scholarly journals Quality of Plain Set Yoghurt as affected by Levels of Ultrafiltration Concentration of Milk and Inoculum of Yoghurt Culture

Author(s):  
Narayana Mudiyanselage Nayana Kumari Narayana ◽  
Vijay Kumar Gupta

Quality of plain set yoghurt was investigated by varying levels of ultrafiltration concentration of cow skim milk (1-without ultrafiltration, 1.5 and 2 folds) and inoculum (2, 2.5 and 3%) of yoghurt culture (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus 1:1). Titratable acidity development and pH reduction were significantly faster during incubation of yoghurt with increasing ultrafiltration concentration level and inoculum level. Increased ultrafiltration concentration level decreased spontaneous whey syneresis, but increased water holding capacity and firmness of the product significantly. Body & texture and overall acceptability scores were significantly better in yoghurts prepared from 1.5 fold concentrated milk irrespective of the inoculum level studied. Inoculum level did not show any significant effect on the quality of yoghurt, but higher inoculum level decreased the incubation period significantly. Optimized product was obtained with 1.5 fold concentrated skim milk standardized to 3.3% fat and incubated with 2% inoculum level in about five and a half hour of incubation. Optimized product had 13.60±0.02% total solids, 3.31±0.01% fat, 5.27±0.04% protein, 4.20±0.03% lactose and 0.82±0.02% ash. Whey syneresis, water holding capacity and firmness in optimized product were nil, 63.49% and 1.89 N, respectively. Thus, high quality plain yoghurt could be prepared by employing ultrafiltration, without addition of stabilizers, which is otherwise widely used commercially for the manufacture of yoghurt to control its wheying off and body.

2013 ◽  
Vol 650 ◽  
pp. 717-722
Author(s):  
Min Zhang ◽  
Ming Ye ◽  
Dong Liu ◽  
Yong Liu

Adding hawk teas (Litsea coreana L.) of 2% and 4% (W/V) to reconstituted milk, and inoculated with Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus to prepare hawk tea yogurts, named LCY1and LCY2. Compared with the control yogurt (CY), the viscosity of LCY1and LCY2respectively increased by 0.39 and 0.57, the syneresis values increased by 1.3% and 1.0%, while its water holding capacity decreased by 3.96% and 7.77% and the titratable acidity had no more changed. The sensory test revealed that the overall acceptability scores of hawk teas yogurt were quite similar to those of the control yogurt. In LCY1and LCY2, the total content of essential amino acid was remarkably higher than that of CY. There were 10-undecenal, (-)-Spathulenol, Cadina-3,9-diene and a-Cubebene detected in hawk tea yogurts, except for 20 volatile components in the CY. The numbers of S. thermophilus in LCY1and LCY2respectively increased by 0.5 and 0.52 log cfu/ml.


Foods ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 217
Author(s):  
Joanna Teichert ◽  
Dorota Cais-Sokolińska ◽  
Romualda Danków ◽  
Jan Pikul ◽  
Sylwia Chudy ◽  
...  

Color is important for the consumer when making a purchase decision. Mare’s milk and, thus, fermented mare’s milk is little known to consumers. Thus, it is worth presenting research showing the extent of color change during the production and storage of mare’s milk. Herein, we examined the range of color changes in mare’s milk and cow’s milks adapted to mare’s milk composition. These samples were further fermented and stored for 3 weeks at 5 ± 1 °C. Starter cultures containing Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus were used for fermentation. Mare’s milk reached the required pH of 4.5 during fermentation faster (255 min) than cow’s milk (300 min). After fermentation, mare’s milk compared to cow’s milk and adapted cow’s milk had lower titratable acidity (0.75%) and firmness (145. 6 |(g∙s)|). The water holding capacity (95.6%) and number of Lactobacillus (7.71 log CFU/mL) and Streptocococcus (7.20 log CFU/mL) in mare’s and other’s milks were the same. Mare’s milk was furthest from the ideal white (WI) color, with its chrome (C*) being 1.5-times larger than cow’s milk. However, fermented mare’s milk was darker than the fermented adapted milk and cow’s milk by 36% and 58%, respectively. Storage caused a decrease in the WI, C*, and yellowness index (YI). The fermented mare’s milk color stability during production and storage was less than that of fermented cow’s milk. After 3 weeks storage, it was observed that the titratable acidity increased to 1.05%, and the pH decreased to 4.3 in fermented mare’s milk. The water holding capacity decreased but was still higher compared to fermented cow’s milk.


2016 ◽  
pp. 11-18 ◽  
Author(s):  
Mirela Ilicic ◽  
Spasenija Milanovic ◽  
Katarina Kanuric ◽  
Vladimir Vukic ◽  
Dajana Vukic

The objective of this work was to investigate the effect of addition of transglutaminase (TG-0.02%, w/w) and whey protein concentrate (WPC-0.03%, w/w), on quality of kombucha fermented milk product. Samples were prepared from pasteurized semi-skim milk (0.9%, w/w fat) and kombucha inoculum (10%, v/v). The pH values were measured during the fermentation of milk (lasted until reached 4.5). Syneresis, water holding capacity and the product texture (firmness and consistency,) were assessed after production. Rheological properties of kombucha fermented milk samples were measured during ten days of storage. The sample containing TG had the lowest syneresis (21 ml), the highest water holding capacity (62%) and the highest textural characteristics (firmness - 23.99g, consistency - 626.54gs) after production. The addition of WPC to milk improved the rheological properties, while the addition of TG improved it even to a significantly greater extent after the production and during 10 days of the storage.


FOODSCITECH ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 33
Author(s):  
Wehandaka Pancapalaga ◽  
Bagus Ashari

This research aims to discover the quality of yoghurt added by rabbit skin gelatine of various concentrations. Qualities measured are protein content, fat content, acidity, pH, water holding capacity (WHC), syneresis, viscosity, and yoghurt texture. Materials used in this research are skim milk, rabbit skin gelatine, and yoghurt culture, which consisted of bacteria such as L. bulgaricus, S. thermophilus, and L. Acidophilus. The experiment is conducted using Completely Randomised Design, consisted of four treatments and five-time repetition. If there is an effect, the treatment later continued to Duncan's Multiple Range Test. Experimentation on texture is conducted through an organoleptic test with 25 panellists and later analysed with the Kruskal-Wallis Test. The treatments determined in this experiment are the effect on the addition of rabbit skin gelatin proportion of 0% (P0), 0.4% (P1), 0.6% (P2), and 0.8% (P3). The result of the Analysis of Variance (ANOVA) shows that the addition of gelatine has a significant difference (P<0.05) towards protein content, water holding capacity (WHC), and syneresis and no significant difference (P>0.05) towards the fat content, viscosity, pH, and yoghurt's acidity degree. The Kruskal-Wallis test result shows the significant difference (P>0.05) towards yoghurt's texture. This research concludes that the best yoghurt quality is obtained by the addition of 0.8% of rabbit skin gelatine. 


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Yang Jiang ◽  
Jinhua Du ◽  
Liguo Zhang

AbstractTo comparatively investigate the applications potential of pectin from steeped hawthorn wine pomace (SHP), pectin-enriched yogurt was produced at set/stirred form using apple-sourced commercial pectin (CP) as control. The focus was mainly on the effect of pectins on the texture and stability of yogurt, as well as the analysis of appearance and taste, which were mainly characterized by texture analysis and sensory evaluation. Texture analysis indicated that the performance of SHP was better than that of CP, which could increase the gel rupture strength and rupture distance of set yogurt. SHP could also improve the firmness, denseness and viscosity of stirred yogurt. In other respects, SHP could also significantly increase the water holding capacity and sensory acceptance of both types of yogurt. The utilization of SHP for improving the quality of yogurt demonstrated its great potential in developing the sustainable applications of the by-product from steeped hawthorn wine.


2019 ◽  
Vol 39 (04) ◽  
Author(s):  
Kimia Banikarimi K Rai ◽  
Habibollah Mirzaei K Basu ◽  
Mohammad Farsi K Basu

The effect of edible coating of gelatin (1, 2 and 3%) containing aqueous extract of rosemary (1% and 2%) on physiochemical (pH, total volatile nitrogen, peroxide values and water holding capacity) and microbiological (psychrotrophic) properties of duck fillet were evaluated. The pH of coated samples were significantly (plessthan0.05) lower than that of untreated sample. TVN (total volatile nitrogen) value increased with storage period in all the samples but coatings significantly decreased production of TVN compared to the control. Also the coatings decreased lipid oxidation of the meat as rosemary postponed primary oxidation of fillet, while this parameter in control group was sharply increased by time. WHC (water holding capacity) increased significantly (plessthan0.05) with storage period and level coatings. Coating had a significant reducing effect on growth of psychrotrophic bacteria during 9 days at 4°C. In conclusion, gelatin edible coating enriched with rosemary could retard chemical and microbial reactions related to spoilage of meat during refrigerated storage.


2002 ◽  
Vol 47 (2) ◽  
pp. 219-231 ◽  
Author(s):  
Jelena Denin-Djurdjevic ◽  
Ognjen Macej ◽  
Snezana Jovanovic

Skim milk was reconstituted to obtain milk with 8.44% DM, which was standardized with demineralized whey powder (DWP) to obtain milk sample A (9.71% DM) and milk sample B (10.75% DM). Milk samples were heat treated at 85?C/20 min and 90?C/10 min, respectively. Untreated milk was used as control. Milk samples were inoculated with 2.5% of commercial yogurt culture (containing Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus in the ratio 1:1) at 43?C. Samples were incubated until pH 4.6 was reached. Samples were immediately cooled to 4?C and held at that temperature until analyses. Samples of acid casein gels were stirred after 1, 7 and 14 days of storage. Measurements of viscosity were done with Brookfield DV-E Viscometer. Spindle No 3 at 30 rpm was used for all samples. Duration of fermentation decreased when DWP was used for standardization of milk dry matter content. Yogurt samples produced from milk heat treated at 85?C/20 min, obtained by stirring of gel 1 day after production had a higher viscosity than sample produced from milk heat treated at 90?C/10 min. On the other hand, samples produced from milk heat treated at 90?C/10 min had a greater viscosity after 7 and 14 days of storage, which indicates a greater hydrophilic properties and a more pronounced swelling of casein micelles.


2012 ◽  
Vol 5 (1-2) ◽  
Author(s):  
Milka Stijepić ◽  
Dragica Đurđević-Milošević ◽  
Jovana Glušac

Due to a growing demand for functional fermented dairy foods with improved nutritional qualities, the food processing industry has prompted to cut down on ingredients such as fat, sugar and additives, thereby necessitating some important changes in sensory qualities that influence consumer acceptance of fermented dairy products. Addition of functional ingredients such as whey protein concentrate (WPC) and honey may improve overall quality of yoghurt. It is well known ability of WPC to support formation of whey protein aggregates which highly improve physical properties of yoghurt. Honey may be an ideal sweetener for yoghurt due to its sugar concentration, low pH and a variety of beneficial nutritional properties.The aim of the present study was to examine the effect of WPC (1%), as well as combination of WPC and honey (H: 2% and 4%) on the physical and chemical properties of low fat set-style yoghurt during 21 days of storage at 5°C. Yogurt was prepared from milk (1.5% fat), treated on 95ºC for 10 min and yoghurt culture VIVOLAC DriSet Yogurt 442: 10% Lactobacillus delbrueckii subsp. bulgaricus and 90% Streptococcus thermophilus (Vivolac Culture Corporation, Indiana, USA), applying standard manufacturing procedure. It was concluded that the addition of honey in combination with WPC improved quality of produced yoghurt. On the other side, as honey presents a higher nutrition value ingredient, the addition of different percent of honey in combination with WPC could present a novel formulation for functional fermented dairy food.


2020 ◽  
Vol 8 (5) ◽  
pp. 656 ◽  
Author(s):  
Xiang Fang ◽  
Qinchun Duan ◽  
Zhuo Wang ◽  
Fuyun Li ◽  
Jianxiong Du ◽  
...  

‘Red Globe’ table grapes are large, edible, seeded fruit with firm flesh that tastes good, but can have poor postharvest shelf-life. This study was conducted to explore the effects of products of Lactobacillus delbrueckii subsp. bulgaricus strain F17 and Leuconostoc lactis strain H52 on ‘Red Globe’ table grapes for the enhancement of shelf-life and improvement of grape quality characteristics during postharvest storage. Strains F17 and H52 were isolated from traditional fermented yak milk obtained in the Qinghai–Tibetan Plateau. Samples from untreated and treated grapes were analyzed for physicochemical, biochemical, and microbiological properties (weight loss, decay rate, pH, total soluble solids content, titratable acidity, total phenols, sensory evaluation, and microbial growth) for 20 days. The results demonstrated that supernatants from both strains significantly reduced weight loss, decay rate, aerobic mesophilic bacteria, and coliform bacteria counts; delayed maturity and senescence of table grapes; and reduced titratable acidity and total phenols. However, the supernatant of strain F17 was more effective and resulted in better sensory evaluations and had a significant inhibitory effect on yeast and molds by day 5. Meanwhile, the supernatant from strain H52 had a significant inhibitory effect on fungi over the whole storage period. In addition, the results of the Pearson correlation analysis suggested that weight loss, decay rate, total soluble solids content, and microorganisms were highly correlated with the sensory evaluation data and quality of postharvest grapes when treated with the products of strain F17. On the basis of these data and sensory organoleptic qualities, the supernatant containing products from strain F17 had the best potential as a biopreservative to improve the postharvest quality of ‘Red Globe’ table grapes.


2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Lin Yang

In this research, the synergistic effect of trisodium citrate (TSC) and microbial transglutaminase (TGase) treatment on the textural properties of acidified yak skim milk gels was investigated. TSC was added to yak skim milk to concentrations of 0, 20, and 40 mmol/L, followed by adjusting the pH to 6.7. The samples were incubated with TGase for the cross-linking reaction, after which the samples were acidified with 1.4% (w/v) gluconodelta-lactone (GDL) at 42°C for 4 h to form gels. The stiffness and water holding capacity (WHC) of gels exhibited higher values at 20 or 40 mmol/L than without TSC. The final storage modulus (G′) of yak milk gels was positively related to the concentration of TSC prior to TGase treatment. Cryoscanning electron microscopy observations showed that the gel networks were more rigid with higher TSC concentrations. Overall, TSC dissociated particles in yak milk into smaller ones. The newly formed particles in yak skim milk could form acid-induced gels with greater stiffness and higher WHC in the presence of TGase.


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