Food Biotechnology
Shohreh Nikkhah; Fakhri Shahidi; Mohebbat Mohebbi; Farideh Tabatabaei Yazdi
Abstract
IntroductionCucumber is an economically important crop, containing vitamins, minerals, antioxidants, and flavonoids. However, due to loss of weight and firmness, microbial contamination, mechanical damage, and yellowing, the storage duration of cucumber is limited to 3–5 days at room temperature. ...
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IntroductionCucumber is an economically important crop, containing vitamins, minerals, antioxidants, and flavonoids. However, due to loss of weight and firmness, microbial contamination, mechanical damage, and yellowing, the storage duration of cucumber is limited to 3–5 days at room temperature. Therefore, pretreatments are crucial for prolonging its shelf life. Chitosan is a cationic polysaccharide and can interact electrostatically with anionic, partially demethylated pectin. Besides, chitosan has inhibitory effects on fungal rot and prevents weight loss in fruits. Pectin can form excellent films. Because of increasing demand to reduce synthetic chemicals as antimicrobial agents, substances derived from plants, such as essential oils, can play a significant role in the future. Several essential oils and essential oil components have shown antimicrobial activity against spoilage and pathogenic microorganisms during fruit and vegetable storage. Essential oils of thyme and cinnamon contained phenolic groups have been found to be most consistently effective against microorganisms, however, essential oils are volatile and irritant. Therefore, forming an inclusion complex using b-cyclodextrin can improve solubility, control volatile, and induce off-flavors and unpleasant odor of the essential oils. The objectives of this study were to develop the microencapsulated thymol (thyme) and trans-cinnamaldehyde (cinnamon) essential oils to produce antimicrobial agents and subsequently evaluate the effectiveness of edible coating made of chitosan and pectin containing microencapsulated trans-cinnamaldehyde or thymol essential oils to improve qualitative and quantitative characteristics and shelf life of cucumber.Materials and MethodsThe inclusion complexes of trans-cinnamaldehyde and thymol in beta-cyclodextrin (CD) were prepared separately by freeze-drying. Each essential oil was dispersed in 1000 ml of beta-cyclodextrin aqueous solution (16 mmol/L, 18.15 g) in molecular ratio 1:1 (2.4 gr thymol, 2.11 gr trans-cinnamaldehyde) and mixed in a laboratory stirrer for 24 hour at room temperature , then frozen (-70 ºc) and freeze-dried (<20Pa, 48 h). Lyophilized samples were stored inside a freezer (-20 ºc) until further use. Cucumbers cv. Nagene with uniform size, appearance, ripeness and without mechanical damage or fungal contamination were selected. Then They were then sanitized by immersion in chlorine solution (150 mg/kg) for 1 min and air dried. Edible coatings were prepared as three immersion solutions of chitosan, pectin, and calcium chloride (CaCl2). The fruits were coated with pectin (1%) and chitosan (0-0.5%-1%) containing beta-cyclodextrin microencapsulated trans-Cinnamaldehyde or thymol each (0-0.25%-0.5%). After coating by chitosan, the fruits were immersed in 1% Calcium chloride solution to induce crosslinking reaction. After dipping step, fruits dried for 8 minutes at room temperature to remove the excess solution attached to the surface .Uncoated fruits served as control. Then fruits were preserved in cold storage (temperature: 10ºc; relative humidity: 90-95%) for 15 days. chemical (total soluble solids, titratable acidity) and physical (total color difference, Hardness, and weight loss) Characterization of fruits were measured immediately after harvest and after 5, 10 and15 days. Microbial tests (total count, mold, and yeast) were done at the end of preservation time. Analytical data were subjected to analysis of variance and factorial adopted completely randomized design and a Duncan comparison test was used. Results and DiscussionThe results showed that weight loss, total soluble solids, and the total color difference increased and hardness and titratable acidity decreased gradually in all samples during cold storage (<0.05). Chitosan and essential oils slowed down this rising or decreasing trends. Interactive effects of chitosan, essential oil type, essential oil concentration, and storage time had positive effects on these quality attributes. The fruits coated with the highest concentration of chitosan (1%) and thymol (0.5%) essential oils showed the least weight loss, loss of hardness, and color change throughout 15 days of storage. Besides thymol in comparison with trans-Cinnamaldehyde was more efficient to prevent yeasts and molds on the surface of cucumber. By increasing chitosan and essential oil amounts, the ability of inhibiting microbial growth by coating is enhanced. ConclusionThe results of chemical, physical and microbial tests, showed that multi-layer coating solution containing chitosan 1% with thymol 0.5% was effective in extending the shelf life of cucumber. The combined usage of microencapsulated thymol essential oil and chitosan-based coating on cucumber could be considered a healthy and effective treatment that reduces microbial spoilage and preserves quality and color characteristics in cucumber and represents an innovative method for commercial application. Therefore, this coating can be used as an alternative to chemical fungicides to prevent fungal rot of cucumber and other fruits, however, it is suggested that more studies should be done in this field.
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%).
Food Biotechnology
Sahar Roshanak; Behrooz Alizadeh Behbahani; Fakhri Shahidi; Farideh Tabatabaei Yazdi; Alireza Vasiee; Neda Hashemi
Abstract
Usage of natural products like herbals, provide unlimited opportunities for novel and suitable additives. Mocheh can be used in fresh form or as an ingredient in soup and salad. This study was aimed to determine the antimicrobial and antioxidant activities of Mocheh (Lepidium draba) extract. The antimicrobial ...
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Usage of natural products like herbals, provide unlimited opportunities for novel and suitable additives. Mocheh can be used in fresh form or as an ingredient in soup and salad. This study was aimed to determine the antimicrobial and antioxidant activities of Mocheh (Lepidium draba) extract. The antimicrobial activity of Mocheh extract was tested against Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus and Aspergillus niger. The extract showed a strong antimicrobial activity with a concentration dependence and a broad antimicrobial spectrum for all tested microorganism species. The results showed that MIC of leaf extract of Lepidium draba on Aspergillus niger, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus was 128, 128, 128 and 128 mg/mL respectively. The results showed that MBC/MFC of leaf extract of Mocheh on the examined microorganisms was 256, 256, 256 and 256 mg/mL respectively. The values obtained for total flavonoid content and total phenolic contents were 22.13 µg/mL and 18.88 mg/mL, respectively. Measured value in the radical scavenging activity was IC50= 168/21 µL/mL. The results showed that Mocheh leaf aqueous extract is a novel source of natural antimicrobial and antioxidant agents for the food and pharmaceutical industries.
Food Biotechnology
Sahar Roshanak; Behrooz Alizadeh Behbahani; Fakhri Shahidi; Farideh Tabatabaei Yazdi; Alireza Vasiee; Neda Norouzi
Abstract
In this research, the chlorophyll content, total flavonoid content (TFC), total phenolic content (TPC) and antioxidant activity of aqueous extract of Dandelion was determined. In addition, the effect of aqueous extract of Dandelion, obtained by maceration, was tested on various food borne and food spoilage ...
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In this research, the chlorophyll content, total flavonoid content (TFC), total phenolic content (TPC) and antioxidant activity of aqueous extract of Dandelion was determined. In addition, the effect of aqueous extract of Dandelion, obtained by maceration, was tested on various food borne and food spoilage microorganisms. Antimicrobial activity of leaf extract of Dandelion was investigated using disk agar diffusion, well agar diffusion, minimum inhibitory concentration and minimum bactericidal/fungicidal concentration methods. The values obtained for TFC, TPC, chlorophyll a and b were 22.82 (µg/mL), 116.89 (mg/mL), 0.081 (mg/l) and, 0.063 (mg/l), respectively. The result of the radical scavenging activity was IC50= 68.81µl/mL. The results showed that MIC of leaf extract of Dandelion on Aspergillus niger, Salmonella typhimurium, Bacillus subtilis and Staphylococcus epidermidis was 512, 256, 256 and 64 mg/ml respectively. MBC for Aspergillus niger was more than 512, for Salmonella typhimurium, and Bacillus subtilis was 512, and for Staphylococcus epidermidis was 128mg/ml. In addition, the diameter of inhibitory growth zone in well diffusion method was more than disk diffusion. Generally, it can be stated that the aqueous leaf extract of Dandelion on Gram-positive bacteria showed more antimicrobial activity than Gram-negative bacteria, while there is no significant inhibition on mold. Based on the results of this study, Dandelion aqueous extract might be used as a natural agent to prevent the growth of food borne microorganisms, particularly, that cause food poisoning that leading to the reduction of gastroenteritis risk.
Fakhri Shahidi; Farideh Tabatabaei Yazdi; Majid Nooshkam; Zahra Zareie; Fereshte Fallah
Abstract
Introduction: Lipid oxidation leads to the generation of off-flavors and potential toxic compounds. Synthetic antioxidants are frequently applied for inhibiting this reaction, however; there is a concern regarding to the potent toxic effects of synthetic antioxidants on human health. The non-enzymatic ...
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Introduction: Lipid oxidation leads to the generation of off-flavors and potential toxic compounds. Synthetic antioxidants are frequently applied for inhibiting this reaction, however; there is a concern regarding to the potent toxic effects of synthetic antioxidants on human health. The non-enzymatic glycosylation reaction (Maillard reaction) has been broadly used to ameliorate the biological and functional features of proteins and polysaccharides. The Maillard reaction produces products with versatile functions such as antioxidant, antimicrobial, antihypertensive, anti-browning, and prebiotic properties. In this regard, the Maillard reaction products (MRPs) can be used in the food industry to inhibit the oxidation reaction due to their superb antioxidant effect. In this study, chitosan was glycosylated with inulin, fructose, and glucose. Chitosan is a chitin derivative with cationic nature having antimicrobial, antioxidant, metal chelation, and film-forming features. Inulin is recognized as a prebiotic sugar with vast applications in food and pharmaceutical sciences. The purpose of this study was to chemically modify chitosan through the Maillard reaction in order to boost its antioxidant and antimicrobial properties. Materials and methods: Chitosan (0.5% w/v) was dissolved in 1.0% v/v acetic acid solution followed by stirring for 1.0 h at room temperature. Afterwards, sugars inulin, glucose, and fructose were separately added to the chitosan solution at final concentration of 1.0% w/v. The obtained solutions were then stirred until complete sugar dissolution. The pH of solution was adjusted to 6.07 by adding 2.0 M sodium hydroxide and then the chitosan-sugar Maillard conjugates were fabricated through autoclaving the solutions at 121 °C. Changes in pH after the reaction were measured using a pH meter. The extent of the Maillard reaction was estimated via measuring the absorbance of the conjugated solutions at 294 nm (the intermediate products) and 420 nm (final products). Fourier transform infrared (FTIR) spectroscopy at transmission mode and 400-4000 cm-1 was employed to evaluate the structural changes of chitosan upon conjugation. Antioxidant activity of the conjugates was evaluated based on the reducing power assay. One mL of the samples was charged with 1.0 mL of distilled water and 1.0 mL of potassium ferricyanide (1.0% w/v). The solution was mixed and incubated at 50 °C for 20 min. After adding 2.5 mL of tri-chloroacetic solution (10% w/v), the obtained solution was centrifuged at 5000 g for 5.0 min. Afterwards, 2.0 mL of the supernatant was mixed with 2.0 mL of distilled water and 1.0 mL of ferric chloride (0.1% w/v). The solution was stand for 10 min at ambient temperature and then its absorbance was recorded at 700 nm. Antimicrobial effect of the conjugates against pathogenic microorganisms (E. coli, S. aureus, B. subtilis, P. aeruginosa, A. niger, and C. albicans) was measured according to the minimum inhibitory (MIC) and microbiocidal (MBC) concentrations. SPSS software (version 21) and one-way ANOVA were applied for data analysis. Duncan’s multiple range test was employed to determine the differences between means. Results & discussion: The Maillard reaction led to a significant decrement in pH value of chitosan-saccharide systems, mainly due to the covalent coupling of amino groups of chitosan to carbonyl groups of reducing sugars in conjugation with the production of acetic and formic acids. The highest intermediate compounds (A 294nm) and lowest browning intensity (A 420nm) observed in chitosan-fructose conjugate, which was likely attributed to the lower reactivity of fructose. Chitosan-inulin conjugate presented the highest A 420nm and lowest intermediate-to-final ratio (A 294nm/A 420nm), probably due to the lower inulin molecules and subsequently carbonyl groups compared to fructose and glucose. These groups may react with amino groups of chitosan at initial reaction times, leading more conversion rate of the intermediate compounds to the final ones. FTIR spectra of the chitosan and conjugates revealed that absorbance peak at 1661 cm-1 in chitosan spectrum decreased and shifted to 1578 cm-1 (in chitosan-fructose conjugate), 1579 cm-1 (in chitosan-glucose conjugate), and 1580 cm-1 (in chitosan-inulin conjugate), indicating the stretching C-N group and -C=N group and the formation of Schiff base (-C=N) between reducing end of the saccharides and amino groups of chitosan. Reducing power of the chitosan-saccharide systems improved after the thermal process. Although, chitosan-glucose and chitosan-fructose conjugates had significantly higher reducing power than unconjugated counterparts, but chitosan-inulin conjugate showed non-significantly improved antioxidant activity compared to its non-heated mixture. Antioxidant activity of the Maillard conjugates was ascribed from the electron donating ability of their hydroxyl and pyrrole groups. The conjugates had lower MIC and MBC in comparison to their unconjugated pairs, except for chitosan-glucose conjugate, which showed no differences in MIC and MBC compared with its non-heated mixture. Antimicrobial property of the Maillard products, especially melanoidins has been attributed to their metal chelating features; melanoidins exert a bacteriostatic effect at low concentration and bactericidal effect at high levels through sequestering ionic iron from medium and magnesium from outer membrane, leading to the cell membranes destabilization. Additionally, antioxidant capacity, high surface activity, and inhibiting effect towards catabolic enzymes have been reported as another antimicrobial mechanisms of the Maillard products. In general, it can be concluded that chitosan-saccharide Maillard-based conjugates, particularly inulin-chitosan one could be used in the food sector as a novel prebiotic-based active bio-compound with antioxidant and antimicrobial features.
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.
Mohammad Ebrahim Goharjoo; Mohammad Reza Edalatian Dovom; Fakhri Shahidi; Farideh Tabatabaei Yazdi; Mohammad Javad Varidi
Abstract
Introduction: Carrot products such as carrot juice and fermented carrot products possess high nutritional value and they are considered as a major source of β-carotene. Carotenoids because of containing conjugated double bonds, have antioxidant properties and provide the natural yellow, orange and red ...
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Introduction: Carrot products such as carrot juice and fermented carrot products possess high nutritional value and they are considered as a major source of β-carotene. Carotenoids because of containing conjugated double bonds, have antioxidant properties and provide the natural yellow, orange and red colors in fruits and vegetables. Due to the outbreak of some problems such as lactose-intolerance and high blood cholesterol especially in dairy products’ consumption, great attention has been drawn toward fermented vegetable products. Lactic acid bacteria (LAB) including important genera: leuconostocs, lactobacilli, streptococci and pediococci are wide-spread and have been divided according to morphological features and fermentation pathway, which utilize glucose. Current knowledge regarding involved microorganisms in vegetable fermentation is still dependent on biochemical and classical data. Nowadays, application of molecular methods in the field of microbial identification has been provided better understanding from fermented foods ecology. Since local starter cultures are considered as precious genetic resources in each country and also they play an important role in production and creation of organoleptic characteristics in fermented products, therefore, the objective of present study was the isolation and identification of lactic flora from fermented carrot with the help of conventional (biochemical) and molecular methods and determination of phylogenetic relationships.
Materials and methods: Following the production of fermented carrot samples, they were packed in plastic container and stored at ambient temperatures (25-27°C). In the next step, total LAB count was performed according to Iranian standard of 5484. Isolation and selection of LAB was done during 32 days with the intervals of 0, 4, 8, 16, 24 and 32. For initial identification of LAB, isolated were subjected to gram staining and catalase tests. Also biochemical tests including growth at 15 and 45C, at NaCl 6.5% and 18%, pH=4.4 and 9.6, were done in order to identify and classify at genus level. Carbohydrate fermentation profiles were obtained for isolates with the aid of 10 sugars. Molecular identification was done with DNA extraction followed by amplification of 16S gene with universal primers (27 F and 1492 R). For sequencing of resulted PCR-products, they were sent to Macrogen Company, South Korea. Phylogenetic tree was plotted with Clustal Omega and Fig. Tree soft wares.
Results and discussion: In the first step, 144 gram positive, catalase negative isolates were screened and selected as presumptive LAB according to gram staining and catalase test and morphological characteristics. Among them, 48 representative isolates were chosen and identified up to genus level according to biochemical tests. Five distinct genera were identified as Pediococci (4.08%), homofermentative lactobacilli (34.69%), hetero fermentative lactobacilli (36.74%), Leuoconostocs (20.41%) and enterococci (4.08%). Carbohydrate fermentation profiles revealed Lactobacilli constitute the highest percent among other genera and also some species like Lb. kimchi and Lb. parakefiri were detected. Growth of lactic acid bacteria experienced increasing trend up to day-16 but thereafter showed decline trend until the end of storage time (day-32). 26 out of 48 isolates were subjected to molecular analysis. Results of sequencing revealed following species: Lb.plantarum (9), Lb. brevis (8), Leu. mesenteroides (4), Lb. casei (1), Lb. paracasei (1), and Lb, pantheris (1). Changes and variation of lactic flora during fermentation stages revealed that at initial stages of fermentation (0- day-8) Leuconostocs sp. were predominant species but disappeared then. In the next stages of fermentation Leuconostocs sp. were replaced by homo-fermentative strains such as Lb. plantarum which was present from the first day up to day-24 but constituted the majority of species on day-16. In the final stage, Lb. brevis dominated the others due to better survival and resistance of this bacterium at the increased acidity level. Phylogenetic tree results revealed three clusters including cluster I (composed of three sub-clusters), cluster II (three sub-clusters) and cluster III (two sub-clusters). Cluster I included two genera: Leuconostocs sp. (mesenteroides) and Lactobacillus (pantheris, casei and paracasei). Cluster II included Lb. brevis and finally cluster III composed of Lb. plantarum.
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.
Vahid Mosayebi; Farideh Tabatabaei Yazdi; Zahra Emam-Djomeh
Abstract
Introduction: Pectin is a complex heteropolysaccharide presented naturally in the middle lamella and primary cell walls of plant tissues. Pectin is mostly composed of a linear backbone of α-(1, 4) linked D-galacturonic acid residues which are partially esterified with methyl alcohol or acetic acid at ...
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Introduction: Pectin is a complex heteropolysaccharide presented naturally in the middle lamella and primary cell walls of plant tissues. Pectin is mostly composed of a linear backbone of α-(1, 4) linked D-galacturonic acid residues which are partially esterified with methyl alcohol or acetic acid at the carboxylic acid. Pectin is widely used as a gelling agent in food systems such as jams and jellies, fruit juices, confectionaries, bakery fillings and as a stabilizer in acidified milk drinks. Black mulberry (Morus nigra.L), originating from Iran, is a juicy fruit with dark red color and slightly acidic flavor. Black mulberry has gained an important position in fruit markets and food industry due to its distinctive flavor and phytonutrients in recent years. Black mulberries can be consumed as fresh or processed into several products such as juice, marmalades, liquors, natural dyes or even be used as frozen fruit in ice cream production. However, due to short harvesting season and susceptibility to spoilage, black mulberries are mostly processed into juice besides its fresh consumption. Press cake residue or pomace is the main by-product which is generated in large amounts from the commercial juice extraction processes from berry fruits which contain several bioactive compounds and valuable ingredients including antioxidants, phenolics, pigments, pectin and so on. These berry pomaces are considered suitable for pectin recovery although their pectin content is somewhat lower in comparison to rich known sources of pectin. Recently, ultrasound assisted extraction technique, as a novel method of extraction, has gained remarkable attention due to its some advantageous effects including shorter extraction time, reduced solvent and energy consumption and higher yield and better quality of extracted compounds as compared to conventional acid extraction method. Therefore, the present work was aimed to evaluate and optimize the ultrasound assisted extraction parameters (time of extraction, ultrasound power and liquid/solid ratio) to maximize the extraction yield, degree of esterification and galacuronic acid content of pectin from black mulberry pomace using three level three factor face centered central composite design.
Materials and methods: Fresh and fully ripe black mulberry fruits were purchased from a local fruit market in Karaj (Iran) and subsequently pressed to separate pomace from juice. The obtained pomace was then vaccuum dried (until 7.8±1% moisture content), ground to obtain a homogenous powder, sieved, filled into polyethylene containers, and stored at refrigerator. Pectin extraction from this powdered pomace was carried out using an ultrasonic bath at operating frequency of 35 kHz under different parameters including extraction time (20-60 min), ultrasonic intensity (40-100%) and liquid-solid ratio (15:1 to 30:1 mL/g). The initial pH value of the solution was adjusted to 2.0 by adding 1.0 N HCl solution. At the end of extraction, extracts were quickly cooled, centrifuged, filtered using Buchner funnel, concentrated by 5 fold, coagulated with 96% ethanol (ER=1.5) and left for 8 hours in room temperature. The precipitated pectin was separated by Buchner funnel, rinsed twice with 96% ethanol, dried under vacuum (45°C) and finally powdered. The degree of esterification of pectin was determined by titrimetric method according to Bochek et al. (2001). The galacturonic acid content was quantified by the colorimetric method with m-hydroxydiphenyl reagent using a spectrophotometer at 520 nm. The intrinsic viscosity [ƞ] of pectin was determined using a capillary tube viscometer and accordingly the viscosity average molecular weight [Mv] was calculated from the Anger-Berth equation. Finally, the frequency sweep test was performed using a controlled stress rheometer to determine the values of storage modulus (G′) and loss modulus (G″). The experimental design and statistical analysis were performed using response surface methodology (RSM).
Results and discussion: According to the obtained results, the extraction yield, degree of esterification and galacturonic acid content of pectin varied in the range of 4.73-7.68%, 42.42-58.33 and 18.70-31.45%, respectively. The extraction yield of pectin was linearly affected by the extraction conditions and its value significantly increased with increasing all the studied independent variables (p
Behrooz Alizadeh Behbahani; Ali Alghooneh; Farideh Tabatabaei Yazdi; Fakhri Shahidi; Mohebbat Mohebbi
Abstract
Introduction: Avicennia marina, commonly known as gray or white mangrove, is a specie of mangrove tree classified in the plant family Acanthaceae. It is distributed along Africa's east coast, south-west, south and south-east Asia, and southern Iran along the Persian Gulf coast. It grows as a shrub or ...
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Introduction: Avicennia marina, commonly known as gray or white mangrove, is a specie of mangrove tree classified in the plant family Acanthaceae. It is distributed along Africa's east coast, south-west, south and south-east Asia, and southern Iran along the Persian Gulf coast. It grows as a shrub or tree to a height of three to ten meters. Mixture design is one of the most popular smart systems which is based on simulation of linear and non-linear systems using mathematical and statistical techniques, and a useful tool for dealing with completely unknown systems. Chemical preservatives are commonly used for inhibition of pathogens in foods, people are concerned about the side effects of preservatives on their health. Replacement of chemical preservatives with natural substances have a great importance in food preservation. Natural preservatives, as well as, essential oils and plant extracts are suitable alternatives for chemical preservatives. The main purposes of this study are the evaluation of the effects of different combinations of four solvents (water, ethanol, methanol and glycerin) on the efficiency of mangrove leaf extraction using response surface method with mixture optimal design, the optimization of solvent formulation for mangrove leaf extraction, and, finally, the evaluation of the in vitro inhibitory and bactericidal effects of mangrove leaf extract on Listeria innocua ATTC33090 ، Enterococcus faecium ATTC 51559 and Escherichia coli ATTC 25992.Materials and method:Fresh mangrove leaves were prepared from Qeshm Island, Persian Gulf, Iran, in August 2012. Water, ethanol, methanol and glycerin extracts were prepared by adding 50 g of powdered mangrove leaf to 250 mL of the solvent. Extraction was carried out for 48h, in ambient temperature. The mixture of extract and leaf powder was separated by Watman filter paper, then the filtrate was centrifuged in 3000g for 10 minutes and filtered using a 0.45 µm Millipore filter. Finally, in order to separate the solvent and concentrated extract, the solutions were evaporated using a rotary vacuum evaporator. The concentrated extract was stored in dark aluminum containers at 4°C. In this study, the effects of water, ethanol, methanol and glycerin at five levels (0, 31.25, 83.33, 125 and 250 ml) on efficiency of mangrove leaf extraction by mixture optimal design has been investigated. Modeling and optimization has been carried out by Scheffe polynomial. The antimicrobial activity of mangrove leaf extract was evaluated using disk diffusion method. The minimum inhibitory concentration (MIC) of mangrove leaf extract was determined using serial dilution tubes. For each extraction method (based on solvent, Water, Ethanol, Methanol and Glycerin), 8 serial concentrations (2, 4, 8, 16, 32, 64, 128, 256 mg/mL) and 1 control tube of mangrove leaf extract were prepared in Mueller-Hinton broth. The minimum bactericidal concentration (MBC) of mangrove leaf extract was determined using serial dilution tubes.Results and Discussion:The Results indicated that Scheffe polynomial model was highly significant for prediction of efficiency of mangrove leaf extraction (R2 and R2adj values equal to 0.940 and 0.8447, respectively and The lack-of-fit tests did not result in a significant, also F-value (14.62) indicated that the model is sufficiently accurate). The optimum formulation was found as following: glycerin (0 ml), water (28.22 ml), methanol (59.83ml) and ethanol (161.95 ml) respectively. Maximum of antimicrobial effect on Listeria innocua and highest resistance against mangrove leaf extract on Escherichia coli were observed. Increasing concentration of mangrove extracts had a significant effect (p< .05) on inhibition zone diameter. This may have been resulted from the increment of the solvent polarity associated with glycerin increase. In order to study the mentioned hypothesis, Pearson Square statistical test was used to determine the correlation between the extraction rate and polarity. The results showed that a significant (P≤0.05) and inverse relationship between the extraction rate and polarity of the solvent. Moreover, in order to check the accuracy of the model fitted on the data obtained from mangrove leaf extraction rate the goodness of fit was investigated using both coefficient of determination (R2) and lack of fit test. A 94% coefficient of determination and lack of significance (P≤0.05) for lack of fit test suggested that Schef model could accurately fitt the data and predict it The results of this study showed that Schef polynomial and numerical optimization using mixture design method were suitable to fit efficiency of mangrove leaf extraction and solvent formulation optimization data, respectively. According to the results, the optimized solvent formulation was glycerin (0 mL), water (28.22 mL) and ethanol (161.95 mL). Conclusion: Finally, the results showed that mangrove leaf extract had a notable antimicrobial effect on the studied strains “in vitro”. More “in vivo” studies seem to be required in order to determine the best extract dosage which leads to inhibition of microbial infection.
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.
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.
Naeimeh Kazemi Taskooh; Mohammad Javad Varidi; Mohammad Hossein Hadad Khodaparast; Farideh Tabatabaei Yazdi
Abstract
In this study,The effect of Ozonated water(0.2, 0.5, and 1 ppm) with different exposure times (5,10, and 15 min) for control of Staphylococcus aureus , Escherichia coli and total counts in poultry Carcass, on Chiller water in slaughter house were investigated. For this purpose, Control samples passed ...
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In this study,The effect of Ozonated water(0.2, 0.5, and 1 ppm) with different exposure times (5,10, and 15 min) for control of Staphylococcus aureus , Escherichia coli and total counts in poultry Carcass, on Chiller water in slaughter house were investigated. For this purpose, Control samples passed chiller water(without Ozone) for (5,10, and 15 min) .Other examples also treated (5, 10 , and 15 min) with ozonated water(0.2, 0.5, and 1 ppm) in the laboratory, under the same temperature of chiller water(0 - 4 C) and immediately analyzed for microbiological tests. The results indicated that the use of ozonated water redused1.7 Log of Staphylococcusaureus , 2.3 Log of Escherichia coli and 1.16 Log of total counts. Results showed that Escherichia Coli (As a Gram- Negative Food Infection Bacteria) was more sensitive to Ozone treatment than Staphylococcus aureus(As a Gram-Positive Food Infection and Toxicogenic Bacteria),(2.3 Log reduction in Escherichia coli and 1.7 Logreduction in Staphylococcus aureus), At all levels observed significant differences (P
Parviz Bashiri; Mohammad Hossein Hadad Khodaparast; Nasser Sedaghat; Farideh Tabatabaei Yazdi; Mehdi Nasiri mahalati
Abstract
In this research effectiveness of immersing three types of contaminated pistachios fresh with hull (exocarp or epicarp), dried in shell and dried with hull from Ohady cultivar in ozonated water 0 ppm (control), 4 and 8 ppm ozone concentrations in aqueous solution for range of exposure times 0(control), ...
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In this research effectiveness of immersing three types of contaminated pistachios fresh with hull (exocarp or epicarp), dried in shell and dried with hull from Ohady cultivar in ozonated water 0 ppm (control), 4 and 8 ppm ozone concentrations in aqueous solution for range of exposure times 0(control), 2, 4, 6, 8, 10 and12 hours, to decrease of aflatoxin (B1, B2, G1, G2 and total) were investigated. Water temperature and pH were 10°C and 5.5± 0.3 respectively. For all samples, interaction between, ozone concentration and exposure times or pistachio type, were investigated. Aflatoxin (AF) B1 content was more and was reduced easily. Results showed that differences between the control samples (zero hour and/or 0ppm ozone) and treated pistachios for total aflatoxins and aflatoxin B1 were significant(P < 0.05). For control samples, the means of aflatoxin reduction for B1, B2, G1, G2 and total were, 5.6, 9.7, 14, 6, 15 and 6.4 percentage, respectively and for ozonated pistachios were 32.7, 8.55, 30.6, 34 and 35 percentage, by 4ppm ozone concentration. The results for 8ppm ozone concentration were, 47.9, 12.5, 45.8, 43.9 and 44.4percentage, respectively. The results indicated that the effect of ozonated water on reduction of aflatoxin content from the samples significantly depends on the level of ozone concentration and exposure times. The results also demonstrated that ozone susceptibility of aflatoxins to destruction were B1 & G1 >G2 & B2 respectively.
Fereshteh Dehghan Nassiri; Mohebbat Mohebbi; Farideh Tabatabaei Yazdi; Mohammad Hossein Hadad Khodaparast
Abstract
The objective of this work was to determine the effect of pre-frying elimination through the addition of methylcellulose and the influence of wheat flour partial replacement with corn flour (5 and 10%) on some quality factors of deep fat fried shrimp nuggets and compare the results with traditional process ...
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The objective of this work was to determine the effect of pre-frying elimination through the addition of methylcellulose and the influence of wheat flour partial replacement with corn flour (5 and 10%) on some quality factors of deep fat fried shrimp nuggets and compare the results with traditional process including pre-frying step. All batters showed shear-thinning behavior (n ≤ 0.624) and provided a good fit with power law model (R2 ≥ 0.979). Methylcellulose produced a significant increase in the consistency index of the batters. The highest pick-up value (57.68%) and the lowest oil content were found in 2% MC added batters that contained 5% corn flour, which was consistent with its high apparent viscosity. Results showed that the pre-frying elimination is an effective way in reducing oil content (%46) in deep fat fried shrimp nuggets.
Seyed Hossein Razavizadegan Jahromi; Farideh Tabatabaei Yazdi; Mahdi Karimi; Seyed Ali Mortazavi
Abstract
Efforts to improve the quality of bakery products are increasing every day. Several techniques were developed for this purpose. In this study the possibility of betterment and optimization of quality properties of dough and Barbari bread with emphasis on process variables using rotatable response surface ...
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Efforts to improve the quality of bakery products are increasing every day. Several techniques were developed for this purpose. In this study the possibility of betterment and optimization of quality properties of dough and Barbari bread with emphasis on process variables using rotatable response surface methodology were investigated. The independent process variables for baking process were dough mixing time at low speed (MTLS) (63 rpm) and high speed (MTHS) (180 rpm) from 2 to 8 min and dependent process variables were dough adhesiveness, dough cohesiveness, dough hardness, dough resilience, dough stickiness and specific volume of Barbari bread. Statistical results showed that all the process variables have a significant effect on all the responses. The linear terms of MTHS was the most effective factor on dough stickiness and dough resilience. Quadratic terms of MTHS and MTLS were the most effective factor on dough cohesiveness and dough hardness and specific volume of Barbari bread, respectively. Interaction terms of process variables have significant effect (p
Elham Zaerzadeh; Seyed Ali Mortazavi; Mahmoud Reza Jafari; Sima Afsharnejad; Farideh Tabatabaei Yazdi; Mehdi Nasiri mahalati
Abstract
The objective of this study was evaluating the effectiveness of encapsulated nisin in liposoms in contrast to free nisin in control of Listeria monocytogenes ATCC 19117 in Feta cheese during its ripening. The size of the nano-encapsules with nisin was around 103-150 nm and of the nano-encapsules without ...
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The objective of this study was evaluating the effectiveness of encapsulated nisin in liposoms in contrast to free nisin in control of Listeria monocytogenes ATCC 19117 in Feta cheese during its ripening. The size of the nano-encapsules with nisin was around 103-150 nm and of the nano-encapsules without nisin was of approximately 101-143 nm. Addition of 500IU/g nisin to cheese resulted into 0.57, 4 and 3.7 log reduction in viable cells, respectively in free nisin, nano-encapsulated nisin (formulation 1) and nano-encapsulated nisin (formulation 2) at the end of four weeks ripening. In addition, changes in pH during this period of time was also affected by the form of addition of nisin, it was significantly different from liposomal nisin formulations(p
Rassoul Kadkhodaee; Seyed Ali Mortazavi; Farideh Tabatabaei Yazdi
Abstract
The aim of this work was to investigate the influence of interactions between modified starch (Hi-Cap 100) and the nonionic surfactant Tween 80 on the properties of cardamom oil-in-water emulsion and its corresponding spray dried microcapsules. To this end the mean diameter and size distribution of droplets ...
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The aim of this work was to investigate the influence of interactions between modified starch (Hi-Cap 100) and the nonionic surfactant Tween 80 on the properties of cardamom oil-in-water emulsion and its corresponding spray dried microcapsules. To this end the mean diameter and size distribution of droplets as well as their polydispersity index and also the viscosity and flow behavior of emulsion samples along with the encapsulation efficiency of powders were determined in the presence of various ratios of Tween 80. The results showed that increasing the concentration of Tween 80 up to 1% decreased the size of droplets and their polydispersity index while further increase beyond this point led to adverse effect. Also significant rise in the viscosity and marked alteration in the flow behaviour of emulsions was observed within this limit, which clearly indicates the influence of Hi-Cap 100 and Tween 80 interaction on the quality attributes of samples. Moreover, the findings of this study demonstrated that the aforementioned interaction considerably affected the microstructure and overall encapsulation efficiency of spray dried powders.
Keywords: Emulsion, Microencapsulation, Surfactant, Modified starch, Hi-Cap 100, Tween 80
Farideh Tabatabaei Yazdi; Khalil Behzad; Mostafa Mazaheri Tehrani; Mostafa Shahidi Noghabi
Abstract
One of the most important stages in sugar industry that making wastewater and contamination is the water obtained to washing of CO2 in mazoot furnace and related pumps. Amount of water consumption in this stage is about 30 to 35 percent of weight of sugar beet, so amount of this stream is considerable. ...
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One of the most important stages in sugar industry that making wastewater and contamination is the water obtained to washing of CO2 in mazoot furnace and related pumps. Amount of water consumption in this stage is about 30 to 35 percent of weight of sugar beet, so amount of this stream is considerable. Mixing of carbon black and water compose the colloid in liquid phase. These colloids do not separate easily. This water is black, thus it is unuseable. In this study used liming to refining of wastewater. Samples obtained from tow factories (sugar plant of torbat heydariyeh and joveyn ). Lime was added into samples directly. Relationship of pH to amount of added liming , rate of deposition of carbon black, volume of mud and coagulation percent was investigated. the results shown that there is a strong correlation between amount of lime milk and given parameters and rate of deposition of carbon black, volume of mud and coagulation percent evaluate with obtained equations. Additionally the results shown that carbon black separate completely in pH = 11.65, and obtain glassy water.
Key words: Refining of wastewater, Sugar factory, Lime furnace
