The influence of probiotic bacteria on the properties of Iranian white cheese

The viability of Bifidobacterium animalis (ATCC 25527) and Lactobacillus rhamnosus (ATCC 7469), study of interaction between probiotic and starter and their effect on the properties of Iranian white cheese were investigated during 60 days of ripening. The results indicated that probiotics did not exert any effect on the growth of commercial starters, but starters showed a synergistic effect on the growth of probiotics, and probiotics survived above the recommended level for the therapeutic minimum (10⁶–10⁷ cfu/g) after 60 days. Addition of probiotic adjunct did not alter the chemical composition except for moisture and protein. Also, the highest pH value was in probiotic cheeses without starter.     

Effect of Microencapsulation on Viability of Lactobacillus acidophilus LA-5 and Bifidobacterium bifidum BB-12 During Kasar Cheese Ripening

The viability of encapsulated Lactobacillus acidophilus LA-5 and Bifidobacterium bifidum BB-12 by emulsion or extrusion techniques in Kasar cheese was investigated. The microbiological, biochemical and organoleptic properties of cheeses were assessed throughout 90-day storage. Results showed that the viability of probiotic bacteria was maintained to a great extent by microencapsulation. No difference was noted between the two encapsulation techniques with regard to bacterial counts, proteolysis and organoleptical properties of the final products. Scalding caused a drastic decline in the counts of probiotic bacteria in all cheeses. Following scalding, while the numbers of nonencapsulated probiotic bacteria decreased continuously in the control cheese, the numbers of encapsulated bacteria remained well above the threshold for a minimum probiotic effect (10⁷ cfu/g).     

In vivo demonstration of enhanced probiotic effect of co-immobilized Lactobacillus acidophilus and Bifidobacterium bifidum

The present study was undertaken to evaluate the effectiveness of co-immobilization as an efficient method for delivering high numbers of viable probiotic cultures to the host for an enhanced probiotic effect, using in vivo mice models. The co-immobilized culture of Lactobacillus acidophilus and Bifidobacterium bifidum was fed to eight groups of conventional mice. A greater persistence of probiotic cultures was noticed in the intestinal contents of the groups fed on co-immobilized cells. Further, the supplementation of diet with co-immobilized culture also resulted in maximum lowering of faecal coliforms and the enzymatic activity as compared to the prestudy level.     

Effect of Lactobacillus plantarum LS5 on oxidative stability and lipid modifications of Doogh

The oxidative stability and lipid modifications of Doogh prepared with Lactobacillus plantarum LS5 and control Doogh were compared during storage for 22 days. In vitro scavenging activity against 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) free radicals showed that L. plantarum LS5 had radical scavenging activities (49.6%). Peroxide value, conjugated diene value and anisidine value measurements in Doogh lipid samples in combination with Fourier transform infrared spectroscopy demonstrated that Doogh prepared with L. plantarum LS5 was more stable than the control against formation of primary and secondary oxidation products. Furthermore, higher concentrations of short‐chain fatty acids (butyric and caproic) and unsaturated fatty acids were found in Doogh treated with L. plantarum LS5. Changes in the thermograms of all samples were also observed. Results of differential scanning calorimetry indicated that melting points of lipids from treated Doogh were lower than for the control. It was concluded that L. plantarum LS5 could be used as a natural preservative in functional dairy products and could beneficially affect the consumer by providing dietary sources of antioxidants.     

Preliminary investigation of the combined effect of heat treatment and incubation temperature on the viability of the probiotic micro-organisms in freshly made yogurt

The combined effects of heat treatment and incubation temperature were studied on the viability and fermentation time of probiotics in ABY 1 probiotic yogurt ( Lactobacillus acidophilus , Bifidobacterium spp. and yogurt bacteria). Three levels of heat treatment (85°C for 30 min, 95°C for 5 min and 95°C for 15 min) and three levels of incubation temperature (37, 40 and 44°C) were selected. At the end of fermentation, the maximum viability of probiotics (for both L. acidophilus and Bifidobacterium spp . ) was observed when the milk was heated at 95°C for 15 min and incubated at 37°C. Incubation time was only affected by the incubation temperature and, at 37°C, the longest incubation time of about 6 h was needed to achieve the highest viable counts of L. acidophilus and Bifidobacterium spp.     

Effect of refrigerated storage temperature on the viability of probiotic micro-organisms in yogurt

The effect of refrigerated storage temperature was studied at 2, 5 and 8°C on the viability of probiotics in ABY ( Lactobacillus acidophilus, Bifidobacterium lactis BB-12 and yogurt bacteria. Bulgaricus , i.e. Streptococcus thermophilus and Lactobacillus delbrueckii ssp. Bulgaricus ) probiotic yogurt. The study was carried out during a 20-day refrigerated storage period to identify the best storage temperature(s). Also, the viability change of the probiotic micro-organisms was analysed at 5-day intervals throughout the refrigerated storage period. After 20 days, storage at 2°C resulted in the highest viability of L. acidophilus , whereas for Bifidobacterium lactis the highest viability was obtained when yogurt was stored at 8°C.     

双歧杆菌方管计数法的设计与应用

利用双层半固体培养基具有良好厌氧性的特性，在实验的基础上，提出了采用方形试管对双歧杆菌进行计数的方法，介绍了该方法的基本原理和操作步骤。结果表明，该方法具有操作简例、检测时间短、设备要求低等特点。     

两歧双歧杆菌与嗜酸乳杆菌微生态制剂的工业化生产工艺研究

研究了两歧双歧杆菌和嗜酸乳杆菌双联微生态制剂的工业化生产工艺。对发酵培养基及发酵条件进行了研究和优化，并确定了发酵奶的冷冻干燥工艺条件。冻干后的产品中两歧双歧杆菌和嗜酸乳杆菌的活菌数均达到了10^9-10^10g^-1，而且在冻干工艺条件下，发酵产物中的各种活性成分得以最大限度地保存下来，使产品可以达到作为微生态制剂应用的相关标准。     

Microbiological and physicochemical properties of dry‐cured neck inoculated with probiotic of Bifidobacterium animalis ssp. lactis BB‐12

The effect of inoculum level of Bifidobacterium animalis ssp. lactis BB‐12 probiotic strain and ripening period on the quality of dry‐cured neck was studied. The microbiological parameters (Enterobacteriaceae, LAB and TVC) and physicochemical attributes (pH value, a_w, TBARS index, colour) were determined directly after fermentation at 15 °C for 3 weeks, after 6 and 12 months of ripening at 4 °C. The highest LAB count and a lower pH value were found in the meat inoculated with probiotic strain at 6.6 log cfu g^?1 (B2) followed by inoculation with probiotic strain at 6.3 log cfu g^?1 (B1). Level of inoculation had not had an influence on water activity, TBARS index and total colour parameters. Changes of fat oxidation during half‐year of ripening were limited in probiotic meat samples compared to naturally fermented control meat (C). Based on the results, it can be concluded that the most favourable physicochemical and microbiological parameters of the dry‐cured neck were obtained after 6 months of ripening. At that time, the Bifidobacterium BB‐12 at both levels is a good potential starter for meat fermentation.     

Viability of probiotic micro-organisms (Lactobacillus casei Shirota and Bifidobacterium animalis subspp. lactis) in a milk-based dessert with cranberry sauce

The objective of this study was to evaluate the survival of two probiotic micro-organisms, Lactobacillus casei Shirota and Bifidobacterium animalis subspp . lactis , in a milk-based dessert (2.7% fat) with cranberry sauce added. B. lactis had a final concentration of 1.99 × 10⁶ cfu/g after 21 days of study, with a logarithmic decrease of 8.87%. On other hand, L. casei Shirota had a final concentration of 2.05 × 10⁷ cfu/g at the end of the same period, a logarithmic decrease of 8.41%. Statistical analysis showed that significant differences existed between both micro-organisms and over various storage times, the more viable micro-organism being L. casei Shirota , which decreased less than one logarithmic cycle after 21 days.     

海藻酸钠二次包衣对益生菌微胶囊包埋效果的影响研究

为了考察海藻酸钠二次包衣对两歧双歧杆菌F-35包埋效果的影响,本研究分别制备得到了海藻酸钠微胶囊（AL-M）、蛋白质微胶囊（WP-M）和海藻酸钠二次包衣的微胶囊（AL-CM）,并从三个方面（壁材降解速度、益生菌释放速度和益生菌存活情况）对这三种微胶囊在连续模拟胃肠液环境下的降解进行了比较。结果表明,海藻酸钠二次包衣能够显著降低胃蛋白酶对乳清蛋白的降解作用。相比于AL-M和WP-M,AL-CM会延缓两歧双歧杆菌F-35在模拟肠液中的释放速率,并且在连续的模拟胃肠道中经过二次包以后的微胶囊中对两歧双歧杆菌F-35保护效果最好,两歧双歧杆菌F-35最终的存活率高达51.0%。      

不同提取工艺对花生乳物理、化学及感官特性的影响

研究了不同提取工艺对花生乳物理、化学及感官特性的影响。花生在含有0.5%NaHCO3的溶液中浸泡后提取的花生乳滋味更好,色泽更白;均质能增进乳白色,并使花生乳稳定。磨浆前将花生预煮致使花生乳中的蛋白质和可溶性固形物降低,同时也使引起不良气味的主要物质———己醛含量大为减少。最佳工艺条件为:在含0.5%NaHCO3的溶液中浸泡,预煮10min,在28MPa压力下均质。     

Effects of coagulant type on the physicochemical and organoleptic properties of Kashar cheese

Kashar cheeses were manufactured using different coagulants (calf rennet, chymosin derived by fermentation and proteases from Rhizomucor miehei and Cryphonectria parasitica) and ripened for 90 days. Use of different coagulants did not influence the dry matter, fat, protein, salt, pH, titratable acidity, total free fatty acids and texture profile analyses. The levels of water‐soluble nitrogen, 12% trichloroacetic acid‐soluble nitrogen, and for 5% phosphotungstic acid‐soluble nitrogen, the sensory properties were significantly influenced by the use of different coagulants. β‐casein was more hydrolysed in the cheese manufactured using protease from Cryphonectria parasitica than the other cheeses during 90 d of ripening.     

Probiotic properties of ice creams produced with dietary fibres from by‐products of the food industry

The objective of this study was to investigate the effects of adding dietary fibre‐rich by‐products to probiotic ice creams. For this purpose, fruit (grape, apricot, apple)‐ and grain (rice, corn, sunflower, barley)‐based by‐products were added to ice cream. The viability of Lactobacillus acidophilus (ATCC 4357D‐5) and Bifidobacterium animalis subsp. lactis (ATCC 27536) was determined with microbial analyses at 1, 15, 30 and 60 days of storage. In conclusion, it was shown that dietary fibre‐rich by‐products could be used in ice cream with improved survival of the probiotic strains without any adverse effects on the physicochemical, microbiological and sensory properties of the ice cream.     

Effect of whey protein concentrate,pH and salt on colloidal stability of acid dairy drink (Doogh)

Serum separation of Doogh, an Iranian yoghurt drink, is a major problem. In this study, the effects of whey protein concentrate (WPC) addition, pH of the product and dissolved salt (sodium chloride) in milk on the colloidal stability of Doogh were investigated. By increasing the amount of WPC (from 0.5 to 3%) and salt in milk (from 0 to 1.6%), the serum separation decreased. Increasing pH values of sample (from 3.5 to 4.5), WPC (from 0.5 to 4%) and salt concentration in milk (from 0 to 2%) also increased the samples’ viscosity. All samples showed Newtonian behaviour except samples at pH 4.5, containing 4% WPC and 2% dissolved salt in milk.     

Volatile Profile of Non-Fermented Milk and Milk Fermented by BifidoBacterium animalis subsp. lactis

The aim of this work was to determine low-molecular volatile compounds in milk supplemented with the strain Bifidobacterium animalis subsp. lactis Bb-12 with or without fermentation process, stored at 6°C for 4 weeks. The chromatographic analysis of probiotic-supplemented non-fermented milk and milk fermented by strain Bb-12 revealed the presence of volatile compounds, such as ketones, organic acid, and alcohols. The changes in the volatile profile were influenced by fermentation process and/or prolonged cold storage. The fermentative activity of strain Bb-12 and its intensification between the 2nd and 4th weeks were observed in the cold storage condition of milk.     

Potential application of Saccharomyces boulardii as a probiotic in goat's yoghurt: survival and organoleptic effects

Potential application of Saccharomyces boulardii in yoghurts could offer an alternative probiotic product to people suffering from antibiotic‐associated diarrhoea whilst on treatment. Three different yoghurts were made using goat's milk. Yoghurt 1 was the control with only starter culture added to the milk. For Yoghurt 2, S. boulardii was added in parallel with the starter culture, and for Yoghurt 3, the yeast was added after the yoghurt was coagulated by the starter. Duplicate counts for lactic acid bacteria (LAB) and S. boulardii alongside organoleptic assessment were carried out every 3 days following manufacture and storage at 6 °C. Our results demonstrate that S. boulardii can survive in high numbers for the period of 4 weeks tested without significant changes in taste. Very important is the fact that the presence of the yeast stimulated the survival of the LAB, which in both yeast yoghurts were significantly higher than in the control.     

Modelling the effects of pH, storage temperature and redox potential (Eh) on the survival of bifidobacteria in fermented milk

The effects of storage temperature, pH and E _h on the survival of Bifidobacterium longum and Bifidobacterium animalis ssp. lactis were modelled in a 3 × 4 × 3 factorial design using three storage temperatures (4, 8, 12 °C), four pH (4.0, 4.25, 4.5, 4.75) and three E _h (0, 200, 400 mV) values. Bifidobacterium animalis ssp. lactis showed significantly better survival than B. longum ( P  < 0.0001) in fermented milk under normal environmental conditions. Bifidobacterium longum was more susceptible to acidity and survival was log-linear at low pH values whereas at higher pH pronounced shouldering and tailing effects were apparent. Both individual environmental conditions ( T , pH, E _h) and interactions between E _h and pH affected survival and death was always more rapid in B. longum . Bifidobacterium animalis ssp. lactis generally showed a simple log-linear reduction over time. Temperature, pH and E _h could be manipulated to enhance survival but E _h reduction appears to be the best way to enhance survival without adversely affecting other properties.     

Impact of polylactic acid packaging on the organoleptic and physicochemical properties of tvarog during storage

The influence of polylactic acid (PLA) relative to polyamide/polyethylene (PA/PE) packing material on selected physicochemical attributes of acid curd cheese (ACC) (tvarog) packed in modified atmosphere (90% N₂/10% CO₂) and stored for 3 weeks at 5 ± 1°C was analysed. Three variants of tvarog were produced: (i) one packed in PLA film, (ii) one stored in metalised PLA film and (iii) tvarog packed in PA/PE film. The cheeses were assessed organoleptically. Changes in water and fat contents, titratable acidity, pH, water activity and fat oxidation were measured. Moreover, cheese hardness was determined by means of a double compression test (TPA). ACCs had the appropriate organoleptic attributes and the proper chemical compositions. The type of wrapping film highly significantly differentiated the samples regarding chemical composition, titratable acidity, pH and hardness. The films inhibited fat oxidation, but they did not inhibit transformation of fatty acids into conjugated diene and triene structures. Moreover, the samples differed in the course of changes in lipid extractability and in water activity.