Plain Yogurt Research Articles

Influence of Ethanol on Probiotic and Culture Bacteria <i>Lactobacillus bulgaricus</i> and <i>Streptococcus thermophilus</i> within a Therapeutic Product

Probiotic bacteria in plain yogurt namely of Lactobacillus ssp. have been reported to treat thrush, diarrhea, athlete’s foot, jock itch and vaginal yeast infections. Lactobacillus delbrueckii ssp. bulgarius (LB-12) and Streptococcus thermophilus (ST-M5) are lactic acid bacteria widely used in the manufacture of yogurt. Alcohol is used in manufacture of some medications such as cough syrups and some products such as eggnog and rum-raisin ice cream. The objectives were to study the effect of food grade ethanol on the growth of yogurt culture bacteria and the physico-chemical characteristics of therapeutic yogurt. The treatments were 0% (control), 2.5%, 5%, and 7.5% v/v ethanol in plain yogurt. The ethanol was incorporated by stirring it into one day old plain yogurt. Product characteristics were studied weekly for a month of refrigerated (4?C) storage. Data were analyzed using Proc Mixed model of Statistical Analysis System. The ethanol amount × storage period interaction effect was significant for Lactobacillus bulgaricus counts while the ethanol amount × storage period effect was not significant for Streptococcus thermophilus counts, viscosity, pH and titratable acidity (TA). Therapeutic yogurts with ethanol, at these concentrations, can successfully be manufactured without adversely influencing counts of its probiotic bacteria over product shelf life.

Quality Comparison and Acceptability of Yoghurt with Different Fruit Juices

Yoghurt is consumed worldwide for its nutritional and health benefits. The research was conducted to prepare fruit yoghurt with different level of fruit juice (5%, 10% and 15%) of different fruits (strawberry, orange and grape). Different physico-chemical and microbiological characteristics were analyzed to assay the quality of the yoghurts. Yoghurts fortified with 10% orange juice was the best in quality among the others. The smell and taste, body and consistency and color and texture of the fruit yoghurts were equally acceptable. 10% and 15% strawberry fruit yoghurt contain more acid and its texture was cracked down in refrigeration temperature. The moisture and acidity content of fruit yoghurts were increased than plain yoghurt because of high content of these in the fruits. The fat, protein, carbohydrates and ash content of strawberry and orange fruit yoghurt were decreased than normal plain yoghurt. But the carbohydrates content of grape yoghurt were increased because grape contains more sugar than milk and other two fruits. Statistical analysis showed that yoghurt with 10% orange juice was more acceptable than others comparing all quality characteristics. The microbiological quality of the fruit yoghurts was also acceptable because of acid content of the fruits. In case of strawberry yoghurt, fruit juice concentration more than 5% was not suitable for fruit yoghurt because that are highly acidic and curd was cracked down at refrigerated condition. This formulation and quality findings will be helpful to set up fruit yoghurt industry.

Influence of Various Antioxidants on the Characteristics of Plain Yogurt

Free radical damage has been implicated in ageing and in certain degenerative conditions such as Alzheimer’s disease and other forms of dementia. Ageing is also associated with a progressive decline in the function of the immune system and an increased susceptibility to infection. Antioxidants protect the body from free radical damage. Vitamin E is the major antioxidant vitamin in body tissues and is considered the first line of defense against cell membrane damage. Other antioxidant defenses that protect the body from free radical damage include vitamin C and beta carotene. Yogurt is considered a healthy food product and its sales have been steadily increasing over the past 5 years. The objective was to study the influence of various antioxidants on the quality characteristics of yogurt. The antioxidants Vitamin C, vitamin E and beta carotene individually and in combination were incorporated at 100% of their respective recommended dietary allowance of 60 mg, 12 mg and 3 mg in 240 mL of yogurt. Yogurt manufacture and all experiments were conducted in triplicate. Use of antioxidants in yogurt manufacture significantly influenced yogurt viscosity, flavor, appearance, body texture but did not influence syneresis, lactic acid bacterial counts and pH.Depending upon the application antioxidants can be recommended in yogurt manufacture.

Influence of Micro-Encapsulated Probiotic <i>Lactobacillus acidophilus</i> R0052 on the Characteristics of Plain Yogurt

Micro-encapsulation is a method of providing probiotic living cells with a physical barrier against adverse environmental conditions. Lactobacillus acidophilus is one of the most effective forms of probiotic bacteria and is commercially available as pure culture and encapsulated form. It is not clear whether the use of micro-encapsulated L. acidophilus will result in yogurt of a better quality compared to non micro-encapsulated L. acidophilus. The objective was to determine the influence of micro-encapsulated L. acidophilus on the characteristics of fat free plain yogurt. Yogurt mixes were pasteurized and at 37℃ were inoculated with Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus and micro-encapsulated L. acidophilus R0052 or non micro-encapsulated L. acidophilus R0052. Yogurt manufacture was replicated three times. Yogurts with micro-encapsulated L. acidophilus R0052 had significantly (P < 0.05) higher flavor scores, compared to yogurts with non micro-encapsulated L. acidophilus R0052. The L. acidophilus counts, apparent viscosity, pH and syneresis, of the yogurts with micro-encapsulated L. acidophilus R0052 were not significantly (P < 0.05) different from those of the yogurts with non micro-encapsulated L. acidophilus R0052. Use of micro-encapsulated L. acidophilus R0052 resulted in better tasting yogurts probably because of the taste imparted by the trace amounts of the micro-encapsulating material.

Unsteady peristaltic transport of Maxwell fluid through finite length tube: application to oesophageal swallowing

This paper analytically investigates the unsteady peristaltic transport of the Maxwell fluid in a finite tube. The walls of the tube are subjected to the contraction waves that do not cross the stationary boundaries. The analysis is carried out by a long wavelength approximation in the non-dimensional form. The expressions for the axial and radial velocities are derived. The pressures across the wavelength and the tubelength are also estimated. The reflux phenomenon is discussed, which culminates into the determination of the reflux limit. Mathematical formulations are physically interpreted for the flow of masticated food materials such as bread and white eggs in the oesophagus. It is revealed that the Maxwell fluids are favorable to flow in the oesophagus as compared with the Newtonian fluids. This endorses the experimental finding of Takahashi et al. (Takahashi, T., Ogoshi, H., Miyamoto, K., and Yao, M. L. Viscoelastic properties of commercial plain yoghurts and trial foods for swallowing disorders. Rheology, 27, 169–172 (1999)). It is further revealed that the relaxation time does not affect the shear stress and the reflux limit. It is found that the pressure peaks are identical in the integral case while different in the non-integral case.

Regular consumption of vitamin D-fortified yogurt drink (Doogh) improved endothelial biomarkers in subjects with type 2 diabetes: a randomized double-blind clinical trial

BackgroundEndothelial dysfunction has been proposed as the underlying cause of diabetic angiopathy that eventually leads to cardiovascular disease, the major cause of death in diabetes. We recently demonstrated the ameliorating effect of regular vitamin D intake on the glycemic status of patients with type 2 diabetes (T2D). In this study, the effects of improvement of vitamin D status on glycemic status, lipid profile and endothelial biomarkers in T2D subjects were investigated.MethodsSubjects 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, n1 = 50) or vitamin D3-fortified yogurt drink (FYD; containing 170 mg calcium and 500 IU/250 mL, n2 = 50) twice a day for 12 weeks. Anthropometric measures, glycemic status, lipid profile, body fat mass (FM) and endothelial biomarkers including serum endothelin-1, E-selectin and matrix metalloproteinase (MMP)-9 were evaluated at the beginning and after the 12-week intervention period.ResultsThe intervention resulted in a significant improvement in fasting glucose, the Quantitative Insulin Check Index (QUICKI), glycated hemoglobin (HbA1c), triacylglycerols, high-density lipoprotein cholesterol (HDL-C), endothelin-1, E-selectin and MMP-9 in FYD compared to PYD (P < 0.05, for all). Interestingly, difference in changes of endothelin-1, E-selectin and MMP-9 concentrations in FYD compared to PYD (-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) but disappeared for E-selectin (P = 0.092). On the contrary, after controlling for serum 25(OH)D, the differences disappeared for endothelin-1(P = 0.066) and MMP-9 (P = 0.277) but still remained significant for E-selectin (P = 0.011).ConclusionsAmeliorated vitamin D status was accompanied by improved glycemic status, lipid profile and endothelial biomarkers in T2D subjects. Our findings suggest both direct and indirect ameliorating effects of vitamin D on the endothelial biomarkers.Trial registrationClinicalTrials.gov: NCT01236846

Effects of Yogurt and Applesauce on the Oral Bioavailability of Nilotinib in Healthy Volunteers

Nilotinib, a potent orally bioavailable BCR-ABL tyrosine kinase inhibitor, is currently available as a hard gelatin capsule that must be swallowed whole. For patients who may have difficulty swallowing the intact capsule, an alternative mode of administration is desirable. The authors compared the bioavailability of nilotinib from the following administrations in 48 healthy subjects: (1) 400 mg nilotinib given as two 200-mg nilotinib intact capsules; (2) contents of two 200-mg nilotinib capsules, each capsule dispersed in 1 teaspoon of nonfat plain yogurt; and (3) contents of two 200-mg nilotinib capsules, each capsule dispersed in 1 teaspoon of applesauce. Nilotinib absorption was modestly increased following the administration of nilotinib dispersed in yogurt. The geometric mean ratios (90% confidence intervals) for nilotinib C(max), AUC(0-tlast), and AUC(0-inf) were 1.31 (1.22-1.41), 1.11 (1.05-1.16), and 1.08 (1.02-1.15), respectively. Administration of nilotinib dispersed in applesauce showed equivalent bioavailability compared with administration of nilotinib as intact capsules. The geometric mean ratios (90% confidence intervals) for nilotinib C(max), AUC(0-tlast), and AUC(0-inf) were 0.95 (0.88-1.02), 0.99 (0.94-1.04), and 0.97 (0.90-1.03), respectively. Each treatment was well tolerated in the study subjects. The data support a feasible alternative method of nilotinib administration; each capsule's contents may be dispersed in 1 teaspoon of applesauce and taken immediately.

Physico-chemical and Sensory Evaluation of Market Yoghurt in Nigeria

This study examined the quality of some yoghurts made and sold in the Nigerian market. Nine commercially available brands of yoghurt drinks which represent seven different manufacturers were randomly selected. The samples included seven plain yoghurt and two fruit yoghurt samples. All yoghurt samples were analyzed for chemical properties (moisture%, ash %, total solids, SNF, fat, pH and titratable acidity) and the organoleptic tests (color, thickness, appearance, body, texture, taste, smell, flavor and over all acceptability). The results of the study showed that the physico-chemical composition of the manufactured yogurts was different. The pH values of the samples ranged between 3.70-4.33 which were reasonably suitable for yoghurt marketed in tropical areas. No direct relationship was observed between pH values and titratable acidity. There was marked variation in the % fat content of the products. The results of the sensory evaluation revealed that flavor with respect to taste and smell had significant influence (p<0.05) on overall acceptability of yogurt product. So, the yogurt manufacturers need to improve on the sensory properties in particular flavor and taste for better consumer acceptability. Also, they may improve on packaging by labeling to specifications that precisely represent the content and type.

Efficacy of vitamin D3-fortified-yogurt drink on anthropometric, metabolic, inflammatory and oxidative stress biomarkers according to vitamin D receptor gene polymorphisms in type 2 diabetic patients: a study protocol for a randomized controlled clinical trial

BackgroundDevelopment of type 2 diabetes mellitus (T2DM) is determined by the interactions of genetic and environmental factors. This study was designed to evaluate the possible role of VDR single nucleotide polymorphisms (SNPs) on different aspects of diabetic host response (anthropometric, metabolic, oxidative stress and inflammatory) to daily intake of vitamin D through fortified yogurt drink for 12 weeks.Methods/DesignThis study comprises two parts: (i) a case-control study; and (ii) an intervention trial. In the first part, VDR polymorphisms (Taq1, FokI, Apa1, Bsm1, and Cdx2) are determined in 350 T2DM patients and 350 non-diabetic subjects. In the second part, the possible effects of daily intake of two servings of vitamin D3-fortified yogurt drink (FYD; 500 IU vitamin D/250 mL) on some selected metabolic (including insulin resistance), inflammatory and oxidative stress biomarkers in 135 T2DM patients are assessed. To relate the resulted changes in the biomarkers to vitamin D replenishment, another group of diabetic patients (n = 45) are also included in the study who receive 2 servings of plain yogurt drink (PYD) a day. The primary outcome is serum level of 25(OH) D, which it is expected to be elevated only in FYD group. Secondary outcomes include improvements in glycemic, metabolic, inflammatory and oxidative stress biomarkers in FYD group compared to PYD group. Three VDR FokI polymorphisms are determined only in FYD group followed by comparison of changes in the biomarkers among these genotypic variants.DiscussionThe present study, at least in part, elucidates the discrepancies in the results of different vitamin D-diabetes studies pertaining to the genetic variations of the population. If VDR polymorphisms are found to influence the response to our intervention, then knowing distribution of VDR polymorphisms in both diabetic and non-diabetic populations can give a picture of the proportion of the community in whom up to 1000 IU/d vitamin D may not be effective enough to improve insulin resistance and related morbidities. Therefore, they should ideally receive further nutritional support according to their genotype.Trial RegistrationClinicalTrials.gov: NCT01236846

Food labels: Do consumers perceive what semiotics want to convey?

In this research work, a multidisciplinary approach was applied to answer the question: do consumers perceive what semiotics want to convey? The idea behind was to determine if consumers’ expectations and associations raised by simulated yogurt labels, designed with different sign combinations frequently applied in commercial products, were in agreement with results from a semiotic analysis, and to check for cultural differences, comparing results from two Spanish-speaking countries (Spain and Uruguay). A survey of the plain yogurt market was performed, followed by a semiotic analysis of the gathered labels performed by a team of semiotics experts. Only the non-verbal elements such as images, visual structure, colors, typography and their combinations, were considered; so brand, price, nutritional information, composition, etc. were nor taken into consideration. The main messages conveyed by the labels were summarized and based on that, five yogurt model labels were designed and subsequently used as stimuli in a consumer study. An online consumer questionnaire, based on a word association task, was performed in both countries to understand the words, descriptions, associations, thoughts or feelings generated by the model labels. The approach was successful, and the results obtained showed that the main messages conveyed by the model labels were well understood in Spain and Uruguay; however some cultural differences in the perception of the messages could be highlighted.

Daily consumption of vitamin D– or vitamin D + calcium–fortified yogurt drink improved glycemic control in patients with type 2 diabetes: a randomized clinical trial

Low serum concentrations of 25-hydroxyvitamin D [25(OH)D] have been associated with impaired glucose tolerance and diabetes. This study aimed to compare the effects of daily intake of vitamin D- or vitamin D(3) + calcium-fortified yogurt drink on glycemic status in subjects with type 2 diabetes (T2D). Ninety diabetic subjects were randomly allocated to 3 groups to consume plain yogurt drink (PY; containing no vitamin D and 150 mg Ca/250 mL), vitamin D-fortified yogurt drink (DY; containing 500 IU vitamin D(3) and 150 mg Ca/250 mL), or vitamin D + calcium-fortified yogurt drink (DCY; containing 500 IU vitamin D(3) and 250 mg Ca/250 mL) twice per day for 12 wk. Fasting serum glucose (FSG), glycated hemoglobin (Hb A(1c)), homeostasis model assessment of insulin resistance (HOMA-IR), serum lipid profile, and percentage fat mass (FM) were assessed before (baseline) and after the intervention. In both the DY and DCY groups, mean serum 25(OH)D(3) improved (+32.8 ± 28.4 and +28.8 ± 16.1 nmol/L, respectively; P < 0.001 for both), but FSG [-12.9 ± 33.7 mg/dL (P = 0.015) and -9.6 ± 46.9 mg/dL (P = 0.035)], Hb A(1c) [-0.4 ± 1.2% (P < 0.001) and -0.4 ± 1.9% (P < 0.001)], HOMA-IR [-0.6 ± 1.4 (P = 0.001) and -0.6 ± 3.2 (P < 0.001)], waist circumference (-3.6 ± 2.7 and -2.9 ± 3.3; P < 0.001 for both), and body mass index [in kg/m(2); -0.9 ± 0.6 (P < 0.001) and -0.4 ± 0.7 (P = 0.005)] decreased significantly more than in the PY group. An inverse correlation was observed between changes in serum 25(OH)D(3) and FSG (r = -0.208, P = 0.049), FM (r = -0.219, P = 0.038), and HOMA-IR (r = -0.219, P = 0.005). Daily intake of a vitamin D-fortified yogurt drink, either with or without added calcium, improved glycemic status in T2D patients. This trial was registered at clinicaltrials.gov as NCT01229891.

The impact of tea supplementation on microflora, pH and antioxidant capacity of yoghurt

Yoghurts prepared from cows’ milk with 5, 10 or 15% (v/v) addition of green or Pu-erh tea infusions were subjected to analyses of the antioxidant capacity by the ‘diphenyl picrylhydrazyl’ (DPPH) and ‘ferric reducing antioxidant power’ (FRAP) methods, pH and the count of yoghurt bacteria at the 1st, 7th, 14th, 21st and 28th day of cold storage. The average DPPH radical scavenging activity of yoghurts with 15% of green tea and Pu-erh tea was respectively 31 and 15-fold higher in relation to the yoghurt without tea, the respective FRAP values were 12 and 5-fold higher. Moreover, tea supplementation positively influenced the initial acidity of yoghurts and the count of Lactobacillus delbrueckii ssp. bulgaricus compared with the plain yoghurt, with no significant differences between the types and levels of tea used. That effect was also found for the Streptococcus thermophilus number in yoghurts with 10 and 15% of tea infusions.

Volatile Flavor Compounds in Yogurt: A Review

Considerable knowledge has been accumulated on the volatile compounds contributing to the aroma and flavor of yogurt. This review outlines the production of the major flavor compounds in yogurt fermentation and the analysis techniques, both instrumental and sensory, for quantifying the volatile compounds in yogurt. The volatile compounds that have been identified in plain yogurt are summarized, with the few key aroma compounds described in detail. Most flavor compounds in yogurt are produced from lipolysis of milkfat and microbiological transformations of lactose and citrate. More than 100 volatiles, including carbonyl compounds, alcohols, acids, esters, hydrocarbons, aromatic compounds, sulfur-containing compounds, and heterocyclic compounds, are found in yogurt at low to trace concentrations. Besides lactic acid, acetaldehyde, diacetyl, acetoin, acetone, and 2-butanone contribute most to the typical aroma and flavor of yogurt. Extended storage of yogurt causes off-flavor development, which is mainly attributed to the production of undesired aldehydes and fatty acids during lipid oxidation. Further work on studying the volatile flavor compounds-matrix interactions, flavor release mechanisms, and the synergistic effect of flavor compounds, and on correlating the sensory properties of yogurt with the compositions of volatile flavor compounds are needed to fully elucidate yogurt aroma and flavor.

Impact of sensory differences on consumer acceptability of yoghurt and yoghurt-like products

The aim of this work was to obtain information about how perceptible sensory differences affect consumer acceptability for yoghurt and a yoghurt-like product. Descriptive sensory profiles of six commercial samples, three of plain yoghurt and three of plain fermented milk, were determined using a trained panel (n=10). Sample acceptance was determined by a group of consumers (n=120). Initially, two groups of consumers were identified using Cluster analyses. For one group 46 (38%) of the consumers, variability in sensory attributes did not affect sample acceptability. For the second group, of 74 (62%) of the consumers, variability in sensory attributes had a significant effect and three consumer subgroups with different preference criteria were detected. Partial least squares regression was used to determine the sensory factors driving liking/disliking for each consumer subgroup. The information obtained can be important in predicting or explaining the market response to these types of products.

EVALUTION OF THE MICROBIOLOGICAL QUALITY OF YOGHURT BLENED WITH SOME FRUIT JUICE

A study was carried out on the plain yoghurt was prepared on laboratory in a scale production from cow's milk obtained from dairy farm in Cairo. Plain yoghurt blended with fresh juice (Guava, Mango, Strawberry juice) and commercical yoghurt fortified by juice have been investigated. The microbiological quality of yoghurt, yoghurt juice blends and fresh juice samples were investigated during refrigerated storage at 40C for two weeks, and six months for juice kept frozen. The microbial analyses including Yeast and moulds counts, and coliform organisms were recorded statistically evaluated. The result of the study showed that fresh juice had significant effect on acceptability of yoghurt before and after storage.

Spray Drying of Yogurt: Optimization of Process Conditions for Improving Viability and Other Quality Attributes

Plain yogurt was subjected to spray drying to determine the optimum processing conditions that yield maximum survival ratio of lactic acid bacteria, maximum overall sensory attributes, minimum color change, and acceptable moisture content. The inlet (150–180°C) and outlet air temperatures (60–90°C) and the feed temperature (4–30°C) were the independent factors. A pilot-scale spray dryer was used to conduct a set of drying experiments where the process conditions were selected according to central composite rotatable design (CCRD). The resulting yogurt powder at each condition was also subjected to the measurement of some physical properties (water activity, titratable acidity [lactic acid, %] and pH) to determine the effects of spray-drying conditions. The morphological structure of the powder was inspected by scanning electron microscopy (SEM) analysis. Optimization by the application of the desirability function method resulted in air inlet temperature of 171°C, air outlet temperature of 60.5°C, and feed temperature of 15°C as the optimum processing condition. The mathematical optimum condition was experimentally verified.

Pilot case-control investigation of risk factors for hip fractures in the urban Indian population.

BackgroundDespite the reported high prevalence of osteoporosis in India, there have been no previous studies examining the risk factors for hip fracture in the Indian population.MethodsWe carried out a case control investigation comprising 100 case subjects (57 women and 43 men) admitted with a first hip fracture into one of three hospitals across New Delhi. The 100 controls were age and sex matched subjects who were either healthy visitors not related to the case patients or hospital staff. Information from all subjects was obtained through a questionnaire based interview.ResultsThere was a significant increase in the number of cases of hip fracture with increasing age. There were significantly more women (57%) than men (43%). Univariate analysis identified protective effects for increased activity, exercise, calcium and vitamin supplements, almonds, fish, paneer (cottage cheese), curd (plain yogurt), and milk. However, tea and other caffeinated beverages were significant risk factors. In women, hormone/estrogen therapy appeared to have a marginal protective effect. For all cases, decreased agility, visual impairment, long term medications, chronic illnesses increased the risk of hip fracture. The multivariate analysis confirmed a protective effect of increased activity and also showed a decrease in hip fracture risk with increasing body mass index (odds ratio (OR) 0.024, 95% confidence interval (CI) 0.006-0.10 & OR 0.81, 95% CI 0.68-0.97 respectively). Individuals who take calcium supplements have a decreased risk of hip fracture (OR 0.076; CI 0.017-0.340), as do individuals who eat fish (OR 0.094; CI 0.020-0.431), and those who eat paneer (OR 0.152; 0.031-0.741). Tea drinkers have a higher risk of hip fracture (OR 22.8; 95% CI 3.73-139.43). Difficulty in getting up from a chair also appears to be an important risk factor for hip fractures (OR 14.53; 95% CI 3.86-54.23).ConclusionsIn the urban Indian population, dietary calcium, vitamin D, increased body mass index, and higher activity levels have a significant protective effect on hip fracture. On the other hand, caffeine intake and decreased agility increase the risk of hip fracture. Future studies should be done in order to direct primary preventive programs for hip fracture in India.

KINETIKA FERMENTASI YOGHURT YANG DIPERKAYA UBI JALAR (Ipomea batatas)

&lt;p&gt;The purpose of this research is to know the behavior of kinetics fermentation of yoghurt enriched by sweet potato (Ipomea batatas L.). The parameter of kinetics fermentation consist of spesific growth rate (μ), doubling time (td), multiplication degree (n), growth yield constant (Yx/s), product yield constant (Yp/s), and production efficiency of lactic acid. The result indicate that, the number of spesific growth rate (μ), in plain yoghurt is 0.4809/hour, white yoghurt is 0.4510/hour, purple yoghurt 0.5589/hour and orange yoghurt is 0.5880/hour. The number of doubling time (td) in plain yoghurt is 1.4513 hours, white yoghurt is 1.8393 hours, purple yoghurt is 1.3806 hours, and orange yoghurt is 1.2074 hours. The number of multiplication degree (n) in plain yoghurt is 4.9567 times, white yoghurt is 5.5671 times, purple yoghurt is 5.6837 times, and orange yoghurt is 6.0985 times. The number of Growth Yield Constant (Yx/s) and Product Yield Constant Yp/s successively in plain yoghurt is 4,5 x105cfu/mg and 0.082 mg, white yoghurt is 4,2 x105cfu/mg and 0.139 mg, purple yoghurt is 7,5x105 cfu/mg and 0,0712 mg, orange yoghurt is 6,8x105cfu/mg and 0.1046 mg. The number of production efficiency of lactic acid during the fermentation in plain yoghurt is 7,633 %, white yoghurt is 6,458%, purple yoghurt is 4,739% and orange yoghurt is 6,479%.&lt;/p&gt;

A Highly Sensitive Method for the Analysis of Long-Chain Free Fatty Acids in Yogurt by High Performance Liquid Chromatography with Fluorimetric Detection

The fat content in food is concerned by genera l public, because over uptake of some saturated fatty acids could lead to heart related disease. Therefore, practical method for the analysis of fatty acids in food is essential. In this article, a highly sensitive HPLC method is described for the quantitative analysis of long-chain free fatty acids in yogurt, including lauric, myristic, palmitic, stearic, palmitoleic, oleic and linoleic acids. The fatty acids were labeled with a fluorophore by reacting with 2-(2-naphthoxy) ethyl 2-(piperidino) ethanesulfonate (NOEPES) at 95℃ for 0.5 h in the presence of 18-crown-6 and solid potassium carbonate. The resulting naphthoxyethyl derivatives were separated on a C8 column with a mobile phase of methanol-water (92:8, v/v) and detected fluorimetrically (excitation at 235 nm and detection at 350 nm). Before labeling, the fatty acids in yogurt were extracted with toluene and the resulting toluene extract was directly subject to the labeling without time-consuming steps of solvent evaporation and solvent replacement. The fluorimetric HPLC analysis of fatty acids could be measured at few μ M levels in yogurt. The results indicate that the content of free fatty acids in low-fat yogurt is lower than that in plain yogurt from the same food producer.

MAPPING THE EFFECT OF INFORMATION ABOUT ANIMAL WELFARE ON CONSUMER LIKING AND WILLINGNESS TO PAY FOR YOGURT

ABSTRACT Preference mapping identified different groups of consumers on the basis of their disconfirmations (occurring when the product is either better or worse than expected) and assimilations (occurring when actual liking [L] moves toward the expectations). The negative disconfirmation of a group of consumers (Group 1) was based on the information about animal welfare (the products were worse than expected because the information about animal welfare induced high expectations), whereas in Group 2 the sensory properties of the products prevailed in orienting consumer disconfirmation (products were worse than expected because the sensory properties of low‐fat yogurt were disliked). The map of assimilation showed that consumers from Group 1 had higher assimilation for plain yogurt associated with high welfare standards as a consequence of the high discrepancy between blind and expected L for these products. A similar behavior was observed for Group 2 (higher discrepancy between blind and expected L corresponding to higher assimilation for low‐fat yogurt paired with high welfare standards). PRACTICAL APPLICATIONSConsumers based their choices both on sensory properties (plain yogurts were preferred to low‐fat yogurts) and on information about animal welfare (products associated with high welfare standards were preferred to the others). Preference mapping was able to identify groups of consumers behaving differently, as compared with the general trend, on the basis of their disconfirmations and assimilations.Consumer willingness to pay reflected the hedonic behavior, thus validating the auction procedure for food liking evaluation purposes and providing a useful tool to obtain information about the real value (i.e., in monetary terms) consumers give to animal welfare.