Zhaleh Sadat Ladjvardi; Mohammad Saeid Yarmand; Zahra Emam-Djomeh; Amir Niasari-Nasalji
Abstract
Introduction: In recent decays, consumers have more information about foods. Vegetables, crops and other natural food with high nutritional value replace hazardous substances. In this study, the effects of locust bean gum and xanthan gum with β-glucan were investigated in camel synbiotic yogurt ...
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Introduction: In recent decays, consumers have more information about foods. Vegetables, crops and other natural food with high nutritional value replace hazardous substances. In this study, the effects of locust bean gum and xanthan gum with β-glucan were investigated in camel synbiotic yogurt functional. Locust bean gum (LBG) has about 88% of galactose and mannose, 4% other polysaccharides, 6% protein, 1% cellulose and 1% the ashes (Nasirpour, 2013; Hansen, 1993).Xanthan gum is an extracellular polysaccharide produced by Compestris Xanthomonas in aerobic fermentation process. Xanthan reactions synergies with guar and LBG, so the low concentrations in the presence of LBG viscosity increase (Ramirez-Figueroa et al., 2002).In this study, the oats β-glucan inoculated with probiotic bacteria to camel milk for production of functional synbiotic yogurt was employed. The camel milk has high nutritional value such as insulin-like substance, less lactose, immuno-globulins and lactoferrin, antioxidants and antimicrobial agents and other nutrients (ladjevardi et al., 2015; Niasari Naslaji et al., 2011). Synbiotic dairy product made from combinations of probiotic bacteria with prebiotics agent (β-glucan). About 108- 107 cfu/mL of live bacteria should be in the final products (Faraj et al., 2012). β-glucan is an indigestible carbohydrate complicated (Theuwissen & Mensink, 2008) with very high nutritional properties, including improved intestinal activity (fibers), lowering uric acid blood, stimulating the immune system (Xue et al., 2013; Chao et al., 2013). Materials and Methods: At first, camel milk (from Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tehran, Iran) was standardized by centrifugation (Universal 320, Hettich, Tuttlingen, Germany) to 1.9% fat content. Then xanthan gum and locust bean gum (1:1) were added in three level 0.1, 0.2 and 0.3%. β-glucan (extracted from oats as described by Moura et al. (2011() in 1.5, 2 and 2.5% levels was added to milk. Camel milk was homogenized with ultra-turrax blender (T25, IKA, Staufen, Germany) in speed 9000 r.p.m. Then, the milk sample was pasteurized for 15 min at 75±1 °C. Samples were prepared by adding yogurt starter culture (1.5%) containing probiotic microorganisms (ABY1, Cristian Hansen, Hørsholm, Denmark) at 42 °C. The mixtures were redistributed into 50 mL sterile plastic cups, incubated at 42 °C until their pH decreased to 4.6, they cooled and stored at 4±1 °C ( Mazloomi et al. 2011). Determination of water-holding Capacity (WHC)5 g of yogurt was centrifuged (Mikro 220R, Hettich, Tuttlingen, Germany) at 4500 r.p.m. for 30 min at 10°C. After centrifugation, the supernatant was removed and the pellet was collected and weighed. Microbial Analyses1 g of yogurt with 9 mL of normal saline (a solution of 0.9 % (w/v) NaCl ( Merck, Darmstadt, Germany)) was mixed and diluted to a concentration of 106 and 107, and then 1 mL of each dilution was repeated in 2 plate containing the MRS-Agar (Merck, Darmstadt, Germany) with 0.15% Bovin-Bile (Sigma-Aldrich, Louis, MO, USA). Bacteria were counted by the pour plate technique. The plates in duplicates were incubated anaerobically at 37 °C for 72 h, after this period, colonies were counted (Mishra and Mishra 2012). Statistical AnalysisThe response surface methodology (RSM) and ANOVA (p<0.05) were used for data analysis using Design Expert 8 (Version 8.0.7.1, Minneapolis, MN, U.S.A) software. The experiment was designed according to central composite design (CCD). All experiments and measurements were conducted in triplicate, mean value ±sd are reported. Result and discussionWater-Holding Capacity (WHC)Changes of xanthan gum, LBG, β-glucan and time storage have a significant effect on the WHC. Increasing the percentage of LBG, xanthan gum and the percentage of β-glucan significantly increased the WHC. Time storage reduced the WHC similar results of Ladjevardi et al. (2015) and Sahan et al. (2008).According ANOVA table, the products had maximum water holding capacity at the highest percentage of LBG and xanthan gum. The percentage of xanthan gum and β-glucan increased water holding capacity. These factors (LBG and xanthan gum, xanthan gum and β-glucan) have a synergistic effect on each other mutually.Xanthan gum and LBG showed interaction effect with time storage on changes in WHC including maximum water retention in the sample tissue, the high percentage of gums and the early days of production. Viability of probiotic bacteriaViability of probiotic bacteria significantly increased when used from high percentage of β-glucan (as a prebiotic agent) in synbiotic yogurt. This change was related to increasing food for probiotic bacteria (Kearney et al., 2011). According to the results mentioned a good environment for the growth and activity of the microorganisms (ladjevardi et al., 2015). The unfavorable conditions in production of synbiotic yogurt, was time duration. During storage, the number of probiotic bacteria that are present in the product is reduced Xanthan gum and LBG have no significant effect on viability of probiotic bacteriaXanthan gum and time storage have interaction effect on the viability of probiotics bacteria. As expected, the best conditions for probiotic bacteria to maintain a high percentage of xanthan gum was at the early days of the sample production ((Norton and Lacroix, 1990; Sanderson, 1990).According to the results, it was found that gums such as xanthan gum and LBG showed similar results to those of El-Salamt et al. (1996) and Hematyar et al. (2012) and had adverse influence on the growth and activity of beneficial bacteria.
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
Ghasem Yousefi; Zahra Emam-Djomeh
Abstract
The present research surveyed the effect of five factors including: microwaves power, air temperatures and its flow rates, microwaving time onset and amount of substances on the requested time and energy for combined fluidized bed- microwaves drying of black raspberry into 50% dry base wet content. Response ...
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The present research surveyed the effect of five factors including: microwaves power, air temperatures and its flow rates, microwaving time onset and amount of substances on the requested time and energy for combined fluidized bed- microwaves drying of black raspberry into 50% dry base wet content. Response surface methodology and Central composite was used as experimental design. Multiple linear regression was used for obtaining second polynomials models for each analyses followed by ANOVA analysis in order to confirming the adequacy and accuracy of resulted models. Using the empirical resulted model the relationship between variables and responses were determined via response surface method. Correlation coefficients of the regression models were 0.964 and 0.970 respectively for the drying time and energy consumption. The Optimized drying condition were including; 600 watts for microwaves power and microwaving onset from that time as the moisture content was 344% decreased,73 g for amount of substances, and 85˚C and 15 m.s-1 for air temperatures and its flow rates respectively. Under mentioned conditions, the fitted model was predicted 52.66 Min and 65.2 Kj respectively for the requested drying time and energy consumption at combined drier. As a conclusion, the results showed that requested drying time and energy consumption were decreased with increasing of temperatures, microwaving time and its power, and decreasing of air flow rates. In this regard, the drying kinetics curve samples were drawn under the conditions listed that showed drying time is reduced to 76% with increasing temperature from 55 to 85 and use the microwave reduced drying time until 30 to 80%.
Zohreh Karami; Habibollah Mirzaee; Zahra Emam-Djomeh; Alireza Sadeghi Mahoonak; Morteza Khomeiri
Abstract
In this research, anti-microbial activity of ethanolic extract of licorice root against food spoilage microorganisms (Lactobacillus delbrueckii, Leuconostocmesenteroides, Candida krusei, Saccharomyces cerevisiae) in an orange flavored carbonated soft drink was investigated. The MIC and MBC of extract ...
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In this research, anti-microbial activity of ethanolic extract of licorice root against food spoilage microorganisms (Lactobacillus delbrueckii, Leuconostocmesenteroides, Candida krusei, Saccharomyces cerevisiae) in an orange flavored carbonated soft drink was investigated. The MIC and MBC of extract against Lactobacillus delbrueckii was 0.7 mg/ml and 0.8 mg/ml respectively, and against Leuconostoc mesenteroides MIC and MBC were 0.9 mg/ml. Also, MIC and MBC against Candida krusei and Saccharomyces cerevisiae using microdillution method was equal to 0.8mg/ml. In this research an orange flavored beverage preserved with natural licorice root extract was formulated and parameters such as phenolic contents, changes in population of aerobic mesophilic bacteria, yeast and acid-resistant micro-organisms during storage time were evaluated. Concentrations of 1000, 1500 and 2000 ppm of licorice root extract and samples containing 1000, 1500 and 2000 ppm of licorice root + 50% benzoate was used to control growth of food spoilage microorganisms in the beverage. Samples enriched with licorice root and a blank sample (commercial sample) were kept at room temperature and microbial counts were monitored during 1, 10, 20, 30, 40, 50, 60, 70, 80 and 90 days. Results of microbial examinations showed that the use of licorice root extract preserved the orange flavor carbonated soft drink during 90 days storage. Also, phenolic compounds showed good stability during 90 days storage time.
Hossein Mirsaeedghazi; Zahra Emam-Djomeh
Abstract
Limonene is a major flavor Producing Compound in orange - flavored soft drinks. It is an important parameter in marketability of products. Effect of molar fraction, time and CO2 on Limonene activity coefficient was evaluated using Dortmund-UNIFAC thermodynamic model. Results showed that activity coefficient ...
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Limonene is a major flavor Producing Compound in orange - flavored soft drinks. It is an important parameter in marketability of products. Effect of molar fraction, time and CO2 on Limonene activity coefficient was evaluated using Dortmund-UNIFAC thermodynamic model. Results showed that activity coefficient decreased by increasing molar fraction. Also, activity coefficient was in minimum level at 30 days storage and increased before and after this period of time. CO2 had a negative effect on Limonene activity coefficient.
Zahra Emam-Djomeh
Abstract
The effect of pre-treatments in combination with hot air, vacuum and hot-a microwave drying methods the progress of the drying process, and textural, and colour and rehydration rate on button mushroom (Agaricus bisporus) slices were investigated. In this work, one of the following methods: hot air, vacuum ...
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The effect of pre-treatments in combination with hot air, vacuum and hot-a microwave drying methods the progress of the drying process, and textural, and colour and rehydration rate on button mushroom (Agaricus bisporus) slices were investigated. In this work, one of the following methods: hot air, vacuum drying or microwave-assisted convective drying and also different pre-drying treatments, viz. blanching (with hot water or vapour) and sulphitation, were applied. Textural properties of button mushroom were measured during drying and rehydration using a texture analyser. The colour changes of samples during drying and rehydration were analysed applying a Hunterlab Colorimeter. During drying, hardness of mushrooms was increased. Sulphitation pre-treatment improved the structural and rehydration rate of the dried samples, but had varying effects on the colour. Microwave energy reduced drying time and can modify the structure, colour and texture strength of the final product. The effect of microwave treatment on colour varied with the type of pre-treatment applied before drying. Microwave samples showed also the highest rate of rehydration among all samples.
Keywords: Microwave-assisted convective drying, Mushroom, Colour changes, Rehydration rate, Textural properties
Zahra Emam-Djomeh; Rasoul Ghaheri; Gholamhasan Asadi
Abstract
In this research the effect of substituting sugars (glucose and sucrose) by low caloric sweeteners (sorbitol and isomalt) on the physical properties of Gazz was studied. Textural properties of Gaz were investigated using Instron and micro-structure was studied by Scanning Electron Microscope (SEM). The ...
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In this research the effect of substituting sugars (glucose and sucrose) by low caloric sweeteners (sorbitol and isomalt) on the physical properties of Gazz was studied. Textural properties of Gaz were investigated using Instron and micro-structure was studied by Scanning Electron Microscope (SEM). The results of texture investigation showed that the sample containing 25% of sorbitol and 65% of isomalt had the most similarity with the control sample. Increasing the content of sorbitol will soften the texture. Micro-structural studies showed that the texture of control sample has lots of bubbles inside, and this will decrease its density in comparison with dietary Gazz. No bubbles were observed when low caloric sugars were replaced which can be explained by the functional properties of sorbitol including its lubricant characteristics. This fact can led to a decrease in the density of the product in comparison with the control one.
Keywords: Gazz, Low caloric sweeteners, Isomalt, Sorbitol, Texture
Hossein Mirsaeedghazi; Zahra Emam-Djomeh; Seyed Mohammad Ali Ebrahimzadeh Mousavi; Abdolreza Aroujalian; Mahdi Navidbakhsh
Abstract
The pomegranate juice with high nutritional value has turbid appearance that makes it difficult to preserve and concentrate. Microfiltration is useful process which can clarify it. One of the most important problems in this process is fouling phenomenon which affected by several parameters. The effects ...
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The pomegranate juice with high nutritional value has turbid appearance that makes it difficult to preserve and concentrate. Microfiltration is useful process which can clarify it. One of the most important problems in this process is fouling phenomenon which affected by several parameters. The effects of fluid velocity, transmembrane pressure, membrane type and its pore size on membrane fouling were studied. The results showed that the membrane fouling increased with increase in the fluid velocity and transmembrane pressure. Also, more hydrophilic property and pore size resulted more membrane fouling due to greater flux which move more particles to membrane surface. Scanning electron microscopy (SEM) images support these results.
Keywords: Clarification, Fouling, Membrane, Pomegranate juice
Zahra Emam-Djomeh; Manuchehr Hamedi; Seyed Hadi Razavi; Mohammad Taghi Golmakani
Abstract
In this study the antimicrobial effects of essential oils from dill and coriander seeds on
staphylococcus aureus, Escherichia coli O157:H7 and salmonella typhimuruim were investigated and
the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of each
essential oil ...
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In this study the antimicrobial effects of essential oils from dill and coriander seeds on
staphylococcus aureus, Escherichia coli O157:H7 and salmonella typhimuruim were investigated and
the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of each
essential oil were determinate. For this purpose 5 concentration of each essential oils (125, 250, 500,
1000, 2000 and 4000 ppm) were chosen. For microbial count, Broth Dilution Test with Mueller
Hinton Agar and Broth were used. Results showed that Staphylococcus aureus had more susceptibility
and Salmonella typhimuruim was the resistant one. Our results also showed that essential oil from
coriander seed had more antimicrobial effect on the gram-negative bacteria. The essential oil from
coriander seed had MIC and MBC equal to 1000ppm and the essential oil from dill seed had MIC
equal to 500ppm and MBC equal to 1000 ppm against Staphylococcus aureus.
Key word: Broth Dilution Test, Staphylococcus aureus, Escherichia coli O157:H7, Salmonella
typhimuruim, essential oils, dill seed, coriander seed
Ehsan Jenab; Keramatoallah Rezaee tireh shabankareh; Zahra Emam-Djomeh
Abstract
Samples of crushed and cooked canola seeds (Okapy Double Zero) were extracted using supercritical carbon dioxide (SCCO2) at 34 MPa and 40ºC and a commercial organic solvent (AW406). The oil solubility in SCCO2 was determined and extracted oils were examined with respect to their chlorophyll contents, ...
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Samples of crushed and cooked canola seeds (Okapy Double Zero) were extracted using supercritical carbon dioxide (SCCO2) at 34 MPa and 40ºC and a commercial organic solvent (AW406). The oil solubility in SCCO2 was determined and extracted oils were examined with respect to their chlorophyll contents, nonsaponifiable matters, fatty acid composition and iodine value. The yield of SCCO2 extraction was significantly (P
