An Influence of Fructan Containing Concentrate from Jerusalem Artichoke Tubers on the Development of Probiotic Dairy Starters on Milk and Oat-based Substrates

Supplementation of milk and oat hydrolysate containing medium with Jerusalem artichoke concentrate (JAC) and subsequent fermentation with probiotic dairy starters resulted in substantial stimulation of probiotics Bifidobacterium lactis and Lactobacillus acidophilus as well as yogurt starter culture Lactobacillus bulgaricus development and acidification rate. The strain-specific responses of the general yogurt cultures, as well as probiotics to the addition of JAC, should be considered to achieve optimal composition of probiotic strains and conformable fermentation conditions. JAC is suggested to be perspective prebiotic additive for fermented synbiotic milks or oat-hydrolysate-based products.     

Effect of milk base and starter culture on acidification,texture, and probiotic cell counts in fermented milk processing

In the present work, the compared effect of milk base and starter culture on acidification, texture, growth, and stability of probiotic bacteria in fermented milk processing, was studied. Two strains of probiotic bacteria were used, Lactobacillus acidophilus LA5 and L. rhamnosus LR35, with two starter cultures. One starter culture consisted only of Streptococcus thermophilus ST7 (single starter culture); the other was a yogurt mixed culture with S. thermophilus ST7 and L. bulgaricus LB12 (mixed starter culture). For the milk base preparation, four commercial dairy ingredients were tested (two milk protein concentrates and two casein hydrolysates). The resulting fermented milks were compared to those obtained with control milk (without enrichment) and milk added with skim milk powder. The performance of the two probiotic strains were opposite. L. acidophilus LA5 grew well on milk but showed a poor stability during storage. L. rhamnosus LR35 grew weakly on milk but was remarkably stable during storage. With the strains tested in this study, the use of the single starter culture and the addition of casein hydrolysate gave the best probiotic cell counts. The fermentation time was of about 11 h, and the probiotic level after five weeks of storage was greater than 106 cfu/ml for L. acidophilus LA5 and 10(7) cfu/ml for L. rhamnosus LR35. However, an optimization of the level of casein hydrolysate added to milk base has to be done, in order to improve texture and flavor when using this dairy ingredient.     

Probiotic fermented beverages based on acid whey

Acid whey is a byproduct of cheesemaking that is difficult to use because of its low pH and less-favorable processing properties compared with rennet whey. The aim of this study was to evaluate the qualities of fermented beverages made using acid whey. In manufacturing the beverages, we used probiotic cultures Lactobacillus acidophilus LA-5 or Bifidobacterium animalis ssp. lactis BB-12. The production process included combining pasteurized acid whey with UHT milk, unsweetened condensed milk, or skim milk powder. We introduced milk to enrich casein content and obtain a product with characteristics similar to that of fermented milk drinks. The products were stored under refrigerated conditions (5 ± 1°C) for 21 d. During storage, we assessed the beverages' physicochemical properties and organoleptic characteristics. The properties of the beverages depended on their composition, microbial culture, and storage time. Beverages containing L. acidophilus had higher acidity, which increased during storage; the acidity of samples containing B. animalis was more stable. Beverages made with skim milk powder (La1 and Bb1) had higher acetaldehyde content, but this parameter decreased in all samples during storage. The hardness of the samples did not change during storage and was highest in beverage La3, made from whey, condensed milk, and L. acidophilus. Beverage La2, made from whey, milk, condensed milk, and L. acidophilus, had the best sensory properties. The whey beverages we developed provided a good medium for the probiotic bacteria; bacteria count throughout the storage period exceeded 8 log cfu/mL, distinctly higher than the minimum therapeutic dose.     

Physical properties and microstructure of yoghurts supplemented with milk protein hydrolysates

The physical properties and the microstructure of yoghurts containing probiotic bacteria, and supplemented with milk protein hydrolysates, were studied. Three casein hydrolysates and three whey protein hydrolysates were added to milk at a concentration ranging from 0.25 to 4 g L⁻¹. The milks were then fermented with either of two different cultures. The resulting yoghurts with added hydrolysates were compared to the control yoghurt without supplementation. For both cultures, addition of hydrolysates decreased the complex viscosity and graininess in yoghurts. The addition of hydrolysates also reduced fermentation time. Microstructural observations showed a more open and less branched structure in yoghurts when milk protein hydrolysates were incorporated. The difference in fermentation time between milks with different levels of added hydrolysates could partially explain the differences in microstructure and physical properties of the final yoghurts.     

Growth of Probiotic and Traditional Yogurt Cultures in Milk Supplemented with Whey Protein Hydrolysate

ABSTRACT: Growth of some probiotic bacteria was significantly improved in milk supplemented with whey protein hydrolysate (WPH). However, WPH had no effect on the growth of Lactobacillus delbrueckii ssp. bulgaricus 18, L. delbrueckii ssp. bulgaricus 10442, and Streptococcus thermophilus 1. When the probiotic bacteria were grown in combination with different yogurt cultures in milk, WPH caused significant increases in growth of Bifidobacterium longum S9, L. acidophilus O16, and L. acidophilus L-1. However, by day 28 of refrigerated storage, the populations of the probiotic cultures that had been grown in samples supplemented with WPH were similar or below those in the control samples.     

Effect of milk fat replacement by polyunsaturated fatty acids on the microbiological,rheological and sensorial properties of fermented milks

A modified milk (W3DD) where fat had been replaced by oils enriched in ω‐3 polyunsaturated fatty acids was used for the manufacture of a set‐type fermented product. In order to improve the organoleptic properties of the product, 30 g l^?1 whey protein concentrate (WPC) was added during the manufacturing process. Samples were fermented employing a commercial probiotic starter culture (ABT‐2), which contained Streptococcus thermophilus ST‐20Y, Lactobacillus acidophilus LA‐5 and Bifidobacterium lactis BB‐12. The acidification process was dependent on the WPC addition, which favoured the increase of viable counts, but fermentation was not influenced by the milk fat composition. The highest counts of the probiotic strains, L acidophilus LA‐5 (3.3 × 10⁵ cfu g^?1) and B lactis BB‐12 (5.5 × 10⁷ cfu g^?1), after 21 days of storage at 4 °C, were found in fermented products derived from W3DD supplemented with WPC. Addition of WPC also increased the firmness of the products and reduced syneresis. No apparent colour changes due to fat composition or WPC supplementation were observed in the products. Milk fat replacement by oils rich in ω‐3 polyunsaturated fatty acids had a negative influence on the product texture but did not affect the typical yoghurt flavour. These defects were overcome by the addition of 30 g l^?1 WPC, which improved the appearance, texture and general acceptability scores in the product. Copyright © 2004 Society of Chemical Industry     

Influence of cofermentation by amylolytic Lactobacillus strains and probiotic bacteria on the fermentation process,viscosity and microstructure of gruels made of rice,soy milk and passion fruit fiber

Gruels tailored to school-age children and made of soy milk and rice flour with or without total dietary fiber from passion fruit by-product were fermented by amylolytic lactic acid bacteria strains (Lactobacillus fermentum Ogi E1 and Lactobacillus plantarum A6), by commercial probiotic bacteria strains (Lactobacillus acidophilus L10, Lactobacillus casei L26 and Bifidobacterium animalis subsp. lactis B94) and by co-cultures made of one amylolytic and one probiotic strain. The influence of ingredient composition and bacterial cultures on kinetics of acidification, α-amylase activity of the bacteria, apparent viscosity and microstructure of the fermented products was investigated. During fermentation of the gruels, α-amylase activity was determined through the Ceralpha method and apparent viscosity, flux behavior and thixotropy were determined in a rotational viscometer. Rheological data were fitted to Power Law model. The combination of amylolytic and probiotic bacteria strains reduced the fermentation time of the gruels as well as increased the α-amylase activity. The addition of passion fruit fiber exerted less influence on the apparent viscosity of the fermented products than the composition of the bacterial cultures. Scanning electron microscopy provided evidence of exopolysaccharide production by amylolytic bacteria strains in the food matrices tested. The co-cultures made of amylolytic and probiotic bacteria strains are suitable to reduce the fermentation time of a soy milk/rice matrix and to obtain a final product with pH and viscosity similar to yoghurt.     

Physiochemical Properties,Microstructure, and Probiotic Survivability of Nonfat Goats’ Milk Yogurt Using Heat‐Treated Whey Protein Concentrate as Fat Replacer

There is a market demand for nonfat fermented goats’ milk products. A nonfat goats’ milk yogurt containing probiotics (Lactobacillus acidophilus, and Bifidobacterium spp.) was developed using heat‐treated whey protein concentrate (HWPC) as a fat replacer and pectin as a thickening agent. Yogurts containing untreated whey protein concentrate (WPC) and pectin, and the one with only pectin were also prepared. Skim cows’ milk yogurt with pectin was also made as a control. The yogurts were analyzed for chemical composition, water holding capacity (syneresis), microstructure, changes in pH and viscosity, mold, yeast and coliform counts, and probiotic survivability during storage at 4 °C for 10 wk. The results showed that the nonfat goats’ milk yogurt made with 1.2% HWPC (WPC solution heated at 85 °C for 30 min at pH 8.5) and 0.35% pectin had significantly higher viscosity (P < 0.01) than any of the other yogurts and lower syneresis than the goats’ yogurt with only pectin (P < 0.01). Viscosity and pH of all the yogurt samples did not change much throughout storage. Bifidobacterium spp. remained stable and was above 10⁶CFU g^‐1 during the 10‐wk storage. However, the population of Lactobacillus acidophilus dropped to below 10⁶CFU g^‐1 after 2 wk of storage. Microstructure analysis of the nonfat goats’ milk yogurt by scanning electron microscopy revealed that HWPC interacted with casein micelles to form a relatively compact network in the yogurt gel. The results indicated that HWPC could be used as a fat replacer for improving the consistency of nonfat goats’ milk yogurt and other similar products.     

Molecular Characterization and Identification of Bioactive Peptides Producing Lactobacillus sps. Based on 16S rRNA Gene Sequencing

In the present study, 3 bacterial cultures were isolated from faecal samples of human infant. The biochemical traits showed similarity with Lactobacillus sps and 16S rRNA sequence analyses, confirmed as Lactobacillus plantarum, Lactobacillus casei, and Lactobacillus rhamnosus. The cultures were screened for their proteolytic activity and good ability to release peptides from milk proteins was found. Hence, these bacteria were used as a proteolytic starter culture for the fermentation of skim milk and whey for the liberation of small peptides. Bioactive nature of the peptides released from whey and skim milk was tested, and results demonstrated that peptides obtained after fermentation of whey and skim milk by Lactobacillus strains showed antimicrobial activity against all the pathogens causing food borne infections in humans. These peptides also indicated antioxidant as well as ACE (angiotensin-converting enzymes) inhibitory activity.     

EFFECT OF COLD STORAGE ON CULTURE VIABILITY AND SOME RHEOLOGICAL PROPERTIES OF FERMENTED MILK PREPARED WITH YOGURT AND PROBIOTIC BACTERIA

ABSTRACT

We examined the effect of storage time on culture viability and some rheological properties (yield stress, storage modulus, loss modulus, linear viscoelastic region, structural recuperation and firmness) of fermented milk made with Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus acidophilus (LA) and Bifidobacterium animalis ssp. lactis in coculture with Streptococcus thermophilus (ST). Acidification profiles and factors that affect viability (postfermentation acidification, acidity and dissolved oxygen) were also studied during 35 days at 4C. Fermented milk prepared with a coculture of ST and Bifidobacterium lactis gave the most constant rheological behavior and the best cell viability during cold storage; it was superior to ST plus LA for probiotic fermented milk production.

PRACTICAL APPLICATIONS

Probiotic cultures should grow quickly in milk, provide adequate sensory and rheological properties to the product, and remain viable during storage. Commercially, it is very common to use yogurt starter culture (i.e. Streptococcus thermophilus[ST] and Lactobacillus delbrueckii ssp. bulgaricus) in combination with the probiotic bacteria in order to reduce fermentation time. However, LB tends to post acidify fermented milk, which reduces the viability of the probiotic bacteria; thus, it is recommended to use starter cultures devoid of this species. We found that the technological properties and the viability of the probiotic bacterium Bifidobacterium animalis ssp. lactis BL O4 in coculture with ST make it suitable for probiotic fermented milk production; it produces rheological characteristics similar to those of yogurt.     

The first dairy product exclusively fermented by Propionibacterium freudenreichii: A new vector to study probiotic potentialities in vivo

Dairy propionibacteria display probiotic properties which require high populations of live and metabolically active propionibacteria in the colon. In this context, the probiotic vector determines probiotic efficiency. Fermented dairy products protect propionibacteria against digestive stresses and generally contain a complex mixture of lactic and propionic acid bacteria. This does not allow the identification of dairy propionibacteria specific beneficial effects. The aim of this study was to develop a dairy product exclusively fermented by dairy propionibacteria. As they grow poorly in milk, we determined their nutritional requirements concerning carbon and nitrogen by supplementing milk ultrafiltrate (UF) with different concentrations of lactate and casein hydrolysate. Milk or UF supplemented with 50 mM lactate and 5 g L⁻¹ casein hydrolysate allowed growth of all dairy propionibacteria studied. In these new fermented dairy products, dairy propionibacteria remained viable and stress-tolerant in vitro during minimum 15 days at 4 °C. The efficiency of milk fermented by the most tolerant Propionibacterium freudenreichii strain was evaluated in piglets. Viability and SCFA content in the colon evidenced survival and metabolic activity of P. freudenreichii. This work results in the design of a new food grade vector, which will allow preclinical and clinical trials.     

Effect of the addition of pulse ingredients to milk on acid production by probiotic and yoghurt starter cultures

Pulses contain carbohydrates, proteins, minerals and vitamins which are essential requirements in the human diet and which could also serve as growth nutrients for probiotic and yogurt starter cultures. In this study, milk supplementation with pulse ingredients is examined as a means to increase the nutritional properties of yogurt and probiotic type beverages. The acid production rate of two yogurt starters (A and B) and two probiotic cultures (Lactobacillus rhamnosus and Lactobacillus acidophilus) was followed in milk supplemented with the following soy and pulse ingredients: pea protein, chickpea flour, lentil flour, pea fibre, soy protein concentrate and soy flour. The pulse ingredients had no negative effect on the acidification trends of the fermented milks. On the contrary, with yogurt culture B, pea fibre, pea protein and lentil flour significantly enhanced the acidification rate. All ingredients used for supplementation improved the acidification rate of probiotic cultures, and the highest effects were obtained with lentil and soy flour. Lentil flour had the lowest pH after 12 h which was significantly lower than the product enriched with the same quantity of skim milk powder. The effect of ingredient supplementation on the microbial composition (ratio of cocci to bacilli) of the yoghurt products was also examined. The ratio of cocci to bacilli was between 1.8 and 2.5 for all supplemented yogurt samples obtained with culture A, and these variations were not judged to be statistically significant (p < 0.05). With yogurt products obtained from culture B, however, there was a higher proportional level of lactobacilli in all supplemented samples, as compared to the milk control; the enhanced growth of the lactobacilli was particularly noted when lentil flour was added to milk.     

干酪乳杆菌纯种发酵燕麦乳工艺及其产品质量分析

针对目前益生菌发酵乳制品多为混合菌种发酵动物源乳制品的研究现状,本研究以燕麦为主要原料,通过制备纯燕麦乳,酶解,添加20％牛乳和7％蔗糖以及适量乳化剂与稳定剂,组成发酵培养基,以发酵乳制品中选育出的生长繁殖力强,发酵活力高的干酪乳杆菌05-20为试验菌株,研究接种量、发酵温度、发酵时间等单因素对干酪乳杆菌纯种发酵燕麦乳...     

Survival and activity of 5 probiotic lactobacilli strains in 2 types of flavored fermented milk

The viability of 5 probiotic lactobacilli strains (Lactobacillus acidophilus LA-5, Lactobacillus casei L01, Lactobacillus casei LAFTI L26, Lactobacillus paracasei Lcp37, and Lactobacillus rhamnosus HN001) was assessed in 2 types of probiotic flavored drink based on fermented milk during 21 days of refrigerated storage (5°C). Also, changes in biochemical parameters (pH, titrable acidity, and redox potential) during fermentation as well as the sensory attributes of final product were determined. Among the probiotic strains, L. casei LAFTI L26 exhibited the highest retention of viability during refrigerated storage period, while L. acidophilus LA-5 showed the highest loss of viability during this period. The decline in cell count of probiotic bacteria in strawberry fermented milk was significantly greater compared to peach fermented milk. In an overall approach, peach fermented milk containing L. casei LAFTI L26 was selected as the optimal treatment in this study in both aspects of viability and sensory accpeptibility.     

Viability of the Lactobacillus rhamnosus HN001 Probiotic Strain in Swiss‐ and Dutch‐Type Cheese and Cheese‐Like Products

The objective of this study was to determine the viability of the probiotic Lactobacillus rhamnosus HN001 in Swiss‐type and Dutch‐type cheese and cheese‐like products (milk fat is substituted by stearin fraction of palm fat) during manufacture, ripening, and storage. The use of the probiotic L. rhamnosus HN001 in Dutch‐type cheese and cheese‐like products significantly (P = 0.1) changed their chemical composition (protein and fat content) and an insignificant increase (approximately 1.6% in cheese‐like products and approximately 0.3% in cheese) in yield. L. rhamnosus HN001 did not affect the rate of changes in the pH of ripened cheese and cheese‐like products. A minor increase in probiotic counts was observed in initial stages of production and were partially removed with whey. Ripened cheese and cheese‐like products were characterized by high survival rates of probiotic bacteria which exceeded 8 log CFU/g after ripening. An insignificant reduction in the number of viable probiotic cells was noted during storage of Swiss‐type and Dutch‐type cheese, whereas a significant increase in probiotic cell counts was observed in cheese‐like products during storage.     

The potential use of hydrolysed konjac glucomannan as a prebiotic

Konjac glucomannan hydrolysate was derived enzymatically from konjac flour under optimal conditions. A number of culture strains of lactobacilli and bifidobacteria were grown on De Man, Rogosa and Sharpe (MRS) media supplemented with the hydrolysate. This hydrolysate stimulated the growth of all strains examined. Colony sizes of those strains grown on konjac hydrolysate were significantly (P = 0.001) bigger than those grown on pectin or xylan hydrolysates. Bacterial growth profiles were also conducted on nutrient agar (MRS or modified MRS agar containing konjac hydrolysate) using single strains of lactobacilli or bifidobacteria (Lactobacillus acidophilus, Lactobacillus casei or Bifidobacterium adolescentis), single pathogen cultures (Escherichia coli or Listeria monocytogenes) or mixed bacterial cultures (from chicken breast extract). Although the growth of lactobacilli inhibited the growth of pathogens (single or mixed culture) the pathogens could not grow on the konjac hydrolysate as a sole carbon source. Microbial growth profiles using konjac hydrolysate or inulin in UHT milk were also investigated. The results showed that the numbers of colony forming units (cfu) obtained from milk containing the konjac hydrolysate were significantly (P = 0.01) higher than those containing inulin. It is suggested that the unique properties of konjac hydrolysate make it universally valuable as a prebiotic which can be applied to a wide range of foods, feeds and healthcare/pharmaceutical products. Copyright © 2007 Society of Chemical Industry     

Influence of addition of raffinose family oligosaccharides on probiotic survival in fermented milk during refrigerated storage

The influence of the addition of raffinose family oligosaccharides (RFOs) extracted from lupin seeds on the survival of Bifidobacterium lactis Bb-12 and Lactobacillus acidophilus La-5 in fermented milk during 21 days of storage in refrigerated conditions was studied. For this purpose, viability and metabolic activity (expressed as pH, lactic and acetic acid production and utilization of soluble carbohydrates) of probiotic bacteria were determined. Retention of viability of B. lactis Bb-12 and L. acidophilus La-5 was greater in fermented milk with RFOs. The pH of probiotic fermented milk at 21 days of storage was lower (4.27) compared with probiotic fermented milk with RFOs (4.37). The highest levels of lactic and acetic acid were produced in probiotic fermented milk without RFOs compared with probiotic fermented milk with RFOs during storage at 4 °C. Soluble carbohydrates were utilised in fermented milk with and without RFOs, respectively, for maintaining B. lactis Bb-12 and L. acidophilus populations during refrigerated storage. In conclusion, all these experiments provide convincing evidence that RFOs have beneficial effects on the survival of these probiotic cultures in dairy products. As a result, such stored dairy products containing both probiotics and prebiotics have synergistic actions in the promotion of health.     

Production of a whey‐based functional beverage supplemented with soy isoflavones and phytosterols

Reconstituted whey beverages were prepared from whey powder by adding either soy isoflavones or phytosterols as functional compounds (at levels of 0%, 0.25%, 0.50% or 1.0% w/v) and probiotic bacteria (Lactobacillus acidophilus LA‐5 or Lactobacillus casei LBC‐81). The addition of nutraceuticals did not change the basic composition of the products. However, a time‐dependent increase in sedimentation/phase separation and acidity of fermented functional beverages was observed. Samples supplemented with phytosterols were more preferred by the panel group than the samples supplemented with isoflavones, and no considerable differences were noted between the control and phytosterol‐added samples in terms of overall perception.     

Enhancement of survival of probiotic and non-probiotic lactic acid bacteria by yeasts in fermented milk under non-refrigerated conditions

The effects of yeasts on the survival of probiotic and non-probiotic lactic acid bacteria (LAB) were studied in fermented milk under non-refrigerated conditions (30 °C) with a view to develop ambient-stable fermented milk with live LAB. Five yeasts tested (Saccharomyces bayanus, Williopsis saturnus var. saturnus, Yarrowia lipolytica, Candida kefyr and Kluyveromyces marxianus) enhanced the survival of Lactobacillus bulgaricus (but not Streptococcus thermophilus) in a mixed yoghurt culture in yoghurt by ~ 10² to 10⁵-fold. Seven yeasts examined (Candida krusei, Geotrichum candidum, Pichia subpelliculosa, Kloeckera apiculata, Pichia membranifaciens, Schizosaccharomyces pombe and Y. lipolytica) improved the survival of Lactobacillus rhamnosus in fermented milk by ~ 10³ to 10⁶-fold. W. saturnus var. saturnus enhanced the survival of Lactobacillus acidophilus, L. rhamnosus (probiotic) and Lactobacillus reuteri by up to 10⁶-fold, but the same yeast failed to improve the survival of Lactobacillus johnsonii (probiotic), S. thermophilus and L. bulgaricus in fermented milk. These results provide definitive evidence that yeasts possess stability-enhancing effects on LAB and that the specific effects of yeasts on LAB stability vary with yeasts as well as with LAB. However, the molecular mechanism of such interaction of yeasts with LAB remains to be found.     

产ACE抑制肽乳酸菌的筛选、益生特性评定及应用

目的:筛选出富产血管紧张素转化酶(Angiotensin converting enzyme,ACE)抑制肽的乳酸菌并评定其益生特性.方法:依据蛋白水解度及ACE抑制率对乳酸菌进行初筛,然后依据模拟胃肠消化后的ACE抑制率最终筛出2株乳酸菌ZJUIDS09和ZJUIDS11,进一步评价其耐酸、耐胆盐、抗生素耐药性和抑菌...