formulation at two levels (0.4 and 0.8%), and (0.05. 0.07 %) respectively. Bread was part baked in an electric oven with an incorporated proofing chamber (Zuccihelli, forni, Hal, Italy) at 210˚C for 7 min to obtain texture structure before starting coloring reaction. Barbari bread sample were packaged in polyethylene bags and frozen in a blast freezer. After storage at -18°C for 15 day, PBF bread was thawed at room temperature for 10 min and rebaked at 260°C for 8 min. The fresh bread baked at 230 °C for 15 mines (Ba´rcenas and Rosell, 2007). Specific volume , porosity, texture evaluation, image analysis (L*a*b*) and sensory evaluation of bread were measured using AACC methods (2000). Results were reported as the average of three replications (all treatments were evaluated in three batches). The data obtained were statistically treated by a complete randomized design (factorial) analysis while the means were compared by the Duncan’s test at a significance level of 5%, in both cases using SPSS statistical software (version 17). Result and discussion: The results showed that frozen storage had significant effects on the specific volume, moisture content, crumb hardness, sensory properties and bread color. Addition of gum and enzyme to bread recipe improved bread quality, alone and in combination. The presence of guar and amylase removing the negative effects of process conditions. Addition of guar at 0.4% improved specific volume, textural properties, color, sensory score and decrease bread firmness. Also using of amylase in 0.07%,increased bread quality. When guar used in combination with amylase, the synergistic effect was observed. The best result, obtained with 0.4% guar and 0.07% amylase. Conclution: In summary, the result of this study has shown that textural and sensory properties of part baked frozen bread were poor. Addition of guar gum increased specific volume and sensory score of bread. Guar in 0.4% concentration in comination with amylase in 0.07%, were more effective and it could introduce as a improver for part baked frozen bread.
Seyed Ali Mortazavi; Elnaz Milani; Marzieh Moeenfard
Abstract
Kurdish cheese is semi-firm cheese which has been traditionally manufactured from whole raw cow or sheep milk, in the East of Iran. It is ripened in goat’s skin bags. The microbial diversity of kordish cheese originates from natural microbiota present in the raw milk and its unique organoleptic ...
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Kurdish cheese is semi-firm cheese which has been traditionally manufactured from whole raw cow or sheep milk, in the East of Iran. It is ripened in goat’s skin bags. The microbial diversity of kordish cheese originates from natural microbiota present in the raw milk and its unique organoleptic properties have made it excellent among other traditional cheeses in Iran. This study has been conducted to evaluate microbiological diversity during ripening of Kurdish cheese. Samples were taken from 6 batches of cheese on day 1, 20, 40 and 60. Sensory properties of Kurdish cheeses were determined at 60,120 and 180 days of ripening. Based on results, the diversity and microorganisms count of were mainly influenced by ripening time. Lactic acid bacteria and Enterobacteriaceae were the predominant families of micro-organisms during the first 20 days of ripening and lactobacilli was the most abundant lactic acid bacteria in cheese. Coliforms and E.coli decreased more rapidly in cheese, whereas mows and yeasts decreased gradually and then increased in ending days. At the end of ripening period, mo coliforms, salmonella and coagulase positive staphylococcus were detected in the samples. Changes in textural and chemical characteristics in relation to ripening time showed that; pH, Moisture, Total solid, aw and fat content of samples decreased during 40d and reached to 4.69, 33.9, 64.07, 0.927, 28.1 at 60 days respectively. no significant variations observed in Protein values during ripening period. The values for sensory characteristics such as taste, aroma, colour and total acceptance of the full-ripened cheeses (120th days) increased as ripening progressed. According to our results, from a safety point of view, the optimum time for consuming Kurish cheese would be after passing ripening time of 60 days (during 1-2 months) due to decrease in pH, undesirable flora and increase in desirable LAB counts.
Mahboubeh Sarabi; Fakhri Shahidi; Ahmad Reza Bahrami; Seyed Ali Mortazavi; Mohammadreza Nassiry; Massoumeh Mehraban Sangatash; Marzieh Hosseininejad
Abstract
Raisins are dried grapes that may be eaten raw or used in cooking, baking and brewing as an ingredient. Iran is one of the major exporters of raisins in recent years and Iranian raisins are exported to many countries. It is important to ensure of microbiological quality and safety of raisins. The aim ...
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Raisins are dried grapes that may be eaten raw or used in cooking, baking and brewing as an ingredient. Iran is one of the major exporters of raisins in recent years and Iranian raisins are exported to many countries. It is important to ensure of microbiological quality and safety of raisins. The aim of this study was isolation and identification of mycoflora from main raisin’s varieties (Poloie, Pikami & Teiphi) produced in Khorasan Razavi Province. Four types of culture medium (Yeast Extract Glucose Chloramphenicol Agar (YGC), Potato Dextrose Agar (PDA), Czapek Dox Agar (CA) and Dichloran Glycerol Agar (DG18)) were used for isolation. The highest contamination was found in Teiphi raisin samples. The drying method was not effect on fungi contamination. For Fungi Identification, Macroscopic and Microscopic features were investigated. The Result showed that frequently isolated fungi were Aspergillus and Penicillium species. The fragment (600 bp) of Internal Transcribed Spacer 5.8SrRNA of isolated colonies was amplified using polymerase chain reaction for identification down to the species level. According to the results, the raisins had varius species of Aspergillus, Penicillium, Rhizomucor, Mucor, Alternaria and Cladosporium. Aspergillus niger was the most abundant fungi.
Reza Farahmandfar; Seyed Ali Mortazavi; Farideh Tabatabaei Yazdi; Arash Koocheki
Abstract
In this study, variations of the pasting properties, swelling power and solubility of two rice starches, low amylose (8.7%) and high amylose (26%) at two citric acid concentrations (0 and 0.01 M) was investigated. The results showed that the peak viscosity and breakdown viscosity of rice starch decreased ...
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In this study, variations of the pasting properties, swelling power and solubility of two rice starches, low amylose (8.7%) and high amylose (26%) at two citric acid concentrations (0 and 0.01 M) was investigated. The results showed that the peak viscosity and breakdown viscosity of rice starch decreased significantly (P<0.05) with increased the proportion of amylose while hot past viscosity and cold past viscosity increased significantly (P<0.05). As the concentration of citric acid increased, pasting properties decreased but did not change (P>0.05).The swelling power and solubility of both starch pastes with and without citric acid increased with the increase of the temperature. As the concentration of citric acid increased, swelling power of low and high amylose starch decreased and this event was clearer in low amylose samples. On the other hand, citric acid induced solubility of samples particularly in high amylose rice starches. Furthermore, the swelling power and solubility of treatments decreased and increased with increasing amylose content of rice starch, respectively.
Elnaz Milani; Fakhri Shahidi; Seyed Ali Mortazavi; Seyed Alireza Vakili
Abstract
Traditional raw milk cheese is one of the most consuming cheeses in the world. Kurdish cheese is a semi-firm, traditionally made in the East of Iran. It is manufactured from raw sheep or cow milk and kept in goat’s skin bags during ripening period. As a result Kurdish cheese is often more complex ...
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Traditional raw milk cheese is one of the most consuming cheeses in the world. Kurdish cheese is a semi-firm, traditionally made in the East of Iran. It is manufactured from raw sheep or cow milk and kept in goat’s skin bags during ripening period. As a result Kurdish cheese is often more complex in different varieties of microorganisms, which whose organoleptic properties make it highly esteemed. Changes in free fatty acid (FFA) and free amino acids (FAA), could have great importance in Kurdish cheese final Characteristics. In this project, Changes in FFA and FAA contents of Iranian Kurdish cheese, in local condition, during 10, 30, 50 and 70 days of ripening periods were evaluated. Most FFA significantly increased throughout maturation (P
Farideh Tabatabaei Yazdi; Mohebbat Mohebbi; Seyed Ali Mortazavi; Arash Ghaitaranpour; Behrooz Alizadeh Behbahani
Abstract
The effects of a couple of factors (cooking period of wheat: 0, 1 and 3.5 h and temperature of drying 70, 80 and 90 ْC) on drying behavior of Tarkhineh during hot-air drying has been investigated. Tarkhineh pill samples with 8 cm diameter and 11 mm thickness were dried to 0.64(d.b). Results showed that ...
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The effects of a couple of factors (cooking period of wheat: 0, 1 and 3.5 h and temperature of drying 70, 80 and 90 ْC) on drying behavior of Tarkhineh during hot-air drying has been investigated. Tarkhineh pill samples with 8 cm diameter and 11 mm thickness were dried to 0.64(d.b). Results showed that cooking of wheat led to higher water absorption of Tarkhineh dough, while increased drying rate. On the other hand, increasing drying temperature resulted in higher drying rate of samples. The effects of temperature on drying rate was pronounced in raw samples compared to cooked ones, which could be attributed to the cracking in the cooked samples during drying . Drying kinetics of Tarkhineh in raw samples unlike cooked samples presented a falling rate period followed by a constant rate period. The effective moisture diffusion coefficient of Tarkhineh varied between 1.611E-10 & 7.822E-10 (m2/s)) for the given temperature range) and corresponding activation energy was between 37.928 and 17.941(kJ/mol) respectively.
Ana Abdolshahi; Seyed Ali Mortazavi; Ali Akbar Shabani; Amir Hossein Elhami Rad; Mehrdad Taheri; Mojtaba Heidari Majd
Abstract
Pistachio oil has important nutritional and therapeutic properties because of high concentration of essential fatty acids. The extraction method used to obtain natural compounds from raw matter is critical for product quality and especially protection of nutrition value of them. The study was conducted ...
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Pistachio oil has important nutritional and therapeutic properties because of high concentration of essential fatty acids. The extraction method used to obtain natural compounds from raw matter is critical for product quality and especially protection of nutrition value of them. The study was conducted to compare fatty acid composition of pistachio oil extracted by two conventional procedures: soxhlet extraction (Sox) and maceration. Different solvents: n-Hexan (Hx), dichloromethane (DCM), ethyl acetate (EtAc) and ethanol (EtOH) in term of polarity index was used. The higher unsaturated fatty acid (88.493%) was obtained by Sox with EtAc. Although linoleic acid had higher concentration (36.32%) in mac method. Sox method extracted highest concentration of oleic and linolenic acids (51.99% and 0.385% respectively).
Mohammad Bagher Habibi Najafi; Mohebbat Mohebbi; Fakhri Shahidi; Seyed Ali Mortazavi
Abstract
The effect of pretreatment osmotic-ultrasonic dehydration on the drying kinetic, rehydration kinetic, texture, shrinkage and color change of quince slices was investigated. Quince slices were osmotic-ultrasonic processed at 27.25 min for ultrasonic time, 120 min for osmotic dehydration and 50.52 % for ...
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The effect of pretreatment osmotic-ultrasonic dehydration on the drying kinetic, rehydration kinetic, texture, shrinkage and color change of quince slices was investigated. Quince slices were osmotic-ultrasonic processed at 27.25 min for ultrasonic time, 120 min for osmotic dehydration and 50.52 % for sucrose concentration. The un-treated and pre-treated samples were then dehydrated at80°C. The effective diffusivity calculated by applying the Fick’s diffusion model. The pretreatment caused a decrease in Deff. Application of osmotic-ultrasonic dehydration reduced the sample hardness, color changes and shrinkage while it had increased the sample springiness, and chewiness.
Parnian Pezeshki; Abdolmajid Maskooki; Mohammad Elahi; Seyed Ali Mortazavi
Abstract
Baker's yeast is one of the most important additives for improving the bread quality and molasses is a commonly used source of sugars for producing baker's yeast. Nowadays, due to increasing the fermentation industries and limitation in suitable sources of sugars, the use of other carbohydrate sources ...
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Baker's yeast is one of the most important additives for improving the bread quality and molasses is a commonly used source of sugars for producing baker's yeast. Nowadays, due to increasing the fermentation industries and limitation in suitable sources of sugars, the use of other carbohydrate sources may be considered.In this study, the possibility of baker's yeast production in three cultures of date , raisin , enzymatic hydrolyzed whey and molasses as a control was investigated.Also, the total amount of biomass, consumption of sugar, strength of levy and kinetic's parameters of growth in all mediums were determined.For enriching the mediums, yeast extract and pepton were used in order of 3.5 and 7%, respectively. Fermentation process carried out during 12 houres and the temperature is maintained constant to 30 C° .Agitation was of 150 turns per minutes and ventilation fixed at 2 V.V.M .According to the results,maximum and minimum amount of biomass were 93.33 and 81.35 g/l that they related to date and whey, respectively.The consumption of sugar except whey which had the lowest level, in other cultures had no significant difference.The highest yield (0.35g/g) is observed in date but the lowest yield was 0.32 g/g in whey. Also, the baker's yeast which growed in raisin extract, had the highest value in strength of levy.
Esmail Khazaei; Fakhri Shahidi; Seyed Ali Mortazavi; Mohebbat Mohebbi
Abstract
In this research, the production of a new kiwi- based product by applying kiwi puree, agar (0.25, 0.5 and 1%), guar (0.25, 0.5 and 1%) and other formulation ingredients (kiwi puree, sweeteners and pH modulators) has been investigated. Dependent variables include moisture content measurement, instrumental ...
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In this research, the production of a new kiwi- based product by applying kiwi puree, agar (0.25, 0.5 and 1%), guar (0.25, 0.5 and 1%) and other formulation ingredients (kiwi puree, sweeteners and pH modulators) has been investigated. Dependent variables include moisture content measurement, instrumental texture analysis and sensory evaluations were carried out in a factorial design and the means were compared at significance level of 5 % by Duncan test. The results indicated that guar had a significant effect on the moisture content of final product. Textural properties of the kiwi pastille were influenced by the type and amount of hydrocolloids. Synergistic effects of agar and guar on the textural properties were also observed. While all products were acceptable regarding sensory properties, the samples prepared with 1% agar and 1% guar obtained the highest score.
Amir Pourfarzad; Mohammad Hossein Hadad Khodaparast; Mahdi Karimi; Seyed Ali Mortazavi
Abstract
The effect of adding sodium stearoyl-2-lactylate (SSL) and propylene glycol (PG) (0 - 0.5 g/100g) to emulsifier gel formulation on the crumb and crust characteristics of Barbari bread fortified with soy flour in order to optimize these characteristics were evaluated. The obtained results showed that ...
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The effect of adding sodium stearoyl-2-lactylate (SSL) and propylene glycol (PG) (0 - 0.5 g/100g) to emulsifier gel formulation on the crumb and crust characteristics of Barbari bread fortified with soy flour in order to optimize these characteristics were evaluated. The obtained results showed that addition of SSL caused an increase in the crumb and crust L* and cell density. The a*, b*, average cell size and porosity of bread crumb decreased by increasing SSL. PG had increasing effect on b* of crumb and decreasing effect on L* of crust. However, no significant difference (p ≥ 0.05) was observed in a* and b* of crust. The results for optimization using central composite design suggested that a mixture containing 0.5 g/100g of SSL and 0.5 g/100g of PG could be a proper improver gel to achieve the best characteristics.
Hashem Razavi Setoti; Seyed Ali Mortazavi; Monirosadat Shakeri; Shahram Beiraghi-Toosi; Elham Asadolahi
Abstract
In this study, antimicrobial effects of Zataria Multiflora boiss added to sodium caseinate film on four bacterial species: Staphylococcus aurous, Escherichia coli, Bacillus subtilis and Salmonella intertidis was investigated. Disk diffusion method was used to study the antimicrobial activity of Zataria ...
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In this study, antimicrobial effects of Zataria Multiflora boiss added to sodium caseinate film on four bacterial species: Staphylococcus aurous, Escherichia coli, Bacillus subtilis and Salmonella intertidis was investigated. Disk diffusion method was used to study the antimicrobial activity of Zataria multiflora Boiss in sodium caseinate film. 9 mm disks were prepared from produced films with different concentrations of Zataria multiflora Boiss. with 1, 2, 3 and 4%. Surface culture was done under sterile condition using 0.1 ml of broth culture of each bacterial (106 -107 cfu/ml) on BHI agar. Then the disks were placed. Diameter of inhibition zone was considered as an index of antimicrobial activity of the film. Statistical analyses were done by means of SigmaSDAT software and mean comparison was carried out by LSD test. Results showed that disks containing essential oils of Zataria multiflora Boiss. in each concentration inhibited growth of E.coli, Sa.interitidis and B.cereus. Since there was no significant differences between 3% and 4% concentrations for these bacteria (p>0/05), concentration of 3% is the most appropriate and cost-effective concentration with the highest antimicrobial effect. Only the film containing 1% of essential oil of Zataria multiflora Boiss. Made no inhibition zone on S.aurous, in the other word had no inhibitory effect in this concentration. But inhibition zones created by 2, 3 and 4% for S.aurous were significantly different (p
Mohammad Reza Edalatian Dovom; Mohammad Bagher Habibi Najafi; Seyed Ali Mortazavi; Majid Hashemi; Masoud Yavarmanesh
Abstract
The objective of this study was to evaluate lactic flora identification in fresh (one-day) and ripened (90-day) Koozeh cheese samples as one of the raw milk cheeses. In first step, in order to isolate the different genera of Lactic acid bacteria (LAB), selective and differential (corresponding) media ...
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The objective of this study was to evaluate lactic flora identification in fresh (one-day) and ripened (90-day) Koozeh cheese samples as one of the raw milk cheeses. In first step, in order to isolate the different genera of Lactic acid bacteria (LAB), selective and differential (corresponding) media were used as follow: MRS for lactobacilli and pediococci, MRS+ vancomycin for leuconostocs, M17 for lactococci and KAA for enterococci. Totally, 48 single, purified colonies were selected and identified using confirmatory, biochemical and phenotypic tests down to the genus level. Lactobacilli (33.33%), lactococci (12.5%), pediococci (2.08%), enterococci (47.91%) and aerococci (4.16%) were determined as the most abundant genera. At last, carbohydrate fermentation profile using API 50 CH and API 20 STREP kits was used for identification down to species level. Finally, following species were identified: Lactobacillus. plantarum, Lb. brevis, Lb. lindneri, Lb. helveticus, Lb. delbrueckii ssp. delbrueckii, Lb. pentosus, Lb. fermentum, Lactococcus. lactis ssp. lactis, Enterococcus. faecium, Ent. faecalis, Ent. avium, Ent. durans and Aerococcus. viridans. In fresh cheese, the Lactococci and lactobacilli genera were predominant but in ripened cheese the enterococci replaced them. Predominant species in fresh cheese were as follow: Lac. lactis ssp. lactis (44.44%) and Lb. plantarum (22.22%) but Ent. faecium (43.58%), Lb. brevis (12.82%) and Ent. faecalis (7.69%) constituted the major part in ripened cheese. We can mention that these predominant lactic acid bacteria play an important role during ripening and also flavor production in raw milk cheeses like Koozeh. So, more precise identification is very necessary using culture- based molecular and culture- independent methods down to strain level.
Elmira Haghighi; Massoumeh Mehraban Sangatash; Seyed Ali Mortazavi; Mahboubeh Sarabi; Reyhaneh Noorbakhsh; Mohammad Armin
Abstract
The aim of this study was to investigate the mold contamination of main raisins varieties produced in Khorasan Razavi Province with aflatoxin-producing fungi and determine amount of aflatoxins. For this purpose 50 samples were collected from different markets in Kashmar, Khalil abad, Bardaskan, Mashhad ...
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The aim of this study was to investigate the mold contamination of main raisins varieties produced in Khorasan Razavi Province with aflatoxin-producing fungi and determine amount of aflatoxins. For this purpose 50 samples were collected from different markets in Kashmar, Khalil abad, Bardaskan, Mashhad and Quchan (10 samples from each city). The result showed that from 50 raisin samples, 44 samples (88%) were contaminated with fungi. The lowest and highest level of fungal contamination were observed in Quchan and Kashmar, respectively. Aflatoxigenic potential of fungi that isolated from contaminated samples were evaluated using Coconut Agar Medium and under UV light (365 nm). It is observed that 29 samples (65.9%) had Aflatoxigenic fungi. The presence of aflatoxin was confirmed by high pressure liquid chromatography. No sample had greater AFB1 levels than the maximum allowed levels (5 ng/g) in raisins accepted by ISIRI (Institute of Standards and Industrial Research of Iran). Although the amount of AFB1 in raisin varieties produced in Khorasan Razavi Province, does not appear to create a serious public health problem at present, because of Percapita consumption of raisins in Iran (22 kg/year) it is necessary to consider it as a serious health problem.
