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Effect of Low pH on the Ability of Lactobacillus acidophilus to Survive and Adhere to Human Intestinal Cells
Journal of Food Science
Abstract
Lactobacillus acidophilus was suspended in broth and buffer at pH 2, 3 and 4 and incubated at 37°C for 2 hr. In both broth and buffer pH 2, viable cell numbers decreased rapidly, and none were recovered after 45 min. At pH 4 in broth and buffer, the number of cells was not significantly reduced in 2 hr. In potassium phthalate buffer at p 3, no viable cells were recovered after 30 min, while in KCl buff and broth at pH 3, no significant reduction was seen. Cells subjected to low pH for up to 5 h were able to adhere to human intestinal cells in vitro. Exposure to low pH did not appear to disrupt the ruthenium red staining layer exterior to the cell wall.
... ab Means within the same row (pH =2) that do not share a letter are significantly different (p<0.05) for pH 2.0 and pH 5.0. Similar effect of pH on the viability of L. acidophilus BG2F04 was observed by Hood and Zottola (1988)At pH 2.5, approximately 3.5 log cfu/g survived at the end of 3 hr incubation whereas, at pH 1.5, almost no survival was observed similar to present study where the viability was 0% at the end of first hour incubation at pH 2.0 for L. acidophilus La-5 as well as L. ...
... Majority of the studies have conducted acid resistance test in the pH range of 1.0-5.0 and have found that pH 2.0 or below has been most detrimental compared to pH 3.0, 4.0, and 5.0 to the viability of tested probiotic bacteria. At pH 1.0 and 2.0, maximum mortality has been reported (Conway et al., 1987; Hood and Zottola., 1988; Abghari et al., 2011; Kawther et al., 2010), whereas, at pH 3.0 or above, survivability has been more or less maintained steady (Chou and Weimer, 1999; Alamprese et al., 2002; Basyigit et al., 2006) or has shown a slower reduction overtime maintaining viability of up to 4 log units or more (Collado et al., 2005; Faye et al., 2012) depending on the species and strains, initial inoculation level, incubation pH and suspension medium. Similarly, in this study, pH 2.0 was found to be extremely detrimental and progressive reduction in viable counts were observed at pH 5.0. ...
In recent years, there has been an upsurge in medical research assessing the therapeutic benefits of probiotic bacteria and growing commercial interest in food fortification with these bacteria. Probiotic bacteria such as L. acidophilus are known to be predominant Lactobacilli species in the intestinal tract of healthy humans and suggested to provide clinical health benefits such as enhancement of immunity against intestinal infections, prevention of diarrhea and hypercholesterolaemia and improvement in lactose utilization. Many studies have demonstrated the possibility of incorporating probiotic bacteria in an ice cream matrix and shown its viability can be maintained throughout the shelf life of the ice cream. However, there is limited information about the protective effect of ice cream on viability of incorporated probiotic bacteria during simulated gastric digestion using an in vitro dynamic model stomach.
In phase one of this study, a preliminary study was conducted to determine the effect of air addition on the viability of L. acidophilus La-5. This was done by manufacturing low fat (4%) non-fermented ice cream mix supplemented with L. acidophilus La-5 to yield an initial population of 107cfu/g. The mix was processed with 60% and 100% overrun (OR) and stored at -10ᵒC for 90 days. The effect of air addition at different levels was tested post freezing and every 30 days throughout its shelf life of 90 days. The results showed less than one log reduction in the viable counts of L. acidophilus La-5 for both samples incorporated with 60% and 100% OR after freezing and the number of viable cells did not differ significantly (p>0.05) from day 1 to day 90.
In phase two of this study, a 22 full factorial experimental design was used to evaluate whether the viscous nature of ice cream mix plays an important role in improving the survivability of L. acidophilus La-5 during simulated digestion against low pH and presence of mechanical shear and to determine whether initial inoculation level has any effect on the viability of L. acidophilus La-5 at the end of 2 hr simulated digestion. Non-fermented low fat (5%) ice cream mixes with high and low viscosity were produced by changing the amount of stabilizer/emulsifier blend and each of the two mixes were supplemented with two levels of L. acidophilus La-5 to obtain an initial population of 108cfu/g and 106cfu/g before freezing. These mixes were frozen with 60% overrun. The ice cream samples were digested for 2 hr in an in vitro model stomach called Human Gastric Simulator (HGS). This model included factors such as gastric secretions, mechanical shearing due to peristaltic contractions and temperature and pH control. No significant effect (p>0.05) of different levels of viscosity on the survivability of L. acidophilus La-5 was found during and at the end of 2 hr simulated in vitro digestion, irrespective of the difference in initial inoculation level. The initial supplementation level of L. acidophilus La-5 had a significant impact (p0.05).
These studies demonstrated the efficacy of low fat non-fermented ice cream in maintaining high viable numbers of L. acidophilus La-5 throughout its tested shelf life of 90 days. In addition, protective effect of ice cream on the viability of L. acidophilus La-5 against harsh stomach conditions was observed, but this effect was not as a result of viscosity of ice cream. It was also found that an ice cream supplemented with 106cfu/g would result in a similar overall log reduction of L. acidophilus La-5 at the end of 2 hr simulated digestion compared to an ice cream supplemented with 108cfu/g.
The aggressive stomach conditions had a negative impact on the survivability of L. acidophilus La-5 during digestion of all the ice cream samples, but this detrimental effect can be reduced by incorporating L. acidophilus La-5 into an ice cream matrix which would increase the opportunity of bacteria to reach the small intestine and provide the desired health benefit.
... Differently, cocultivation increased cellular viability of L. gasseri up to 10 7 CFUs/mL, compared to 10 5 CFUs/mL attained in singleculture ( Fig. 1). In agreement with our results, reduced viability of L. gasseri cells upon short-medium term cultivation in MRS have been reported in other studies, presumably due to autolysis [74][75][76][77][78][79]. In order to exclude straindependent effects, we have repeated the co-cultivations using four vaginal C. glabrata and C. albicans strains and in both cases it was clear that co-cultivation with L. gasseri resulted in reduced viability of the yeast strains (see results in Supplementary Fig. S1). ...
The exploration of the interference prompted by commensal bacteria over fungal pathogens is an interesting alternative to develop new therapies. In this work we scrutinized how the presence of the poorly studied vaginal species Lactobacillus gasseri affects relevant pathophysiological traits of Candida albicans and Candida glabrata. L. gasseri was found to form mixed biofilms with C. albicans and C. glabrata resulting in pronounced death of the yeast cells, while bacterial viability was not affected. Reduced viability of the two yeasts was also observed upon co-cultivation with L. gasseri under planktonic conditions. Either in planktonic cultures or in biofilms, the anti-Candida effect of L. gasseri was augmented by acetate in a concentration-dependent manner. During planktonic co-cultivation the two Candida species counteracted the acidification prompted by L. gasseri thus impacting the balance between dissociated and undissociated organic acids. This feature couldn't be phenocopied in single-cultures of L. gasseri resulting in a broth enriched in acetic acid, while in the co-culture the non-toxic acetate prevailed. Altogether the results herein described advance the design of new anti-Candida therapies based on probiotics, in particular, those based on vaginal lactobacilli species, helping to reduce the significant burden that infections caused by Candida have today in human health.
... The conditions present in the stomach including ionic strength, enzyme activity (pepsin), and mechanical churning have been shown to have an impact on the viability of probiotics. Eventhough, the peak of growth of L. acidophilus was in neutral condition, L. acidophilus was still viable and survived at pH 2. This finding was in contradiction with previously reported by Hood and Zotola indicating that L. acidophilus in soy yogurt had a good viability and survival capability in acidic condition [12]. In the present experimental study, we have demonstrated that L. acidophilus in the form of soygurt was still remain alive in the very acidic gastric juice of mamalian and potentially applied as a probiotic. ...
... Yet some strains are reported to tolerate acidic conditions and moderate bile concentrations (Clark & Martin, 1994;Clark et al., 1993). For example, upon exposure at pH 2 for 45 minutes, all cells of Lb. acidophilus died, whereas, upon exposure at pH 4 for 4 hours, there was no significant reduction in the numbers of cells (Hood & Zoitola, 1988). Similar observations are found for the viability of bacteria at pH 1À7 especially Lb. rhamnosus GG (Goldin et al., 1992). ...
... Other Lactobacilli are reported to tolerate extremely low-pH stresses by arresting growth and favouring colonization. For instance, L. acidophilus cultured in pH 3 revealed enhanced ability to survive and adhere to human intestinal cells 16 . Other studies have shown that the low pH (3.5-4.5) ...
The probiotic bacterium Lactobacillus plantarum is often reckoned as a ‘generalist’ for its ability to adapt and survive in diverse ecological niches. The genomic signatures of L. plantarum have shown its intricate evolutionary ancestry and dynamic lifestyles. Here, we report on a unique geometrical arrangement of the multicellular population of L. plantarum cells. Prominently, a phenomenon of the cone-shaped colony formation and V-shaped cell chaining are discovered in response to the acidic-pH environment. Moreover, subsequent cold stress response triggers an unusual cellular arrangement of consolidated bundles, which appeared to be independently governed by a small heat shock protein (HSP 1). We further report that the V-shaped L. plantarum chaining demonstrates potent antagonistic activity against Candida albicans, a pathogenic yeast, both in vitro and in a Caenorhabditis elegans co-infection model. Finally, we deduce that the multifaceted traits manifested by this probiotic bacterium is an outcome of its dynamic flexibility and cellular heterogeneity.
... In addition, the chosen strain should tolerate the manufacturing, transportation, storage and application processes, maintaining its viability and desirable characteristics (Collins et al., 1998). The capacity of potential probiotic microorganisms to withstand the gastro-intestinal environment can be tested in vitro by challenging with low pH (Hood and Zoitola, 1988;Collado and Sanz, 2006). The capacity to tolerate an acidic environment and bile varies among strains (Mishra and Prasad, 2005). ...
Probiotics as a potential substitute for antibiotics in animal farm especially poultry industry has become an area of great interest. The use of antibiotics in poultry farming results in presence of antibiotics residue in poultry product and may consequently affecting human health by developing pathogenic microbes to be drug-resistance. In addition to that, poultry are normally grown in dense population for economic efficiency which caused stress and disturbance in the intestinal microbiota of the poultry. This will lead to lower immune system of the poultry against diseases. Therefore, the use of probiotics is an alternative method to cater these challenges in poultry farming. This increase attention toward probiotic supplementation has generated an extensive body of research in the present day. However, there is still a lot of debate in scientific literature regarding the significant effect of probiotic on immune system against specific pathogens and growth performance in poultry. Taking into account the immune response and performance research work, this review provides a summary on the mode of actions and the potential application of probiotics in the growth performance of poultry, with critical evaluation of the recent published works.
... Có thể thấy, năng suất và hiệu suất lên men acid được cải thiện khi điều chỉnh pH 6,0 so với mức pH ở nội dung 3.1 (sinh ra cao nhất đạt 10,20 g/L với hiệu suất 19,39%). Trong nghiên cứu của mình trên Lactobacillus sp., Hood and Zoitola (1988) nhận định pH ảnh hưởng khả năng thích ứng của vi khuẩn và hoạt tính của đại phân tử enzyme trong tế bào, từ đó ảnh hưởng khả năng lên men sinh sản phẩm. Bảng 3 và Bảng 4 cũng cho thấy Lactobacillus casei L9 lên men acid đạt hàm lượng và hiệu suất cao nhất vào ngày 5 tương đồng kết quả ngày lên men tốt nhất ở nội dung 3.1. ...
Lactic acid fermentation can add value to molasse and reduce pollution. The objectives of this study were to select and analyze for the fermentation by seven strains of lactic acid bacteria (L7, L9, L11, L26, L30, L37 and the control strain of Lactobacillus thermotolerans) using sugarcane molasses, a low-cost material from Phung Hiep sugar factory. Among them, Lactobacillus casei L9 could ferment and create 10.20 g/L total acid content after 5 days which is higher than that of the control Lactobacillus thermotolerans (9.40 g/L after 7 days). The suitable conditions for lactic acid fermentation from molasses were determined at pH 6.0, 8% (w/v) total sugar, 10 7 cells/mL inoculum. In the suitable conditions, Lactobacillus casei L9 could create 18.30 g/L lactic acid after a 6-day fermentation.
TÓM TẮT Lên men acid lactic có khả năng tạo giá trị gia tăng cho rỉ đường và giải quyết ô nhiễm môi trường. Đề tài này được tiến hành với mục tiêu tuyển chọn và khảo sát quá trình lên men acid lactic từ rỉ đường, một nguồn phụ phẩm thu từ nhà máy đường Phụng Hiệp, sử dụng 7 chủng vi khuẩn lactic chịu nhiệt (L7, L9, L11, L26, L30, L37 và chủng đối chứng Lactobacillus thermotolerans). Trong đó, Lactobacillus casei L9 có khả năng lên men tốt nhất ở 39ºC tạo hàm lượng acid lactic đạt 10,2 g/L sau 5 ngày lên men, cao hơn so với chủng đối chứng Lactobacillus thermotolerans (9,4 g/L sau 7 ngày). Điều kiện thích hợp cho lên men acid lactic từ rỉ đường là ở pH 6,0, sucrose 8% (w/v), mật số giống chủng 10 7 tế bào/mL. Ở điều kiện thích hợp, Lactobacillus casei L9 có khả năng chuyển hoá tạo 18,30 g/L acid lactic sau 6 ngày lên men. Trích dẫn: Bùi Hoàng Đăng Long, Phạm Quang Sin, Huỳnh Xuân Phong, Nguyễn Ngọc Thạnh và Ngô Thị Phương Dung, 2019. Khảo sát điều kiện lên men acid lactic từ rỉ đường sử dụng vi khuẩn lactic chịu nhiệt. Tạp chí Khoa học Trường Đại học Cần Thơ. 55(Số chuyên đề: Công nghệ Sinh học)(2): 103-109. 1 GIỚI THIỆU Acid lactic là một trong những gốc acid hữu cơ phổ biến nhất trong tự nhiên và được ứng dụng rộng rãi trong các ngành công nghiệp y dược, mỹ phẩm, hóa chất và đặc biệt là thực phẩm (Narayanan et al., 2004). Theo thống kê, lượng tiêu thụ acid hàng năm tăng từ 12-15% với 50% lượng acid lactic sản xuất mỗi năm được sử dụng vào các ngành công nghiệp thực phẩm và giải khát. Bên cạnh đó, nhu cầu acid
... Có thể thấy, năng suất và hiệu suất lên men acid được cải thiện khi điều chỉnh pH 6,0 so với mức pH ở nội dung 3.1 (sinh ra cao nhất đạt 10,20 g/L với hiệu suất 19,39%). Trong nghiên cứu của mình trên Lactobacillus sp., Hood and Zoitola (1988) nhận định pH ảnh hưởng khả năng thích ứng của vi khuẩn và hoạt tính của đại phân tử enzyme trong tế bào, từ đó ảnh hưởng khả năng lên men sinh sản phẩm. Bảng 3 và Bảng 4 cũng cho thấy Lactobacillus casei L9 lên men acid đạt hàm lượng và hiệu suất cao nhất vào ngày 5 tương đồng kết quả ngày lên men tốt nhất ở nội dung 3.1. ...
Lên men acid lactic có khả năng tạo giá trị gia tăng cho rỉ đường và giải quyết ô nhiễm môi trường. Đề tài này được tiến hành với mục tiêu tuyển chọn và khảo sát quá trình lên men acid lactic từ rỉ đường, một nguồn phụ phẩm thu từ nhà máy đường Phụng Hiệp, sử dụng 7 chủng vi khuẩn lactic chịu nhiệt (L7, L9, L11, L26, L30, L37 và chủng đối chứng Lactobacillus thermotolerans). Trong đó, Lactobacillus casei L9 có khả năng lên men tốt nhất ở 39ºC tạo hàm lượng acid lactic đạt 10,2 g/L sau 5 ngày lên men, cao hơn so với chủng đối chứng Lactobacillus thermotolerans (9,4 g/L sau 7 ngày). Điều kiện thích hợp cho lên men acid lactic từ rỉ đường là ở pH 6,0, sucrose 8% (w/v), mật số giống chủng 107 tế bào/mL. Ở điều kiện thích hợp, Lactobacillus casei L9 có khả năng chuyển hoá tạo 18,30 g/L acid lactic sau 6 ngày lên men.
... [19] Below such ap H, the growth of the lactobacillus strain is strongly inhibited and leads to af ast decreaseo f the number of viable cells. [20] Because the pH is ac rucial factor in LA fermentation, its influence on the adsorption behavior of HCP and PBSAC was investigated. The typical adsorption experiments described above with no buffer solution applied were performeda ta pproximately pH 1. ...
The utilization of biomass is one of the major challenges for the transition from fossil to renewable resources. Often, the separation of the desired product from the reaction mixture is the most energy‐intensive step. Liquid‐phase adsorption is a promising separation technology that could significantly improve downstream processing in biorefineries. Highly hydrophobic adsorbents were applied for the separation of lactic acid (LA) from aqueous solutions and to avoid the formation of gypsum as a byproduct. High uptakes and selectivity were obtained in single‐solute and co‐adsorption experiments. Porous hyper‐crosslinked polymers (HCP) and polymer‐based spherical activated carbon performed best and showed excellent selectivity for the selective removal of LA. Desorption experiments revealed that HCP was the ideal adsorbent for the separation of LA from aqueous solution and enabled the production of gypsum‐free LA.
... 3.7 to promote electrostatic attraction between the oppositely charged proteins and bacteria. This low pH is not optimal for the survival of lactobacillus (Corcoran, Ross, Fitzgerald, & Stanton, 2004;Hood & Zoitola, 1988). In the present work, the experiment was conducted at a more neutral pH where the bacteria possess higher negative charges. ...
... Furthermore, any encapsulation method also needs to maintain the viability of encapsulated microorganisms during storage of the product until administration. Thus, the hydrogel system must offer the capability of quickly releasing the encapsulated bacteria in the intestine in order to allow colonization of the intestinal tract with beneficial bacteria [214][215][216][217]. ...
Hydrogels are materials specially suited for encapsulation of biological elements. Their large water content provides an environment compatible with most biological molecules. Their crosslinked nature also provides an ideal material for the protection of encapsulated biological elements against degradation and/or immune recognition. This makes them attractive not only for controlled drug delivery of proteins, but they can also be used to encapsulate cells that can have therapeutic applications. Thus, hydrogels can be used to create systems that will deliver required therapies in a controlled manner by either encapsulation of proteins or even cells that produce molecules that will be released from these systems. Here, an overview of hydrogel encapsulation strategies of biological elements ranging from molecules to cells is discussed, with special emphasis on therapeutic applications.
... Small sample sizes, lack of a placebo group, and use of non-standardised strains were some of the limitations of these studies. Findings from various preclinical studies included the following: (1) Viable and non-viable lactobacilli had equal ability for adherence to gut mucosa [58], and heat-killing and protease treatments impaired the mucus adherent property [59]; (2) Heat-killing changed the intestinal location of the bacteria. Live bacteria were seen in Peyer's patches and lamina propria whereas most heat-killed bacteria were in the lumen and cleared rapidly [60]; (3) Heat-killed lactobacilli inhibited pathogen adhesion to the gut mucosa by competitive exclusion [61]; (4) Inactivated lactobacilli enhanced gut epithelial barrier [62]; (5) Non-viable probiotic components such as cell wall extracts [63], lipoteichoic acid [64], bacterial DNA [65,66], and surface (S)-layer proteins [67] can have immunomodulatory effects by various mechanisms including increased salivary IgA production [68], modulation of host T-cell responses [69] and gene expression [70]; (6) Live and inactivated probiotics had comparable effects on innate immunity [71][72][73]; (7) Live as well as killed B. lactis HN019 enhanced phagocytic responses in peripheral blood cells; however, only viable bacteria increased the phagocytic activity of peritoneal cells [74]; (8) As for adaptive immunity, many studies favoured live over non-viable bacteria [60,[75][76][77][78], but some showed that both forms had similar effects on the phenotype and functions of human myeloid dendritic cells [79]. ...
Current evidence supports the use of probiotics in preterm neonates for prevention of necrotizing enterocolitis, mortality and late onset sepsis. Despite the strong evidence, the uptake of this intervention has not been universal due to concerns including probiotic sepsis, pro-inflammatory response and transmission of antibiotic resistance. Critically ill extremely preterm neonates with potentially compromised gut integrity are at higher risk of probiotic sepsis due to translocation. In most countries, probiotics are sold as food supplements with poor quality control. The traditional definition of probiotics as “live microorganisms” has been challenged as many experts have questioned the importance of viability in the context of the beneficial effects of probiotics. Paraprobiotics (ghost probiotics), are defined as non-viable microbial cells (intact or broken) or crude cell extracts (i.e., with complex chemical composition), which, when administered (orally or topically) in adequate amounts, confer a benefit on the human or animal consumer. Current evidence indicates that paraprobiotics could be safe alternatives to probiotics in preterm neonates. High-quality pre-clinical and clinical studies including adequately powered randomised controlled trials (RCTs) are warranted in preterm neonates to explore this new frontier.
... 유산균이 살아있는 상태로 장내에 도달하기 위해서는 위와 장의 pH 2~8 범위에서 생존할 수 있어야 한다 (Hood, 1998 (Fig. 1(A)). 내담즙성 실험에는 유산균이 위를 통과하여 장으로 이동되는 것을 고려하여야한다 (Rial, 2000). ...
... Data (mean ± SD) with different letters are significantly different (p < .05). (a) IL-8; (b) IL-1β; (c)TGF-β1; (d) TLR-5 culture cells of animals (Coconnier, Bernet, Chauvière, & Servin, 1993;Hood & Zoitola, 1988), but also elevate the systemic and mucosal immune responses in host (Wei et al., 2015). Our previous study observed the heat-killed B. pumilus SE5 could modulate the intestinal microbiota and stimulate intestinal mucosal immunity in E. coioides, and this maintenance of intestinal homoeostasis may benefit the digestion and metabolism in intestine and therefore improve the feed efficiency. ...
In recent years, more and more attentions have been paid to the development and application of probiotics in aquaculture, and viable probiotics have been extensively studied, while rare information was available about inactivated probiotics in aquaculture. Therefore, in this study, a feeding trial was designed to investigate the effect of dietary supplementation of heat-inactivated probiotic Bacillus clausii DE5 on growth performance, immune response and key immune genes expression in head kidney and intestine in grouper Epinephelus coioides. Fish were fed for 60 days with control diet (C) and two experimental diets containing 1.0 × 108 CFU/g live (T1) and heat-inactivated (T2) B. clausii DE5, respectively. The probiotic treatments did not affect the final weight, weight gain (WG) and specific growth rate (SGR) of E. coioides at days 30 and 60 (p > .05), while both heat-inactivated and live B. clausii DE5 significantly decreased the feed intake and feed conversion ratio (FCR) at day 60 (p < .05). Serum lysozyme activity and complement C3 level in the two probiotic treatments were significantly higher than those in the control (p < .05). The lysozyme activity and complement C3 level at day 60 were significantly higher than those at day 30 (p < .05), while no significant interaction effect between diet and administration date was observed. Moreover, the heat-inactivated B. clausii DE5 significantly improved the expression of TLR5, pro-inflammatory cytokines (IL-8 and IL-1β) and TGF-β1 in head kidney and intestine (p < .05), while the live probiotic did not show any significant effect on the expression of these key immune-related genes in head kidney and intestine. These results indicate that dietary supplementation of heat-inactivated B. clausii DE5 effectively improved feed utilization and both the local and systemic immune responses of E. coioides.
... Though the level of acid resistance of probiotic cultures is expected to be in the pH range of 2.5 -3.0, the combination of the gastric acid with the food materials in the stomach provides more protection increasing their ability to survive in the gut [24] [25] [26] [27]. Moreover, acid tolerance of probiotic bacteria is known to depend on the type of organisms tested, growth medium and the incubation conditions and thus meaningful comparison could be done in consideration to these variables [28]. Different concentration of bile salt has been used for the same assay and accordingly, concentration of 0.3 % was found to be discriminatory and is also recommended for the screening of probiotic isolates [29] [30] [31]. ...
... Before reaching the intestine, probiotic bacteria must first survive the deleterious action of gastric juice during passage through the stomach. In general, the acid tolerance of lactic acid bacteria depends on the pH profile for H þ transport relative to ATPase activity and on the composition of the cytoplasmic membrane (Hood and Zoitola, 1988;De Angelis and Gobbetti, 2004). Compared to MRS, selected lactic acid bacteria and bifidobacteria strains cultivated in GMG showed a higher cell survival, especially, in gastric juice at pH 2.0. ...
This study aimed at using grape marc for the growth of lactic acid bacteria and bifidobacteria with the perspective of producing a functional ingredient having antioxidant activity. Lactobacillus plantarum 12A and PU1, Lactobacillus paracasei 14A, and Bifidobacterium breve 15A showed the ability to grow on grape marc (GM) based media. The highest bacterial cell density (>9.0 CFU/g) was found in GM added of 1% of glucose (GMG). Compared to un-inoculated and incubated control fermented GMG showed a decrease of carbohydrates and citric acid together with an increase of lactic acid. The content of several free amino acids and phenol compounds differed between samples. Based on the survival under simulated gastro-intestinal conditions, GMG was a suitable carrier of lactic acid bacteria and bifidobacteria strains. Compared to the control, cell-free supernatant (CFS) of fermented GMG exhibited a marked antioxidant activity in vitro. The increased antioxidant activity was confirmed using Caco-2 cell line after inducing oxidative stress, and determining cell viability and radical scavenging activity through MTT and DCFH-DA assays, respectively. Supporting these founding, the SOD-2 gene expression of Caco-2 cells also showed a lowest pro-oxidant effect induced by the four CFS of GMG fermented by lactic acid bacteria and bifidobacteria.
... In general, the cell viability depends on the strains used, interactions between species present, culture condition, oxygen content, final acidity of the product, and the concentration of lactic acid and acetic acid. The main factors for loss of viability of probiotic organisms have been attributed to the decrease in the pH of the medium and accumulation of organic acid as a result of growth and fermentation (Hood and Zottola 1988;Saarela et al., 2002). (a*) values were the highest in samples with mixed culture (1:1) then L. plantarum, and L. bulgaricus, at 9 days of storage, were 24. ...
... The Hood & Zottola, 1998 and. In general, the concentration of probiotics in all batches except control, was above the lowest recommended therapeutic level of 6 log cfumL 1 (Kurmann & Rasic, 1991 ...
Herbs are antimicrobials, they may affect probiotic
viability. The present study was conducted with
objectives to find antagonistic effect of herbal extracts,
probiotics and normal flora of yoghurt and its effect
on its viability, sensory and rheological parameters.
The result indicates that selected herbs have low
antagonistic effect against beneficial probiotic
bacteria, while it is effective in much lesser
concentration against pathogen. The presence of Inula
racemosa Hook and Saussurea lappa resulted in
higher count of yoghurt culture, S.thermophilus and
L bulgaricus (9.61 log10 cfu/ml), non significant
difference was absorbed within 1% and 1.5% (w/v)
concentration of Inula racemosa hook and 9.50 log10
cfu/ml, non significant difference was absorbed within
0.5 % and 1% (w/v) concentration of Saussurea
lappa, however significant difference was absorbed
within the two herbal yoghurt. The former resulted
in higher count of Yogurt culture on 0 day of storage
compared to plain-yogurt (9.27 log10 cfu/ml; p>0.05).
Viable Probiotic culture bifidobacteria and L. casei
counts reduced from day 7 to day 21 of storage for all
yogurts with the fastest rate occurred in plain-yogurt.
Viable Probiotic culture counts on day 21 of storage
was significant for Inula racemosa Hook (6.79 log10
cfu/ml) and Saussurea lappa yogurt (7.00 log10 cfu/
ml) was higher than plain-yogurt (5.02 log10 cfu/ml)
The increase in the viable cell counts for both yogurt
bacteria during the first 7 days coincided with the
increase in TTA and marked reduction (p<0.05) in
pH recorded on day 7 of storage. All mean scores for
the different sensory attributes of the two herbal
yoghurts were within the commercially acceptable
range (4–9 scores) recommended for yoghurt by the
Karl Ruther nine points scheme. Herbal yoghurt
resulted in significant decrease in firmness of
yoghurt however consistency (g s) of herbal yogurt
with 1 % (w/v) of Inula racemosa Hook and 1.5 %
(w/v) Saussurea lappa was at par with control. In
general Cohesiveness (g), and Index of Viscosity (g s)
in herbal yoghurt showed a significant increase
(p>0.05) compared to control.
... In addition, the chosen strain should tolerate the manufacturing, transportation, storage and application processes, maintaining its viability and desirable characteristics (Collins, Thornton and Sullivan, 1998). The capacity of potential probiotic micro-organisms to withstand the gastro-intestinal environment can be tested in vitro by challenging with low pH (Hood and Zoitola, 1988;Collado and Sanz, 2006). The capacity to tolerate an acidic environment and bile varies among strains (Mishra and Prasad, 2005). ...
This document presents a unique and exhaustive review of the state-of-knowledge on the use of probiotics in diverse livestock production systems, and their impact on animal productivity. It focuses specifically on definitions, production, mechanisms of action, applications, effects, safety and potential public health risks of probiotics. In addition the labelling of probiotic products and global regulatory status of probiotics in animal feed is also covered. This publication will inform those that are interested in identifying and designing interventions for increasing animal productivity. It would also give an impetus to the development of new probiotics having consistent long-term effects that could possibly be used in feed in place of antibiotic growth promoters.
... The Hood & Zottola, 1998 and. In general, the concentration of probiotics in all batches except control, was above the lowest recommended therapeutic level of 6 log cfumL 1 (Kurmann & Rasic, 1991 ...
The result indicates that selected herbs have low
antagonistic effect against beneficial probiotic
bacteria, while it is effective in much lesser
concentration against pathogen. The presence of Inula
racemosa Hook and Saussurea lappa resulted in
higher count of yoghurt culture, S.thermophilus and
L bulgaricus (9.61 log10 cfu/ml), non significant
difference was absorbed within 1% and 1.5% (w/v)
concentration of Inula racemosa hook and 9.50 log10
cfu/ml, non significant difference was absorbed within
0.5 % and 1% (w/v) concentration of Saussurea
lappa, however significant difference was absorbed
within the two herbal yoghurt. The former resulted
in higher count of Yogurt culture on 0 day of storage
compared to plain-yogurt (9.27 log10 cfu/ml; p>0.05).
... http://scidoc.org/IJDSP.php lation of organic acids as a result of bacterial growth during the fermentation of the milk [13,14]. Yogurt with additives such as stabilizers, flavouring ingredients, sweeteners, preservatives, etc., raises some doubts about the actual viable bacteria concentration when the product reaches the consumers [15]. ...
Viable counts of lactic acid bacteria (LAB) Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus claimed to be present in commercially available yogurts in the Philippines were determined. Seven (7) yogurt samples with three (3) replicates
per sample namely: NAV, NCY, CYP, NFB, LYB, CYI, and NFJ were examined. The highest S. thermophilus count was obtained in LYB with 10.20 ± 0.06 log10 CFU/ml and lowest in CYI with 8.18 ± 0.02 log10 CFU/ml. The highest L.
bulgaricus count was also found in LYB with 9.96 ± 0.01 log10 CFU/ml while CYI also had the lowest count of 8.15 ± 0.09 log10 CFU/ml. Mean LAB counts of all six (6) yogurt samples were significantly higher (P ≤ 0.05) than CYI. The ratio of S. thermophilus to L. bulgaricus in all yogurt samples examined was about 1:1. LYB had the highest titratable acidity of 0.98% lactic acid while CYI had the lowest titratable acidity of 0.35% lactic acid. No correlation was found between viable LAB counts and titratable acidity of yogurt samples. The viable counts of S. thermophilus and L. bulgaricus in all seven (7) commercial yogurts examined met the prescribed minimum viable count of 106 CFU/ml for the suggested therapeutic effects and health benefits for the consumers.
... http://scidoc.org/IJDSP.php lation of organic acids as a result of bacterial growth during the fermentation of the milk [13,14]. Yogurt with additives such as stabilizers, flavouring ingredients, sweeteners, preservatives, etc., raises some doubts about the actual viable bacteria concentration when the product reaches the consumers [15]. ...
Zearalenone (ZEN, ZEA) contamination in various foods and feeds is a significant global problem. Similar to deoxynivalenol (DON) and other mycotoxins, ZEN in feed mainly enters the body of animals through absorption in the small intestine, resulting in estrogen-like toxicity. In this study, the gene encoding Oxa, a ZEN-degrading enzyme isolated from Acinetobacter SM04, was cloned into Lactobacillus acidophilus ATCC4356, a parthenogenic anaerobic gut probiotic, and the 38 kDa sized Oxa protein was expressed to detoxify ZEN intestinally. The transformed strain L. acidophilus pMG-Oxa acquired the capacity to degrade ZEN, with a degradation rate of 42.95% at 12 h (initial amount: 20 μg/mL). The probiotic properties of L. acidophilus pMG-Oxa (e.g., acid tolerance, bile salt tolerance, and adhesion properties) were not affected by the insertion and intracellular expression of Oxa. Considering the low amount of Oxa expressed by L. acidophilus pMG-Oxa and the damage to enzyme activity by digestive juices, Oxa was immobilized with 3.5% sodium alginate, 3.0% chitosan, and 0.2 M CaCl2 to improve the ZEN degradation efficiency (from 42.95% to 48.65%) and protect it from digestive juices. The activity of immobilized Oxa was 32–41% higher than that of the free crude enzyme at different temperatures (20–80 °C), pH values (2.0–12.0), storage conditions (4 °C and 25 °C), and gastrointestinal simulated digestion conditions. Accordingly, immobilized Oxa could be resistant to adverse environmental conditions. Owing to the colonization, efficient degradation performance, and probiotic functionality of L. acidophilus, it is an ideal host for detoxifying residual ZEN in vivo, demonstrating great potential for application in the feed industry.
In this study evaluation of the beneficial properties and survival for eight LAB putative probiotic
strain was conducted including their ability to survive at different ox-bile concentrations and in the models
representing different parts of digestive tract, ability to produce diacetyl, GABA and specific enzymes. The
survival rates and release rates of the cells under the SSDP and AOS models were evaluated by encapsulation
using sodium alginate. Interaction between studied LAB and the pathogen in the artificial oral saliva
was evaluated. Str. salivarius ST48HK, ST59HK, ST61HK and ST62HK generated positive results for
gadL and only L. gasseri ST16HK for gadP, genes associated with GABA production. According to biochemical
approach in the evaluation of GABA production, strains Str. salivarius ST48HK, ST59HK, and L.
sakei ST69HK can be considered as the most promising producers, even if other evaluated strains showed
levels of assimilation of sodium glutamate. Overall, tests for the beneficial properties, survival rate for
the planktonic and encapsulated strains under different ox-bile conditions, SSDP, AOS models, indicates
that the studied strains can be promising candidates for oral probiotics application. Evaluation of probiotic
properties of new strains is a complex process, with essential basic requirement – survival in the different
parts of digestive tract, stability for the extended storage time, expression of beneficial properties and safety
characteristics. We have evaluated Str. salivarius ST48HK, ST59HK, ST61HK, and ST62HK, L. plantarum
ST63HK and ST66HK, L. sakei ST69HK, and L. gasseri ST16HK as putative probiotics, promising candidates
for complementary animals’ studies and future human applications.
The subcritical water extraction method (SWE), as a proper alternative to conventional methods due to low cost, short processing time, environmental sustainability, and mild operating conditions, has been applied to produce valuable materials from different biomass. Rice milling byproduct (RMB) as abundant and locally available agricultural wastes is normally used for extracting oil and as animal feed. In this study, the quality and quantity of valuable compounds extracted by the SWE were investigated to select the optimum SWE conditions and the best extract to produce healthy cereal‐based milk analogs. The most appropriate SWE parameters were investigated by the combined design method were 130°C and 45 min, rice bran: broken rice ratio of 10:90, the solid‐water ratio of 0.12, and a particle size of <710 μm, respectively. SWE positively affected the release and production of some bioactive compounds such as total phenolic, flavonoids, organic acids, etc. The milk analogs consisted of the optimum RMB extract, inulin, and Persian grape molasses (as a sucrose alternative) were then fermented by either Lactobacillus casei or Lactobacillus plantarum (0.5 McFarland). The fermentation process also rose the values of some nutrients, including vitamin B (B3, B6, and B9), organic acids, total phenolic compounds, and flavonoids. it decreased the contents of monosaccharides (p<0.5), while the increased content of alcohol was negligible (<0.3%). Compared to L. plantarum, L. casei had a higher impact on the production of these bioactive compounds and more considerably increased antioxidant activity of the related beverages; nevertheless, beverages containing L. plantarum had the greatest over‐acceptability. Moreover, the survival of L. casei and L. plantarum in beverages was in the standard range (106‐108 CFU/mL) during storage, demonstrating that RMB ingredients along with inulin can positively affect LAB survival.
The effect of enzymatic and physical modifications of the surface of two different strains from lactic acid bacteria, Lactobacillus rhamnosus (LGG) and Lactobacillus delbruekii subs. lactis ATCC 4797 (LBD), to stabilize medium-chain triglyceride (MCT) oil based Pickering emulsions were investigated. A section of cell wall degrading enzymes, lysozyme from chicken egg white and human, lysostaphin, mutanolysin from Streptomyces globisporus and proteinase k and the hydrophobic protein zein were used for enzymatic and physical surface modifications. Cell surface modifications were characterized by optical microscopy, scanning electron cryo-microscopy (Cryo-SEM), transmission electron microscopy (TEM), microbial adhesion to hexadecane (MATH) test and zeta potential measurements. The modified cell hydrophobicity in terms of MATH values were increased (around four times) by the enzymatic and physical modifications for LBD and LGG compared to the control. Emulsions stabilized by modified bacterial cells showed higher stability in comparison with unmodified samples, especially for the samples modified with chicken egg lysozyme. Confocal microscopy revealed that the modified bacterial cells were absorbed at the interface between oil and water and preventing the oil particles from coalescence. Thus, modified bacterial cells can be used to formulate food-grade stable Pickering emulsions. Such Pickering emulsions can potentially be clean label alternatives to replace the conventional emulsion preparations.
A vegetable blend slurry consisting of aloe vera (Aloe barbadensis miller), garlic (Allium sativum), ginger (Zingiber officinale), liquorice (Glycyrrhiza glabra) and pumpkin seeds (Cucurbita pepo L.) was used as a probiotic medium to evaluate the impact of probiotic fermentation on its chemical composition and flavour compound changes. Two commercial probiotic bacteria, Bifidobacterium animalis subsp. lactis HN019 and Lactobacillus acidophilus La-14, were used for monoculture and coculture fermentation over 72 h. After fermentation, sugars, organic acids and amino acids changed differently due to differences in metabolic pathways. In addition, there was a significant decrease in organosulfur compounds (from 10.56 ± 0.98 mg/L to 6.14 ± 0.83 mg/L, 7.80 ± 1.09 mg/L and 6.02 ± 0.61 mg/L for B. lactis HN019 monoculture, L. acidophilus La-14 monoculture, and coculture fermentation, respectively) and total phenolic contents (TPC, from 24.61 ± 1.23 mg gallic acid equivalent (GAE)/g dry extract (DE) to 16.29 ± 1.22 and 15.66 ± 1.03 mg GAE/g DE for L. acidophilus La-14 monoculture and coculture fermentation, respectively). Interestingly, no significant changes in oxygen radical absorbance capacity (ORAC), total dietary fibre content and fat content after fermentation. Coculture fermentation did not show any significant synergistic or antagonistic effect. Our results suggest that the vegetable blend and the bacterial strains used have potential to create a novel probiotic product.
Fermented beverages are increasing in demand to fulfill the health needs of the human population. Increasing medical costs are forcing us to find cheaper and effective resources for protecting human health. The use of probiotics has been proven in the treatment of several inflammatory conditions including arthritis, pouchitis, Crohn’s disease, and colitis. The ingredients of dairy-based fermented beverages contain protein, minerals, and vitamins that provide a favorable environment for the growth of probiotics. Modern fermented beverage production includes a defined starter culture with desirable characteristics to ensure consistency and commercial viability of the final product. The selection of defined starters depends on specific phenotypes that benefit the product by guaranteeing shelf life and ensuring the safety, texture, and flavor of the final product. Recent research revealed that the whey-based fermented beverage cosupplemented with Lactobacillus casei possesses high bactericidal activity. In the production of dairy-based fermented beverages, the industrialist is concerned about the new approaches towards the active viability of the probiotic culture involved in beverage production. Hence, the novel starter culture plays a key role in modern dairy-beverage production. In the modern production process, the industrialist is much concerned about the increasing level of bacteriocin and bioactive peptide production and minimizes the presence of biogenic amines in the final products by selecting a novel starter culture. In large scale fermented dairy-beverage production, viability, stability of starter cultures, and certain technological challenges are also faced by the industrialists. Some novel approaches to improve the stability and survival of probiotic strains include protective compounds such as glucose to energize cells on exposure to acid during protection, and cryoprotectants such as inulin to improve survivability during freeze-drying. Genetically manipulated strains have shown improved performance due to overexpression of heat shock proteins GroESL under a variety of conditions including heat, spray drying, and exposure to gastric acid. The major difficulty in probiotic dairy-beverage production is the preservation of the physical stability of the product. Process optimization of probiotic or functional dairy-based beverages needs extra care, including the selection of concentration and type of stabilizer and optimization of pretreatment conditions such as high-effect homogenization and heating regimes.
This chapter concentrates on the overview of fermented dairy beverages, recent scientific, technological, and commercial development in the production of dairy beverages which includes the strain selection, processing, starter cultures and selecting appropriate foods as a vehicle. The chapter also discusses their challenges, improvements made to overcome these challenges, diversified beverages and its production, screening of novel organisms for the production of new beverages with eliminated challenges and improvement of sensory properties.
Three cereal-legume complementary foods (weanimix) were formulated and evaluated for their ability to enhance the survival of probiotic bacteria Lactobacillus plantarum NCIMB 8826 in simulated gastrointestinal tract conditions. The three different blends of weanimix: MCPPM (maize:cowpea:peanut:powdered milk), MCP (maize:cowpea:peanut) and MC (maize:cowpea) were used. L. plantarum was inoculated and cultured in the weanimix slurry media to immobilize the cells. L. plantarum free cells in MRS broth were used as a control. Simulated gastric fluid (SGF) of pH 2.5, 3.0 and 3.5, and bile salt (0.3 and 1 g/100 ml of ox gall) were used to simulate the gastrointestinal conditions. The three complementary blends offered a protective shield, which improved cell viability in SGF at all pH levels. L. plantarum survived well in MCPPM, MCP and MC with <2 log cell reduction compared with the free cells reduction of ∼5 log after 180 min of incubation for each pH. For bile tolerance, viable cell counts in the weanimix were higher than the free cells after 24 hr suspension. The results of the study showed that weanimix improved the survival and viability of L. plantarum.
Petit‐Suisse goat cheese with multifunctional properties associated with acerola pulp and a potentially probiotic autochthonous strain of Lactobacillus plantarum were developed. The effect of incorporating acerola pulp into the cheese on the viability and survival of Lb. plantarum to in vitro gastrointestinal conditions, antioxidant capacity, and sensory features were studied. The freeze‐dried culture of Lb. plantarum exhibited high viability (8.34 log CFU/g), which remained above 8 log CFU/g in the cheeses. Acerola pulp incorporation did not affect in vitro survival of the probiotic (73% at 14 days), and enriched the Petit‐Suisse cheese with antioxidant compounds, increasing concentrations of ascorbic acid, and polyphenols (up to 132.73 mg.100/g and 255.08 mg.100/g, respectively), and EC50 values of DPPH● and ABTS●+ (up to 6,331.74 g/g DPPH● and 7.91 µM Trolox/g, respectively). The cheese showed high sensory acceptance. Petit‐Suisse cheese flavored added by acerola pulp is promising as a multifuncional food product. The use of acerola pulp is an interesting option, as the fruit is well accepted and Brazil is one of the largest producers in the world. In this study, acerola pulp (10%) and potentially probiotic Lb. plantarum CNPC003 were used to develop Petit‐Suisse goat cheese. The effect of acerola pulp on physicochemical, probiotic, and antioxidant properties were evaluated. Acerola pulp can provide remarkable antioxidant activity without affecting the viability and in vitro survival of the potentially probiotic strain, indicating that the developed cheese may have dual function of antioxidant and probiotic potential, thus making it more attractive to consumers.
Probiotics are defined as live microorganisms, which, when administered in adequate amounts, confer health benefits to the host. Traditionally, probiotic food research has heavily focused on the genera Bifidobacteria and Lactobacilli, along with their benefits for gut health. Recently with the identification of new probiotic strains specifically intended for oral health applications, the development of probiotic foods for oral health benefits has garnered interest, with a renewed focus on identifying new food formats for delivering probiotics. The development of novel oral probiotic foods is highly complex, as the composition of a food matrix dictates: (1) bacterial viability during production and shelf life and (2) how bacteria partition with components within a food matrix and subsequently adhere to oral cavity surfaces. At present, virtually no information is available on oral probiotic strains such as Streptococcus salivarius; specifically, how orally-derived strains survive under different food parameters. Furthermore, limited information exists on the partition behavior of probiotics with food components, governed by physico-chemical interactions and adhesion phenomena. This review aspires to examine this framework by providing a foundation with existing literature related to the common probiotic genera, in order to inform and drive future attempts of designing new oral probiotic food formats.
Super absorbent polymers (SAPs) have been applied as soil conditioners to reduce soil water loss, but there are few studies about how SAPs affect structures of soil bacterial community, and these associated chemical residues are uncertain. Treatments under different soil moisture conditions by application of sodium polyacrylate in repacked soil columns were used to investigate their effects on the soil bacterial community structures by Illumina MiSeq sequencing. Alpha diversity analysis showed that adding SAPs had an impact on bacterial diversity. On phylum level, adding SAPs significantly reduced the amount of Actinobacteria (1.9–2.4-fold), Bacteroidetes (1.1–2.1-fold) while increased the amount of Firmicutes (1.9–4.6-fold). At genus level, effects of SAPs on the soil bacterial community structures varied with the soil moisture conditions. Under water deficit, SAPs reduced the soil pH, which promoted the proliferation of Lactobacillus (9.9–29.1-fold), and acid production by these bacteria might further promote the reduction of pH, potentially inhibiting growth of Acidobacteria (1.3–1.8-fold) and Chloroflexi (1.6–2.3-fold). The pyrolysis analysis showed that some substances such as methanesulfonyl chloride, long-chain amides and esters, were only derived from water-saturated soil treated with SAPs, which might subsequently have negative impacts on the environment and associated agriculture.
Digestive health plays key role in our active daily life; but maintaining proper bowel movements, i.e., being free from constipation, diarrhea, irritable bowel syndrome, inflammatory bowel disease, flatulence, bloating, and abdominal pain, is complex. Dietary fibers often are recommended to maintain proper digestive health, but none seems to provide a single comprehensive solution for overall maintanance of proper digestive health. Guar fiber, however, has emerged as a credible candidate for just such a solution. This review focused on summarizing the clinically observed effects of guar fiber on digestive health. Several clinical studies suggest the guar fiber normalizes both constipation and diarrheal conditions. Also, it was effective in alleviating the symptoms associated with irritable bowel syndrome. The studies suggest that a regular intake of 5 to 10 g/d guar fiber is effective to treat most of the morbidities associated with digestive health. Guar fiber is all natural. It may offer potential protection and promotion of digestive health both alone and when combined with probiotics as a synbiotic formula.
Guar gum is a galactomannan obtained from the endosperm portion of seed of the plant Cyamopsis tetragonolobus. Guar gum is used as thickener and stabilizer in food industry due to its high viscosity in aqueous solution. The partial hydrolysis of the guar galactomannan leads to production of partially hydrolyzed guar gum (PHGG) which is similar in structure to native guar galactomannan. PHGG can be produced by enzymatic hydrolysis, acid hydrolysis, irradiation, microwave and ultrasonication techniques. Enzymatic hydrolysis of guar gum is preferred for food processing applications. In enzymatic hydrolysis, enzymes such as mannanse, pectinase, cellulase cut the linkages between mannose units in the main chain. Partial hydrolysis of guar gum leads to the reduction in molecular weight of native guar gum. Partially hydrolyzed guar gum shows low viscosity in aqueous solutions. X-ray diffraction analysis of partially hydrolyzed guar gum revealed that it is little crystalline in nature as compared to native guar galactomannan which is amorphous in nature. Partially hydrolyzed guar gum produced from enzymatic hydrolysis can be used mainly for nutritional purpose i.e. for development of fiber enriched processed food products such as cookies, bread, noodles, yoghurt etc. Its specific physicochemical properties make it possible to improve the quality of food products. Partially hydrolyzed guar gum as soluble dietary fibre is beneficial in diabetes, heart disease and digestive problems.
The objective of this research was to determine the fermentation and quality properties of soy yogurt incorporating insoluble components fermented with Streptococcus thermophilus (S. thermophilus) and Lactobacillus bulgaricus (L. bulgaricus) for 24h. Boiled soybeans were ground and reconstituted into equivalent total solids (18%). After soymilk was homogenized with sugar, it was pasteurized in a water bath at 90℃ for 30 min. Two kinds of lactic acid bacteria were inoculated into two types of soymilk after cooling down 40∼45℃ and fermentation at 37℃ for 24h. Titrable acidity, pH, viscosity, sugar content, and number of viable cells were determined in triplicate. Soy yogurt fermented with L. bulgaricus did not reach pH 4.5, where as S. thermophilus was considered good for achieving pH 4.08 and titratable acidity of 2.27% for 24 h. Soy yogurt fermented with S. thermophilus had a higher viscosity and lower sugar contents than that fermented with L. bulgaricusas incubation time increased. Total viable count was 1.80 × 10¹⁰ CFU/mL on S. thermophilus and 2.16 × 10⁸ CFU/mL on L. bulgaricus after 24 h at 37℃. However, there was no significant difference in sensory intensities and preference between the two samples. As a result, S. thermophilus was identified as a better culture than L. bulgaricus for the manufacture of soy yogurt incorporating insoluble components.
In this chapter current developments in biotechnology and bioengineering in the fermented dairy products industry are introduced. Some historical events and the importance of fermented dairy products in the diet and health of humans are presented at the beginning of this chapter. Then starter cultures as well as probiotics that are present in fermented dairy products are analyzed. Cheese and yogurt, which are the most important and well-known products, are presented next. Near the end of this chapter kefir, koumiss, curd, and shrikhand are introduced. At the end of this chapter there is a discussion on the future perspectives for fermented dairy products.
Survivability of probiotics in foods is essential for developing functional food containing probiotics. We investigated polymerized whey protein (PWP)-based microencapsulation process which is developed for protecting probiotics like Lactobacillus acidophilus NCFM and compared with the method using sodium alginate (SA). The entrapment rate was 89.3 ± 4.8% using PWP, while it was 73.2 ± 1.4% for SA. The microencapsulated NCFM by PWP and SA were separately subjected to digestion juices and post-fermentation storage of fermented cows’ and goats’ milk using the encapsulated culture. The log viable count of NCFM in PWP-based microencapsulation was 4.56, compared with that of 4.26 in SA-based ones and 3.13 for free culture. Compared with using SA as wall material, PWP was more effective in protecting probiotic. Microencapsulation of L. acidophilus NCFM using PWP as wall material can be exploited in the development of fermented dairy products with better survivability of probiotic organism.
The present study was conducted to isolate and characterize probiotic properties of bacteria isolated from flour and batter samples of sorghum and pearl millet. A total of five different selective media including plate count agar, yeast glucose chloramphenicol agar, Bifidobacterium agar, actinomycetes isolation agar and de ManRogosa and Sharpe agar were used and the most prominent bacteria (which were found abundantly in the plate) were isolated and maintained on the respective media slants at 4°C for further studies. The bacteria were characterized for various traits including Gram staining, morphology (color, size, shape, elevation, margin, form and surface), biochemistry (urease, catalase, oxidase, hydrogen sulphide, nitrogen reduction, gelatin liquefaction, starch hydrolysis and carbohydrate utilization), IMViC tests (indole, methyl red, Voges Proskauer and citrate utilization), probiotic potentials [acid (pH 2, 3), bile (0.5%), NaCl (6 and 9%)], phenol tolerance [0.4%], antibiotic tolerance (tetracycline, streptomycin, kanamycin, chloramphenicol, ciprofloxacin, ampicillin, penicillin, erythromycin and vancomycin) and antimicrobial activity against human pathogens (Escherichia coli, Staphylococcus aureus and Salmonella typhi). A total of nine probiotic bacterial isolates were short listed based on these traits. The sequences of 16s rDNA gene of the nine isolates were found matched with Bacillus subtilis (two isolates), Bacillus cereus (three isolates), Bacillus pumilus (one isolate), Bacillus amyloliquefaciens (one isolate), Sphingobacterium thalpophilum (one isolate) and Brevibacterium sp. (one isolate) in BLAST analysis. The sequences of the nine bacteria were submitted to NCBI and accession numbers obtained. This study indicated that the selected bacteria could be exploited to develop new probiotic foods.
The problem of the identification and naming of probiotic organisms arose together with the first suggestion that viable microrganisms could be an aid to human well-being.
This study was conducted to obtain a good probiotic strain of L. acidophilus from infant feces which have the acid and bile tolerance. The selection criteria for the strain included antimicrobial activity, serum cholesterol reduction, resistance to the hydrogen peroxide, angiotensin converting enzyme (ACE) inhibition activity and iron solubility. To this end, five probiotic Lactobacillus strains have been isolated from infant feces. Especially, L. acidophilus SD 105 had strong antimicrobial activity against Listeria sp., high deconjugation activity in the medium which contained 0.5% of glycocholate (GCA) and high resistance to the hydrogen peroxide. L. acidophilus SD 102 showed the highest ACE inhibition activity among the tested cultures and L. acidophilus SD 103 showed iron solubility of more than 70%.
This study was performed to examine the quality characteristics and antioxidant activity of the curd yogurt with different contents (0.5-2%, w/w) of acanthopanax powder (AP). The pH decreased with increasing AP content until 16 h, whereas the treated groups showed higher pH levels than the control group after 20 h. The viscosity and the viable cell counts of the yogurt with 2% AP were lower than those of the control group during fermentation, significantly. Color values of AP yogurt were lower in terms of brightness, whereas redness and yellowness values were higher compared to the control group. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and soluble content significantly increased with increasing AP content. Consumer acceptability score of yogurt with 0.5% AP was ranked higher than other yogurts. Yogurt added with 0.5% AP showed no differences in pH, titrable acidity, and viable cell counts compared to the control group after storage at 4oC for 14 days.
Milk and dairy products have received much interest in research, industrial applications and commercially as a commodity. They have been used for their functional properties, nutritional value and recently as a functional food for their physiological impact in promoting human health, especially for their bioactive components. These bioactive compounds are either naturally present in milk, such as conjugated linoleic acid, or are released in large amounts through protein hydrolysis by the digestive or microbial enzymes to produce bioactive peptides. These components, formed inside the gastrointestinal tract such as caseinophosphopeptides and other smaller peptides, have demonstrated benefits to human health and well-being. The health benefits through the bioactive components in milk are discussed individually with emphasis on bioactive peptides and probiotic bacteria. Their definition, production, potential health benefits and mechanisms are also highlighted.
Lactobacillus acidophilus exerted antagonistic actions on growth of Staphylococcus aureus, Salmonella typhimurium, enteropathogenic Escherichia coli, and Clostridium perfringens when grown with each in associative cultures. S. aureus and C. perfringens were more sensitive to the inhibition than were S. typhimurium and E. coli. The amount of the antagonism produced varied among strains of L. acidophilus and could not be directly related to amounts of acid produced; hydrogen peroxide produced by the lactobacilli appeared to be partially responsible for the antagonistic interaction. The inhibitory effect was produced also under anaerobic conditions in a pre-reduced medium.
Increased use of lactobacilli as dietary supplements has emphasized the need for preparations of those cultures that possess the attributes of cell viability. resistance to bile and capability of establishing in the intestinal tract. Incompatibility of different species of lactobacilli may limit development of products designed to overcome objectionable, or impart improved flavor to cultured foods. Stresses that are imposed on cultures during their preparation and distribution must minimize damage to cells which would detract from the foregoing characteristics.
Despite the opinion of many scientists and laymen that lactobacilli benefit adult intestinal health, the medical and scientific communities do not accept this as fact. This paper offers possible beneficial and detrimental roles which lactobacilli could play; relevant literature citations also are made. Healthful roles include those exerted as a result of their presence as members of the intestinal flora as well as their benefits as culture or enzyme preparations. Speculative detrimental effects discussed are nutrient competition, carcinogen activation and detoxification interference (glucuronide hydrolysis).
Reassessment of the ;gastric bactericidal barrier' to enteric bacteria in man included studies of the bactericidal activity of (1) the normal and achlorhydric stomach in vivo and (2) normal and achlorhydric gastric juice and other media in vitro. Within 30 minutes virtually all bacteria (Serratia marcescens) were eliminated in the normal stomach whereas no reduction occurred in the achlorhydric stomach in one hour. In vitro, identical bactericidal activity was observed at the same pH (from 2.0 to 7.0) in normal gastric juice, achlorhydric gastric juice, aqueous HCl, and nutrient broth. At pH less than 4.0, 99.9% of the bacteria were killed within 30 minutes. The presence of profuse bacterial flora, including coliforms, found in markedly acid-deficient but not in normal stomachs, correlates well with the absence of bactericidal activity. Thus, the ;gastric bactericidal barrier' is primarily pH-hydrochloric acid dependent, with other constituents of gastric juice contributing little, if any, detectable effect on the destruction of microorganisms.
Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the means by which three strains of Lactobacillus acidophilus adhere to surfaces. When observed with SEM, all strains adhered to glass coverslips; however, no attachment fibrils were seen. When viewed with TEM, strain BG2F04 showed a polysaccharide (PS) material outside the cell wall. This strain had previously been shown to adhere strongly to human intestinal tissue cells, while strain Lac 12 had shown weak adherence, and strain NCFM did not adhere. The PS layer on strain Lac 12 was variable, and a PS layer on NCFM could not be seen. These observations suggested that this PS material may be involved in the adherence of strain BG2F04 to surfaces.
The microflora and pH of gastric contents were determined in breast-fed and in bottle-fed normal infants, in well nourished infants with acute diarrhoea and in infants with chronic diarrhoea and protein-calorie malnutrition. The last group of infants was reevaluated after recovery from diarrhoea and protein-calorie malnutrition. A bactericidal pH effect below 2-5 was observed. Bottle-fed controls had low pH values and low bacterial concentrations, whereas infants with chronic diarrhoea and protein-calorie malnutrition had high pH values and bacterial overgrowth, essentially of Gram-negative bacilli. After recovery, the only remaining alteration was the frequent isolation of yeast-like fungi in low concentrations. Infants with acute diarrhoea, except for the isolation more frequently of yeast-like fungi, presented no alterations; this seems to indicate that pH alterations and Gram-negative bacilli overgrowth occurred during the evolution of the disease to a chronic state. Breast-fed normal infants had hydrogen-ion concentrations similar to those of the chronic diarrhoea group, but without Gram-negative bacilli overgrowth, suggesting that other factors, besides pH, regulate bacterial growth in the gastric contents of these groups of infants.
Lactobacilli attached to the chicken crop wall appear in conventionally fixed and stained material to make little or no direct contact with the host cells. However, using cationic dyes and the periodic acid-thiosemicarbazide-silver proteinate technique, it has been shown that layers of carbohydrate-rich material at the surface of both bacterial and crop cells make direct contact at presumed sites of adhesion. It is suggested that specific adhesion is a function of their mutual interaction. Numerous filamentous extensions of the bacterial carbohydrate coat that make contact with other bacteria and adjacent areas of crop cell membrane are considered to be of secondary importance. A comparison of the lactobacillus grown in vitro with Lactobacillus acidophilus, which does not adhere to the crop wall, indicates that qualitative and quantitative differences in the surface carbohydrate-rich layer of the cell wall may account for differences in their adhesive behavior in vivo.
Using an in vitro method, some factors affecting the attachment of a strain of lactobacillus to chicken crop epithelial cells have been studied. Time of contact beyond 10 min, pH value, age or growth temperature of the bacterial culture, or nature of the energy source in the growth medium had little or no effect on attachment. Heating to 100 degrees C for 10 min, or treatment with EDTA or surface active compounds was also without effect. Treatment with sodium periodate markedly decreased adhesion, proteolytic enzymes had a smaller effect but wheat germ lipase was completely inactive. The pronounced inhibition of adhesion by periodate suggested the invovement of carbohydrate. However, enzymes known to attack carbohydrate substrates were inactive in reducing adhesion. Concanavalin A, which binds specifically to certain sugar residues, reduced attachment. It is suggested that these concanavalin A receptors on the lactobacillus are responsible for its attachment to crop epithelial cells.
The survival of four strains of lactic acid bacteria in human gastric juice, in vivo and in vitro, and in buffered saline, pH 1 to 5, has been investigated. The strains studied include two Lactobacillus acidophilus strains, Lactobacillus bulgaricus, and Streptococcus thermophilus. In addition, the adhesion of these strains to freshly collected human and pig small intestinal cells and to pig large intestinal cells has been studied and the effect of milk on both survival and adhesion tested. As a result of these investigations, an in vitro test system for screening potential cultures for use as human dietary adjuncts can be developed. The ability to survive in gastric juice and to adhere varied significantly for the strains tested; L. acidophilus ADH survived and adhered better than the others while S. thermophilus survived and adhered poorly. For all strains, both survival and adhesion was enhanced by milk. As all strains adhered to some extent to both human and pig intestinal cells, the adhesion mechanism is probably a nonspecific attachment as opposed to other reported specific Lactobacillus adhesion to gastric tissue. From the survival and adhesion data it seems feasible to obtain elevated levels of viable Lactobacillus sp. in human intestine by careful selection of the bacterial strains ingested. Furthermore, the in vitro methods used here should be valuable to screen potential strains. The data presented here can then be correlated with human in vivo studies monitoring the beneficial effect of ingestion of these Lactobacillus.
Considerable variation was found among strains of Lactobacillus acidophilus isolated from the fecal flora of pigs with regard to the ability to grow well in the presence of bile and to assimilate cholesterol from a laboratory growth medium. The uptake of cholesterol occurred only when the culture(s) was growing in the presence of bile under anaerobic conditions. Consumption of L. acidophilus RP32, which was selected for its ability to grow well in the presence of bile and to assimilate cholesterol from the laboratory medium, significantly inhibited increases in serum cholesterol levels of pigs (P less than 0.05) fed a high-cholesterol diet. Consumption of L. acidophilus P47, which was selected for its ability to grow in the presence of bile and lack of ability to remove cholesterol from the growth medium, failed to have a similar effect. This indicates that certain strains of L. acidophilus act directly on cholesterol in the gastrointestinal tract, and thus may be beneficial in reducing serum cholesterol levels.
The inorganic dye, ruthenium red, stains extracellular materials in animal tissues which probably are acidic mucopolysaccharides. It complements other techniques, its advantages being fine grain, high resolution and good contrast. Localization is shown in mouse and rat muscle, heart, lung and intestine, frog cartilage and cells scraped from oral epithelium of human beings. Attention is paid to collagen bundles, the cell/collagen interface and particularly the myotendinal junction, cartilage matrix and agar gel, desmosomes, intestinal microvilli, erythrocytes and vascular endothelium, nerve fibers and the T-system of striated muscle. Although ruthenium red generally is excluded by plasma membranes, it penetrates giving intracellular density, if the membrane is broken. Even when the cell membrane is intact, exceptions occur with selective staining of the T-tubules or the sarcoplasmic sacs depending upon the state of contraction of the muscle cell, and with intracellular staining of certain nuclei and epithelial cells. Ruthenium red stains intracellular lipid droplets revealing lamellae, and stains myelin forms grown from crude egg lecithin but cannot penetrate deeply. It is localized in extracellular materials which have an important mechanical function. Its exclusion by cell membranes permits tracing tortuous cellular invaginations and those exceptions to its exclusion invite a comparison of the localization of the dye with the function of the cell.
A low-viscosity embedding medium based on ERL-4206 is recommended for use in electron microscopy. The composition is: ERL-4206 (vinyl cyclohexene dioxide) 10 g, D.E.R. 736 (diglycidyl ether of polypropylene glycol) 6 g, NSA (nonenyl succinic anhydride) 26 g, and S-1 (dimethylaminoethanol or DMAE) 0.4 g. The medium is easily and rapidly prepared by dispensing the components, in turn by weight, into a single flask. The relatively low viscosity of the medium (60 cP) permits rapid mixing by shaking and swirling. The medium is infiltrated into specimens after the use of any one of several dehydrating fluids, such as ethanol, acetone, dioxan, hexylene glycol, isopropyl alcohol, propylene oxide, and tert.-butyl alcohol. It is compatible with each of these in all proportions. After infiltration the castings are polymerized at 70°C in 8 hours. Longer curing does not adversely affect the physical properties of the castings. Curing time can be reduced by increasing the temperature or the accelerator, S-1, or both; and the hardness of the castings is controlled by changes in the D.E.R. 736 flexibilizer. The medium has a long pot life of several days and infiltrates readily because of its low viscosity. The castings have good trimming and sectioning qualities. The embedding matrix of the sections is very resistant to oxidation by KMnO4 and Ba(MnO4)2, compared with resins containing NADIC methyl anhydride. Sections are tough under the electron beam and may be used without a supporting membrane on the grids. The background plastic in the sections shows no perceptible substructure at magnifications commonly used for biological materials. The medium has been used successfully with a wide range of specimens, including endosperms with a high lipid content, tissues with hard, lignified cell walls, and highly vacuolated parenchymatous tissues of ripe fruits.
The present report deals with the survival of micro-organisms in the gastric lumen of fasting human subjects. Studies were carried out on hospitalized adult patients during the day, at night and over a 24-hour period.It is concluded that the survival of bacteria in the gastric lumen depends on the pH of the gastric juice. The duration of survival of the organisms at the pH <3.0 varied; however, at pH> 4.0, when a subsequent rapid drop in pH occurred, the clearing of viable organisms occurred within the hour sampling period in most cases. It is possible that medications which decrease gastric acidity favour an increase in the growth of gastric bacteria, while substances with a low pH may decrease bacterial growth.
Some characteristics of the association between lactic acid bacteria and pig squamous epithelial cells were studied. Strains from several sources were tested for adhesion in vitro but only those from pigs and chickens attached. The adhesion rate of pig isolates was very variable and, of the isolates tested, strains of Lactobacillus fermentum and Streptococcus salivarius attached in largest numbers. These strains were selected for further study. They did not attach to columnar epithelial cells from the small and large intestine. Adhesion was reduced by sodium periodate or protease. Both strains had a microcapsule with fibrils which stained with ruthenium red. The adhesive bond between lactobacilli and squamous tissue was strong enough to resist washing 50 times but there was a persistent release of bacteria during the washing process. When the strains of both species or of L. fermentum alone were fed to artificially reared pigs there was a statistically significant reduction in the numbers of Escherichia coli in the stomach.
The adhesion of various lactobacilli and streptococci to columnar epithelial cells of pigs and calves were studied, by in vitro methods. The porcine strains isolated most frequently were Lactobacillus delbrueckii, Lact, acidophilus and Lact. fermentum. Thirteen of the 22 lactobacilli were adhesive. All the streptococci isolated belonged to Lancefield's D-group; none of them adhered to pig epithelial cells. The adhesive strains (9 of 22) of calves were identified as Lact. fermentum. Adherence was variable even between strains of the same species. Isolates from plant material, cultured milk and cheese did not adhere to the columnar epithelial cells in vitro. The adhesive porcine strains tolerated low pH and bile acids, which is important for their survival under conditions in the stomach and intestine.
Thirty-two lactobacilli were tested for ability to adhere to a human fetal intestinal epithelial cell line. By an in vitro system, two adherence mechanisms were found. One mechanism, requiring calcium in the adherence reaction, was nonspecific and allowed all lactobacilli tested to adhere. The other system, not requiring calcium, was found in four strains, all human Lactobacillus acidophilus isolates. Colonial morphology, serial broth passage, and exposure of cell crops to freezing or lyophilization did not affect adherence of Lactobacillus acidophilus. In vitro adherence, combined with subsequent in vivo studies, may provide a basis for screening candidate organisms for use in microbiotic supplements.