Journal of food science and technology
Year:2016 | Volume:13 | Issue:53|Papers Count:20

The aim of this work was identified lactic floraas a traditional fermented food and then evaluates antimicrobial activities of some strains. A total of 140 Gram-positive and catalase-negative isolates were subjected to grouping by physiological and biochemical tests and carbohydrates fermentation. Based on the results these 140 isolates were divided in to 9 groups. Two or three isolated were selected from each group and 16S rRNA was amplified using universal primers. Diversity of lactic acid bacteria in horreh was as followings: Lactobacillus fermentum (30.00%), Lactobacillus plantarum (28.57%), Lactobacillus brevis (15.00%), Weissellacibaria (8.57%), Enterococcus (faecium and faecalis) (7.14 %), Leuconostoc (citreumand mesenteroides subsp. Mesenteroides) (6.42%) and Pediococcus pentosaceus (4.28%). Antagonistic activity of 20 isolates (strains) of lactic acid bacteriaobtained from horreh was evaluated against food- borne bacteria. Sixteen isolates in Agar spot method and 14 isolates in well diffusion as say showed antibacterial activity against at least one of these indicators. Eight isolates including: Ent. faecium (1), Ent. faecalis (1), P. pentosaceus(1) and Lb. plantarum (2) exhibited the highest antagonistic activity toward Listeria innocoa. Antagonistic activity of cell free supernatant (CFS) from Lb. plantarum showed the highest thermal stability. Also, two isolates belonging to: Ent. faecium, Ent. Faecalis presented antibacterial activity at pH=7. Only, the supernatant of Lb. plantarum was not influenced by proteinase K. The results showed that the supernatant of some isolates tested can be used as a bio preservative in food products.

Cake is one of the most popular products in baking industry and consumption due to the relatively high presence in oil field products and the risk of hypercholesterolemia is limited to a specific group of people. Therefore, in this study a complete melon seeds flour at levels 5, 10, 15 and 20% due to lower cholesterol and unsaturated fatty acids, high-fat alternative to the original formulation of oil cake and the moisture content, specific volume, porosity, texture, crust color and overall acceptability of the samples produced were evaluated. The results showed that the addition of more than 10% melon flour reduces the amount of moisture and L* value. However, the specific volume and porosity of 10% melon seed flour with control samples showed no significant difference (P<0.05). Also the results clearly showed that the samples containing 10 and 15% melon seed flour and control sample had a similar texture. On the other hand, increasing the amount of melon seed flour in the formulation of oil cake increase the b* value of the samples. The sensory evaluation of samples containing 10% of melon seed flour as the best example, along with control samples (samples containing oil) were introduced. Thus, 10% of melon seed flour can maintain the quantity and quality of product and it’s a suitable substitute for oil in oilcake formulation.

This study was carried out in order to measuring Hg in some varieties of the most consumed imported and most locally cultured rice and comparing together and assess potential health risk. The correlation between Hg content of soil and rice samples, and effect of cooking and washing treatment on Hg concentration in rice, were investigated. In November 2008, locally most cultured rice and soil samples were collected from the Mazandaran province. High consumption of imported Indian rice with commercial brands collected from source, according to purposed method of standard office of Hormozgan. Advanced mercury analyzer Leco AMA 254 used to determination of Hg levels. The results showed that Hg concentration in Iranian rice (0.044±0.003 mg g-1 d.w) significantly over imported rice (0.039±0.001 mg g-1 d.w). Comparing the tolerable daily intakes (TDI) given by FAO/WHO with the mean estimated daily intakes (EDI) through rice consumption in this study was lower than TDI. In addition, results showed that no relationship was found between Hg concentration in rice and soil samples (r=0.079, p=0.567), and cooking and washing treatment has not significant effect on mercury concentration. Finally, relationship between Hg concentration in soil and rice samples with soil parameters were studied that was not observed any correlation.

The purpose of this study was to evaluate the effect of time, kind of extract, extract concentration and temperature on the dynamically the population of Escherichia coli (infectious agents) in the complex food system (frankfurter sausage) and Genetic Algorithm- Artificial neural network and neuro fuzzy system (CANFIS) were used for dynamic modeling of population of E. coli. At this research laboratory, Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of aqueous and ethanolic extracts were studied using the micro broth dilution method. GAANN, neuro fuzzy (CANFIS) were fed with four inputs: concentration at the five level (0, 2000, 4000, 6000, 8000 ppm), kind of extract (watery, ethanol), temperature at the three level (5, 15, 25oС) and time (1-20). The results showed that the ANN with 1 hidden layer comprising 10 neurons, Tangent hyperbolic function, momentum training rule and percent of used data 30/30/40 for training/cross validation/testing respectively gives the best fitting with the experimental data, which made it possible to predict with high determination coefficient (R2 equal to 0.995). Also the correlation between CANFIS predictions and experimental data was very good (R2 equal to 0.96). It's worth to mention that in this research GA- ANN was better approach to simulation dynamically the population of E. coli.

Rheological study of date syrup, date concentrate and date liquid sugar can improve their industrial applications specially for sugar (sucrose) substitution. In this research the rheological behavor of date syrup, date concentrate, date liquid sugar and sucrose solutions was investigated using a Brookfield Viscometer at 50, 55, 60 and 65oBrix, 25oC and shear rate of 80-480 s-1 .The variables were product type and concentration. Moreover, for textural evaluation a texture analyser was used to examine date syrup, date concentrate and date liquid sugar at 50, 60 and 70o Brix. The results showed that the Power law model was suitable to the rheological behavior of all samples and all concentrations. In date syrup by increasing concentration from 50 to 65o Brix, consistency coefficient (K) increased, flow behavior index (n) decreased and the sample became more shear thinning. However, all other samples were Newtonian. Therefore a similar flow type behavior for these three samples is expected in food processings. Among all tested concentrations, the date syrup sample with a Brix of 65 had the highest consistency coefficients. This indcates using date syroup in food formulations, usage level of hydrocolloids can be reduced. These findings were confirmed by texture data.

The objective of this experiment was to investigate the antimould effect of 19 Lactobacillus plantarum strains isolated from different production stages of Lighvan cheese (3, 8 and 8 strains from raw milk, curd and fresh cheese stages, respectively) a traditional raw milk cheese, on Penicillium expansum (PTCC 89046) as an indicator in fruit juice spoilage. This antimould spectrum was determined by agar spot and well diffusion method, followed by determination the influence of different technological or physico-chemical factors including temperature (80oC for 1 h, 100oC for 10 min, 100°C for 30 min and 121oC for 15 min) and pH (2 to 7) and different dilution (Titre test). Serial twofold dilutions were conducted to the CFE in order to assess of CFE Titre against mould indicator. Findings revealed that Lactobacillus plantarum strain C28 has the highest antimould properties in both antimicrobial methods (Agar Spot and Well Diffussion Assay) and antimould effect showed decreasing trend with pH increasing. In 121o C for 15 min, no antimould effect was observed. The Lactobacillus plantarum strain C28 showed the highest titre factor of 160 (AU / ml). Finally, we can assume that these strains which isolated from different production stages of Lighvan cheese or their Cell Free Extract (CFE) can be used as biopreservative in food systems.

Bakery products, like many processed foods, are subjected to the physical, chemical and microbiological spoilage. Mold growth is a problem that limits the shelf life of high and intermediate- moisture bakery products .Water activity is a physical property that has a direct implication for microbiological safety of food. Foods with lower water activities are quite shelf life since they contain small a mount of water available for microorganisms to use for growth. In this research, effects of polyols (Glycerin, Sorbitol, Propylene glycol), invert and glucose syrup on the quality of batter and cake were evaluated. Polyols, invert and glucose syrup at five levels (1, 2, 3, 4 and 5%) were considered as variable treatments. The results showed that, cakes containing with propylene glycol had higher specific volume of batter, less height of cake and higher moisture of cake (P<0.05). Propylene glycol and glycerol were significant different in decreasing water activity other than sorbitol, invert and glucose syrup (P<0.05). Cakes containing propylene glycol and glycerol were more than sorbitol shelf life, invert and glucose syrup. Samples of cakes containing invert had the lowest pH (P<0.05). Thus, the polyols can be used to increase the quality and shelf life of cake.

In order to improve the quality of shrimp (Litopenaeus vannamei) at refrigerated temperature (4±1oC), the shrimp samples were coated with solutions of chitosan (0, 0.5, 1, 1.5 and 2%), gelatin (0, 2 and 3%) and combination of them in 15 treatment group. Preservative effect of the coatings was evaluated by biochemical analyses, microbiological assays and physical measurements over 8th day of storage time. The findings indicated that 1% chitosan and 3% gelatin based coating was superior to others in preservation spoilage, inhibiting oxidation, improvement physical properties. The coating significantly (p£0.05) reduced chemical spoilage as reflected in pH and total volatile basic nitrogen, microbial growth as reflected in total and psychrotrophic bacterial count and lipid oxidation as displayed in peroxide value and thiobarbituric acid compared to other treatment. Also, coated shrimps with the optimized coating were significantly (p£0.05) indicated improvement in weight loss, color as reflected in a*, b* and L* values and texture as reflected in hardness compared to others. The optimized coating could enhance the shelf life of shrimp under refrigerated storage.

The aim of the present study was to identify changes in the antioxidant properties of soy proteins. Soy proteins- maltodextrin conjugates were prepared by Maillard type reaction in a controlled dry state condition (60oC, 75% relative humidity, pH: 8 for 1, 3, 5 and 7 days). The formation of glycoconjugates was confirmed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration chromatography. Browning intensity, 1, 1 Diphenyl 2 picryl hydrazyl (DPPH) and hydroxyl radical scavenging activity and reducing power measured their antioxidant properties. Browning and intermediate products, as monitored by absorbance at 420 nm, sharply increased with conjugation. DPPH and hydroxyl radical scavenging activity increased with increasing incubation time, this improved free radical scavenging activity mediated by antioxidant maillard reaction products. Reducing power of conjugates was remarkably increased compared with the control sample. The results demonstrated that the Maillard type soy protein-maltodextrin products can be used as an effective natural antioxidant.

Investigation of quality characteristics of food products during different manufacturing stages such as storage, processing and consumption is important to reduce food loss. In recent years many researches have established for developing rapid and non-destructive techniques for quality control. In this study the potential of visible and near infrared spectroscopy (Vis/NIRS) in determining the quality parameters of lime including total soluble solid and acidity in reflection mode was investigated in the wavelength range of 400 to 1000 nm. The effects of different pre-processing techniques and spectral treatments, such as standard normal variable transformation (SNV), multiplicative scatter correction (MSC), median filter, Savitzky & Golay and the derivatives were evaluated. The model was developed based on partial least squares (PLS) regression. The correlation coefficient (R2) and root mean square error of prediction (RMSEP) for predictive model of soluble solids content was 0.949, 0.105o Brix respectively. These parameters of the model predicting acidity was found to be 0.909 and 0.118 respectively. These results showed the high potential of Vis/NIRS and the important role of preprocessing techniques in developing precise models for the prediction of lime internal quality characteristics.

Virgin olive oil due to having unsaturated fatty acids is exposed to various types of corruptions such as enzymatic reactions and lipid oxidation. One way to prevent oxidation of oils and fats is addition of antioxidants. Rosemary due to phenolic compounds and other antioxidant compounds have antioxidant as well. In this study, the extraction phenolic compounds of rosemary leaves in virgin olive oil with was performed using by ultrasonic technique. In this method, rosemary leaves with three levels (5, 7 and 10%) and three ultrasonic times (10, 15 and 20 minutes) were added to the olive oil. Phenolic compounds present in the extracts, was measured. The results showed that in the ultrasonic method the sample of virgin olive oil with 10% rosemary and 10 minute extraction time has the highest total polyphenols (457.59 ppm). In this case study the effect of this extract in retarding oxidation of virgin olive oil during the 4-month by determining the peroxide value, thiobarbituric acid, oxidative stability, at the end of each month were reviewed. After four months keeping, the ultrasonic’s peroxide number, the thiobarbituric acid (20.75meq O2/kg oil, 1.32 molonaldehyde/kg oil, respectively) significantly decreased. The results of antioxidant activity of the extracts using rancimat method showed that during the period of induction at 110oC in the ultrasonic’s sample (29.10 hours) with respect to control's sample (6.28 hours) are increased. The acidity value of the ultrasonic's sample (2.05 FFA%) and thermal's sample (1.84 FFA%) are less than the control's (3.18 FFA%). Measurement results showed that the amount of chlorophyll pigments within ultrasonic’s sample (1.4mg/kg) had the highest value and with respect to control's sample (0.63mg/kg) had high value. Also in the sensory evaluation, the ultrasonic’s sample has top rated in terms of taste, odor, bitter and won general acceptance. Therefore, the phenolic compounds in the olive oil containing rosemary and extracted by ultrasonic method, be able to retard the oxidation process well. Thus, rosemary can be recommended as a source of natural antioxidants for increase virgin olive oil oxidative stability.

The use of Ultrasound in food industry is the main issue in research and development .Regarding to the wide application of modified starches in food industry and their associated hazards, the aim of this study was to investigate the possibility of modifying physicochemical properties of wheat starch by ultrasound treatment, so 6 samples of 10% wheat starch suspension was prepared and treated by 200 and 400 W ultrasound probe and also ultrasound bath for 15 and 30 minutes. Solubility, Swelling power, Oil absorption, Turbidity and SEM tests was performed to assess the physicochemical changes of ultrasound treated starches. According to the obtained results, the highest solubility and oil absorption and the lowest swelling power was related to the samples treated by 200W ultrasound probe. This sample also showed the most transparency after 15 min treatment and did not have any significant difference with control sample. Scanning electron microscopy images of samples also showed complete disintegration of the granular structure of the samples treated by 200 w ultrasound probe for 15 and 30 minutes while the structure of other samples were changed a little.

Ice cream is a complex food colloid including fat droplet and air cells that dispersed on the relatively frosted aqueous phase. Since ice cream is a multiphase material, the complex interactions among the phases can be happen that not yet well understood. Thus, there are many factors that influence on the texture and acceptability of ice cream. In this research investigated fat at the four level (2.5, 5, 7.5, 10%) and sugar at the three level (0, 50, 100%) and effect two types of hydrocolloids (carboxyl methyl cellulose and balangu) each at the four level (0.1, 0.3, 0.5, 0.7%) on the sensory properties fat reduced ice cream by response surface methodology. In this research, modeling Obtained responses from Sensory texture analysis are done by Quadratic and 2 Factor interaction equations. Grape juice is used as replace of sugar. Increase of gum concentration has significant effect on the viscosity and raising firmness and decreased sandiness and coldness. Grape juice due to raising isomeric diversity colloid system led to decrease sandiness of texture. Although ice cream prepared using 10% fat has grater point in the sensory properties compared to ice cream that containing 7.5% fat. But this difference was not significant. Balangu seed gum (BSG) in comparison to carboxyl methyl cellulose did not have a significant effect (P>0.05) on the sensory properties of ice cream and could use as a appropriate stabilizer. Result of sensory properties test (except consumer acceptability) used for modeling consumer acceptability by principal component analysis and coefficient of determination (R2) 96% obtained.

During the last decade, there has been growing interest in edible or biodegradable films based on biopolymers. Edible films and coatings are of interest since they have potential to improve shelf-life, maintain quality and prevent microbial deterioration and physical damage of foods. In this research, edible films based on red tilapia (Oreochromis niloticus) protein in the presence of cryoprotectants of sucrose and sorbitol at different levels (4%sucrose, 4% sorbitol, 2% sucrose+2% sorbitol, 4% sucrose+4% sorbitol) were prepared by casting method using glycerol as plasticiser. Films containing cryoprotectants, except for 4% sucrose, had lower tensile strength (TS) accompanied with higher elongation at break (EAB), compared with the control film (P<0.05). However with increasing in cryoprotectant levels, Water vapour permeability (WVP), film and protein solubility significantly increased. Regarding color, whiteness increased and yellowness declined as the cryoprotectants levels increased. Also, film with cryoprotectants had a smoother and more homogeneous surface without cracks. Results show that cryoprotectants present in the fish mince or surimi due to the plasticizing effect, directly affected properties of films.

Drying is one of the preservation techniques in which moisture removal through simultaneous heat and mass transfer occurs. Due to low energy efficiency and prolonged time of hot air drying, the new drying techniques such as infrared, must be employed. In this study, the effects of temperature and drying method on the kinetics of persimmon slices with 5 mm fixed thickness were investigated. The tests were performed at 3 temperature levels (50, 60 and 70oc) using both hot air and infrared dryers in 3 replicates. The experimental data obtained from drying treatments were fitted to 9 mathematical models in order to evaluate the drying kinetics of persimmon slices. The fitting quality of the proposed models was evaluated using the coefficient of determination (R2), root mean squares error (RMSE), chi- square (χ2) and sum square error (SSE). Based on the results, Wang and Singh model was found to be the best model fitted to the experimental hot air drying data at all temperature levels. In the case of experimental infrared drying data at 50 and 60oc, the logarithmic model showed the best fitting results while at 70oC, 2-term model showed the highest fitting quality. These models exhibited the highest value of R2 and the least RMSE, χ2 and SSE comparing to the other models.

The aim of this study was to analyze the components of Consumer behavior toward food waste. The study was a kind of applied and descriptive -correlational method. The research population was consumers of food products in Tehran city. Sample size was determine by Kerjice and Morgan table (n=384). Proportional stratified random sampling method was used. The research instrument was a researchermade questionnaire. Validity of the questionnaire was confirmed by a panel of expert in Agricultural Extension and Education Department, Tarbiat Modarres University. Reliability was conducted by a Pilot test and Cronbach’s alpha coefficient assumed (0.86) which show its suit for research conduct. Results of exploratory factor analysis revealed six components of consumer behavior: Cultural values, social participation, motivation, beliefs, education and awareness and perception which are composed of 60 percent of consumer behavior changes, explain.