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Comparative studies on the effect of probiotic additions on the physicochemical and microbiological properties of yoghurt made from soymilk and cow's milk during refrigeration storage (R2)
Abstract
Soymilk yoghurt is an option to consumers who are allergic to cow's milk yoghurt. Probiotics can provide gut health. The objective of this study was to investigate the physicochemical characteristics, including pH, colour, firmness and syneresis of yoghurt made from soymilk and cow's milk as affected by the addition of probiotics during storage at 4 °C for 28 days at 7-day intervals. Microstructure and bacterial populations were also determined. Two types of yoghurt were prepared. The first type was prepared with the additions of commercially available yogurt starter containing Lactobacillus delbrueckii ssp. bulgaricus (LB) and Streptococcus thermophilus (ST). The second type was prepared with the same yogurt starters plus three probiotics, including Bifidobacterium animalis subsp. lactis BB-12 (BB), L. acidophilus La-5 (LA), and L. rhamnosus (LGG). Probiotics reduced syneresis and increased compact network of soymilk yoghurt significantly (p < 0.05) and shortened the time needed to reach pH 4.5 in both cow's milk and soymilk yogurts. During storage, the pH of cow's milk yoghurts slightly decreased (4.37–4.26 with probiotics and 4.54 to 4.33 without probiotics), however, the pH of soymilk yoghurts remained relatively constant. The firmness of yoghurt made from cow's milk was significantly decreased with the addition of probiotics, however, it remained stable in soy milk yoghurt during storage. Soymilk yoghurt (34–50 g force during compression) was generally firmer than cow's milk yoghurts (9.8–12.5 g force). The cow's milk yogurt had slightly higher counts of ST, LB and LA than soymilk yogurt, but the count of BB in soymilk yogurt is significantly higher than that in cow's milk yogurt.
... Therefore, achieving and maintaining a higher probiotic count in dairy yoghurts through the symbiotic relationship between probiotics and prebiotics foods have been a major research focus (Hasani et al., 2016;Mousavi et al., 2019). Probiotic enrichment in soy milk yoghurt improve the physicochemical (i.e., reduce syneresis, compact network and microstructure) and microbiological properties (Cui et al., 2021). ...
... Soy milk is identified as a suitable culture medium than cow milk for the simultaneous growth of bifidobacteria and probiotic lactic acid bacteria (Cui et al., 2021;Wang et al., 2002). Hence, the present study aimed to investigate the feasibility of formulating a vegan, fermented soy-gel to deliver comparable probiotic effect with acceptable sensory properties. ...
... Viable cell counts of lactic acid bacteria (a) and Bifidobacteria (b) in cowmilk yoghurt and soy milk yoghurt upon storage (4°C) up to 7 days storage than cow's milk yoghurt in the current study is in agreement with the findings of (Cui et al., 2021) who reported higher survival of BB(B. animalis subsp. ...
The demand for vegetable protein substitutes for animal protein is growing. Soymilk, the water extract of soaked and ground soybeans is a popular alternative for bovine milk. Soymilk was tested with several non‐animal derived stabilizers to produce fermented soy‐gels and found agar‐agar provides promising organoleptic properties in fermented soy‐gels. The sensory analysis proved that Bifidobacteria (BB) used together with Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus as starter culture bacteria (SCB) gives better (P<0.05) sensory properties. Physicochemical properties were evaluated for gels fermented with SCB and BB. Results indicated, upon storage at 4°C, pH reduced (P<0.05) and viscosity increased (P<0.05). Both titratable acidity and syneresis were initially decreased and increased after the 10th day of storage. After seven days, the viability of BB in fermented soy‐gel was higher (P<0.05) than in a regular bovine milk set‐gel, proving the feasibility of using as a promising probiotic carrier vegan food.
... Soymilk, rice-milk and coconut-milk are the major carrier matrices used in probiotic plant-milk-based food development. However, other matrices such as maize [24,25], oats-milk [26], quinoa-milk [20,27], buckwheat [28], chickpea [29], peanut [5,30], cashew-milk [1,31], hemp-milk [32][33][34] and walnut-milk [35,36] have also been used for extracting and developing plant based milk. Apart from these, some mixed beverages produced by blending soymilk, almondmilk, coconut-milk as well as chickpea and coconut extract were also found to be promising matrices to deliver probiotics with satisfactory viability levels [5, 29,37]. ...
... In plant-based milks, probiotic viability seems to be strain-dependent. Cui et al. [35] compared the growth of probiotic bacteria in cow's milk and soymilk yoghurts and found that the growth of B. animalis was significantly high in soymilk yoghurts compared to that of S. thermophilus, Lb. acidophilus and Lb. rhamnosus, which showed slightly higher counts in cow's milk yoghurt. ...
... Whereas, fermentation process contributed significantly to achieve increased survivability of probiotics in both coconut-milks and hemp-milks [34]. Addition of prebiotics could also be effective in maintaining viable counts well above the minimum therapeutic level [1,31,35,52]. Effect of prebiotic substances on probiotic survivability seems to be strain dependent. ...
At present, there is an increasing demand for probiotic enriched plant-based milk products. Although many varieties of plant-based milk exist, soymilk, rice-milk and coconut-milk are the major carrier matrices used in probiotic food development. In general, these products are safe for consumption and can be considered as a suitable vehicle for delivering probiotics due to their ability in maintaining sufficient probiotic levels during product shelf life. However, studies that are focusing on the evaluation of functional efficacy of probiotics in these products with special reference to gastrointestinal survival, adhesion to intestinal epithelium and immunomodulation are scarce and these aspects need to be further assessed.
... In general, there was an increasing trend in hardness values among the treatments with increasing storage time. Similar results were previously reported by Cui and others [34] in cow milk yogurt stored for 28 days. One interesting observation throughout the storage was that the hardness values for probiotic yogurts (PY0, PY5, and PY10) were relatively higher than the control yogurt. ...
... One interesting observation throughout the storage was that the hardness values for probiotic yogurts (PY0, PY5, and PY10) were relatively higher than the control yogurt. In a previous study, LGG reported producing EPS which could improve the texture of yogurt by interacting with the free water in the gel structure [34]. In another study, the firmness of yogurts made using capsular EPS-or ropy EPS-producing starter cultures was generally lower than that in yogurts produced with non-EPS-producing starter cultures [11]. ...
Background
Producing functional food by adding fruits or fruit pulps have attracted great attention. Simultaneously, buffalo milk is gaining an increasing demand as an alternative to cow milk. Thus, value addition and diversification of buffalo milk products have gained much commercial and research interest. Hence, we aimed to investigate the potentials of developing and characterizing probiotic enriched buffalo milk yogurts with bael fruit pulp using exopolysaccharides producing probiotic Lacticaseibacillus rhamnosus GG (LGG).
Methods
Four types of buffalo milk yogurts were tested, e.g. fermenting with the yogurt starter culture only (e.g., control) and fermenting with the combination of yogurt starter culture and LGG with varying levels (w/v) of bael fruit pulp incorporations, i.e., 0%, 5% and 10%. Variation in pH, syneresis, hardness, probiotic viability and sensory attributes during 21 days of storage in 4 °C were assessed for all treatments.
Results
Fermenting with LGG had a positive effect on post-acidification and syneresis rate compared to the control yogurt. Bael incorporation did not affect the post-acidification, but significantly decreased the level of syneresis at the end of storage. All probiotic formulations maintained LGG counts of >107 CFU/mL and the highest counts were observed in 5% (w/v) bael incorporated yogurt.
Conclusions
Results confirmed the possibility of using buffalo milk yogurt as an ideal matrix to deliver LGG with promising probiotic capacity. The use of 5% bael incorporation provides an optimal combination for synbiotic product development.
... Sugar (5.5% w/w) and modified cassava starch were added according to the percentages used for each treatment with respect to the additional water, mixed and homogenized (APV Rannie, Lockerbie, United Kingdom) at 160 bars. The heat treatment was carried out at 85°C for 15 min according to the protocol proposed by Cui et al. (2021). ...
Fermented soybean beverages are an alternative for improving intestinal health, and fermentation reduces the anti-nutritional factors of this legume. However, they do show high syneresis and low viscosity. Modified cassava starches could be added as a thickener and/or stabilizer to improve the quality of the product. The aim of this research was to assess the effect of adding modified cassava starch on the physicochemical properties of a fermented soybean beverage. Preliminary tests were carried out varying the concentration (0.8%, 1.0%, and 1.2%) of 3 types of modified cassava starch: octenyl succinic anhydride (OSA), acetylated distarch adipate (ADA) cross-linked starch, and substituted-crosslinked starch (mixed). A commercial culture of starter microorganisms and probiotics was used in the fermentation process. The statistical analysis was carried out with a two-factor (type of starch and concentration) and 3-level design; quality parameters such as pH, acidity, soluble solids, syneresis, and viscosity comparable to commercial fermented dairy beverages were evaluated. OSA starch had a lower syneresis and higher viscosity than the other starches for each concentration. Furthermore, the addition of 1.0% OSA and mixed starch, as well as 1.2% ADA starch, are comparable to the control commercial soybean beverage (SC).
... animalis subsp. lactis, L. acidophilus, and L. rhamnosus) were observed with shortened fermentation time as compared to the addition of starter culture alone (Cui et al., 2021). All these physico-chemical characteristics including decline in pH and fermentation time, textural and rheological changes, might also influence the changes occurring during later stages of post-acidification including fatty acid profiling, pH trend, color and generation of bioactive compounds (Soni et al., 2020). ...
... Comparable results were observed by Mishra and Mishra (2018) where they observed that probiotic soymilk added with 2% (w/v) inulin and 2% (w/v) fructooligosaccharide when stored at 4 • C storage showed a gradual and slow decrease in pH (4.06) by the end of 28 days. Similarly, Mishra et al. (2019) and Cui et al. (2021) conducted storage studies under refrigeration conditions (6-8 • C) for probiotic soy-based yogurts and observed a decreasing pH values up to 4.2 by the end of 10th day of storage. The authors concluded that this increased acidity of the probiotic product is due to the production of lactic acid content throughout the storage period via probiotics belonging to the Lactobacillus family, that caused a decrease in pH values. ...
... The global fermented plant-based alternatives market is expected to have a compound annual growth rate of 5% from 2021 to 2026 (BIS Research, 2021). Plant-based milk substitutes, such as soy beverages, can preserve the viability of LAB during their storage (Cui et al., 2021;D'Alessandro et al., 2023); therefore, they can be considered promising carriers for probiotics. Probiotics are defined as living microorganisms that, when administered sufficiently, provide a health benefit to the host, starting from the intestinal tract and beyond (Sanders et al., 2018). ...
... The water-holding capacity (WHC) was based on previous studies and modified slightly [23]. The mass of the empty centrifuge tube was recorded as Z. ...
The purpose of this study was to investigate the effects of Polygonatum sibiricum (P. sibiricum) on microbial fermentation, physicochemical properties, and functional properties of fermented soymilk. Three types of fermented soymilk were prepared. The first type was fermented directly from regular soymilk (fermented soymilk, FSM), and the other two were fermented after adding P. sibiricum (P. sibiricum fermented soymilk, P-FSM) or P. sibiricum polysaccharides (P. sibiricum polysaccharides fermented soymilk, PP-FSM). The differences in physical and chemical indexes such as pH value, acidity, and water-holding capacity were mainly compared, and the differences in the contents of functional components such as total phenols, total flavonoids, soy isoflavones, γ-aminobutyric acid, and organic acids were compared. The functionalities of the three samples in terms of antioxidant activity were evaluated, and the relevance of each active substance was explored. Compared with the FSM group, the addition of P. sibiricum and P. sibiricum polysaccharides could not only significantly promote the fermentation of Lactobacillus but also significantly improve the stability of the finished products during storage and prolong the shelf life of the finished product. The conversion rates of glycoside soybean isoflavones in the PP-FSM and P-FSM groups were 73% and 69%, respectively, which were significantly higher than those in the FSM group (64%). At the end of fermentation, the γ-aminobutyric acid contents of the PP-FSM and P-FSM groups were 383.66 ± 1.41 mg/L and 386.27 ± 3.43 mg/L, respectively, while that of the FSM group was only 288.66 ± 3.94 mg/L. There were also great differences in the content and types of organic acids among the three samples, especially lactic acid and acetic acid. By comparing the antioxidant capacity of DPPH (1,1-Diphenyl-2-picrylhydrazyl free radical), AB-TS (2,2′-Azinobis-3-ethylbenzthiazoline-6-sulphonate), and iron chelation, it was found that both PP-FSM and P-FSM were superior to FSM, and the antioxidant capacity had a certain correlation with the contents of total phenols and total flavonoids.
... The values of TS in the present study ranged between 10.2 and 10.9%, which comply with the regulation for non-fat set yogurt (Codex Alimentarius, 2003). WHC refers to the water-holding capacity of the protein gel network in yogurt, which designates the firmness and compactness of the yogurt curd (Cui et al., 2021). Changes in this property may be due to modifications in the protein network, which affect the appearance of the yogurt and may limit its shelf-life and sensory acceptability (Huang et al., 2022). ...
Some lactic acid bacteria (LAB) are capable of producing exopolysaccharides (EPS), which can be used in the dairy industry to reduce syneresis and improve the viscosity and texture of fermented products. The aim of the present study was to screen the EPS-producing capacity of 123 LAB strains isolated from fermented foods to search for those able to produce EPS with the optimal technological aptitude to be applied in non-fat set yogurt manufacture. They were grown on MRS-sucrose and assigned to ropy or mucoid phenotype depending on the appearance of the colonies. Twenty-five of them were selected and assayed for production of both cell-bound EPS (EPS-b) and EPS released to the medium (EPS-r). Those resulting in the most EPS producers ( Levilactobacillus brevis UCLM-Lb47, Leuconostoc mesenteroides subsp. mesenteroides 6F6-12 and Leuconostoc mesenteroides subsp. mesenteroides 2F6-9) were used to manufacture non-fat set yogurts. These yogurts were analyzed for microbiological and physicochemical properties (pH, titratable acidity, total solids), water-holding capacity, apparent viscosity, and sensory characteristics during a 28-day cold storage period. The yogurts made with the selected strains showed higher values of water-holding capacity, EPS concentration, and viscosity in the mouth than the control yogurt, which presented a more fluid texture. The results obtained suggest that the three selected strains could be used to replace hydrocolloids in non-fat set yogurt formulation, obtaining a clean-label product that would improve consumer acceptance.
Graphical Abstract
... Then, the sample was stored at 4 • C for four weeks to check the viability of the strain, pH, and enumeration of pathogenic microorganisms. Additionally, scanning electron microscopy (SEM) was done on the curdled milk using the method (Cui et al., 2021). ...
... Internalization of Pediococcus acidilactici with phthalyl inulin nanoparticles of size 203 nm produced Pediocin showcased admirable antimicrobial activity. (Cui et al., 2021) Chitosan-silver nanoparticles (CS-AgNPs) ...
This is proven for a long that the incorporation of probiotics and prebiotics in diet exhibits beneficial effects on intestinal and intrinsic health. Nevertheless, this may encounter loss of vitality all along the absorption in the gastrointestinal tract, leading to meager intestinal delivery of probiotic active ingredients. In recent times, nanotechnology has been passionately used to escalate the bioavailability of active ingredients. Versatile forms of nanoparticles (NPs) are devised to be used with probiotics/prebiotics/synbiotics or their different combinations. The NPs currently in trend are constituted of distinctive organic compounds like carbohydrates, proteins, fats, or inorganics such as oxides of silver and titanium or magnesium etc. This review critically explicates the emerging relationship of nanotechnology with probiotics and prebiotics for different applications in neutraceuticals. Here in this review, formulations of nanoprobiotics and nanoprebiotics are discussed in detail, which behave as an effective drug delivery system. In addition, these formulations exhibit anti-cancerous, anti-microbial, anti-oxidant and photo-protective properties. Limited availability of scientific research on nanotechnology concerning probiotics and prebiotics implies dynamic research studies on the bioavailability of loaded active ingredients and the effective drug delivery system by including the safety issues of food and the environment.
... Some research projects have investigated effects of probiotic incorporation on physicochemical and sensory properties of probiotic yogurts. Cui et al. [419] produced cow milk yogurt with yogurt starter cultures alone and with yogurt starter cultures combined with probiotics (Bifidobacterium animalis subsp. lactis BB-12, L. acidophilus La-5, and L. rhamnosus GG) and found probiotic supplementation decreased time to reach pH 4.5 and pH obtained during storage but increased initial firmness. ...
Probiotics are commonly added to yogurt to provide many health benefits for the consumer. A description is provided for some commonly used probiotics in yogurt. A GRAS (generally recognized as safe) list of probiotic bacteria that can be added to yogurt or similar types of products is provided. Additionally, prebiotics, synbiotics (combination of prebiotics and probiotics), postbiotics, paraprobiotics, and psychobiotics can be added to yogurt. Probiotic yogurt can come in various forms in addition to spoonable yogurt, and yogurt can be used as an ingredient in other food products. Many useful functional ingredients can be applied to probiotic yogurt. The safety of probiotics must be addressed, especially for critically ill patients and other susceptible populations. Probiotics must survive within yogurt throughout its entire shelf-life and within the gastrointestinal tract after consumption by the consumer to provide health benefits, and many techniques can be used to maintain survival of probiotics in yogurt. Furthermore, probiotics can be added to Greek yogurt acid whey. Many opportunities exist for adding a wide variety of probiotics to a wide variety of yogurt-based products.
... The fermentation and starter cultures and the nutritive compounds like; calcium, zinc, and vitamin B have a high impact on human health (El-Abbadi et al., 2014). Moreover, the natural functionality can be enriched with a few simple methods like fruit addition (do Espírito Santo et al., 2010;Sanchez-Segarra et al., 2000;Tarakçi & Kucukoner, 2003), probiotic enrichment (Cui et al., 2021;Molaee Parvarei et al., 2021), prebiotic additions Esmaeilnejad Moghadam et al., 2019;Gustaw et al., 2011), fat reduction (Akgun et al., 2016;García-Gómez et al., 2019;Nikoofar et al., 2013), lactose reduction (Dekker et al., 2019;García-Gómez et al., 2019) and protein enrichment (Brückner-Gühmann et al., 2019;Keršienė et al., 2020). ...
Yoghurt is a coagulated dairy product that is fermented by typical starter cultures. Yogurt has the highest demand rate among fermented products due to its sensory properties. Well‐consumed food products are being enriched by either adding nutrients or improving the already available content for the development of the product. From this point of view, protein enrichment is one of the approaches that contribute to the nutrient content of food products. The addition of plant‐based protein is a step that improves the nutrient content and is a sustainable approach for the functionalization of the product. In the present study, two types of plant protein were added; chickpea and pea in two different concentrations of 0.5% (w/w) and 1% (w/w) to determine the changes in the physicochemical, textural, microbiological, and sensory properties of the yoghurt during storage at 4°C for 21 days. In yoghurt samples, pH value, titratable acidity, colour measurements (L*, a*, b*), texture parameters (firmness, consistency, cohesiveness), microbiological contents show a significant difference during the storage period (p<0.05). On the other hand, adding plant protein had no significant difference in syneresis value during storage (p>0.05). The sensory evaluation results highlighted that protein enrichment develops consistency, mouthfeel, and oiliness scores compared to the control product (no plant protein added sample). These significant sensory modalities are determined by the casein network and water‐binding capability of the proteins, which was visible as a result of this study.
... For instance, soymilk is favored by consumers for its excellent protein quality, absence of cholesterol and lactose, and functional properties. Very recently (Cui, Chang, & Nannapaneni, 2021) exhibited that soymilk is a better substitute to cow milk for the proliferation of probiotic bacteria. On the other hand, the presence of low molecular weight polysaccharides (i.e., non-digestible oligosaccharides) in soybean may cause distended stomach, loosening of bowels and abdominal discomfort thereby limiting their consumption in moderation (Battistini et al., 2018). ...
The human gut microbiota is inhabited by approximately 1013 to 1014 microorganisms, which can be divided into four main phyla, that is, Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria. The diet is considered to play a key role in the composition and diversity of gut microbiota. The change in food habits and dietary components, including probiotics and prebiotics, can help to regulating the gut microbiota. Probiotics are intended to follow the different mechanisms of action, such as prevention of pathogen adhesion or colonization, metabolites production (ranging from proteins, carbohydrates, vitamins, enzymes, oligosaccharides, exopolysaccharides, short-chain fatty acids and bacteriocins), and production of immunomodulatory compounds. This chapter focuses on the types of microorganisms forming the gut microbiota implicated in the production of bioactive metabolites and their action mechanism of action linked to health benefits and supplementation in food products.
... Soybean milk is an alternative beverage milk because it is an inexpensive and significant source of protein (Al-Saedi et al., 2020; Chaiwanon et al., 2000) and very similar to diary milk in compositions and physical appearance (Giri &Mangaraj, 2012). Thus, soybean milk is commonly used to substitute dairy milk (Cui et al., 2021;Kundu et al., 2018). The popularity of soybean milk is increasing rapidly worldwide (Peng et al., 2016;Vanga et al., 2020), attributable to its essential health functions (Hatanaka et al., 2014). ...
Soybean milk is a regular beverage commonly sold across the streets and markets in Nigeria and beyond. The demand for soybean milk is fast growing due to its affordability and similarity to dairy milk, including its health benefits. However, there is a growing concern about the public health-related issues associated with this artisanal products production, storage, and distribution. The primary objective of the present investigation was to evaluate the bacteriological composition of the locally produced soybean milk commonly consumed in the Kogi state of Nigeria. The samples for the study were collected from vendors in different locations of the state. The analysis was conducted on the samples using established standard procedures. The result found certain microorganisms such as Micrococcus spp, Lactobacillus spp, Streptococcus spp, Enterobacter spp, Klebsiella spp, and other fungi, which comprises Aspergillus spp and Saccharomyces. The study concludes that the soybean milk consumed in the study parameter was mainly contaminated with varying bacteria.
... The viable counts of S. thermophilus and L. bulgaricus in cheeses were affected by the presence of soy protein isolate. It was in agreement with Cui et al. [53] who observed that the soy yoghurt had high counts of starter bacteria. The potential of L. bulgaricus and S. thermophilus is to withstand the cheese manufacturing process and survive during storage. ...
Soy proteins are used in foods as non-dairy alternatives and they play significant role in human health. The use of different concentrations of soy protein isolate (SPI) (0–6% w/v dry basis) in the development of bacteriologically acidified feta type (BAF) cheeses applied with milk protein concentrate (MPC) was investigated during 45 days of storage. The results showed that substitution of MPC by SPI increased acidity and the time of coagulation. With an increase in the SPI concentration, the viscoelastic behavior of all samples demonstrated the higher Gʹ compared to Gʺ, showing a solid-like behavior of the manufactured samples. The addition of SPI led to the reduction of Gʹ, Gʺ and texture parameters (hardness, cohesiveness, gumminess and springiness). The images of microstructure indicated a more open protein network and weaker structure in BAF cheeses fortified with high levels of SPI. Microbiological results showed that the use of MPC and SPI was able to obtain a matrix that could provide a protection to the starter bacteria. In conclusion, MPC can be substituted by SPI to the rate of 3% without adversely effecting on the sensory properties of BAF cheese.
... The cow's milk and soymilk yogurts fermented with starter cultures and B. animalis subsp. Lactis, L. acidophilus, and L. rhamnosus required shorter fermentation time to reach pH 4.5, and their physicochemical properties were significantly improved compared to yoghurts fermented with starter cultures alone (Cui et al., 2021). Therefore, yoghurt with antioxidant activity can be obtained by addition of probiotics. ...
This study aims to investigate the antioxidative activities of probiotics derived from healthy human infants and to develop probiotic yoghurt. Viable cells, cell free supernatant and intracellular cell free extract of MSMC83 exhibited antioxidant activities. MSMC83 was assigned to Bifidobacterium animalis with 99% similarly based on 16 S rRNA gene sequence analysis. B. animalis MSMC83 showed high survival rate in simulated gastrointestinal conditions, a substantial adherence to Caco-2 cells and production of bile salt hydrolase. Set-style yoghurt fermented with B. animalis MSMC83 and yoghurt starter cultures was produced. Microbiological and physicochemical properties of yoghurt were investigated during refrigerated storage. Fermentation time of probiotic yoghurt was 4.5 h compared to 6.0 h found in regular yoghurt. The viable count of B. animalis remained at 8.53 log CFU/g after 4-week storage at 4 °C. The probiotic yoghurt possessed firmer texture and lower syneresis compared to the yoghurt fermented with starter cultures. Our results support the use of B. animalis MSMC83 as probiotic culture in the development of yoghurt with antioxidative property.
... One interesting observation throughout the storage was that the hardness values for probiotic yoghurts (PY, PY5 and PY10) were relatively higher than the control yoghurt. In a previous study, Lb. rhamnosus GG reported producing EPS which could improve the texture of yoghurt by interacting with the free-water in the gel structure [49]. In another study, the firmness of yoghurts made using capsular EPS-or ropy EPS-producing starter cultures was generally lower than that in yoghurts produced with non-EPS-producing starter cultures [17]. ...
Recently, there is a trend among food manufacturers in producing functional foods containing fruit and milk. On the other hand, there is an increasing demand for buffalo milk as an alternative to cow milk. Therefore, the aim of this study was to investigate the impact of adding bael fruit extract on microbial, physiochemical and sensory characteristics of buffalo yoghurt containing the EPS-producing probiotic Lactobacillus rhamnosus GG (LGG) during 21 days of refrigerated storage. Four formulations of buffalo yoghurt: a control yoghurt manufactured with conventional yoghurt culture (CON); a probiotic yoghurt containing Lb. rhamnosus GG plus yoghurt culture (PY); a probiotic yoghurt containing 5% (w/v) bael (PY5); and 10% (w/v) bael (PY10) were evaluated for changes in pH, syneresis, hardness, probiotic viability and sensory attributes during the storage. Control yoghurt experienced significant post acidification and a higher rate of syneresis. Addition of probiotics had a positive effect on post acidification and syneresis rate. Addition of bael did not affect post-acidification, but significantly decreased the level of syneresis. All probiotic formulations maintained LGG counts of >107 cfu/mL and the highest counts were observed in 5% (w/v) bael incorporated yoghurt. Results showed that buffalo yoghurt is an ideal matrix to deliver LGG and 5% bael incorporation would be ideal or symbiotic product development.
There are a wide variety of plant-based fermented foods around the world. However, the scope of this book is plant-based products that are alternatives to animal-derived products. Therefore, this chapter is based on the utilization of fermentation during plant-based foods and fermented foods from milk analogs, a.k.a. plant-based milk. The demand for plant-based milk and meat alternatives is increasing due to various factors such as food allergies, the downsides of animal-based food production to the environment, as well as ethical discussions regarding the use of animals. The changes in lifestyles through a healthier diet based on more plant-based foods rather than animal-derived products have led the food industry and academia to search for ways to produce plant-based alternatives to meet the needs of consumers. Fermented foods are considered to hold an important place in a healthy diet and have been a part of the human diet since ancient times. Developing alternative products to animal-derived fermented foods has been one of the focuses of the plant-based food market.
Due to the advantages of the approaches used in different disciplines in producing innovative solutions, more technologies are transferred from one discipline to another and can be used successfully. For example, while the extrusion technology used in the production of plastic can be used in the production of pasta, nowadays foodstuffs can be used just like a dye, making them shaped and layered like cement, and for this purpose, highly variable products can be produced through the software used for shaping in the machinery industry. Considering the highly variable consumer demands in the context of broad socioeconomic conditions, innovative approaches gain utmost importance in cases where conventional methods are insufficient. For example, in addition to the need to produce food with improved chewability, that is, to customize food production for a segment with a high-income level but having difficulty chewing due to advanced age, the development of alternative and practical solutions for the masses who have difficulty reaching meat protein. Proteins creates a solution requirement for two different endpoints. Thus, applying the production methods of different disciplines for innovative approaches to the points where traditional production methods cannot provide a solution in terms of improving both food supply and functional properties can enable extremely fast solutions to be produced. Therefore, some innovative and useful approaches such as mincemeat and processing of products that cannot be evaluated in meat production as steak or combining a meat alternative. Meat alternatives herbal mixture with the same meat structure and properties or processing probiotic ingredients in cheese layers are discussed with examples in this chapter.
Human microbial niches such as the healthy vagina, are recently emerging as “unconventional” sources of candidate probiotics capable of preventing from different vaginal diseases. These microorganisms could be provided as oral preparations since they can reach the vaginal niche passing through the gastrointestinal tract. However, their use in food would be challenging. The aim of this work was to develop and characterize fermented soy beverages with encapsulated and non-encapsulated vaginal lactobacilli, namely Lactobacillus crispatus BC4 and Lactobacillus gasseri BC9, as future dietary strategies for vaginal dysbiosis. The viability of vaginal strains remained stable at 7 log CFU/mL of product during the entire 28 days of storage, despite the use of encapsulated or non-encapsulated bacteria. Samples containing encapsulated bacteria, especially E-BC4+BC9, showed higher Water Holding Capacity (62.29%), lactic acid content (1.43%), and a remarkable antagonistic activity against enteropathogens. Moreover, encapsulation protected the strains from simulated GIT conditions (>1 Log) but reduced the acceptability of the final products. Overall, strain BC4 and BC9, alone or in mix, demonstrated to be promising co-starter cultures providing a characteristic flavor (pleasant smell and taste) and aroma (lower hexanal, benzaldehyde and higher diacetyl, and 2,3-pentanedione, compared to control) to the fermented soy beverages.
Cow milk proteins is one of the major food allergens, and some probiotics can abate allergenicity to some extent. Lactiplantibacillus plantarum AHQ‐14 isolated from the traditional dairy products in Xinjiang province, China, has good ability to reduce the allergenicity of β‐lactoglobulin (LG) and good probiotic properties. In the presented study, L.plantarum AHQ‐14 was used to replace half of the commercial yoghurt starter to ferment yoghurt, and the effects of L.plantarum AHQ‐14 fortification on microstructure, textural and rheological attributes of yoghurt was investigated. In addition, milk protein hydrolysis, antigenicity and allergenicity of yoghurts during 28 days cold storage were detected. The results indicated that AHQ‐14 and YC‐X11 fermentation could enhance the texture and rheological properties of yoghurt by reducing the syneresis (37%) and firmness (14%) and improving the cohesiveness by 50%. In addition, AHQ‐14 and YC‐X11 fermentation can shorten the fermentation time by about 30 min, SDS‐PAGE displayed that AHQ‐14 and YC‐X11 fermentation had stronger hydrolysis of whey protein compared with YC‐X11 yoghurt. Additionally, the fermentation by L.plantarum AHQ‐14 and YC‐X11 could significantly reduce the antigenicity and IgE‐binding ability of skim milk by 82% and 94% respectively, thus reduce milk allergic reactions in patients significantly.
Pistachio milk (PM), an extraction product of pistachio, is protein- and fat-dense food. Short-chain fatty acids (SCFAs) are known for inducing cytotoxicity and apoptosis in colon carcinoma cells. This study aimed to find an optimal combination of probiotics that can produce a higher amount of SCFAs in PM. In addition, the anti-cancer effect of fermented PM on human colon carcinoma cells (Caco-2) was determined. The combinations of probiotics were as follows: Streptococcus thermophilus + Lactobacillus bulgaricus (C); C + Lactobacillus acidophilus (C-La); C + Lactobacillus gasseri (C-Lg); C + Bifidobacterium bifidum (C-Bb). The results indicated that fermented PM was produced after a short fermentation time in all the probiotics combinations. C-Bb produced up to 1.5-fold more acetate than the other probiotics combinations did. A significant amount of cytotoxicity, i.e., 78, 56, and 29% cell viability was observed in Caco-2 cells by C-Bb-fermented PM at 1, 2.5 and 5%, respectively. C-Bb-fermented PM (5%) induced early and late apoptosis up to 6-fold. Additionally, Caco-2 cells treated with C-Bb-fermented PM significantly induced the downregulation of α-tubulin and the upregulation of cleaved caspase-3, as well as nuclear condensation and fragmentation. Our data suggest that fermented PM, which is rich in acetate, may have the potential as a functional food possessing anti-colon cancer properties.
Lactobacillus rhamnosus GG (ATCC 53103) is the most studied probiotic bacterium in the area of medicine so it can maintain its viability for a long time in the human gastrointestinal tract, high resistance to stomach acidity and high antimicrobial activity against pathogens. One disadvantage of Lactobacillus rhamnosus GG is poor use of lactose in milk. In this study, soy milk and soy-cow milk mixtures were prepared and coagulation problem was solved and probiotic plant-based drink was produced for vegetarian and vegan consumers. In the study carried out, milk mixtures in 16 different ratios were prepared and fermented with Lactobacillus rhamnosus GG at 37⁰C for 30 hours. After fermentation, pH, acidity, Lactobacillus rhamnosus GG cell count, sensory analysis and organic acid values of all milk samples were determined by HPLC. Lactobacillus rhamnosus GG cell count, acidity and pH analyzes of milk were performed under 4˚C refrigerator conditions for four weeks. The addition of glucose to soy milk at different rates caused a decrease in pH after fermentation, causing the coagulation of soy protein molecules, and increasing the viscosity of soy milk and strengthening the structure, increased the sensory quality of the product. According to the cell count, Lactobacillus rhamnosus GG did not fall below 7 log CFU/ml in all mixtures after 30 fermentation and 4 weeks at 4˚C refrigerator conditions. When the cell viability of Lactobacillus rhamnosus GG was analyzed, it was reported that there was no significant difference only between the 3rd and 4th weeks (p>0.05). According to the HPLC results, after 30 hours of fermentation, the highest lactic acid Lactobacillus rhamnosus GG inoculated 50% soy milk and 50% cow milk (control group) was 16,646 g/L. When the appearance, taste, stability, texture and overall acceptability were evaluated with all milk mixtures, Lactobacillus rhamnosus GG inoculated fermented soy milk with 3% glucose content was determined to have the highest average score. The amount of glucose added to soy milk helped Lactobacillus rhamnosus GG fermented soy milk to produce fermented milk with high sensory values (p<0.05).
This study explored the effects of two mixed fermentation methods: one was fermenting a soymilk and milk mixture by a lactic acid bacteria fermenting agent at 0.1 g/kg and 42 °C until the acidity was 70 °T, which was set as the MFSM method, and the other was fermenting milk alone by lactic acid bacteria at 42 °C for 12 h, placing it in a 4 °C refrigerator after acidification for 24 h and then mixing it with soymilk at a 1.5:1 ratio and storing the mixture at 4 °C, which was set as the SMFSM method. The quality and flavor of the soymilk and milk mixture products were investigated on the 0th, 15th and 30th days during storage. The changes in acidity, pH, number of viable bacteria, viscosity, water-holding capacity, texture, rheological properties, sensory quality and volatile flavors were determined. The results showed that compared with the fermented soymilk and milk mixtures under the MFSM method, the samples of fermented soymilk and milk mixtures under the SMFSM method showed a significant slowdown of acidification during storage, so that the sensory quality of the products was almost unaffected by acidity on the 30th day of storage. Furthermore, the number of viable bacteria was greater than 7 log cfu/mL. The water holding capacity did not change significantly until the 30th day. There was also no whey precipitation, indicating good stability. The samples in SMFSM mode had higher aromatic contents and beans during storage than the fermented soymilk and milk mixtures in MFSM mode. The rich variety of volatile flavors and the presence of acetoin, 2-heptanone, and (E,E)-3,5-octadien-2-one throughout the storage period allowed the samples to maintain a good sensory flavor during storage.
As a nutrient rich emulsion extracted from plant materials, plant-based milk (PBM) has been the latest trend and hot topic in the food industry due to the growing awareness of consumers toward plant-based products in managing the environmental (carbon footprint and land utility), ethical (animal well-fare) and societal (health-conscious) issues. There have been extensive studies and reviews done to discuss the distinct perspective of PBM including its production, health effects and market acceptance. However, not much has been emphasized on the valuable antioxidants present in PBM which is one of the attributes making them stand apart from dairy milk. The amounts of antioxidants in PBM are important. They offered tremendous health benefits in maintaining optimum health and reducing the risk of various health disorders. Therefore, enhancing the extraction of antioxidants and preserving their activity during production and storage is important. However, there is a lack of a comprehensive review of how these antioxidants changes in response to different processing steps involved in PBM production. Presumably, antioxidants in PBM could be potentially lost due to thermal degradation, oxidation or leaching into processing water. Hence, this paper aims to fill the gaps by addressing an extensive review of how different production steps (germination, roasting, soaking, blanching, grinding and filtration, and microbial inactivation) affect the antioxidant content in PBM. In addition, the effect of different microbial inactivation treatments (thermal or non-thermal processing) on the alteration of antioxidant in PBM was also highlighted. This paper can provide useful insight for the industry that aims in selecting suitable processing steps to produce PBM products that carry with them a health declaration.
As a dairy product, yogurt delivers nourishing milk components through the beneficial microbial fermentation process, improved by bioavailability and bioaccessibility - an exclusive combined food asset. In recent decades, there has been considerable attention to yogurt product development particularly in areas like influence by antioxidant-rich fruits, different factors affecting its probiotic viability, and the functionality of inulin and probiotics. Essentially, many published reviews frequently focus on the functionalities associated with yogurt products, however, those articulating yogurt ingredients specific to associated preservation strategies, processing conditions, and analytical detection techniques, are very few, to our best knowledge. The knowledge and understanding of preservation strategies that enhance yogurt products’ ingredients, and their function as modern drug delivery systems are very essential, given the opportunities it can provide for future research. Therefore, this overview discussed how yogurt products’ ingredients have been enhanced, from preservation strategies, processing conditions, analytical detection methods, and therapeutic delivery standpoints. The survey methodology involved major stages, from the brainstorming of research questions, search strategy, effective utilization of databases, inclusion and exclusion criteria, etc. The innovative successes of yogurts would be enhanced via ingredients’/products’ physicochemical, nutritional and therapeutic aspects. Besides processing conditions to influence the yogurt constituents, overall acceptability, quality, and shelf-life, the analytical assays would help detect the hidden product constituents, toxins, and other storage-related changes. Therapeutic role of yogurt - a modern drug delivery system, would be demonstrated via the supplementation (of yogurt) either alone or with bioactive ingredients. The future of yogurt requires the collective action of stakeholders to formulate unique variants with different natural blends, where synthetic ingredients become completely replaced by the plant's derivatives, which enhance the acidification rate and extend shelf life.
Lactic acid bacteria, and especially lactobacilli, are the main producers of γ-amino butyric acid (GABA), which has numerous potential health benefits. In this work, the GABA production capacity in milk of 38 native strains of lactobacilli isolated from different food ecosystems was evaluated, and three of them were selected for the production of fermented sheep's milk enriched in GABA without the addition of monosodium glutamate. Physico-chemical analyses (pH, titratable acidity, total solids), including water retention capacity, viscosity, production of GABA, glutamic acid, were carried out, as well as descriptive sensory analysis in fermented milks for a storage period of 28 days at 4 °C. GABA concentrations around 200 mg/L were found in fermented milks made with the strains Lacticaseibacillus paracasei Lb41 and Lactiplantibacillus plantarum Lb56. Furthermore, these fermented milks also presented higher viscosity values than the control, and they had good and typical sensory characteristics.
The purpose of this paper was to evaluate the potential of plant-based drink based on soy protein and fructooligosaccharide in the development of probiotic beverages after fermentation by Bacillus coagulans VHProbi C08. B. coagulans VHProbi C08 was isolated from sour cabbage, and the sporulation rate was 90.03%. After being treated at 95 °C for 15 min, the survival rate was 6.86 log CFU/mL. The whole gene of VHProbi C08 contains only one chromosome, 4123 protein-coding genes are predicted, and 824 genes are unique. Plant-based drink fermented by VHProbi C08 showed the highest antibacterial activity against B. cereus ATCC 14579, followed by S. aureus ATCC 29213, L. monocytogenes ATCC 19115, S. enteritidis ATCC 14028, V. parahaemolyticus ATCC 17802, and E. coli ATCC 25922. Its DPPH radical scavenging activity, hydroxyl radical scavenging activity and anti-lipid peroxidation activity were 0.39, 0.25 and 0.35 mmol Trolox/L, respectively. After UPLC-MS/MS detection and analysis; 17 major metabolites with significant changes in fermented and unfermented plant-based drink were identified, including 2-Hydroxycinnamic acid, d-Glucarate, L-Tryptophan, Deoxycytidine, Imidazole propionic acid, Hypoxanthine, etc. In addition, the properties of plant-based drink fermented by VHProbi C08 was relatively stable during storage.
Lipoxygenase-based and lipoxygenase-deficient okara were modified by Kluyveromyces marxianus fermentation, then adding modified okara back to the corresponding soymilk to prepare soy yogurt. The physicochemical properties, texture, and volatile components of soy yogurt were characterized. The results showed that okara modified by Kluyveromyces marxianus fermentation was rich in soluable dietary fiber and was imparted better water-holding capacity, swelling capacity, and oil-holding capacity. The soy yogurt with the modified okara was greatly enhanced in its appearance, texture and was relatively stable during storage. Moreover, lipoxygenase-based soy yogurt had a unique soybean flavor while lipoxygenase-deficient soy yogurt had a slight beany flavor and soybean flavor. This article guides a bio-modified method for okara and provides a theoretical basis for the further development and application of soy yogurt with high dietary fiber as well as lipoxygenase-deficient soy yogurt.
Supplementary information:
The online version contains supplementary material available at 10.1007/s10068-021-01003-w.
Soymilk is a high‐quality fermentation substrate, but its flavour is not accepted by many consumers. In this study, soymilk was fermented under different fermentation conditions by different Lactobacillus strains. The antioxidant activity of the soymilk was explored using TOPSIS and the changes in flavour during fermentation were investigated by e‐nose using PCA. The results of TOPSIS showed that Lactobacillus plantarum (LP) ranked first (0.734) and L. acidophilus (LA) ranked second (0.651). In addition, L. bulgaricus (LB) was the only strain that could increase ABTS antioxidant activity (by around 11%). The LP, LA and LB mixed fermentation sample (w/w/w, 1 : 1 : 1) provided 10 new kinds of flavour compounds and stronger antioxidant ability than the unfermented sample. In addition, storage at 4 ℃ after fermentation elicited beneficial changes in the content of key flavour substances. Therefore, multiple‐strain Lactobacillus‐fermentation of soymilk not only improved the antioxidant activity, but also provided a delicate flavour.
The objective of this work was to investigate the effect of fermentation conditions on c9,t11-conjugated linoleic acid (CLA) synthesized by Lactobacillus casei and the variation of physicochemical characteristics, including pH, viable cell number, syneresis and texture profile, of fermented soy milk (FSM) during storage at 4°C for 28 days. Fermentation in 7°Brix of soy milk (SM) supplemented with 0.1% linoleic acid and incubated at 37°C for 72 h was found to be the optimal conditions for c9,t11-CLA biosynthesis. Within the storage of 14 days, viable cell number, total flavonoid content, water-holding capacity, spontaneous syneresis and texture profile in FSM remained stable. During the storage of 28 days, the viable cell number and c9,t11-CLA level were higher than 6.58 log CFU/mL and 816.33 μg/g, respectively.
19 Streptococcus thermophilus with high exopolysaccharide production were isolated from traditional Chinese fermented dairy products. The exopolysaccharide and viscosity of milk fermented by these 19 isolates were assayed. The strains of Streptococcus thermophilus zlw TM11 were selected because its fermented milk had the highest exopolysaccharide content (380 mg/L) and viscosity (7716 mpa/s). Then Streptococcus thermophilus zlw TM11 was combined with Lactobacillus delbrueckii subsp. bulgaricus 3 4.5 and the combination was named SH-1. The quality of the yogurt fermented by SH-1 and two commercial starter cultures (YO-MIX 465, YF-L711) were compared. It was shown that the exopolysaccharide content of yogurt fermented by SH-1 was similar to that of yogurt fermented by YF-L711 and significantly higher than YO-MIX 465 (
p
<
0.05
). In addition, the yogurt fermented by SH-1 had the lowest syneresis (8.5%) and better texture and sensory than the samples fermented by YO-MIX 465 and YF-L711. It manifested that the selected higher exopolysaccharide production starter SH-1 could be used as yogurt starter and reduce the amount of adding stabilizer, which can compare with the imported commercial starter culture.
This review presents selected data on the probiotic strain Bifidobacterium animalis subsp. lactis BB-12® (BB-12®), which is the world’s most documented probiotic Bifidobacterium. It is described in more than 300 scientific publications out of which more than 130 are publications of human clinical studies. The complete genome sequence of BB-12® has been determined and published. BB-12® originates from Chr. Hansen’s collection of dairy cultures and has high stability in foods and as freeze dried powders. Strain characteristics and mechanisms of BB-12® have been established through extensive in vitro testing. BB-12® exhibits excellent gastric acid and bile tolerance; it contains bile salt hydrolase, and has strong mucus adherence properties, all valuable probiotic characteristics. Pathogen inhibition, barrier function enhancement, and immune interactions are mechanisms that all have been demonstrated for BB-12®. BB-12® has proven its beneficial health effect in numerous clinical studies within gastrointestinal health and immune function. Clinical studies have demonstrated survival of BB-12® through the gastrointestinal tract and BB-12® has been shown to support a healthy gastrointestinal microbiota. Furthermore, BB-12® has been shown to improve bowel function, to have a protective effect against diarrhea, and to reduce side effects of antibiotic treatment, such as antibiotic-associated diarrhea. In terms of immune function, clinical studies have shown that BB-12® increases the body’s resistance to common respiratory infections as well as reduces the incidence of acute respiratory tract infections.
Soymilk prepared from germinated soybean [Glycine max (L.) Merrill] with different hypocotyl lengths was fermented at 42 °C for approx. 4 h to produce soy yogurt (sogurt) with the combined probiotics of Lactobacillus helveticus B02, Streptococcus thermophilus IFFI 6038 and Lactobacillus bulgaricus AS1.1482. The physicochemical, textural and sensory characteristics of the fermented products were subsequently analyzed. Results showed that sogurt prepared from germinated soybean with the length of hypocotyls of 3 cm displayed lower pH and higher titratable acidity, and appeared to be more acceptable by the trained panel than sogurts prepared from soybean with hypocotyl length of 0 and 6 cm (p<0.05). Texture profile analysis demonstrated that the hardness of sogurts significantly decreased (from 26.71 to 16.89 g), while the adhesiveness significantly increased (from -71.77 to -31.94 g·s) as hypocotyl length increased (p<0.05). Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) profile of soymilk demonstrated that the α′ and α subunits of β-conglycinin (7S) and the acidic chains of glycinin (11S) were gradually degraded, which may be partly responsible for the decline of water holding capacity and the amelioration of textural properties of the germinated soy yogurt. The total concentration of free amino acids obtained by high-performance liquid chromatography (HPLC) was 515.78 μg/mL in the soymilk from ungerminated soybean (S0), while it reached 847.44 and 880.75 μg/mL from soybean with 3-cm (S3) and 6-cm (S6) hypocotyls, respectively. Some of the increased levels of free amino acids may account for the improvement of flavour and reproduction of lactic acid bacteria. It could be concluded that, with appropriate germination, the physicochemical and textural properties as well as sensory characteristics of sogurt could be improved significantly.
Recent research in the area of importance of microbes has revealed the immense industrial potential of exopolysaccharides
and their derivative oligosaccharides from lactic acid bacteria. However, due to lack of adequate technological knowledge,
the exopolysaccharides have remained largely under exploited. In the present review, the enormous potentials of different
types of exopolysaccharides from lactic acid bacteria are described. This also summarizes the recent advances in the applications
of exopolysaccharides, certain problems associated with their commercial production and the remedies.
KeywordsLactic acid bacteria–Exopolysaccharides–Probiotic–Prebiotic–Oligosaccharides
The objective of this study was to understand the effect of different coagulants in their ability to retain isoflavones in prepared firm tofu. Harovinton beans were processed to obtain soymilk and a specific amount of this soymilk was coagulated using different types of coagulants for the preparation of tofu. A reversed phase high performance liquid chromatographic method was used for determining the concentration of isoflavones in tofu and whey. Quality parameters such as the texture, color and moisture of tofu, prepared from different coagulants were also determined in this study. Tofus coagulated with different coagulants were found to contain different amounts of isoflavones. Calcium sulfate was found to be the most suitable coagulant for tofu making in terms of its high yield, retention of maximum amount of isoflavones and in obtaining a firm, but not hard texture of tofu.
This randomized, placebo-controlled, double blind, parallel dose-response study investigated the impact of 4-week commercial yoghurt consumption supplemented with Bifidobacterium animalis subsp. lactis (BB-12) and Lactobacillus acidophilus (LA-5) on fecal bacterial counts of healthy adults. Fifty-eight volunteers were randomly assigned to three different groups: 1. placebo (no probiotic, no starter and no green tea extract); 2. Yoptimal (10(9)cfu/100g of BB-12 and LA-5 and 40mg of green tea extract) and 3. Yoptimal-10 (10(10)cfu/100g of BB-12, 10(9)cfu/100g of LA-5 and 40mg of green tea extract). These yoghurt products also contained Lactobacillus delbrueckii subsp. bulgaricus (10(7)cfu/100g) and Streptococcus thermophilus (10(10)cfu/100g). The quantitative PCR (qPCR) results showed that there were significant increases (P=0.02) in bifidobacteria counts with the Yoptimal treatment as compared to baseline. The fecal numbers of B. animalis subsp. lactis and LA-5 significantly increased in the two probiotic treatments compared to the placebo treatment. Viable counts of fecal lactobacilli were significantly higher (P=0.05) and those of enterococci were significantly lower (P=0.04) after the intervention when compared to placebo. No significant difference was observed between treatments in volunteers' weight, waist girth, blood pressure, fasting plasma triglyceride and HDL-C concentrations, as well as cholesterol/HDL-cholesterol ratio. However, a significant increase in plasma cholesterol levels was observed in the placebo group (P=0.0018) but the levels remained stable in the two probiotic yoghurt groups. These results show that probiotic strains supplemented in the form of yoghurt remain active during gut transit and are associated with an increase in beneficial bacteria and a reduction in potentially pathogenic bacteria. This trial was registered at clinicaltrials.gov as NCT00730626.
Lactobacillus rhamnosus GG (ATCC 53103) is one of the clinically best-studied probiotic organisms. Moreover, L. rhamnosus GG displays very good in vitro adherence to epithelial cells and mucus. Here, we report that L. rhamnosus GG is able to form biofilms on abiotic surfaces, in contrast to other strains of the Lactobacillus casei group tested under the same conditions. Microtiter plate biofilm assays indicated that in vitro biofilm formation by L. rhamnosus GG is strongly modulated by culture medium factors and conditions related to the gastrointestinal environment, including
low pH; high osmolarity; and the presence of bile, mucins, and nondigestible polysaccharides. Additionally, phenotypic analysis
of mutants affected in exopolysaccharides (wzb), lipoteichoic acid (dltD), and central metabolism (luxS) showed their relative importance in biofilm formation by L. rhamnosus GG.
The physical properties of soymilk gels acidified with glucono-δ-lactone (GDL) or cultures with varying exopolysaccharide (EPS) production capabilities (EXPRESS CN < YFL-903) were studied. The acidification time and final pH were controlled in all samples. Earlier gelation and higher gelation pH were induced using GDL. The rheological properties and size distribution of GDL gel were closer to those of the EXPRESS CN gel than YFL-903 gel. Better lubrication property in the mixed regime was found in culture acidified gels, with YFL-903 gel showing the best results. Firmness, adhesiveness and water holding capacity were higher in culture- induced gels than in the GDL gel. The microstructures of the gels were found to be similar, but the subtle stranded structure of the GDL gel seemed denser than the culture-induced gel. The results suggest that both acidification rate and EPS production should be considered when comparing GDL and culture-induced soymilk gels.
In this study, the most important variables (incubation temperature, fermentation time and yeast extract concentration) responsible for the exopolysaccharides (EPSs) production by Lactobacillus acidophilus LA5 and Bifidobacterium animalis subsp. lactis BB12 were screened. The EPSs synthesize by LA5, BB12, and their co-culture were successfully optimized and were 349.82 ± 5.39, 146.83 ± 3.99 and 187.02 ± 1.54 mg/L, respectively. GC–MS analysis indicated that the purified EPSs are heteropolysaccharide and consisted of glucose, galactose, glucuronic acid, and xylose. The FT-IR analysis was used to investigate functional groups of purified EPSs and NMR analysis was used to study the structure of them. The DSC, TGA and DTG analysis of the extracted EPSs showed that they had high thermal stability and degradation temperature. The results of bioactivity analysis indicated that maximum DPPH and hydroxyl radicals scavenging activity were 59.30 ± 1.95, 56.76 ± 0.79, 62.33 ± 1.02% and 59.94 ± 1.68, 46.40 ± 0.73, 53.54 ± 0.76%, respectively for the EPSs of LA5, BB12, and their co-culture. Additionally, reducing power of the produced EPSs by LA5, BB12, and their co-culture were 1.047 ± 0.001, 1.270 ± 0.045 and 1.139 ± 0.018, respectively. Consequently, all these results showed that the EPSs produced by LA5, BB12, and their co-culture had a high potential as natural antioxidants or bioactive additive in the food industry.
The effects of probiotic-fermented soymilk (fermented by mixture of Bifidobacterium bifidum, Lactobacillus casei, and L. plantarum) on high-fat diet (HFD)-induced hyperlipidemia and liver injury were examined. C57BL/6N mice were randomly assigned into four groups that were treated with different diets: normal chow (NC), HFD, HFD with probiotic-fermented soymilk and HFD with non-fermented soymilk. After treatment for 6 weeks, probiotic-fermented soymilk treatment significantly reduced HFD-induced body weight gain, hyperlipidemia, liver fat accumulation and reactive oxygen species (ROS) production. In addition, probiotic-fermented soymilk consumption significantly reduced the levels of serum alanine aminotransferase (ALT), lipopolysaccharide (LPS), and liver tumor necrosis factor-α (TNF-α) compared with the HFD treatment. Further, probiotic-fermented soymilk significantly increased the serum leptin level. In conclusion, probiotic-fermented soymilk reduced hyperlipidemia and liver injury induced by HFD. The role of probiotic-fermented soymilk may decrease the production of liver LPS, TNF-α, and oxidative stress and induce adipose leptin and triacylglycerol hydrolase (TGH) production.
This study's objective was to characterize the effect of traditional and 3 newly devised (soaking+grinding) methods combined with cooking on the content and composition of phenolic substances, antioxidant, and antiproliferative properties of soymilk prepared from black soybean. Phenolic substances and antioxidant profile were characterized and antiproliferation of prostate cancer DU145 cells was conducted using a cell culture assay. Results indicated Grinding Method 4 produced significantly (P < 0.05) higher total phenolic content (TPC), total flavonoid content (TFC), condensed tannin content (CTC), and total isoflavone content in both raw and cooked black soymilk as compared to Method 1. Cooking soymilk reduced 23% to 38% of total phenolic substances. Raw black soymilk produced by Method 4 displayed the highest antioxidant capability, which was determined using ORAC, FRAP, and DPPH assays, and a higher antiprostate cell proliferation ability. Cooking only slightly reduced the potency to inhibit DU145 prostate cancer cells as IC50 value was increased from the average of about 4.0 mg/mL of raw soymilk extracts to 5.5 mg/mL of cooked soymilk extracts of all grinding methods. Overall, total isoflavone content was the only component that was negatively correlated with IC50 value (r = -0.93, P < 0.05) which indicates the ability to inhibit prostate cancer cell is associated with the increase in total isoflavone content, not with any other phenolic substances or antioxidant properties.
Health benefits associated with dietary fibre consumption have shifted its applications towards inclusions into food products. This work aimed at exploring the influence of adding pineapple peel powder (PPP) as a fibre source on physicochemical, textural, rheological, and microstructural attributes of probiotic yogurt during refrigerated storage for 28 days. Skim milk with or without PPP or inulin as a control was fermented by yogurt cultures with or without addition of the probiotic cultures consisting of Lactobacillus acidophilus (ATCC® 4356™), Lactobacillus casei (ATCC® 393™) and Lactobacillus paracasei spp. paracasei (ATCC® BAA52™). PPP supplementation at 1% remarkably reduced fermentation time of milk co-fermented with probiotic organisms. Syneresis level in probiotic yogurt with PPP (1.16% at day 1) was comparable with the prebiotic-inulin and increased during storage. However, firmness and storage modulus in both plain and probiotic yogurts were lowered significantly with PPP addition. The reported information on physicochemical and structural attributes of probiotic yogurts with PPP could guide the dairy industry to utilize pineapple peel discarded as processing waste to close the fibre gap by developing a new synbiotic product with comparable attributes to inulin, a commercial prebiotic.
ビフィズス菌の単独培養,または乳酸菌との混合培養による発育性ならびに大豆オリゴ糖の資化性について観察した.(1) 豆乳中におけるビフィズス菌の発育性について,24時間培養後のpHは,いずれの菌も4.53～4.76まで低下し,酸度は, 0.67～0.90%まで上昇した.また,培養20時間後の菌数は,いずれの菌種も10 3個のオーダーで増加し,豆乳中におけるビフィズス菌の増殖性はきわめて良好であった.(2) B. breveおよびB. longum とL. acidophilusとの混合培養では,ビフィズス菌数,生酸性は単独培養時のそれらを上回ったが,L. acidophilusの菌数は単独培養時のそれよりも低い傾向を示した.(3) ビフィズス菌による豆乳中のガラクトオリゴ糖の資化性は,特にスタキオースに対して優れていた.また,生成したグルコースは発酵に利用されたが,フルクトースおよびガラクトースは蓄積される傾向がみられた.(4) スクロース,ラフィノースまたはスタキオースを添加したMGLP培地において, B. breveの発育性は,スタキオース添加培地で優れていた.さらに,これらの糖を2種類または3種類含有する培地では,後者の方が良好な発育性を示した.
Currently, the food industry wants to expand the range of probiotic yogurts but each probiotic bacteria offers different and specific health benefits. Little information exists on the influence of probiotic strains on physicochemical properties and sensory characteristics of yogurts and fermented milks. Six probiotic yogurts or fermented milks and 1 control yogurt were prepared, and we evaluated several physicochemical properties (pH, titratable acidity, texture, color, and syneresis), microbial viability of starter cultures (Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus) and probiotics (Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus reuteri) during fermentation and storage (35d at 5°C), as well as sensory preference among them. Decreases in pH (0.17 to 0.50 units) and increases in titratable acidity (0.09 to 0.29%) were observed during storage. Only the yogurt with S. thermophilus, L. delbrueckii ssp. bulgaricus, and L. reuteri differed in firmness. No differences in adhesiveness were determined among the tested yogurts, fermented milks, and the control. Syneresis was in the range of 45 to 58%. No changes in color during storage were observed and no color differences were detected among the evaluated fermented milk products. Counts of S. thermophilus decreased from 1.8 to 3.5 log during storage. Counts of L. delbrueckii ssp. bulgaricus also decreased in probiotic yogurts and varied from 30 to 50% of initial population. Probiotic bacteria also lost viability throughout storage, although the 3 probiotic fermented milks maintained counts ≥10(7)cfu/mL for 3wk. Probiotic bacteria had variable viability in yogurts, maintaining counts of L. acidophilus ≥10(7) cfu/mL for 35d, of L. casei for 7d, and of L. reuteri for 14d. We found no significant sensory preference among the 6 probiotic yogurts and fermented milks or the control. However, the yogurt and fermented milk made with L. casei were better accepted. This study presents relevant information on physicochemical, sensory, and microbial properties of probiotic yogurts and fermented milks, which could guide the dairy industry in developing new probiotic products.
Growth of Lactobacillus plantarum 70810, Lactobacillus rhamnosus 6005 and a commercial yogurt starter culture in soymilk was investigated in the present study. It was found that the fermented soymilk using L. plantarum 70810 had significantly higher viable cell counts, water holding capacity (WHC, 88.27%), apparent viscosity (1840.35 mPa s) and exopolysaccharide (EPS) amount (832.15 mg/L) than the other two starter cultures in soymilk. Direct observation of microstructure in fermented soymilk indicated that the network structures of EPS-protein could improve the texture of fermented soymilk. Considering that the beneficial effects of L. plantarum 70810 in fermented soymilk, volatile compounds in fermented soymilk were further identified. Then the growth and fermentation characteristics of L. plantarum 70810 including changes in viable cell counts, pH, titratable acidity, apparent viscosity and EPS production during storage were investigated. In comparison to original soymilk base, the concentrations of the characteristic flavor compounds for fermented soymilk using L. plantarum 70810 increased, whereas hexanal, 2-pentylfuran and 2-pentanone in relation to beany flavor of soymilk decreased. In addition, fermented soymilk using L. plantarum 70810 maintained high viable cell count (>108 cfu/mL), apparent viscosity (966.43 mPa s) and amounts of EPS (635.49 mg/mL) during storage at 4 °C for 21 days.
In this work, the microbiological and physicochemical differences of three types of low fat set yoghurts were studied, as well as the changes taking place during storage at 4 °C for 28 days. The first yoghurt was produced with yoghurt starters and exopolysaccharide (EPS) producing Bifidobacterium longum subsp. infantis CCUG 52486 (CCUGY), the second with yoghurt starters and Bifidobacterium infantis NCIMB 702205 (NCIMBY) and the third with just yoghurt starters (control yoghurt). No significant differences were observed in terms of cell concentrations; for all three yoghurts, similar final cell concentrations were obtained for the yoghurt starter cultures (~ 7.5 log cfu g− 1) and the Bifidobacterium strains (~ 7.8 log cfu g− 1). Both Bifidobacterium survived well during storage, as in both cases the cell viability decreased by less than 0.5 log cfu g− 1after 28 days of storage. A decrease in pH followed by an increase in lactic acid was observed during storage for all three yoghurts, which was mostly attributed to the activity of the yoghurt starter cultures. The two yoghurts with the EPS producing Bifidobacterium strains exhibited lower syneresis than the control yoghurt. The lowest was shown by CCUGY, which also exhibited the highest storage modulus and firmness, and a well defined porous web-like structure in cryo-SEM. Examination of the micro-structure of the yoghurts using cryo-scanning electron microscopy (cryo-SEM) indicated that the above observations were due to the interaction between the EPS and the milk proteins. Overall, the results indicated that the EPS producing Bifidobacterium longum subsp. infantis CCUG 52486 is the most promising strain, and can be used with yoghurt starter cultures to manufacture low fat set yoghurt with probiotic activities and at the same time enhanced physicochemical and rheological properties.
The objective of this work was to compare the gelation of soymilk particles induced by the acidification of a commercial starter culture with that resulting by addition of glucono-δ-lactone (GDL). Structure formation was followed using rheology, and the microstructure was observed by confocal microscopy. Acidification of lactic acid bacteria resulted in a higher gelation pH (pH 6.29±0.05) compared to that of a gel induced by GDL (pH 5.9±0.04). This difference was attributed to the longer time available for rearrangements of the soymilk particles in soymilk with starter cultures compared to the fast acidification by GDL. In spite of the earlier gelation pH, there were no observed differences in the final gel stiffness measured at pH 5.1, the value of tan δ, the frequency dependence and the linear viscoelastic range of the gels measured at the final pH. Microstructural observations also showed a similar protein network structure.
Different strains of yogurt starter cultures and different incubation temperatures were investigated in the production of plain, unflavored set type yogurt. Milk samples were inoculated with 2% CH-1 (non-filant type which does not produce any ropy like substances) and B-3 (filant type which produces ropy like substances), and then incubated at 35 and 45 °C until the pH reached 4.7. Total solids, fat content, pH, viscosity, consistency, whey separation, organoleptic evaluation and content of lactic acid, acetaldehyde, volatile fatty acids and tyrosine were measured as quality criteria on the yogurt samples at Days 1 and 14 of storage. Lactic acid content and pH values of samples were more significantly affected by starter culture strain than by incubation temperature (P
This study describes selective plating methodologies for enumeration of mixed cultures of Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, L. acidophilus, L. paracasei subsp. paracasei and Bifidobacterium lactis in fermented milk based on selective antibiotic-free media. Enumeration of S. thermophilus was performed using M17-lactose. MRS-fructose was suitable for enumeration of L. bulgaricus and MRS-maltose for differentiation between L. acidophilus and L. paracasei. The selective enumeration of B. lactis was obtained using MRS-raffinose containing 0.05% LiCl. The bacterial counts obtained using selective methods were equivalent to those under optimum culture conditions at a probability level of 95%. Performance of the methods was verified in fermented milk products where identification of the enumerated species was confirmed by species-specific polymerase chain reaction. This study shows that combination of species-specific polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) analysis has great detection and identification potential for verification of accurate species labelling in fermented milk without prior isolation of the bacteria.
This study investigated the physical characteristics of set and stirred yoghurts made at 9% (w/w) total solids with various casein (CN)-to-whey protein (WP) ratios and with exopolysaccharide (EPS)-producing starter cultures (capsular or ropy) during storage. The yoghurt was evaluated for composition, firmness and syneresis of set yoghurt, and for the flow curve and the area of hysteresis loop between the upward and downward curve of stirred yoghurt. Viable counts of starter bacteria and concentrations of lactic acid and EPS in the yoghurt were also determined. EPS concentration did not decrease during storage for 28d. Firmness and syneresis of set yoghurt decreased when the CN-to-WP ratio was reduced from ratio 4:1 to 1:1 and when EPS starter cultures (especially ropy EPS) were used. Stirred yoghurt with a CN-to-WP ratio of 3:1 and made using ropy EPS-producing starter cultures had a higher shear stress and hysteresis loop area than yoghurt made using capsular EPS- or non-EPS-producing starter cultures. The results suggested that the physical characteristics of set and stirred yoghurts can be improved by varying CN-to-WP ratio and by the use of EPS-producing starter cultures.
This study investigated the viability of probiotic (Lactobacillus acidophilus LA5, Lactobacillus rhamnosus LBA and Bifidobacterium animalis subsp. lactis BL-04) in milk fermented with Lactobacillus delbrueckii subsp. bulgaricus LB340 and Streptococcus thermophilus TAO (yoghurt – Y). Each probiotic strain was grown separately in co-culture with Y and in blends of different combinations. Blends affected fermentation time(s), pH and firmness during storage at 4°C. The product made with Y plus B. animalis subsp. lactis and L. rhamnosus had counts of viable cells at the end of shelf life that met the minimum required to achieve probiotic effect. However, L. acidophilus and L. delbrueckii subsp. bulgaricus were inhibited.
Off-flavor of soymilk is a barrier to the acceptance of consumers. The objectionable soy odor can be reduced through inhibition of their formation or through removal after being formed. In this study, soymilk was prepared by three grinding methods (ambient, cold, and hot grinding) from two varieties (yellow Prosoy and a black soybean) before undergoing three heating processes: stove cooking, one-phase UHT (ultrahigh temperature), and two-phase UHT process using a Microthermics direct injection processor, which was equipped with a vacuuming step to remove injected water and volatiles. Eight typical soy odor compounds, generated from lipid oxidation, were extracted by a solid-phase microextraction method and analyzed by gas chromatography. The results showed that hot grinding and cold grinding significantly reduced off-flavor as compared with ambient grinding, and hot grinding achieved the best result. The UHT methods, especially the two-phase UHT method, were effective to reduce soy odor. Different odor compounds showed distinct concentration patterns because of different formation mechanisms. The two varieties behaved differently in odor formation during the soymilk-making process. Most odor compounds could be reduced to below the detection limit through a combination of hot grinding and two-phase UHT processing. However, hot grinding gave lower solid and protein recoveries in soymilk.
The effects of ultra high-pressure homogenization (UHPH) on soymilk were investigated and its suitability for soy-yogurt manufacturing was compared with conventional heat treatments (UHT and autoclaved). UHPH soymilk at 40 and 50 °C inlet temperature was treated at 200 and 300 MPa. Coagulation parameters and acidification curves were determined for the fermentation process. Textural parameters, water-holding capacity and microstructure were performed on soy-yogurts obtained after cold storage during 24 h. Results indicated that conventionally heat-treated soymilks and UHPH-treated samples exhibited different behaviour to coagulation. Heat-treated soymilk had a shorter onset of gelation, and higher aggregation rate and gel network density than UHPH-treated soymilk. However, physical quality parameters, specially firmness, were much better in UHPH than in conventional heat-treated soy-yogurts.
A new selective medium for the detection of bifidobacteria was developed. The medium owes its selectivity to the presence of propionate (15 g/l) and lithium chloride (3 g/l) as inhibitory agents, and raffinose (7.5 g/l) as a selective carbon source. In addition, casein (5 g/l) is used as a protein source, which results in a zone of precipitation around the colonies of bifidobacteria. The medium, Raffinose-Bifidobacterium (RB) agar, is free of antibiotics and easy to prepare. Bifidobacteria growing on RB agar show a yellow colony with a yellow halo and a precipitation zone around the colony. All human and dairy bifidobacteria grew well on RB agar, except for some Bifidobacterium bifidum strains. Some uncommon or animal species, Bifidobacterium gallicum, Bifidobacterium asteroides, Bifidobacterium animalis, Bifidobacterium pullorum, and some Bifidobacterium bifidum either did not grow or did not show the characteristic reactions. No non-bifidobacterial strains used in dairy products grow with the distinctive characteristics. Some faecal strains showed good growth and acid production, resulting in characteristic reactions. These strains were Actinomyces species, a Clostridium perfringens strain and some lactobacilli of animal origin. Comparison with other media indicated that RB agar is more selective than other media used.
Bifidobacterium longum B6 and B. infantis CCRC 14633 were grown in soymilk for a period of 48 h. During various fermentation periods, changes in the contents of crude protein, sugars, B-vitamins, acetic and lactic acids in soymilk were examined. Crude protein and titratable acidity were increased during fermentation. Soymilk fermented with B. infantis had higher titratabale acidity than that fermented with B. longum. The degree of protein hydrolysis, thiamin and riboflavin contents were increased while niacin content was decreased in soymilk fermented with either B. infantis or B. longum. Acetic and lactic acid contents were increased while the molar ratio of acetic and lactic was decreased during fermentation. Stachyose, raffinose and sucrose contents were decreased, with stachyose showing the largest magnitude of reduction. On the other hand, contents of fructose and glucose plus galactose contents were increased during fermentation.
Thermal denaturation of soy proteins is a pre-requisite for tofu-gel formation. Differential scanning calorimetry of soymilk showed that the denaturation temperature of glycinin (92 °C) is about 20 °C higher than that of β-conglycinin (71 °C). This makes it possible to denature soybean proteins selectively using two-step heating, that is, soymilk was heated at 75 °C for 5 min and then heated at 95 °C for another 5 min. The effects of selective thermal denaturation (STD) on soymilk viscosity and tofu's physical properties were investigated with three soybean samples and varied soymilk solid contents (10–12%). Comparing to one-step heating (95 °C, 5 min), STD increased soymilk viscosity by approximately 150% and tofu's apparent Young's modulus by approximately 20%, and reduced tofu's syneresis rate by approximately 10%. Change in tofu microstructure was also observed by scanning electronic microscopy. STD mechanism based on the interaction between glycinin and β-conglycinin was discussed.
In this study, two strains of lactic acid bacteria, Lactobacillus acidophilus CCRC 14079 and Streptococcus thermophilus CCRC 14085 were used in single culture and in combination with either Bifidobacteria infantis CCRC 14633 or Bifidobacteria longum B6 for the production of fermented soymilk. Changes in the content of some components including sugars, organic acids and acidity in soymilk during fermentation were examined.Results revealed that L. acidophilus and S. thermophilus were capable of metabolizing stachyose and raffinose in soymilk. In addition, S. thermophilus exploited these substrates more efficiently than L. acidophilus. During the 24–32 h of fermentation with single culture of either L. acidophilus or S. thermophilus, content of raffinose, stachyose, sucrose, and pH in soymilk decreased, while content of fructose and glucose plus galactose increased.Introduction of bifidobacteria with lactic acid bacteria as the starter culture affected significantly the sugar and acid contents of the fermented soymilk. A further reduction in the content of stachyose and raffinose and a higher content of sucrose, fructose, glucose plus galactose and acetic acid were found in soymilk fermented with mixed cultures of bifidobacteria and lactic acid bacteria than that fermented with single culture of the respective lactic acid bacteria.
To investigate matrix-specifity of probiotic effects and particularly of the reduction of antibiotics-associated diarrhea, a controlled, randomized, double-blind study was performed, in which 88 Helicobacter pylori-infected but otherwise healthy subjects were given for eight weeks either a) a probiotic fruit yoghurt "mild" containing Lactobacillus acidophilus LA-5 plus Bifidobacterium lactis BB-12, n = 30), b) the same product but pasteurized after fermentation (n = 29) or c) milk acidified with lactic acid (control, n = 29). During week five, a Helicobacter eradication therapy was performed. Helicobacter activity was measured via 13C-2-urea breath tests and antibiotic-associated diarrhoea and other gastrointestinal complaints were recorded by validated questionnaires. In intervention group a, b and c the mean number of days with diarrhoea was 4, 10 and 10 (P<0·05), the frequency of episodes 17%, 7% and 27% (n.s.), and the change in total symptoms score before antibiotics treatment was -1·4 ± 1·1, -1·2 ± 1·1, 2·6 ± 1·1 points/four weeks (P<0·05). All milk products decreased Helicobacter activity by 18 to 45% without significant differences between groups. The observed decrease in Hel. pylori activity seems to be not or not only due to probiotic bacteria but (rather) to components of acidified milk (most probably lactic acid). Fruit-yogurt-like fermented milk products with living probiotic bacteria significantly shorten the duration of antibiotics-associated diarrhoea and improve gastrointestinal complaints. Fruit yogurt-like fermented milk is a matrix suitable for probiotic bacteria.
Soybean milk, which serves as a base for a variety of beverages, contains raffinose, stachyose, pentanal and n-hexanal; the former two may be responsible for flatulence after fermentation, whilst the latter two for a beany flavour. Twenty-seven strains of Bifidobacterium were analyzed for their alpha-galactosidase activity and the production of lactic and acetic acids to determine their potential for use in the production of fermented soymilk. The behaviour of three strains in soymilk was studied to determine their ability to reduce alpha-D-galactosyl oligosaccharides and produce lactic and acetic acids. They all were able to reduce stachyose and raffinose. Pentanal and n-hexanal were metabolized by Bifidobacterium breve MB233. These data indicate that bifidobacteria can be used for biotechnological processes that employ soymilk as the substrate. A product with low levels of alpha-D-galactosyl oligosaccharides and alkylic aldehydes may be obtained.
Soymilk prepared from germinated soybean [Glycine max (L.) Merrill] with different hypocotyl lengths was fermented at 42 °C for approx. 4 h to produce soy yogurt (sogurt) with the combined probiotics of Lactobacillus helveticus B02, Streptococcus thermophilus IFFI 6038 and Lactobacillus bulgaricus AS1.1482. The physicochemical, textural and sensory characteristics of the fermented products were subsequently analyzed. Results showed that sogurt prepared from germinated soybean with the length of hypocotyls of 3 cm displayed lower pH and higher titratable acidity, and appeared to be more acceptable by the trained panel than sogurts prepared from soybean with hypocotyl length of 0 and 6 cm (p<0.05). Texture profile analysis demonstrated that the hardness of sogurts significantly decreased (from 26.71 to 16.89 g), while the adhesiveness significantly increased (from –71.77 to –31.94 g·s) as hypocotyl length increased (p<0.05). Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) profile of soymilk demonstrated that the α’ and α subunits of β-conglycinin (7S) and the acidic chains of glycinin (11S) were gradually degraded, which may be partly responsible for the decline of water holding capacity and the amelioration of textural properties of the germinated soy yogurt. The total concentration of free amino acids obtained by high-performance liquid chromatography (HPLC) was 515.78 μg/mL in the soymilk from ungerminated soybean (S0), while it reached 847.44 and 880.75 μg/mL from soybean with 3-cm (S3) and 6-cm (S6) hypocotyls, respectively. Some of the increased levels of free amino acids may account for the improvement of flavour and reproduction of lactic acid bacteria. It could be concluded that, with appropriate germination, the physicochemical and textural properties as well as sensory characteristics of sogurt could be improved significantly.
The aims of this work were to compare antiproliferation, antioxidant activities and total phytochemicals and individual isoflavone profiles in soy milk processed by various methods including traditional stove cooking, direct steam injection, direct ultrahigh temperature (UHT), indirect UHT, and a two-stage simulated industry method, and a selected commercial soy milk product. Various processing methods significantly affected total saponin, phytic acid, and total phenolic content and individual isoflavone distribution. The laboratory UHT and the two-stage processed soy milk exhibited relatively higher total phenolic content, total flavonoid content, saponin and phytic acid than those processed by the traditional and steam processed methods. Thermal processing caused obvious intertransformation but did not cause severe degradation except for breaking down of aglycons. Thermal processing significantly increased antioxidant capacities of soy milk determined by chemical analyses, but decreased cellular antioxidant capacities as compared to the raw soy milk. The raw and all processed soy milk exhibited antipoliferative activities against human HL-60 leukemia cells, AGS gastric tumor cells, and DU145 prostate cancer cells in a dose-dependent manner. The raw soy milk, but not the processed soy milk, exhibited a dose-dependent antiproliferative effect against colorectal adenocarcinoma Caco-2 cells. Taken together, these results indicate that various thermal processing methods change not only phytochemcials but also potential health-promoting effects of soy milk.
Microbial exopolysaccharides are biothickeners that can be added to a wide variety of food products, where they serve as viscosifying, stabilizing, emulsifying or gelling agents. Numerous exopolysaccharides with different composition, size and structure are synthesized by lactic acid bacteria. The heteropolysaccharides from both mesophilic and thermophilic lactic acid bacteria have received renewed interest recently. Structural analysis combined with rheological studies revealed that there is considerable variation among the different exopolysaccharides; some of them exhibit remarkable thickening and shear-thinning properties and display high intrinsic viscosities. Hence, several slime-producing lactic acid bacterium strains and their biopolymers have interesting functional and technological properties, which may be exploited towards different products, in particular, natural fermented milks. However, information on the biosynthesis, molecular organization and fermentation conditions is rather scarce, and the kinetics of exopolysaccharide formation are poorly described. Moreover, the production of exopolysaccharides is low and often unstable, and their downstream processing is difficult. This review particularly deals with microbiological, biochemical and technological aspects of heteropolysaccharides from, and their production by, lactic acid bacteria. The chemical composition and structure, the biosynthesis, genetics and molecular organization, the nutritional and physiological aspects, the process technology, and both food additive and in situ applications (in particular in yogurt) of heterotype exopolysaccharides from lactic acid bacteria are described. Where appropriate, suggestions are made for strain improvement, enhanced productivities and advanced modification and production processes (involving enzyme and/or fermentation technology) that may contribute to the economic soundness of applications with this promising group of biomolecules.
Objective: To study the effect of administration of clindamycin with or without supplementation of the intestinal microflora with Bifidobacterium bifidum and Lactobacillus acidophilus.
Method: Twenty-three healthy subjects received clindamycin by mouth for 7 days. Eleven of the subjects also received capsules containing lyophilized L. acidophilus and B. bifidum for 14 days. The other 12 subjects received placebo.
Results: There was a marked decrease in total numbers of anaerobic bacteria during the administration of clindamycin. In the lactic acid bacteria-supplemented group, a tendency towards delayed reduction and earlier increase in bifidobacteria was observed, and two of 11 subjects (18%) were colonized with Clostridium difficile, in comparison with five of 12 (41%) in the placebo group. The total number of microorganisms was significantly higher in the lactic acid bacteria-supplemented group than in the placebo group (p=0.02) 4 days after the end of clindamycin administration. The difference was mainly due to higher counts of Escherichia coli and enterococci. Mean levels of other enterobacteria increased less in the lactic acid bacteria-supplemented group than in the placebo group between days 0 and 14.
Conclusions: The recolonization with aerobic and anaerobic microorganisms was faster in the lactic acid bacteria-supplemented group than in the placebo group. This may be of importance in preventing colonization with C. difficile.
To further the goal of developing a probiotic dietary adjunct using soymilk, soymilk is fermented with lactic acid bacteria (Lactobacillus acidophilus CCRC 14079 or Streptococcus thermophilus CCRC 14085) and bifidobacteria (Bifidobacterium infantis CCRC 14633 or Bifidobacterium longum B6) individually, and in conjunction. We investigate several antioxidative activities including the inhibition of ascorbate autoxidation, the scavenging effect of superoxide anion radicals and hydrogen peroxide, and the reducing activity exerted by different varieties of fermented soymilks. In addition, the effect of spray-drying and freeze-drying on changes in antioxidative activity is examined. We find that in fermented soymilk both the inhibition of ascorbate autoxidation, and the reducing activity and scavenging effect of superoxide anion radicals varied with the starters used, but nevertheless are significantly higher than those found in unfermented soymilk. In general, antioxidative activity in soymilk fermented with lactic acid bacteria and bifidobacteria simultaneously is significantly higher (P < 0.05) than that fermented with either individually. Moreover, antioxidative activity increases as the fermentation period is extended. However, unfermented soymilk shows an H2O2-scavenging effect, while there is no scavenging effect except for the accumulation of H2O2 in fermented soymilk. Finally, we find that freeze-drying causes a significantly lesser (P < 0.05) reduction in the antioxidative activity of soymilk than does spray-drying. Irrespective of the drying method and the starters used for fermentation. The antioxidative activity of fermented soymilk reduces after drying yet remains higher than that of dried unfermented soymilk.
In vitro approaches to evaluate the effect of processed pinto beans and soybeans on the gut microbiota
- Chen
Chen, Y., Chang, S. K. C., Zhang, Y., Hsu, C. Y., & Nannapaneni, R. (2020). In vitro
approaches to evaluate the effect of processed pinto beans and soybeans on the gut
microbiota. Food Chemistry, 312(15 May 2020), 126040. https://doi.org/10.1016/j.
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Heteropolysaccharides from lactic acid bacteria
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