Fat Yogurt Research Articles

Decomposition of Cost Structure and Evaluating Operational Feasibility of Low Fat Yoghurt Ice Cream

Ice cream and frozen desserts are one of the most dynamic sectors of the Indian dairy industry growing at an annual growth rate of 12–15 percent (IICMA, 2012) where maximum value-addition has taken place in last few decades. The objective of this paper is to calculate the cost of production of a newly developed product ‘low fat yoghurt ice cream ’and delineate the cost components in detail. To achieve this, process wise and component wise cost analysis was undertaken to arrive at the most accurate cost estimate of the product. Further, break even output was calculated to reach an estimate of the minimum amount of output needed for the economic viability of the enterprise. Based upon an initial premise comprising of a set of assumptions related to the plant and manufacturing facility, we are able to bring forth a realistic estimate of the product cost. For establishing a 1000 litres per day ice cream plant, start-up investment-to the tune of 01.19 Crores and total operating expenses of jjl.17 lakhs would be required for the per batch production of low fat yoghurt ice cream mix. The gross return per batch (for a batch size of 1000 litre) was worked out to be [J.13 lakhs. Batch size of 1000 litres per day ice cream mix production was found to be well above the break even output.

Effect of exopolysaccharide-producing starter cultures and post-fermentation mechanical treatment on textural properties and microstructure of low fat yoghurt

The microstructure and texture of yoghurts produced by four different exopolysaccharide (EPS)-producing starter cultures and mechanically treated post-fermentation at four levels of intensity (applied back-pressure) were studied. Two Lactobacillus delbrueckii ssp. bulgaricus (LB) strains were used in combination with two Streptococcus thermophilus (ST) strains and yoghurts were formulated by pairwise combining one LB and one ST strain. The choice of ST strain was the major determinant for the rheological properties of the yoghurts, since one of the ST strains conferred a ropy texture and resulted in yoghurts with decreased water holding capacity and an open microstructure. In addition, one of the LB strains used produced both aggregated and threadlike EPS and improved water holding. When combined with an ST strain that produced neglible amounts of EPS this LB strain resulted in yoghurt where a moderate mechanical treatment post-fermentation was able to further improve the water holding capacity.

Microbiological, functional and rheological properties of low fat yogurt supplemented with Pleurotus ostreatus aqueous extract

Pleurotus ostreatus aqueous extract was incorporated to milk aiming to produce a yogurt with different functional and rheological characteristics. Viable counts of Streptococcus thermophilus and Lactobacillus bulgaricus, pH, lactic acid production, changes in rheological and structural properties (syneresis, texture profile analyses, color and microstructure), antioxidant capacity and total phenolic were followed throughout 28 days of cold storage. Addition of POE increased S. thermophilus and L. bulgaricus CFU counts. Low fat yogurts with POE exhibited lower syneresis and firmness, but more adhesiveness, springiness and cohesiveness than control. Supplemented yogurts were darker, contained more polyphenols and exhibited higher antioxidant activity than controls in cold storage. Overall, the results indicated that POE can be used to manufacture low fat yogurt with functional activity and at the same time modifies rheological properties.

The Association of Dairy Intake With Metabolic Syndrome and Its Components in Adolescents: Tehran Lipid and Glucose Study.

Background:Epidemiological studies have shown that consumption of dairy product plays an important role in prevention and treatment of Metabolic Syndrome (MetS).Objectives:The objective of this study was to examine the association of dairy intake with MetS and its components in Tehranian adolescents.Patients and Methods:In this cross-sectional study, 785 adolescent aged 10 to 19 years, participated from the fourth phase of the Tehran Lipid and Glucose Study. Usual dietary intake was assessed using a valid semi quantitative food frequency questionnaire. Total dairy, low fat and high fat dairy, milk, yoghurt and cheese were evaluated. Assessment of anthropometric, biochemical and blood pressure was performed and MetS was defined according to the de Ferranti criteria.Results:The mean age of subjects was 14.8 ± 2.9 years. The prevalence of MetS was 22.2% (girls: 19.5% and boys: 25.2%). The most prevalent risk factor for MetS in boys was high waist circumference (53.4%) and among girls was low HDL-C (53.1%). Energy density and intake of protein, total fat, saturated fat, cholesterol, calcium and phosphor were higher in the highest quartile of dairy consumption than the lowest quartile. After adjustments for confounders, odds ratios with 95% confidence interval for MetS in the highest quartile of total dairy, low fat dairy, high fat dairy, milk, yoghurt and cheese compared with lowest quartile were respectively 0.97 (0.57 - 1.66), 1.44 (0.83 - 2.49), 0.97 (0.56 - 1.67), 0.70 (0.42 - 1.18), 1.62 (0.99 - 2.64) and 0.72 (0.44 - 1.18).Conclusions:Results of this study did not support the hypothesis that dairy products consumption protects against MetS and its components.

Effects of vitamin D-fortified low fat yogurt on glycemic status, anthropometric indexes, inflammation, and bone turnover in diabetic postmenopausal women: A randomised controlled clinical trial

Low levels of serum 25-hydroxy vitamin D (25(OH)D) are common in type 2 diabetic patients and cause several complications particularly, in postmenopausal women due to their senile and physiological conditions. This study aimed to assess the effects of vitamin D-fortified low fat yogurt on glycemic status, anthropometric indexes, inflammation, and bone turnover in diabetic postmenopausal women. In a randomized, placebo-controlled, double-blind parallel-group clinical trial, 59 postmenopausal women with type 2 diabetes received fortified yogurt (FY; 2000IU vitamin D in 100g/day) or plain yogurt (PY) for 12 weeks. Glycemic markers, anthropometric indexes, inflammatory, and bone turnover markers were assessed at baseline and after 12 weeks. After intervention, in FY group (vs PY group), were observed: significant increase in serum 25(OH)D and decrease of PTH (stable values in PY); significant improvement in serum fasting insulin, HOMA-IR, HOMA-B, QUICKI, and no changes in serum fasting glucose and HbA1c (significant worsening of all indexes in PY); significant improvement in WC, WHR, FM, and no change in weight and BMI (stable values in PY); significant increase of omentin (stable in PY) and decrease of sNTX (significant increase in PY). Final values of glycemic markers (except HbA1c), omentin, and bone turnover markers significantly improved in FY group compared to PY group. Regarding final values of serum 25(OH)D in FY group, subjects were classified in insufficient and sufficient categories. Glycemic status improved more significantly in the insufficient rather than sufficient category; whereas the other parameters had more amelioration in the sufficient category. Daily consumption of 2000IU vitamin D-fortified yogurt for 12 weeks improved glycemic markers (except HbA1c), anthropometric indexes, inflammation, and bone turnover markers in postmenopausal women with type 2 diabetes. www.irct.ir (IRCT2013110515294N1).

Improving the structure and rheology of high protein, low fat yoghurt with undenatured whey proteins

The objective of this study was to investigate the effects of whey protein denaturation and whey protein:casein-ratio on the structural, rheological and sensory properties of high protein (8% true protein), low fat (<0.5% fat) yoghurt. Yoghurt milk bases were made by adding undenatured whey proteins from native whey protein concentrate (NWPC) to casein concentrate in different whey protein:casein-ratios. The degree of whey protein denaturation was then controlled by the temperature treatment of the yoghurt milk bases. Addition of NWPC in low (whey protein:casein-ratio 25:75) or medium levels (whey protein:casein-ratio 35:65) in combination with heat treatment at 75 °C for 5 min gave yoghurts with significantly lower firmness, lower storage modulus (G′), and better sensory properties (less coarse and granular and more smooth), compared with corresponding yoghurts produced from yoghurt milk bases heat-treated at 95 °C for 5 min or with control yoghurts (no addition of NWPC).

Is there any relationship between food habits in the last two decades and gastric cancer in North-Western Iran?

The aims of this case-control study were to assess the correlation between some food habits in the last two decades and gastric cancer in East Azerbaijan of Iran. In this hospital based case control study, 616 patients (212 gastric cancer patients, 404 cancer free patients) were recruited. Food habits of patients over the past two decades were assessed with a structured questionnaire. We used conditional logistic regression analysis for estimating crude and adjusted odds ratios (OR) and their respective 95% confidence intervals (95%CI). In this study, over-eating, consumption of high fat milk and yogurt and especial types of cheese increased the risk of gastric cancer (All<0.05). Consumption of such especial cheeses such as Koze and Khiki increased the risk of gastric cancer by 12.6 fold (95% CI:1.99-79.36) and 7.36 fold (95% CI:1.33- 40.54), respectively. In addition, high fat food, moldy food, and pickled vegetables consumption as well as reuse of cooking oil for frying were significantly associated with gastric cancer risk. Furthermore, intake of Ghorme (deep fried meat) was positively correlated with gastric cancer risk (OR:1.31;95%CI: 0.91-1.87). It can be confirmed that particular food habits which have been very common in East-Azerbaijan in the last two past decades increase risk of gastric cancer. According to our results and taking into account the long latency period of gastric cancer it can be concluded that nutrition education for a healthy diet should be performed from early childhood. However, further well designed cohort studies are needed to achieve more clear results.

Recommended dairy product intake modulates circulating fatty acid profile in healthy adults: a multi-centre cross-over study.

Dairy products are rich sources of an array of fatty acids (FA) that have been shown individually and in certain clusters to exert varying effects on cardiovascular health, for which the circulating lipid profile is a powerful biomarker. Whether the profile of these FA is reflected in blood upon short terms of intake, possibly contributing to the lipid-related health impacts of dairy products, remains to be fully established. The objectives of the present study were to assess a recommended dairy product consumption in relation to circulating FA and lipid profiles, and to evaluate certain FA in dairy fat as potential biomarkers of intake. In a free-living, multi-centre, cross-over design, 124 healthy individuals consumed 3 servings/d of commercial dairy (DAIRY; 1% fat milk, 1·5% fat yogurt and 34% fat cheese) or energy-equivalent control (CONTROL; fruit and vegetable juice, cashews and a cookie) products for 4 weeks each, separated by a 4-week washout period. Plasma FA and serum lipid profiles were assessed by standard methods at the end of each dietary phase. After 4 weeks of intake, plasma levels of FA pentadecanoic acid (15 : 0) and heptadecanoic acid (17 : 0) were higher (0·26 v. 0·22% and 0·42 v. 0·39% of the total identified FA, respectively) after the DAIRY phase than after the CONTROL phase (P< 0·0001). This was accompanied by a small but significant increase in serum LDL-cholesterol levels after the DAIRY phase compared with the CONTROL phase (+0·08 mmol/l; P= 0·04). In conclusion, intake of 3 servings/d of conventional dairy products may modify certain circulating FA and lipid profiles within 4 weeks, where 15 : 0 and 17 : 0 may be potential short-term biomarkers of intake.

Exopolysaccharide from &amp;lt;i&amp;gt;Lactobacillus pentosus&amp;lt;/i&amp;gt; Strain H2 and Its Impact on Rheological Properties and the Sensory Evaluation of Low Fat Yoghurt and UF-Soft Cheese

In this study, a total of 46 exopolysaccarides (EPS) producers were isolated from different Egyptian fermented milk products. Among these isolates, strain H2 was characterized and identified as <i>Lactobacillus pentosus</i> with similarity 98% based on 16S rRNA gene sequencing and phenotypic characterization. The maximum EPS secretion and cell biomass of strain H2 were 2.22 and 2.64 (g/L) at 30oC after 72 and 96 h, respectively. Among eight sugars tested for EPS production, it was noticed that all industrial by-products tested were significantly increased the secretion of EPS from strain H2. The highest EPS amount was recorded for molasses and date debs permeate followed by lactose and glucose which were 4.54, 3.08, 2.86, 2.68 and 2.56 (g/l) respectively. Electrospray Ionization Mass Spectrometry (ESI MS) indicated that EPS of strain H2 was heteropolymer and consists of D-glucose, D-glucuronic acid and L-rhamnose. Different concentration of the purified EPS isolated from <i>Lactobacillus pentosus</i> strain H2 were applied to low fat UF-soft cheese and yoghurt. The results of these experiments indicated the purified EPS of strain H2 significantly improved the organoleptic properties including texture, flavors and mouth feel of both low fat cheese and yoghurt. Furthermore, all parameters of rheological properties of both products including firmness, cohesiveness, gumminess, chewiness, springiness were significantly improved as the purified EPS concentrations increased. The best sensory evaluation score was recorded for low fat cheese and yoghurt fortified with EPS 0.4 and 0.8% which were 94.90 and 95.60, respectively. Finally, the problems like bitterness, low viscosity, high syneresis formation and defects of consistency which are frequently encountered of fermented milk products can be solved by using purified EPS.

Dietary habits contributing to breast cancer risk among Iranian women.

The aim of this study was to investigate demographic features, dietary habits, and some possible risk factors for being susceptible to breast cancer in Iranian women. A study of dietary habits and breast cancer was conducted among 53 Iranian women with histological confirmed disease and 40 matched controls. A dietary habits questionnaire was used to evaluate the pattern of selected food intakes. The risk of cancer was analyzed after adjustment for confounding factors. Age, weight, body mass index (BMI), waist circumference, educational status, parity, lactation, marital status, menopause, history of estrogen therapy, and family history of breast disease or cancer were assessed among participants. Special attention was given to the relationship between consumption of high fat meat, milk, yogurt and cheese as well use of frying oils for frying foods, use of olive/liquid oils for cooking, removing fat from meat and poultry, removing chicken skin and not use of mayonnaise as salad dressing and the risk of breast cancer. Moreover, salad, vegetable and fruit consumption, and eating outdoors owere investigated. Our results revealed significant lower education and higher BMI and waist circumference levels in patients with breast cancer. There was significantly increased breast cancer risk in overweight women in comparison with normal weight (OR=2.91, 95%CI 1.24 to 6.82). High intake of fat dairy products including milk and cheese was found to be a statistically significant factor for increasing breast cancer risk in models adjusting for age, BMI and education. Use of olive/liquid oils for cooking and avoidance of mayonnaise as salad dressing are related to lower risk of breast cancer. The frequency of vegetable and fruit consumption was significantly lower in patients with breast cancer compared to healthy women. Dietary habits might be risk factors for breast cancer among Iranian women. Adoption of a prudent diet could be an appropriate strategy for preventing breast cancer.

Rheological and physical properties of yogurt enriched with phytosterol during storage.

Phytosterols enriched products are innovative types of functional foods, in which dairy products, like low fat yogurt are ideal vehicles for this functional component. In this study, phytosterol dispersions were prepared using an oil/water (O/W) emulsion. The emulsion was added to yogurt milk. pH, titratable acidity (TA), syneresis, firmness and apparent viscosity of enriched yogurt were determined during storage. Moreover, phytosterols distribution in different parts of enriched yogurt was studied. Results indicated that in enriched yogurt, apparent viscosity and syneresis were lower and firmness was higher compared to the control. Addition of phytosterol to the yogurt had significant effect on acidity. Distribution of phytosterols in different parts of one sample was not uniform. Sensory results showed that there was no significant difference between enriched and control on texture, appearance, flavor and overall acceptance.

Dairy food intake is positively associated with cardiovascular health: findings from Observation of Cardiovascular Risk Factors in Luxembourg study

Conflicting findings have been reported about dairy food consumption and risk for cardiovascular disease. Furthermore, few studies have examined dairy food intake in relation to cardiovascular health and the incorporation of lifestyle factors such as diet and physical activity. This study examined whether dairy food consumption was associated with cardiovascular health, recently defined by the American Heart Association. Data were analyzed from 1352 participants from the Observation of Cardiovascular Risk Factors in Luxembourg survey. A validated food frequency questionnaire was used to measure intakes of milk, yogurt, cheese, dairy desserts, ice cream, and butter. Seven cardiovascular health metrics were assessed: smoking, body mass index, physical activity, diet, total cholesterol, blood pressure, and fasting plasma glucose. A total cardiovascular health score (CHS) was determined by summing the total number of health metrics at ideal levels. It was hypothesized that greater dairy food consumption (both low fat and whole fat) would be associated with better global cardiovascular health, as indicated by a higher CHS. Total dairy food intake was positively associated with the CHS. Higher intakes of whole fat milk, yogurt, and cheese were associated with better cardiovascular health. Even when controlling for demographic and dietary variables, those who consumed at least 5 servings per week of these dairy products had a significantly higher CHS than those who consumed these products less frequently. Higher total whole fat dairy food intake was also associated with other positive health behaviors, including being a nonsmoker, consuming the suggested dietary intakes of recommended foods, and having a normal body mass index. Increased dairy food consumption was associated with better cardiovascular health.

The impact of dairy consumption on circulating cholesterol levels is modulated by common single nucleotide polymorphisms in cholesterol synthesis‐ and transport‐related genes (1038.4)

Dairy consumption impacts circulating cholesterol levels, a traditional risk marker for cardiovascular health, however, whether genetics play a role in response to dairy has not been established. Our objective was to evaluate 24 candidate SNPs within 13 cholesterol synthesis‐ and transport‐associated genes in relation to the cholesterol metabolism response to an intake of conventional and commonly‐consumed dairy products in Canada. Normolipidemic adults (n=101) consumed 3 servings/d of dairy (1% fat milk, 1.5% fat yogurt, and 34% fat cheese) or energy‐matched control products for 28 d using a multicentre, randomized, free‐living, crossover design. Relative to the control diet, dairy intake was associated with an increase in plasma levels of total cholesterol (TC) and LDL‐C only in carriers of the cholesterol transport gene ABCG5 SNP rs6720173‐G/G (4.86±0.20 vs. 5.05±0.20 mmol/L, n=72, p=0.008) and (2.86±0.14 vs. 3.03±0.14 mmol/L, p=0.002), cholesterol synthesis gene SREBF2 SNP rs2228314‐G/G (4.98±0.16 vs. 5.21±0.16 mmol/L, n=50, p=0.02) and (3.06±0.15 vs. 3.24±0.15 mmol/L, p=0.03), and bile acid synthesis gene CYP7A1 SNP rs3808607‐G/T (5.00±0.16 vs. 5.21±0.16 mmol/L, n=53, p=0.04) and (2.93±0.14 vs. 3.11±0.14 mmol/L, p=0.01) genotypes, respectively. These findings accordingly suggest the existence of a gene‐diet interaction modulating the impact of dairy intake on circulating cholesterol levels.Grant Funding Source: Supported by Dairy Farmers of Canada (DFC) and Agriculture and Agri‐Food Canada (AAFC)

Development of Symbiotic Yoghurt

The product was developed with both probiotic and Prebiotic incorporation. The probiotics used were Lactobacillus Bulgaricus and Sreptococcus Thermophilus as live starter cultures and the prebiotic was Fructo – oligosaccharide. In addition to this Sweet potato was also added for the stabilization of yoghurt. So the study was conducted to develop a symbiotic yoghurt incorporating sweet potato, to know the consumer acceptability, to determine the shelf life, to evaluate the physico chemical and nutritional parameters of product. In the research work product was formulated and standardised with live probiotics and prebioic combinaion. The product formulations were done in three combinations with different proportions of ingredients. As T1, T2 and T3, the proportions prepared as T1( Plain yoghurt ), T2 ( Plain Yoghurt + FOS ), T3 (Live Active Culture 3%). So the double tonned milk was used for the development of low fat yoghurt. The milk was pasteurized, homogenised and stabilized with boiled and mashed sweet potato divided into three samples with different formulations. The respective formulations are made and kept in incubator for 3 hours, at 41 – 42C and immediately transferred to refrigerator, stored at 4C for further analysis. All the three formulations were subjected to evaluation for Physico chemical and nutritional analysis. Microbial analysis was done to know the shelf life of product. The microbial count estimation were done for bacteria, yeast and Mould count for twice keeping the product for 21 days of storage life. The results from sensory analysis showed that there was a difference in colour attribute T1 sample was more attractive than T2 and T3. In flavor T3 scored high compared to T1 and T2 as the live active culture incorpaorated in 1:1 ratio. In appearance T2 scored more thanT1 and T3. In texture and acceptability T3 sample was the best accepted from consumers. The product T3 sample yoghurt was the best suited with correct proportion of ingredients, 30% sweet potato was suited for good quality product development.

Structure and function of food products: A review

Abstract A proper understanding of the behavior of food products requires knowledge of its structure, i.e., the spatial arrangement of the various structural elements and their interactions. The structure can properly be studied by visual observation techniques. In products such as fat spreads, creams, dressings, cheese, bread, milk, yoghurt, whipped cream, and ice cream, different structural elements can be distinguished. A number of those elements are discussed, viz., water droplets, oil droplets, gas cells, particles, fat crystals and strands. In addition examples of interactions between structural elements are presented, viz., oil droplets/matrix, protein/protein, protein carbohydrate, and fat crystal/fat crystal interactions. Finally, it is indicated how these elements cooperate in the formation of structure and contribute to function and macroscopic behavior of food products. Particular attention is given to fat spreads, processed cheese, protein gelation, and examples of the mutual interaction of milk proteins and of carbohydrates with milk proteins. It is expected that a proper understanding of the relation between structure and function will help us to design new ways of structuring in our continuing efforts to manufacture high quality, healthy and tasty food products.

Antilisterial activity of lactose monolaurate in milk, drinkable yogurt and cottage cheese

Lactose monolaurate (LML) was previously found to be an antimicrobial against Listeria monocytogenes in culture medium at concentrations between 3 and 5 mg ml(-1) . In this study, the microbial inhibitory activity of LML in dairy products inoculated with a 5-strain cocktail of clinical isolates of L. monocytogenes was investigated. Addition of LML at a concentration of 5 mg ml(-1) resulted in 4.4, 4.0 and 4.2 log reductions in 0.5% fat, 1% fat and 3.25% fat milks, respectively; 4.1, 4.4, and 3.5 log reductions in nonfat, 1% fat, and 1.5% fat yogurts, respectively; and 4.0 log reductions in both nonfat and 2% fat cottage cheese. The inhibitory effect of LML was only observed at 37°C and not 5°C. Experiments suggest that both the lauric acid and the esterified lactose moiety of LML play roles in the growth inhibition. A novel sugar ester, lactose monolaurate, inhibited the growth of a five-strain cocktail of Listeria monocytogenes in milk, yogurt and cottage cheese. This is the first report of the use of a sugar ester to inhibit the growth of Listeria in food systems.

Dairy products consumption and risk of type 2 diabetes: systematic review and dose-response meta-analysis.

BackgroundThe consumption of dairy products may influence the risk of type 2 diabetes mellitus (T2DM), but inconsistent findings have been reported. Moreover, large variation in the types of dairy intake has not yet been fully explored.Methods and ResultsWe conducted a systematic review and meta-analysis to clarify the dose–response association of dairy products intake and T2DM risk. We searched PubMed, EMBASE and Scopus for studies of dairy products intake and T2DM risk published up to the end of October 2012. Random-effects models were used to estimate summary relative risk (RR) statistics. Dose-response relations were evaluated using data from different dairy products in each study. We included 14 articles of cohort studies that reported RR estimates and 95% confidence intervals (95% CIs) of T2DM with dairy products intake. We found an inverse linear association of consumption of total dairy products (13 studies), low-fat dairy products (8 studies), cheese (7 studies) and yogurt (7 studies) and risk of T2DM. The pooled RRs were 0.94 (95% CI 0.91–0.97) and 0.88 (0.84–0.93) for 200 g/day total and low-fat dairy consumption, respectively. The pooled RRs were 0.80 (0.69–0.93) and 0.91 (0.82–1.00) for 30 g/d cheese and 50 g/d yogurt consumption, respectively. We also found a nonlinear association of total and low-fat dairy intake and T2DM risk, and the inverse association appeared to be strongest within 200 g/d intake.ConclusionA modest increase in daily intake of dairy products such as low fat dairy, cheese and yogurt may contribute to the prevention of T2DM, which needs confirmation in randomized controlled trials.

GROWTH, SURVIVAL AND ADAPTATION OF Shigella flexneri UNDER ACIDIC CONDITIONS RELEVANT TO THOSE APPLIED DURING DAIRY PROCESSING

Shigella flexneri is an important fooborne pathogen that has been associated with dairy products. This study aimed to assess the growth, survival and adaptation of S. flexneri under acidic conditions relevant to those adopted in dairy processing. S. flexneri could grow at mildly acidic pH values of 6.0 and 5.0 adjusted by HCl, lactic acid, or acetic acid, but at slower growth rates, compared to unacidified conditions of pH 7.3. Lower pH values ranging from 3.0 to 4.5 caused declines in the initial numbers of S. flexneri, but the pathogen could survive exposure to pH 4.0 and 3.5 for variable times depending on the acidifying agent. The order of sensitivity of S. flexneri to acids at those lower pH values were acetic acid > lactic acid > HCl. The survival of S. flexneri under the acidic conditions of yoghurt prepared from full fat (6%) and half fat (3%) buffalo's milk was also studied. The viable numbers of S. flexneri were generally higher in full fat yoghurt than half fat yoghurt on milk coagulation and during the cold storage of yoghurt. S. flexneri could survive for at least 14 days in full fat yoghurt, compared with 7 days in half fat yoghurt. This could be attributed to a potential protective effect of fat. S. flexneri exhibited an ability to adapt to acidic conditions, since its previous exposure to pH 5.5 increased its tolerance to pH 3.5. The pattern of acid tolerance in pH 3.5 by acid-adapted cells of S. flexneri depended upon the adaptation time that ranged from 30 min to 120 min.

Rheological properties of low fat yogurt containing cress seed gum

Yogurt—a milk based mix fermented by lactic acid bacteria is a valuable health food for both young and old. Milk is the main ingredient of yogurt. However, most yogurts contain additional solids such as milk solids nonfat to boost the nonfat milk solids. Stabilizers such as natural gums are added to improve and maintain gel firmness and consistency, while also for many people to improve appearance and mouth feel. Hydrocolloidsspecifically stabilize gel structure, increaseviscosity and either from networks with milk constituents and establish a separate gel structure. In current research, a natural local plant Iranian hydrocolloid, cress seed gum, is added to yogurt formulation and its rheological propertiesare evaluated using a rotational viscometer. Different famous rheological models have beenused to fit shear stress-shear rate data’s. The results demonstrated that cress seed gum has a good potential to be used as a stabilizer in yogurt formula.

Study of compressibility properties of yogurt powder in order to prepare a complementary formulation.

The aim of the present study was to prepare an oral tablet from liquid yogurt by reforming the physical properties for easy transportation, long-term storage and also as a complementary dairy product in case of nutrient deficiency. The liquid fresh yogurt was lyophilized at -40°C and 0.03 mTor pressure. The dry powder was homogenized by a 12 mesh size sieve. Some tests such as Carr's compressibility index, Hausner ratio and the angle of repose were applied to evaluate the flowability of yogurt powder. Study of the deformation of particles during forcing was done by calculation of the elastic recovery index. Carr's compressibility index percent and Hausner ratio were calculated 15 and 0.94, respectively. The range of repose angle was measured between19-20°. The elastic recovery was obtained up to 60%. Since the hardness of tablets increased by decreasing compression velocity, therefore yogurt powder might have a plastic deformation. The reduction of powder volume due to compression force was about 20% (p < 0.05). Tablets with low fat yogurt showed very good compressibility with 6-12 Strong-Cab (SC) hardness units. Producing a complementary formulated as a tablet from yogurt powder is possible and also maybe therapeutically effective against lactose-intolerance syndrome and preventing antibiotic-associated diarrhea.We suggest that for more authentic confirmation of the type of deformation, it should go through Heckel's equation analysis, too.