فصلنامه علوم تغذیه و صنایع غذایی ایران
سال دهم شماره 3 (پیاپی 40، پاییز 1394)

In this study، the effect of improvement of vitamin D status on glycemic status، lipid profile and endothelial biomarkers in T2D subjects was investigated. Subjects with T2D were randomly allocated to one of the two groups to receive either plain yogurt drink (PYD; containing 170 mg calcium and no vitamin D/250 mL، n= 50) or vitamin D3-fortified yogurt drink (FYD; containing 170 mg calcium and 500 IU/250 mL، n = 50) twice a day for 12 weeks. Anthropometric measures، glycemic status، lipid profile، body fat mass (FM) and endothelial biomarkers were evaluated at the beginning and after the 12-week intervention period. Intervention resulted in significant differences in changes of endothelin-1، E-selectin and MMP-9 concentrations in FD compared to PD (-0. 35 ± 0. 63 versus -0. 03 ± 0. 55، P= 0. 028; -3. 8 ± 7. 3 versus 0. 95 ± 8. 3، P = 0. 003 and -2. 3 ± 3. 7 versus 0. 44 ± 7. 1 ng/mL، respectively، P < 0. 05 for all). Even after controlling for changes of QUICKI، FM and waist circumference remained significant for endothelin-1 and MMP-9 (P = 0. 009 and P = 0. 005، respectively). Ameliorated vitamin D status was accompanied by improved glycemic status، lipid profile and endothelial biomarkers in T2D subjects. The research findings suggest both direct and indirect ameliorating effects of vitamin D on the endothelial biomarkers.

Different varieties of peppers have wide applications in traditional medicine. There are evidences that peppers affect some of cardiovascular diseases risk factors. The present study investigated the effect of oral red and black pepper powders on the serum levels of blood lipid profile in animal model. In this study, two groups were used as post-test with control group. Twenty one NMRI male mice were weighed and randomly divided into three groups (n=7), including a control group, fed no chili (pepper) diets, and two experimental groups, fed the red pepper and black pepper powders, each mixed with standard pellet food at a ratio of 1/15 (6/6% of the weight of food) for one month. At the end of the 30-day treatment period, the body weight of the experimental animals was determined under deep anesthesia by chloroform. Then blood samples were collected from the heart directly. Serum levels of total cholesterol, LDL-c and HDL-c were determined by colorimetric method. Black pepper significantly reduced weight, total cholesterol and LDL-c, and increased the HDL-c/LDL-c ratio (p=0.003, p=0.009, p=0.001 and p=0.01, respectively). Red pepper decreased weight and total cholesterol significantly (p=0.01, and p=0.009, respectively). Black and red peppers in nutrition regime can cause a reduction of weight and blood cholesterol. Cholesterol lowering properties in consumption of black pepper show better than consuming red pepper in diet.

Several studies have shown that parents of overweight/obese children sometimes perceive their child's weight as normal. This can affect their level of concern and follow ups to correct their child's weight. This study aimed to evaluate association between maternal weight status and self-efficacy in controlling child’s weight-related behavior with their perception of their child's weight status. A total of 159 overweight/obese first grade students and their mothers from two districts of Tehran city were studied. Their height and weight were measured, and maternal BMI and children's BMI z-scores were calculated. Socio-demographic characteristics of the family, mother's self-efficacy and perception of their child's weight were assessed by a questionnaire through interview. Logistic regression analysis was used to evaluate factors effecting mother's perception. Mean age of children was 6.7±0.34 years. Among the children, 20.1% were overweight and 79.9% were obese, while 48% and 35% of the mothers were overweight and obese, respectively. About 77% of the mothers had misperception about their child's weight status. There was no significant relationship between the mother's occupation, education and weight status with misperception of child weight. Maternal self-efficacy in controlling the child’s weight related behaviors was low in 23.8% of the mothers; while it was medium and high in 50.3 and 25.8%, respectively. There was a reverse but insignificant association between self-efficacy and weight status of children. Considering the critical role of parents, especially mothers in the process of child obesity management, informing mothers on the definition and importance of desirable body weight in children and proper means to combat it is a priority.

Sometimes, in professional soccer, the football match is held three times in a week. Since soccer is a relatively intensive exercise that may cause inflammatory responses of the immune system, so nutritional supplements consumption could help to recover faster. This study investigated the effects of two-week Taurine supplement consumption and three sessions of 90-minute alternative intensive exercise on the serum levels inflammatory cytokines (IL-6, TNF-α) in elite soccer players. Twenty four football players under 21 years old were selected and divided randomly into taurine, placebo and control groups. The Taurine group received 1.5 g taurine supplement 3 times daily, and the placebo group received the same amount of aspartame; both groups preformed three times of 90-minute specific soccer exercise protocol. The control group did not receive any supplement, and just followed their ordinary program. Blood samples were taken in six steps (48 h before the period, before and immediately after the first and third exercise protocols and 48 h after the end of the period).The one way ANOVA with repeated measures and Tukey’s post hoc test were used to compare the means in each group. The results of each step showed that serum levels of IL-6 and TNF-α increased immediately after the exercise protocols (in steps 3 and 5). Whereas, combined study of periods and groups indicated that IL-6 level significantly increased in the control and placebo groups (P=0/043). Also TNF-α level showed significant difference (P=0/013) in the control and placebo groups (P=0/008). It appears that the three times of 90-minute soccer specific protocol a week put pressure on the soccer players’ inflammatory system that may repeat frequently in the competition season. On the other hand, the results showed that taurine supplementation has anti-inflammatory effects before and during this period, and prevents significant alterations of the mentioned cytokines. Thus, short-term taurine supplement consumption could be recommended to elite soccer players during the high pressure competition and the training weeks.

Today nutritionists use dietary pattern to find out the effect of food in health. Most common statistical methods to determine dietary pattern are factor analysis and cluster analysis.Mixture models are a combination of k probability distribution with different probability and provide a parametric model for unknown distributional shapes. Recently mixture model as the third method is used to determine dietary pattern. Then we compared this new method with other two methods available for this purpose. We analyzed data from 25 food groups of 400 high school girls in Ahar (Rashidi’s data), and compared the results of factor analysis, cluster analysis and multivariate normal mixture model for dietary pattern. Selection of the best mixture model was done by AIC and BIC criteria. Three, two and five dietary pattern were obtained from factor analysis, cluster analysis and normal mixture model, respectively. Prevalence of these dietary patterns in normal mixture model was 6%,12%,34%,28%, and 20%, respectively. It is concluded that mixture model has two advantages over the two other methods. First, the proportion of each pattern in population is known and secondly, the average of consumption of each food group gets clear; so more information can be obtained compared to the usual methods.

Lighvan cheese is one of the most popular traditional Iranian cheese due to its excellent taste and flavor. It is traditionally made from unpasteurized (raw) milk, thus, the presence of pathogen and spoilage microorganisms in the fresh final product is inevitable. The aim of this study was to evaluate the use of active LDPE based nanocomposite films containing different metallic and clay nanoparticles in packaging of Lighvan cheese. Cheese packages were prepared from nanocomposite films and stored at 4 oC. Physical and chemical analyses and microbial tests of the packed cheeses were done immediately after packaging (at day 0), and after 7, 14, 21 and 28 days of storage. After 28 days of storage, the growth rate of coliformbacteria and Staphylococcus aureus was significantly (p<0.05) decreased as a result of application of nanocomposite package containing nanometals; however, it did not affect the growth of lactic acid bacteria. The results of migration test of nano-metal particles from package into a food simulant showed that nanocomposites containing metal nanoparticle was safe according to the limits set by FDA and EFSA. Packaging containing nanoclay modified with nano-Ag and nano-CuO would reduce coliform bacteria and Staphylococcus aureus with no detrimental effect on cheese micribiota.

High consumption of some foods and condiments encouraged researchers to use these foods as carrier of functional compounds. The main aim of this research was to evaluate the feasibility of mayonnaise formulation incorporated with flaxseed powder. Flaxseed powder at four levels (4%, 8%, 12% and 16%) was added to low-fat mayonnaise, stored for three months and were compared with control sample. Mayonnaise samples at 4°C and in accelerated state at 55°C were evaluated regarding oil separation and powder settlement. Change in fatty acid profile was determinad by gas chromatography. Acid and peroxide values were also evaluated. Acceptability of all samples was compared by panelists. The obtained results showed that all samples were stable in three months, and there were no oil separation and settlement of flaxseed powder. GC results indicated that by increasing the flaxseed powder, contents of palmetic acid, oleic acid, stearic acid, linoleic acid were decreased but the alpha-linolenic acid had a significant increase. Acid and peroxide values increased during the storage but they were not more than 0.29 (mg KOH/g oil) and 2.07 (meq O2/kg oil), and were in normal range. The average of panelist's scores indicated that treatment with 8% flaxseed was more acceptable among samples. Conclution: Mayonnaise is a good carrier for flaxseed powder, and by addition of flaxseed powder to the mayonnaise formulation, it is possible to produce product with suitable quality and fortified with essential fatty acids.

Dough is an intermediate product of bakery production that represents physicochemical properties of raw materials and also qualitative aspects of the final product.Due to the high performance of artificial neural networks in educability and parallel processing of data with non-linear relations, the purpose of present research is providing suitable models for predicting rheological properties of dough based on the physicochemical properties of flour. A range of flour samples produced in the factories of various regions and provinces of Iran were collected and seven physicochemical properties of them were evaluated. Oscillatory tests of stain and frequency sweep were done on the dough of samples, and two important parameters of them were selected for modeling. After training, and determining the specifications of networks with genetic algorithm and testing them, the sensitivity of output to input parameters was evaluated. Developed networks are four-layer perceptrons in which the first network, with removing gluten index and particle size index of flour, has 5 neurons in input layer and 15 neurons in the first and second layers for prediction of the incept, and the second has 7 neurons of input layer, 24 neurons in the first hidden layer and 17 neuron in the second hidden layer for predicting the slope of fitted model on frequency sweep. Developed networks predict rheological properties of dough with correlation coefficient more than 97%. Gluten index and zeleny number are introduced as important parameters on changing the rheological properties of dough. Artificial neural network-genetic algorithm is a powerful method in predicting dough's rheological properties. Sensitivity analyses of optimum network indicate in the importance of flour's physicochemical properties in predicting the changes in the fundamental rheological properties of dough.

One way to protect the oil against oxidation is using antioxidants. Since the most used synthetic antioxidants are harmful to health, due to safety concerns, there is an increasing trend among food scientists to replace synthetic antioxidants with natural ones, which, in general, are supposed to be safer. Walnut hulls, due to having high antioxidant effects, is a good choice as a natural antioxidant. The aim of this study, is investigation of the antioxidant effects of the extract and powder of green walnut hall on the oxidation of sunflower oil. Green walnut hull extract was prepared with Maceration and Soxhlet extraction methods and the amount of phenolic compounds and antioxidant activity, respectively, was determined by Folin-Ciocalteu and DPPH radical trap methods. Antioxidant effects of different concentrations (100, 250, 500 and 1000 mg/kg) of green hull extract and powder (500 and 1000 mg/kg) were compared with the control and artificial antioxidant TBHQ in the maximum limit amount (200 mg/kg) through evaluation of acidity, peroxide value and thiobarbituric (TBA) on days 0, 5, 10 and 15 days of storage at 70°C. The amount of total phenolics and flavonoids for Maceration method was 17.81 and 1.59 and for Soxhlet method was 98.07 and 38.7, respectively, on the basis of gallic acid and catechin (mg/g sample) for phenols and flavonoids obtained. The walnut hulls’ EC50 was 0.15 mg/ml. The data showed that peroxide value and thiobarbituric oxidation rate increase over time, but the samples containing extract and powder of walnut hulls compared to the control in most concentrations showed less oxidation. The use of high concentrations of green walnut hull extract increased oil oxidation, and the best result was obtained for 100 mg/kg that could well slow the oxidation process and compete with TBHQ at 200 mg/kg. Soxhlet extraction method leads to higher levels of polyphenols than the Maceration method. Less concentration of green hull extract is more effective than higher concentrations in reducing oxidation. Green walnut hull is presented as a source of high antioxidant effect with low price to replace with synthetic antioxidants.

Replacing milk saturated fatty acids with vegetable oil can be a good way for reducing the risk of hypercholesterolemia and improving cardiovascular health. This study was carried out to determine the effects of using grapeseed oil on the sensory and physicochemical properties of ice cream. Milk fat was replaced with milk fat at 5 levels of grapeseed oil (0%, 20%, 40%, 60% and 80% (w/w)). The samples were subjected to physicochemical analysis (pH, titratable acidity, overrun, meltdown, texture and viscosity) and sensory evaluation (color, hardness, viscosity, meltdown, flavor and overall acceptability). The results showed that low levels of grapeseed oil had no significant effect on pH and acidity but at 80%, it significantly reduced the pH and increased the acidity of ice cream. Increasing in the concentration of grapeseed oil was accompanied by decreasing the overrun, meltdown, texture, viscosity, pseudoplasticity and consistency index, and increasing the flow index. The effect of grape seed oil on sensory properties such as smoothness, hardness and color was not significant, and only at 80% of oil, it decreased the acceptance level of viscosity, meltdown and overall acceptability (p<0.05). Grapeseed oil at lower level of 40% replacing had no significant effect on the flavor of ice cream (p>0.05). Incorporation of grapeseed oil in ice-cream to replace milk fat could affect the physicochemical properties of ice-cream. Considering that addition of grapeseed oil at 40% level did not have any adverse effect on the sensory qualities, consumers may enjoy the health benefits of essential fatty acids and antioxidants of grape seed oil in ice cream.

Listeria monocytogenes is a psychrophilic bacterium with drought-resistant characteristics and also stable in osmotic stress; these abilities of Listeria make it grow in food stuff, leading to contamination. The aim of this study was to assess the frequency of Listeria species in raw milk and traditional unpasteurized dairy products in Isfahan, Iran. A total of 292 samples of raw milk and traditional, unpasteurized dairy products was examined for presence of Listeria spp. using a two-step selective enrichment recommended by USDA. All isolates were subjected to standard biochemical test. L. monocytogenes strains were further confirmed by PCR amplification. Of 292 samples, 21 (7.19%) and 4 (1.36%) were positive for Listeria spp. and pathogenic L. monocytogenes, respectively. The prevalence of Listeria spp. in raw milk, ice cream, cream, and freni was 5/91 (5.49%), 12/63 (19.04%), 3/27 (11.11%) and 1/25 (4%), respectively. Listeria was not detected from yogurt, butter, kashk, and cheese. Listeria innocua at 16/21 (5.44%) was the most prevalent species isolated, followed by L. monocytogenes at 4/21 (19%) and L. seeligeri at 1/21 (4.7%). All strains of L. monocytogenes identified by biochemical tests were also confirmed by PCR. The study shows the prevalence of L. monocytogenes in raw milk and traditional dairy products sold in the market. Consumption of raw milk with mild heat treatment or its usage in traditional dishes is a common practice in Iran. Therefore, the lack of appropriate control measures could pose serious health problems. The lack of knowledge of the risks of Listeriosis transmission indicates the need for implementation of a food safety education program. In addition, the Iranian food safety authorities should urgently set up an effective standard to screen all susceptible food products for presence of Listeria.

Due to the climate variation and extension of traditional animal husbandry in Iran, investigation on the physicochemical, microbial and technological characteristics of different kinds of traditional cheese is crucial. In this study, the effect of milk type and fermentation time on the physicochemical, sensorial and rheological properties of Shiraz cheese- soft cheese produced in western Iran- were investigated. Shiraz traditional cheese was produced from bovine and ovine milk with 4 and 6 hour fermentation times. The physicochemical, rheological and sensorial properties of the cheese samples were analyzed with completely randomized design with three replicates.. According to our results, when fermentation time increased, the amount of protein, fat, dry matter and pH of the cheese samples was decreased. Shiraz cheese produced from ovine milk has higher protein, fat and dry matter than bovine cheese. Rheological tests showed that storage modulus (Ǵ) and loss modulus (G̋) of the ovine Shiraz cheese samples were higher than those of bovine samples in each frequency, and when the fermentation time was increased, storage and loss modulus were increased too. The sensorial characteristics –taste and texture- of the ovine Shiraz cheese were improved significantly when the fermentation time was increased. The results showed that the physicochemical, rheological & sensorial properties were affected by the milk type and fermentation time. Ovine Shiraz cheese with 6 hours fermentation had firmer and better texture than bovine Shiraz cheese.