Probiotic yoghurt functionalised with microalgae and Zedo gum: chemical,microbiological, rheological and sensory characteristics

In this study, using a central composite design, the effects of addition of Spirulina platensis and Zedo gum to plain and probiotic yoghurt samples were investigated during storage. Lactobacillus paracasei proliferation was directly dependent on the addition of microalgae and was inversely affected by storage time. Probiotic samples containing S. platensis showed the highest antioxidative activity. Maximum stability was obtained at higher amounts of Zedo gum, while organoleptic and rheological attributes improved at 0.25% Zedo gum. Given the importance of probiotic viability, supplementation of probiotic yoghurt with Zedo gum/S. platensis may be consideredas a novel nutraceutical formulation.     

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.     

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。     

Edible table (bio)spread containing potentially probiotic Lactobacillus and Bifidobacterium species

A prototype of a reduced fat (60% w/w) edible table biospread, with an added viable, nongrowing, mixed-strain and potentially probiotic culture was developed. Conventional commercial aqueous-phase ingredient and reduced fat spread processing technologies were modified to achieve acceptable strain viability ( ≥   10⁵ cfu/mL) during scraped-surface heat exchange emulsion processing and biospread shelf life. The modifications consisted of:

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   spilt-stream pasteurization of the aqueous and lipid phases (thereby obviating the need for in-line pasteurization of the water-in-oil emulsion during processing);

       
  
  

Optimisation of probiotic yoghurt production enriched with phytosterols

To optimise the formulation of phytosterol‐enriched probiotic yoghurt, the effect of different concentrations of phytosterols, fat and the probiotic inoculation rate on the survival of Lactobacillus acidophilus LA‐5, Bifidobacterium lactis BB‐12 and physicochemical indices over 14 days of storage was explored. Data analysis showed that the phytosterol concentration and fat content were two crucial factors affecting probiotic viability. Addition of phytosterols had no adverse effect on the overall scores for sensory attributes. Regarding maximisation of viability and storage time, the optimum conditions were found to be fat = 8.07% (w/v), phytosterol = 18 g/L, probiotic inoculation rate = 71.42 mg/L and storage time = 12 days.     

Synthesis and utilisation of folate by yoghurt starter cultures and probiotic bacteria

Thirty-two bacterial isolates from species commonly used in yoghurts and fermented milks were examined for their ability to synthesise or utilise folate during fermentation of skim milk. The organisms examined included the traditional yoghurt starter cultures, Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus, and probiotic lactobacilli, bifidobacteria, and Enterococcus faecium. Folate was synthesised by S. thermophilus, bifidobacteria, and E. faecium. S. thermophilus was the dominant producer, elevating folate levels in skim milk from 11.5 ng g⁻¹ to between 40 and 50 ng g⁻¹. Generally, lactobacilli depleted the available folate in the skim milk. Fermentations with mixed cultures showed that folate production and utilisation by the cultures was additive. Fermentations using a combination of Bifidobacterium animalis and S. thermophilus resulted in a six-fold increase in folate concentration. Although increased folate levels in yoghurts and fermented milks are possible through judicious selection of inoculum species, the folate levels remain relatively low in terms of recommended daily allowance.     

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).     

Optimisation of a pilot‐scale spray drying process for probiotic yoghurt,using response surface methodology

The influence of drying air temperatures, drying air flow rate and feed flow rate on percentage survival rate (% SR) of starter and probiotic bacteria, moisture content, water activity and colour of probiotic yoghurt powder produced using a pilot‐scale spray dryer was investigated. Optimisation of spray drying conditions was achieved based on the desirability value. Results showed that inlet air temperature, drying air flow rate, feed flow rate and outlet air temperature of 150 °C, 478 m³/h, 2 L/h and 63.3 °C, respectively, were optimal conditions to produce powder that meets quality specifications and with a satisfactory% SR.     

Effect of packaging materials and dissolved oxygen on the survival of probiotic bacteria in yoghurt

The effects of packaging materials on the dissolved oxygen and the survival of the probiotic bacteria in yoghurt were studied. Oxygen adapted and non‐oxygen adapted strains of Lactobacillus acidophilus and Bifidobacterium spp. were incorporated in yoghurts, which were packaged in oxygen permeable high‐impact polystyrene (HIPS), oxygen‐barrier material (Nupak^TM) and Nupak^TM with an oxygen scavenging film (Zero₂^TM). During storage the dissolved oxygen increased steadily in HIPS packaged yoghurt whereas it remained low in yoghurts packaged in Nupak^TM and Zero₂^TM. In all yoghurts, no significant decreases were observed in the viability of either oxygen adapted or non‐oxygen adapted cells of L. acidophilus and Bifidobacterium spp. Thus, although the dissolved oxygen in yoghurt can be influenced by the type of packaging material, it may not affect the survival of probiotic bacteria in yoghurts.     

Effect of milk supplementation and culture composition on acidification, textural properties and microbiological stability of fermented milks containing probiotic bacteria

In the present work, the combined effect of milk supplementation and culture composition on acidification, textural properties, and microbiological stability of fermented milks containing probiotic bacteria, was studied. Three powders (whey, casein hydrolysate, and milk proteins) were tested as supplementation. Two strains of probiotic bacteria, Lactobacillus acidophilus (LA5) and Lactobacillus rhamnosus (LC35), were used in pure culture, and in mixed culture with Streptococcus thermophilus (ST7). Acidifying activity was enhanced with mixed cultures, compared to pure cultures resulting in a shorter time to reach pH 4.5. Acidifying activity was greatly improved with casein hydrolysate, with a reduction of the fermentation time by about 55% by comparison with the other supplementations. The stability of probiotic bacteria was weakly affected by milk supplementation and culture composition. However, pure cultures were more stable than mixed cultures. The texture of the fermented products was not dependent on culture composition, but strongly dependent on milk supplementation. Sweet whey supplementation gave products with lower firmness and viscoelasticity than products supplemented with casein hydrolysate or milk proteins (decrease by 70%). It was observed that all products containing probiotic counts over 2.2×10⁷ CFU mL⁻¹ are suitable for the development of a lactic beverage containing probiotics.     

The effect of hydrolysed tragacanth gum and inulin on the probiotic viability and quality characteristics of low‐fat yoghurt

This study investigates the effect of supplementation of tragacanth gum (GT, 0.05% w/v), low molecular weight gum tragacanth (LMWGT, 0.5% w/v) and inulin (0.5% w/v) on the viability of Bifidobacterium bifidum and the quality parameters of low‐fat yoghurt during a three‐week storage period. The count of probiotics was found to be 7.8 log cfu/g in inulin, and LMWGT enriched yoghurts at the end of the storage period. The minimum water holding capacity and the maximum syneresis values were also obtained in the low‐fat yoghurt enriched with GT throughout the storage time. The samples containing inulin and LMWGT revealed sensory attributes that were judged superior compared to those in GT.     

Viability of probiotic micro-organisms during storage, postacidification and sensory analysis of fat-free yogurts with added whey protein concentrate

The aim of this research was to evaluate the effect of the addition of whey protein concentrate (WPC) on the viability of Lactobacillus acidophilus and Bifidobacterium longum and on postacidification throughout the shelf life of fat-free yogurts, and also to analyse the sensory characteristics of the products. Postacidification was not significantly changed by the addition of WPC, but was decreased by Lactobacillus bulgaricus inoculation. WPC did not influence the viability of the lactic acid bacteria ( L. bulgaricus and Streptococcus thermophilus ), but it improved the growth and survival of the micro-organisms L. acidophilus and B. longum , especially the former. The panellists did not identify significant differences ( P <  0.05) of the yogurts due to the addition of WPC.     

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.     

Influence of microencapsulation and transglutaminase on viability of probiotic strain Lactobacillus helveticus M92 and consistency of set yoghurt

The effect of microencapsulated probiotic Lactobacillus helveticus M92 cells and transglutaminase addition on the probiotic set yoghurt properties was investigated. Addition of probiotic bacteria, either free or microencapsulated in sodium caseinate, decreased the fermentation time and significantly enhanced the appearance and consistency of probiotic set yoghurt. Better survival of microencapsulated than free probiotic bacteria in produced yoghurts during storage, as well as during exposure to simulated gastrointestinal conditions, emphasises the efficiency of microencapsulation in the cell protection. Pretreatment of the milk with transglutaminase increased the gel strength and decreased the syneresis, which resulted in a better appearance and consistency of probiotic set yoghurts.     

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.     

Effect of refrigerated storage time on the viability of probiotic bacteria in fermented probiotic milk drinks

The viability of Lactobacillus acidophilus and Bifidobacterium lactis in fermented milks A, B and AB, containing respectively these strains separately and mixed, was studied over 21 days of storage at 5°C. Samples were analysed for titratable acidity and viable cell counts of probiotics. Milks A and AB showed post-acidification mainly due to the β-galactosidase activity of L. acidophilus . Generally, the viability of the probiotics decreased during storage, whereas, in some cases, the proteoletic activity of L. acidophilus resulted in a higher survival rate of the probiotics even with the adverse effects of low temperature and organic acids.     

Effects of guar gum and arabic gum on the physicochemical,sensory and flow behaviour characteristics of frozen yoghurt

This study investigated the effect of guar gum and arabic gum on physicochemical, sensory and flow behaviour properties of frozen yoghurt. The results indicated that gums significantly affected the viscosity, overrun and melting rate of frozen yoghurt. The highest overrun value was observed in sample containing 0.5% arabic gum. Frozen yoghurt containing 0.3% guar gum had the highest viscosity. The longest first dripping time was observed in sample containing 0.5% arabic gum. Flow behaviour of samples showed that all frozen yoghurts exhibited shear thinning behaviour. Guar gum at a concentration of 0.2% and arabic gum at a concentration of 0.5% presented the best total acceptability. The results of this study revealed that the frozen yoghurt produced with arabic gum had the better overall sensory and physicochemical characteristics.     

益生菌豆酸乳发酵条件的优化

豆酸乳是将大豆磨浆后与牛乳混合经乳酸菌发酵而赋予特殊风味的产品,但尚未有仅用嗜酸乳杆菌和两歧双歧杆菌2株菌来发酵益生菌豆酸乳的报道。对碳源、生长促进因子、稳定剂和温度等发酵条件进行优化,实验结果表明:在豆水比为1:8、牛乳含量为30%的豆浆牛乳混合物中添加4.0%的蔗糖、0.3%的葡萄糖、0.6%的低聚果糖、0.8%的BY-H-260,在无菌条件下添加0.005%的嗜酸乳杆菌菌粉和0.015%的两歧双歧杆菌菌粉,在42℃条件下发酵5～5.5 h,酸度可达70～75°T(pH为4.0左右),活菌数可达108cfu/mL级,组织状态良好。     

嗜酸乳杆菌和双歧杆菌肠溶活菌制剂的研究

对双歧杆菌和嗜酸乳杆菌进行最适pH值流加中和培养，真空冷冻干燥处理后，利用相应的机械设备及特殊的工艺处理，研制出双歧杆菌和嗜酸乳杆菌的肠溶软胶囊、肠溶硬胶囊和普通硬胶囊等系列活菌制剂。并且对这些制剂进行了物理性状、胃肠崩解、模拟胃肠综合试验，以及常温保存试验等分析检测，对上述各种制剂的特性及性能指标作出了客观评价。