Plain Yogurt Research Articles

Sensory, pH, synaeresis, water-holding capacity, and microbiological changes in homemade yogurt prepared with maca (Lepidium meyenii) powder and propolis extract

This study aimed to investigate the effects of maca (Lepidium meyenii) powder and propolis extract supplementation in homemade yogurt. For this purpose, four types of yogurt, including plain yogurt (Y), yogurt with 0.05% propolis (P), yogurt with 5% maca (M), and yogurt containing both 5% maca and 0.05% propolis (MP), were prepared. YC-380 Yo-Flex®-encoded Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus were used as starter cultures in pasteurised milk. Samples were stored at 4 °C for seven days, and their Lactobacillus counts, pH values, water-holding capacity (WHC) values, and densities were analysed. Lactic acid bacterial counts were calculated using the spread on plate method. Sensory analysis of the yogurts was performed by 10 nutritionist panellists. According to the results of these experiments, Lactobacillus sp. could survive in yogurts without maca (Y and P), which showed the highest Lactobacillus counts. The change in the Lactobacillus counts in the different yogurts during storage was not statistically significant. The pH of MP was significantly the lowest, whereas that of Y was significantly the highest. The pH levels of the different yogurts decreased significantly from day 1 to day 7 (p < 0.05). Synaeresis of the yogurts decreased with time, and this change was significantly higher in Y and P. WHC values of all groups increased significantly, and that of Y was the highest during storage (p < 0.01). The increase in the WHC levels was the highest in P and the lowest in M during storage, suggesting an enhancing effect of propolis on WHC of yogurts. Regarding the sensory assessment of the samples, Y was most acceptable and MP was least acceptable (p < 0.05). The sensory features of the yogurts were affected by the distinct colour and odour of maca, and this could be adjusted by changing the doses of this supplement. However, this study comprised of only short-time storage data, and hence, future studies with longer storage periods are required.

Functional Tea-Infused Set Yoghurt Development by Evaluation of Sensory Quality and Textural Properties.

In the present study, the potential to design natural tea-infused set yoghurt was investigated. Three types of tea (Camellia sinensis): black, green and oolong tea as well as lemon balm (Melissa officinalis L.) were used to produce set yoghurt. The sensory quality (using Quantitative Descriptive Profile analysis and consumer hedonic test) and texture analysis, yield stress, physical stability and colour analysis were assessed to describe the profile of the yoghurt and influence of quality attributes of the product on the consumer acceptability of infused yoghurts in comparison with plain yoghurt. Among the analyzed plant additives for yoghurt, addition of 2% oolong tea to the yoghurt allows a functional food to be obtained with satisfactory texture and sensory properties, accepted by consumers at the same level as for control yoghurt. Both types of yoghurt were also characterised by high consumer willingness to buy, which confirms the legitimacy of using oolong tea as a natural, functional yoghurt additive that improves the sensory quality of the product. The high overall quality of yoghurt with oolong tea in comparison to other plant extracts was associated with the intensive peach flavour and odour, nectar and sweet odour and flavour, and the highest creaminess and thickness. That was confirmed by principal component analysis (PCA) where the overall sensory quality of yoghurts was mainly positively correlated with peach flavour and odour, sweet odour and yoghurt odour, while it was negatively correlated with herbs flavor and odour, and green tea flavour and odour. The sensory profile confirmed no differences in textural profile between plain yoghurt and the tea-infused one measured in the mouth, which corresponds to the result of textural properties such as firmness and adhesiveness.

Effects of Saccharin Consumption on Operant Responding for Sugar Reward and Incubation of Sugar Craving in Rats.

Repeated experience with artificial sweeteners increases food consumption and body weight gain in rats. Saccharin consumption may reduce the conditioned satiety response to sweet-tasting food. Rats were trained to press a lever to obtain sucrose for five days. A compound cue (tone + light) was presented with every sucrose delivery. On the following day, each lever press produced only the compound cue (cue-reactivity test). Subjects were then provided with yogurt for three weeks in their home cages. The rats were divided into two groups. Rats in the saccharin group received yogurt sweetened with saccharin on some days and unsweetened yogurt on others. For the plain group, only unsweetened plain yogurt was provided. Subsequently, the cue-reactivity test was conducted again. On the following day, the rats underwent a consumption test in which each lever press was reinforced with sucrose. Chow consumption and body weight gain were larger in the saccharin group than in the plain group. Lever responses increased from the first to the second cue-reactivity tests (incubation of craving) in both groups. During the consumption test, lever responses were higher in the saccharin group than in the plain group, suggesting that the conditioned satiety response was impaired in the saccharin group.

Functional Properties of Yoghurt Fortified with Fruits Pulp

The world interested in food fortification with fruits (e.g. persimmon, mango and guava) that have nutritive and healthy benefits. Therefore, the present study is focused to study the antioxidants properties of yoghurt fortified with fruit pulps. Full fat set yoghurt fortified with different fruit pulps at ratios (5, 10 and 15%, w/w) were prepared and stored at 5±1°C for 14 days. Chemical, rheological, total viable lactic acid bacteria and sensory properties were measured when fresh and after 7 and 14 days of storage period. The results indicated that, there were significant differences between plain yoghurt and fruit yoghurt in the total solids (T.S%), free radical scavenging activity (RSA%), total phenolic compounds (TPC) and total flavonoid compounds (TFC), which increased with the increase of the fruit pulp ratios. While, pH value was decreased with the increase of the fruit pulps percentage added and with extended storage period. The yoghurt containing guava pulp had the highest total viable lactic acid bacteria count compared with plain yoghurt and other fruit yoghurt. Sensory evaluation results showed that there were significant (p < 0.05) differences among the yoghurt treatments. The yoghurt containing 10% mango, 10% persimmon and 5% guava were recorded highest scores in full fat yoghurt compared with plain yoghurt and other ratios. The highest apparent viscosity was recorded in yoghurt containing persimmon, mango and guava pulps, respectively. The results of current study demonstrated that addition of fruits to the yoghurt significantly improved the rheological properties, body & texture and flavour compared with control treatment and support set yoghurt with more bioactive compounds.

Functional Low Fat Fruit Yoghurt

Low fat set yoghurt (0.7%) fortified with different fruit pulps (persimmon, mango and guava) and ratios (5, 10 and 15%, w/w) were prepared and stored at 5±1oC for 14 days. Chemical, rheological, total viable lactic acid bacteria and sensory properties were measured when fresh and at 7 and 14 days of storage period. There were significant (p≤0.05) differences between plain yoghurt (control) and functional low fat fruit yoghurt in the total solids (T.S %), antioxidant scavenging activity (ASA%), total phenolic compounds (TPC) and total flavonoid compounds (TFC), they were increased with the increase of the fruit pulp ratios added. While, the pH value and fat% were decreased with the increase of the fruit pulps percentage. The results showed that pH value decreased with extended storage period. Highest values of ASA, TFC and TPC were belonged to yoghurt fortified with guava, mango and persimmon, respectively at 15 % ratio and at 7 days then decreased. The yoghurt containing guava pulp had the highest total viable lactic acid bacteria count compared with plain yoghurt and other fruits yoghurt. The highest (p≤0.05) apparent viscosity was recorded in yoghurt fortified mango, guava and persimmon pulps, respectively. Yoghurt treatments containing 10% mango, 10% persimmon and 5% guava recorded highest sensory scores in low fat yoghurt compared with plain yoghurt and other ratios. The results of current study demonstrated that addition of fruits to the yoghurt significantly improved the rheological properties, body & texture and flavour and support production of low fat yoghurt with more bioactive compounds.

Evaluation of physicochemical, microbiological, texture and microstructure characteristics of set-style yoghurt supplemented with quince seed mucilage powder as a novel natural stabiliser

The effects of quince seed mucilage powder (QSMP) on the physicochemical, microbiological, textural and sensory characteristics of yoghurts were evaluated. Incorporation of QSMP at different levels (0.05–0.2%) accelerated Lactobacillus bulgaricus growth. QSMP-yoghurts had lower syneresis; addition of QSMP at 0.15% and 0.2% prevented syneresis completely. Highest apparent viscosity values were obtained with 0.05% QSMP followed by 0.1%; however, 0.15% and 0.2% QSMP addition caused a significant (p < 0.05) decrease in viscosity. Yoghurts with QSMP showed lower firmness, consistency and cohesiveness values compared with the plain yoghurt. Microstructure analysis showed the casein network of the yoghurts with 0.15% and 0.2% QSMP was less compact and cohesive, with a thinner gel structure than that of other yoghurts. QSMP addition at levels of 0.05% and 0.1% was more acceptable to panellists in terms of flavour, odour and mouthfeel and addition higher than these levels caused a decrease in sensory attribute scores.

Influence of the addition of chia seeds and germinated seeds and sprouts on the nutritional and beneficial properties of yogurt

This study aims to determine changes in protein profiles of plain yogurt (PY) and yogurt containing chia seeds (CY), yogurt containing germinated seeds and sprouts of lentils and cowpeas (GY), and yogurt containing both chia seeds and germinated seeds and sprouts of lentils and cowpeas (CGY) before and after in vitro digestion and to evaluate how these ingredients affect the production of short-chain fatty acids. The addition of chia seeds and germinated seeds and sprouts caused an increase in protein content. However, increase in fat content was only determined for those containing chia (CY and CGY). Protein contents of PY, CY, GY, CGY were 4.04 ± 0.14%, 4.42 ± 0.07%, 4.37 ± 0.07%, 4.68 ± 0.08% respectively. The fat content of CY and CGY (4.32 ± 0.16%, 4.34 ± 0.16%, respectively) were higher than that of PY and GY. The addition of chia seeds caused the detection of α-linolenic and linoleic acids in CY and CGY. Interestingly, the α-lactalbumin (α-lac) band did not disappear after in vitro gastric and intestinal digestion. The application of protease and carbohydrase to the undigested fraction of PY caused the release of acetic, butyric, and propionic acids. Propionic acid was not found in the enzyme-treated undigested fractions of CY, GY, and CGY. In addition, in silico digestion showed that the PY proteins exhibited a dipeptidyl peptidase IV inhibitory activity.

A Novel Fortified Dairy Product and Sarcopenia Measures in Sarcopenic Older Adults: A Double-Blind Randomized Controlled Trial

ObjectivesTo evaluate the efficacy of daily consumption of fortified yogurt with beta-Hydroxy beta-Methyl Butyrate (HMB) and vitamins D and C on measures of sarcopenia, inflammation, and quality of life in sarcopenic older adults. DesignIn this 12-week randomized double-blind controlled trial, participants received either yogurt fortified with 3 g HMB, 1000 IU vitamin D, and 500 mg vitamin C in the intervention group (n = 33) or plain yogurt in the control group (n = 33). Setting and ParticipantsA total of 66 older adults with sarcopenia recruited from the community in Shiraz, Iran. MeasuresBody composition, muscle strength, and functionality were measured using Dual-energy-X-ray Absorptiometry (DXA), hydraulic handgrip dynamometer, and usual gait speed, respectively. Serum concentrations of vitamin D, insulin-like growth factor-1 (IGF-1), C-reactive protein (hs-CRP), malondialdehyde, and insulin were measured at baseline and after 12 weeks. Health-related quality of life (HRQoL) was also evaluated using SF-12 questionnaire. ResultsConsumption of fortified yogurt was associated with improvement in handgrip strength [mean change (95% confidence interval) 4.36 (3.35–5.37) vs. 0.97 (−0.04 to 1.99)] and gait speed [0.10 (0.07–0.13) vs. 0.01 (0.00–0.04)] in the intervention group compared with the control group (P < .001). In addition, the results revealed a significant increase in vitamin D and IGF-1 levels in the intervention group (P < .001). The nutritional intervention significantly prevented any increase in the serum concentration of hs-CRP compared with the control group (P = .033). The results also showed a more significant decrease in the malondialdehyde level in the intervention group compared with the control (P = .008). Moreover, there were significant differences between the 2 groups regarding physical aspects of HRQoL (P = .035). Conclusions and ImplicationsA novel dairy product fortified with HMB, vitamin D, and vitamin C not only could enhance muscle strength and functionality, but also modulate anabolic and inflammatory conditions as well as quality of life. This study suggested that specific nutritional interventions alone could be beneficial, especially for those who are unable to exercise.

Prevalence oF Enterobacteriaceae in raw milk and some dairy products

Objective: This study was performed to detect and identify members of Enterobacteriaceae in raw milk, yoghurt and ice cream to assess their hygienic quality. Methods: A total number of 200 samples distributed as follows:100 raw milk, 25 small and 25 large scale plain yoghurt, and 25 small and 25 large scale ice cream samples collected from different localities at Kafr El-Sheikh Governorate and examined for Enterobacteriaceae count and identification of members. Results: Enterobacteriaceae were detected in 84% of examined raw milk samples (with mean count of 1.02x106 + 1.98x105 cfu/ml), 40% and 32% of examined small and large scale plain yoghurt samples (with mean value of 6.95x103 + 4x103 and 1.57x103 + 8.95x102 cfu/g), while detected in 64% and 20% of examined small and large scale ice cream samples (with mean count of 1.02x104 + 4.13x103 and 1.4x103 + 8.26x102 cfu/g). The most frequent members isolated were Hafnia alive (30.95%), E. coil (44.44%), and Serratia marcescens (57.14%) from positive raw milk, yoghurt, and ice cream samples, respectively. Other members of Enterobacteriaceae were isolated from positive samples at different percentages. Conclusion: Presence of members of Enterobacteriaceae is a reliable index of fecal contamination and the possibility of the presence of associated enteric pathogenic organisms. So, it is recommended to specify Enterobacteriaceae as a sanitary index of milk and dairy products in the Egyptian food acts and regulations.

Dark red kidney bean (Phaseolus vulgaris L.) protein hydrolysates inhibit the growth of oxidizing substances in plain yogurt

Protein isolate was obtained from dark red kidney bean ( Phaseolus vulgaris , L). The isolate had 86.4% protein and the protein was subjected to enzymatic hydrolysis by pepsin. Enzymatic hydrolysis resulted in a significant ( p < 0.05) increase in total polyphenol content (TPC) in the hydrolysates which was 44.8 ± 1.31 mg GAE/gm. The DPPH radical scavenging activity was also significantly ( p < 0.05) increased in protein hydrolysates than that of the protein isolate with an IC 50 value of 0.002 ± 0.00001 mg/mL. Therefore, the hydrolysates exhibited stronger antioxidant activity than the protein isolate. Moreover, the antioxidant activity of the hydrolysates was higher than ascorbic acid (AA), which is commercially used in the food industry. Besides, owing to antioxidant property, red kidney bean protein hydrolysates were able to suppress the growth of oxidizing substances in yogurt at an application rate of 3 gm/L during storage at room temperature for three (3) days. Protein hydrolysates retarded the formation of oxidizing substances by 45.8% compared to control. Notably, hydrolysis using pepsin improved the ability of red kidney bean protein isolate to inhibit the formation of oxidizing substances. • Hydrolysis of protein isolates resulted in an increase of total polyphenol content. • Hydrolysates had a higher antioxidant activity than that of the protein isolates. • Hydrolysates exhibited stronger antioxidant activity as compared to ascorbic acid. • Reduced growth of oxidizing substances in yogurt by the application of hydrolysates. • Red kidney bean protein hydrolysates can be used as antioxidants in foods.

Changes in the Physicochemical Parameters of Yoghurts with Added Whey Protein in Relation to the Starter Bacteria Strains and Storage Time.

Simple SummaryAddition of whey proteins to yoghurt may be a good solution that could be routinely applied in the dairy industry to offer consumers a new functional product, with health-promoting properties. Conducting a comprehensive analysis of yoghurts made using two different starter cultures, with and without the addition of various levels of whey proteins, we found that the quality of yoghurts with WPC, including sensory quality, can be satisfactory for even 28 days of storage. The use of whey protein concentrate determined both the physicochemical (i.e., lactic acid content, proximate chemical composition, water holding capacity, water activity, firmness, consistency, cohesive strength and colour parameters) and sensory quality of the yoghurts. The additive had a significant effect on potential acidity, inhibiting the increase in the amount of lactic acid in yoghurts during storage, and also reduced syneresis. We suggest that using WPC on a larger scale will create new opportunities on the food market.The stability of the physicochemical characteristics of yoghurts during refrigerated storage is important for industry and the consumer. In this study we produced plain yoghurts with the addition of health-promoting whey protein concentrate (WPC), using two different starter cultures based on Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. Physicochemical changes (acidity, nutritional value, water activity, water-holding capacity, texture, and colour, including whitening and yellowing indices) as well as sensory changes occurring during 28-day refrigerated storage were determined. Starter cultures were found to significantly (p ≤ 0.05 and p ≤ 0.01) influence the water-holding capacity, firmness, consistency, cohesive strength and colour parameters of the curd. Use of whey protein concentrate affected both the physicochemical and sensory quality of the yoghurts. The additive had a significant effect on potential acidity, inhibiting the increase in lactic acid in the yoghurts during storage, and also reduced syneresis. However, it decreased the lightness of curd and negatively affected its sensory characteristics, primarily flavour. Moreover, nearly all parameters changed significantly with the passage of storage time (in most cases negatively). The exceptions were total protein and fat content. The changes, however, were not severe and remained at a level acceptable to tasters. Addition of 1% or 2% whey protein to yoghurt may be a good solution that can be routinely applied in the dairy industry to offer consumers a new functional product. A comprehensive assessment of the physicochemical and sensory changes occurring during refrigerated storage of yoghurts manufactured with the addition of WPC and using different cultures is crucial for modelling such a product.

Proteolytic activity, antioxidant, and α-Amylase inhibitory activity of yogurt enriched with coriander and cumin seeds

Two types of yogurt (Y) were prepared in the presence of coriander (CO) or cumin seeds (CS) at different concentrations (5, 10, 15, & 20 g/100 mL). The effect of these yogurt samples on post-acidification, proteolysis, α-amylase inhibition activity, total phenolic content, and antioxidant activity (2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant potential (FRAP), and ferrous ion chelating (FIC) ability) was studied during 0,7, and 14 days of refrigerated storage at 4 °C. In addition, sensory evaluation of the yogurt was run during the first day of storage. Both COY and CSY at all concentrations showed significant effects on post-acidification, peptide content, and α-amylase inhibition activity as compared to plain yogurt (control). TPC in COY at all concentrations (42.4–165.4 μg GAE/mL) was higher than in CSY (39.0–75.7 μg GAE/mL) during the entire storage period. The radical scavenging activity increased (p < 0.05) in COY at 20, 15, and 10 g/100 mL concentrations (94 ± 0.01%, 93 ± 0.01%, and 89 ± 0.03%; respectively) on 7 days of storage. FRAP values were higher in CSY at all concentrations than COY during 7 days of storage. Higher (p < 0.05) FIC ability was observed in both types of yogurt than control. The highest overall preference score was shown at a concentration of 15 g/100 mL for both types of yogurt. In conclusion, COY and CSY at all concentrations positively enhanced natural yogurt ability to inhibit α-amylase activity with high antioxidant activity.

Using of sugarcane molasses on novel-yoghurt making

Novel molasses-yoghurt was prepared by adding varying concentrations of molasses (0.5, 1.0, 1.5 and 2%) to milk and stored at 6 ± 2°C up to12 days. Results showed that, the molasses is rich in K, Mn, Fe and Cu. It has high of total solids (TS), sugar, total nitrogen (TN) and ash while low of pH values. On the other hand, the TS, acidity, soluble nitrogen (SN), TN, syneresis, firmness, density, fat content and pH values of plain yoghurt and novel molasses-yoghurt found to increase and decrease with increasing of molasses concentrations and during storage periods up to 12 days, respectively. Novel molasses-yoghurt had higher values of K, Ca, Mn, Na, P, Fe, Cu, Mn and Zn contents than that of control samples. All these elements of novel molasses-yoghurt were increased during storage than that of fresh samples in all treatments. Microbiologically, there were increase of total viable bacterial and Lactobacillus bulgaricus counts up to 4 days and decreased up to the end of storage periods in control samples and novel molasses-yoghurt. Whilst, there was decrease of Streptococcus thermophilus in all treatments up to 12 days of storage in most treatments. Moulds and yeasts were not detected in fresh and after 4 days of storage, whereas they were appeared after 8 days. Organoleptically, novel molasses-yoghurt with 0.5% molasses stored at 8 days had superior scores, followed by 1% stored at the same time, while, novel molasses-yoghurt with 2% molasses without storage had the lowest value of overall scores.

Proximate, Physicochemical and Sensory Attributes of Stirred Yoghurt Flavoured with African Star Apple Pulp (Chrysophyllum albidum)

Aims: To Investigate the Proximate, Physicochemical and Sensory attributes of Stirred Yoghurt Flavoured with African Star Apple Pulp (Chrysophyllum albidum). &#x0D; Study Design: Randomized Completely Block Design (RCBD).&#x0D; Place and Duration of Study: Department of Food Science and Technology, Faculty of Agriculture, University of Nigeria, Nsukka, Enugu State Nigeria between December 2018 and October 2019.&#x0D; Methodology: The materials, as well as the other ingredients for the preparation of the flavoured stirred yoghurt (African star apple, skimmed milk, sugar, and Starter culture (YoghurmetTM) were sourced from Ogige main market in Nsukka Local Government Area of Enugu State, Nigeria. The African star apples were sorted to separate the fresh and good fruits from insect-infected and mechanically damaged ones. The fruits were thoroughly washed with water to further eliminate adherent dirt so as to obtain sand-free fruits. Peeling of the fruits was done to remove the back. Each of the peeled fruits was cut into two in order to remove the seeds thereof. The pulps were carefully removed manually with knife and the pulps were blended using a blender after which pasteurization at 83°C for 3 minutes was carried out before being added to the processed yoghurt. Yoghurt flavoured with pasteurized African Star Apple pulp was produced by homogenizing, pasteurizing the milk product followed by cooling to inoculation temperature which is optimum for the starter culture (Yoghurmet). The inoculated milk was made to undergo fermentation after which the pasteurized African star apple pulp at different proportions was added to formulate five samples of stirred yoghurt. The formulation ratios of yoghurt to African star apple pulp were as follows: 100:0, 90:10, 80:20, 70:30, 60:40, 50:50. The flavoured yoghurt samples were mixed, smoothened and packaged for cold storage.&#x0D; Results: The result of physicochemical analysis revealed that viscosity (2.65 ± 0.06 cP – 3.25 ± 0.06 cP), total solids (22.35 ± 0.06% - 30.20 ± 0.06%), total titratable acidity (0.36 ± 0.00% - 0.39 ± 0.01%) and pH (5.20 ± 0.00 - 5.40 ± 0.00) differed significantly (P &lt; 0.05) as the control sample YC (100:0) was compared with the yoghurt samples flavoured with African star apple pulp. The proximate parameters - Carbohydrate (11.20 ± 0.64% - 21.41 ± 0.10%), moisture content (71.53 ± 0.05% - 80.36 ± 1.17%) and ash content (1.30 ± 0.00% - 1.98 ± 0.03%) of the formulated yoghurt samples showed significant (P &lt; 0.05) decrease as concentration of ASA pulp increased while crude protein (3.67 ± 0.01% - 4.92 ± 0.02%), fat (1.21 ± 0.02% - 2.72 ± 0.03%) and crude fibre (0.20 ± 0.00% - 1.40 ± 0.00%) showed significant (P &lt; 0.05) increase with increasing concentration of ASA pulp. Among the formulated yoghurt samples, sample YP1 was the most preferred with respect to color (7.25 ± 0.91), taste (7.25 ± 1.07), aftertaste (7.00 ± 1.17), mouthfeel (6.95 ± 1.40), flavour (7.25 ± 0.64) and overall acceptability (7.30 ± 0.73).&#x0D; Conclusion: Although the control sample YC (100:0) had most preferred sensorial qualities, yoghurt samples flavoured with African Star Apple pulp would rival the “used-to plain yoghurt” with improved awareness, and usage lower than 20% of the ASA pulp in yoghurt samples would maintain the product’s acceptability among the variety-loving dairy consumers.

Optimising a stevia mix by mixture design and napping: A case study with high protein plain yoghurt

A high protein plain yoghurt formulation was optimised using the Euclidian distance on the Napping® test, measuring the distance among formulations sweetened with stevia and standard samples sweetened with sucrose and sucralose. The optimised formulation was validated through temporal dominance of sensations and acceptance tests. The required amounts of the stevias to provide, at a minimum cost, the same sensory characteristics as the standard samples were 55% of stevia 1 (75% rebaudioside A + stevioside), 5% of stevia 2 (95% rebaudioside A), and 40% of stevia 3 (50% rebaudioside A), which was the best stevia mix found in this study. The stevia mix was an excellent alternative in high protein plain yoghurt, since its sensory profile was very similar to those of sucrose and sucralose. Additionally, there was no significant difference with respect to consumer acceptance.

Factors affecting the intake of fermented milk products among university students: a cross-sectional study from Poland and Turkey

Introduction: The aim of the study is to present fermented milk products intake and related factors by Turkish and Polish students of dietetics.Material and methods: Dietetics students of both Medical University of Silesia in Katowice (SUM), Poland and Izmir Katip Celebi University in Izmir (IKCU), Turkey were kindly requested to fill up an on-line questionnaire. The questionnaire consisted of 23 questions about personal data, consumer preferences, substantive knowledge and assessment of factors conditioning the purchase of fermented milk products. Statistical significance between the groups were checked with the Mann-Whitney U test, t test and Chi squared χ2 test. A statistically significant difference met the p&lt;0.05 condition.Results: There were 162 Polish and 181 Turkish respondents taking part in the research. The most common fermented milk product among both the SUM and IKCU students was plain yoghurt. Its intake was declared by over 95% of the respondents in both groups. In the group of the Polish students, fermented milk products are consumed mainly for breakfast (61.11%) and as a snack between meals (58.02%). Turkish students significantly more frequently prefer to eat them for dinner (50.28%) and lunch (48%). Only 21.06% of the Polish students and 29.3% of the Turkish students consume fermented milk products every day. Products with no colour additives and preservatives are selected by 67.9% of the SUM students, while IKCU students more often choose products with probiotics and prebiotics (43.10%) as well as products with reduced fat content (40.3%). Quality, composition of products, manufacturer, packaging, advertisement were determined the significant factors that preconditioning the selection of fermented milk products.Conclusions: Cultural differences concerning fermented milk products are reflected in eating habits and consumer preferences. Plain yoghurt is a frequently chosen product by both the SUM and IKCU students. There were differences between the respondents in terms of times of the day, amount and types of consumed fermented milk products. Moreover, factors preconditioning their selection vary between the two groups.

In vitro angiotensin converting enzyme (ACE)-inhibitory and antioxidant activity of probiotic yogurt incorporated with orange fibre during storage.

In the present work, the effects of orange fibre (OF) supplementation at four different concentrations (0.5%, 1%, 1.5% and 2%) on some quality properties of probiotic set yogurt produced with ABT-2 culture (containing Streptococcus thermophilus ST-20Y, Lactobacillus acidophilus LA-5 and Bifidobacterium lactis BB-12) were evaluated, during 21days of storage. The in vitro angiotensin converting enzyme (ACE)-inhibitory activity and antoxidant capacity as well as some physicochemical and microbiological analyses of probiotic yogurts were analysed and compared with plain yogurt. At the beginning of storage, yogurt samples had high survivability for probiotic bacteria leading to viable counts (> 107CFU/g) higher than the minimum therapeutic threshold (106CFU/g). A significant influence (p < 0.05) of OF supplementation on S. thermophilus ST-20Y and B. lactis BB-12 counts was observed. While OF addition enhanced the viability of B. lactis BB-12, it caused a decrease in S. thermophilus ST-20Y counts. OF addition up to 1.5% concentration affected positively the syneresis, apparent viscosity and consistency index values of yogurt samples. ACE-inhibitory activity showed an increasing trend throughout the storage. Control yogurt had the lowest ACE-inhibitory activity at 1day of storage, and the highest activity was obtained in yogurt containing 1% OF at the end of the storage. Also, yogurts with OF had higher antioxidant activity than the control sample at all days of storage (p < 0.05). Antioxidant activity increased until 14days of storage in all yogurt batches, while it was decreased 21th days of storage. Briefly, this study reflected the performance of using OF as an alternative hydrocolloid to improve the quality properties and bioactivity of bio-yogurt.

Development of Quality Parameters for Yogurt with Strawberry Juice

In this research, we improve the quality parameter of prepared yogurt using different levels (5%, 10%, and 15%) of strawberry juice. We investigated different organoleptic, chemical and microbiological quality characteristics. We found that plain yogurt is clearly better than 15% strawberry juice yogurt while 5% strawberry juice yogurt is almost as like as the plain yogurt. Acceptance of 10% strawberry juice yogurt is between 5% and 15%. We note that the organoleptic characteristics decrease with the addition of strawberry juice level. Analyzed chemical composition showed that strawberry juice incorporation increases the moisture content and acidity from 0% to 15% as strawberry juice contains higher moisture content (90.329%) and acidity (1%) than collected milk which contains 87.15% moisture content and 0.19% acidity. On the other hand, ash and fat content decreases as strawberry juice contains low ash (0.311%) and fat (1.64%) content than collected milk which contains 0.74% ash and 4.36% fat. Thus, nutritional quality decreases with the addition of strawberry juice. After performing the microbiological tests, it was recommended to consume the samples before the 5th day. We also found that various types of microbial (TPC, TCC, TFC) counts decline due to the high acidity of strawberry juice.

Anti-diabetic properties of Synsepalum dulcificum and its potential inclusion in functional yogurt

There has been an enormous interest in the development of alternative medicines for type-2 diabetes, specifically screening for phythochemicals with the ability to delay or prevent glucose absorption. The goals of the present study were to provide in vitro evidence for potential inhibition of α-amylase and α-glucosidase enzymes, followed by inclusion of the extracts of Synsepalum dulcificum in yogurt to enhance the therapeutic properties of the yogurt. The screening results of seed, leaf and pulp of S. dulcificum showed that pulp extracts contained significantly (P<0.05) higher anti-diabetic activities than the other plant parts. More interestingly, S. dulcificum pulp also has stronger anti-diabetic properties than the standard drug, acarbose and hence it was chosen to be incorporated into yogurt. S. dulcificum yogurt had higher (P<0.05) anti-diabetic activities than the plain yogurt throughout the storage period with the highest α-glucosidase and α-amylase inhibitory activities were shown on day 7 of storage. Therefore, S. dulcificum pulp can be developed as functional factor with anti-diabetic activities in food application.

Physico-chemical and rheological properties of plain yogurt made from goat’s milk during refrigerated storage

This study aimed to evaluate the effects of the addition of culture on the physico-chemical and rheological characteristics of plain set goat milk yogurt during four weeks of refrigerated storage. Three goat milk yogurt formulations were prepared, each varying the type of culture used (ABT5, ABY3 and YC380). There were significant differences in the pH values, titratable acidities, moisture content, total solids and percentage syneresis values of all formulations during the storage. All yogurts exhibited shear thinning (thixotropic) flow with different time-independent models for the upward and downward curves. Their viscoelastic behaviour firmly confirmed their weak gel structure that deteriorated during storage time.