فصلنامه علوم تغذیه و صنایع غذایی ایران
سال ششم شماره 4 (پیاپی 23، زمستان 1390)

Considering the high prevalence of hypertension and dyslipidemia in type 2 diabetic patients, the aim of the present study was to investigate the effects of probiotic yoghurt on blood pressure and serum lipid concentrations in these patients. In this controlled, double-blind, randomized clinical trial, 60 patients (23 males and 37 females) with type 2 diabetes and an LDL-cholesterol level higher than 100 mg/dL were assigned to one of two groups. Subjects in the intervention group consumed daily 300 gr of probiotic yoghurt containing Lactobacillus acidophilus and Bifidobacterium lactis, and those in the control group consumed daily 300 gr of conventional yoghurt, for 6 weeks. Dietary intakes, anthropometric measurements, blood pressure and serum lipids concentrations were measured at the baseline and at the end of the study. Statistical analyses were performed using the SPSS software, the statistical tests being analysis of covariance and paired-samples t-test. Systolic and diastolic blood pressure remained unchanged in both groups, while the total cholesterol and LDL-cholesterol concentrations decreased by 4.54% and 7.45% in the intervention group, respectively, as compared with the control values (P = 0.008 andP = 0.004, respectively). However, no significant differences were observed between the initial and final triglyceride and HDL-cholesterol concentrations in the intervention group. Consumption of probiotic yoghurt can decrease the total cholesterol and LDL-cholesterol in type 2 diabetic patients; however, it has no effect on blood pressure. This study shows that probiotic yoghurt may help reduce cardiovascular disease risk factors in type 2 diabetes.

Food poisoning caused by Listeriamonocytogenes results in death in 30% of the cases. Considering the high probability of L. monocytogenes contamination of local fish, the present study aimed at investigating the effects of thyme (Zataria multiflora Boiss) essential oil (EO) and nisin, individually and in combination, on the growth of L. monocytogenes in minced silver carp during refrigerated storage. Minced fish samples were inoculated with 1×104 cfu/g of L. monocytogenes. A total of 11 samples were inoculaetd with thyme EO at a concentration (weight/volume)of 0.3 %, 0.8 % or 1.2%, nisin at a concentration of 500 or 1000 IU/g, or a combination of the two. The treated and control samples were packaged in plastic bags and kept at refrigerator temperature for 12 days.. Samples were cultured on CHROMagarTM Listeria every 2 days and the bacteri counted. Nisin at two different levels (500 and 1000 IU/g)could not inhibit the growth of L.monocytogenes to a level below the acceptable level in raw food (100 cells/g). The antibacterial activity of nisin decreased during the storage period, while simultaneous use of nisin and thyme EO at a concentartion of 0.8 and 1.2% reduced L. monocytogenes viable count to a level below the acceptable limit during 12 days. A combination of 0.8% thyme (weight/volume)and 1000 IU/g nisin has the best inhibitory effect on growth of L. monocytogenes in minced silver carp during cold (4C) storage.

Dietary folate deficiency may contribute to tumorogenesis in many sorts of malignancies. By considering the increasing incidence rate of breast cancer in Iran, this study was conducted to investigate the association between dietary folate intake and breast cancer risk. aterials and In this case-control study, 177 patients with breast cancer and 169 control subjects with no family history of malignancy were recruited from hospitals affiliated to Shahid-Beheshti University of Medical Sciences, Tehran. Standard questionnaires were used to collect data on demographic characteristics, physical activity, and food frequency consumption for the previous year. Total daily energy and folate intakes were estimated using the Nutritionist IV software. No statistically significant correlation was observed between daily dietary intake of folate and breast cancer risk in the sample population. However, the results showed a significant inverse association between daily intake of dietary folate and risk of breast cancer in postmenopausal women (OR=0.17; 95%CI: 0.035-0.88). Increases in the strata of daily folate intakes were associated with decreasing trends of ORs in postmenopausal breast cancer risk (Pfor trend =0.036), where the OR of folate intake at the 2nd tertile was 0.26 (95%CI: 0.05-1.22) and at the 3rd tertile was 0.17 (95%CI: 0.035-0.88). Based on the findings, folate intake was not correlated with breast cancer risk in the total sample population, whereas higher intakes of folate was inversely associated with postmenopausal breast cancer risk.

Frozen yogurt is obtained by freezing a mixture containing milk fat, milk solids-non-fat (MSNF), sweeteners, stabilizers, and yogurt. Increased milk solids-non-fat is one way to avoid undesirable changes in texture observed in low-fat products. Thisincrease in MSNF also helps greatly improve health properties of these products. Since frozen yogurt is considered a low-fat dessert, in this study the effects of milk solids-non-fat content on its physical, chemical and sensory characteristics were investigated.

Ingredients included milk (2.5% fat and 8% solids-non-fat), skim milk powder (98% solids-non-fat), cream (30% fat), starter yogurt (DVS Lat 1/63, including Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp.bulgaricus), sugar, vanilla powder, and panisol ex. All samples contained 8% fat, 13% sugar, 0.3% stabilizer and 0.09% vanilla. To produce test samples,the milk solids-non-fat content was adjusted at 13%, 16% and 19% levels with skim milk powder. Statistical analysis of the data was performed by completely randomized two-factor design with 3 replications using the MSTAT-C software, and analysis of variance was done with Duncan’s multiple range test (p<0.05). For drawing diagrams the Excel software was used.

Titratableacidity, pH, viscosity, overrun capacity and melting characteristics of ice cream were influenced favourably significantly (p<0.05) by increasing MSNF. Increasing the MSNF content significantly (p<0.05) decreased pH, overrun capacity and resistanec to melting of ice cream, while it increased titratable acidity and viscosity. The dataalso showed that samples with 13% MSNF resulted the highest scores in texture and total acceptance (p<0.05).

Increases in milk solids-non-fat content of frozen yogury affects favourably its properties. Based on the findings in this study, 13% MSNF is suggested for producing concentrated frozen yogurt.

The purpose of this study was to determine the effect of dietary supplementation with zinc, magnesium and zinc plus magnesium on muscle strength in active women.

Forty active women selected randomly were randomly divided into 4 groups of 10 each, all undergonig resistance training and receiving, daily, a supplement of either zinc (50 mg zinc sulfate), magnesium (250 mg magnesium oxide), or zinc plus magnesium (50 mg zinc sulfate plus 250 mg magnesium oxide), or no supplement (control group). All the subjects had a history of sports activity. Blood samples were collected and 1-RM was measured at the beginning and after 8weeks.

Independent and paired-sample t-test showed that zinc, magnesium and zinc plus magnesium supplements had no statistically significant effects on the strength of lower body muscles. However, the magnesium supplement had a significant positive effect on the strength of upper body muscles (chest, back, as well as back and hand bending muscles). In addition, the zinc and zinc plus magnesium supplements affected significantly the strength of the back and hand bending muscles. Further analysis of the data showed that the zinc plus magnesium supplement had no significant effect on the serum zinc and magnesium concentrations.

Dietary supplementation with zinc, magnesium and zinc plus magnesium can effect desirably the upper body muscles strength in active women. Keywords:

In the recent years, hydrocolloids have been the subject of much investigation as functional foods. In the present study beta-glucan was acid-extracted from barley and its effects on some rheological properties of wheat flour were investigated.β-glucanwas extracted from whole barley flour by the acid-extraction method. The total β-glucan content of the extracted gum was determined using the Megazyme assay kit. The β-glucan gum obtained was added to 3 samples of wheat flour, namley Nol, Setareh, and their Mix (50:50) flours at a level of 0.0%, 0.5%, or 1%. Doughs wer prepared from the what flour samples and theirrheological properties investigated. The SPSS software was used for data analysis. A completely randomized design was used for the experiment, the means being compared using the LSD test. The rheological behavior of β-glucan-enriched doughs depended on flour quality and β-glucan concentration. All the farinographic characteristics, specially water absorption, improved with increasing β-glucan concentration. Extensograph results also showed that resistance to extension and extensibility increased with increasing β-glucan concentration. The mix flour with 1% β-glucan showed the best rheological properties (p<0.05). In all the treatments addition of beta-glucan increased water absorption, dough resistance time, dough development time, extensibility, resistance to extension, and the surface area under the curve, and it decreased dough loss. Beta-glucan at1% level showed better rheological properties as compared to the 0.5% sample. Overall, considering all the chemical and rheological tests, it can be concluded that addition of 1% beta-glucan to mix flour results in the best treatment, although it is not the most effective.

Little information is available on the effects of monounsaturated fatty acid-rich (MUFA-rich) diets on the serum adipocytokine levels. The objective of this study was to determine the effects of a MUFA-rich diet on the serum levels of insulin, visfatin and IL-6 in overweight women (25.0≥ BMI ≥ 2.9.9). This randomized cross-over clinical trial included 17 overweight women aged 20-50 years with a mean BMI of 27.6±2 kg/m2. The participants were randomly assigned to one of two groups consuming either a saturated fat-rich (SFA-rich; 16% SFA and 8% MUFA) or a MUFA-rich (16% MUFA and 8% SFA) diet for 6 weeks, with a 2-week washout period between the 2 periods. The percentages of energy derived from the other macronutrients were similar in the two diets. Biochemical assessments were done at the beginning and at the end of each period. Paired t-test was used for statistical analysis. The mean proportions of MUFA intakes were 13% and 7% of the total energy intake for MUFA- and SFA-rich diets, respectively, the corresponding values for SFA being 8.5% and 14%. The mean changes in the serum visfatin, insulin and IL-6 levels were not significantly different between the two diet periods; however, for serum visfatin levels, the difference (0.7± 0.5 vs 0.4± 0.4 nanogr/ml) was marginally significant (P=0.08). Adjustment for potential confounders did not alter these findings (P=0.1). The difference between the two diets as regards their effects on the serum insulin and adipocytokine levels did not reach statistical significanec (it was only marginal). We recommend conducting long-term interventional studies with larger sample sizes to be able to draw more definite conclusions.

French fries are a food product with an upward consumptuion trend in Iran. Because of high oil uptake during frying, French fries are an energy-dense food item, providing a very large number of calories to the body. Therefore, efforts to reduce the rate of oil uptake by this popular food item would contribute to the public’s health. The purpose of this study was to determine the effects of blanching and coating of potatoes with methyl cellulose and tragacanth on French-fries oil uptake and qualitative properties. Strips of potato (Agria variety) were prepared, blanched in water or a calcium chloride solution (0.5%), coated with a solution of methyl cellulose (0.5, 1.0 and 1.5%), tragacanth (0.5, 1.0 and 1.5%), methyl cellulose (0.5, 1.0 and 1.5%) and sorbitol (0.5%), or tragacanth (0.5, 1.0 and 1.5%) and sorbitol (0.5%) and deep-fried. Oil uptake, moisture content, and color of the French fries were measured and their sensory properties determined and compared with those of control samples. Blanching and hydrocolloid coatings of the samples brought about a decrease in oil uptake and increases in moisture content and texture tenderness of the potato strips (p<0.01). Blanching in calcium chloride alone reduced oil uptake by 8.61%. In comparison with the control samples, coating with methylcellulose (1.5%) with sorbitol (0.5%) decreased oil uptake from 19.85% to 16.29%. Blanching in calcium chloride resulted in a significant 5%increase in moisture content. The hydrocolloid coatings caused significant increases in moisture content and resistance to cutting of the samples (P<0.01), such that the highest moisture content (44.60%) was obsereved in the samples coated with methyl cellulose (1.5%). Tragacanth at aconcentartion of 1.5% with sorbitol at a concentartion of 0.5% brought about the highest resistance (211/13 Newton) to cutting. The findings also showed that hydrocolloid coatings resulted in significant incremets in the L * b *, a * factors of the French fries color as compared to the control samples. However, there were no significant differences among samples with regard to sensory characteristic. It can be concluded that methylcellulose is a more suitable coating than tragacanth for French fries. A coating containing 1.5% methyl cellulose is the best coating for potato strips due to less oil uptake, higher moisture content, and better texture and color. Coatings of methylcellulose and tragacanth plus sorbitol result in noticeabe differences in oil uptake and other qualitative properties. However, for economic reasons it is not essential to use sorbitol in coatings for potato strips.

This study was conducted to determine the relationship between stunting and major dietary patterns among the first-grade pupils in Tehran in 2008. In this case-control study, children’s height (n=3147) was measured in 5 areas of Tehran by expeienced nutritionists using standard protocols. Children with a height lower than the 5th percentile of height for age of the CDC2000 standard were considered as stunted (n = 86, the case group). Control children were selected randomly from among healthy, non-stunted children with the same age and sex (n=308). Data on demographic characteristics, socio-economic status, birth weight and length, and duration of breast feeding were collected using standard questionnaires. In addition, two 24-hour dietary recall questionnaires were completed for each subject on 2 cosecutive days by interviewing their mothers. Factor analysis was used to identify major dietary patterns. Logistic regression models were adjusted for sex, mother's age and education, father's education, birth weight, family size, and energy intake. There were significant differences between the stunted children and their control group with regard to sex, birth weight, age of mother, and parent's education of (P<0.05). Based on the 24-hour dietary recalls, the mean consumptions of dairy products (308±167 g/day) and dried fruits and nuts (2.58±9 g/day) in the case group were significantly lower than the respective control values (7.15±26 and 382±232 g/day, respectively; p<0.05). However, consumption of the fat and oils group in the case group (37.85±29 g/day) was higher than in the control group (30.94±22 g/day; P< 0.05). Three dietary patterns were identified using factor analysis: dietary pattern 1, high in bread, potatoes, fats, eggs, relish, other vegetables, sugar, and soft drinks; dietary pattern 2, high in leafy vegetables, fast foods, nuts, other cereals, fruits, legumes, and offal; and dietary pattern 3, high in biscuits and cakes, chicken, dairy products, fruits, etc. Dietary patterns 1 and 2 were not significantly associated with stunting, while children in the third quartile of dietary pattern 3 had a lower risk for stunting as compared to those in the first quartile of that dietary pattern (p<0.05). It seems that following dietary patterns high in protein (e.g., dairy and meat products) and carbohydrate (e.g., fruits and biscuits/cakes) may reduce the risk of stunting in children.

Starch is one of the most abundant carbohydrate biopolymers with excellent film-forming properties. However, it has a poor resistance to water vapour and poor mechanical properties. The objective of this studt was to determine the effects of glycerol, oil and salep on the film properties of starch. Edible films based on mixtures of starch and salep (an Iranian gum) were prepared and their properties (mechanical and optical charactersitics, solubility, and water vapor permeability (WVP)) investigated. The mixtures were as follows: potato starch and salep (1-5%), potato and glycerol plasticizer (10-40%), and potato and sunflower oil (0-20%). The results showed that the physical and mechanical properties of potato starch-based edible films were affected by the their contents of salep, glycerol, and sunflower oil. The salep gum increased tensile strength, elastic modulus, and C*, but reduced elongation at break and L*, while glycerol reduced tensile strength, elastic modulus, and UV transparency but increased elongation at break, L*, opacity, solubility and WVP. On the other hand, sunflower oil decreased elongation at break, tensile strength, elastic modulus, UV transparency, solubility, and water vapor permeability, but it increased opacity. Based on the findfings, it can be concluded that the optimum contents of salep, glycerol, and sunflower oil in potato starch-based edible films are 3%, 32%, and 8%, respectively.