Reduction of the Off-Flavor Volatile Generated by the Yogurt Starter Culture Including Streptococcus thermophilus and Lactobacillus delbrueckii subsp.bulgaricusin Soymilk

2014 ◽  
Vol 62 (7) ◽  
pp. 1658-1663 ◽  
Author(s):  
Daisuke Kaneko ◽  
Toshinori Igarashi ◽  
Kenji Aoyama
2021 ◽  
Author(s):  
Vincent Somerville ◽  
Hélène Berthoud ◽  
Remo S. Schmidt ◽  
Hans-Peter Bachmann ◽  
Yi Hélène Meng ◽  
...  

AbstractUndefined starter cultures are poorly characterized bacterial communities from environmental origin used in cheese making. They are phenotypically stable and have evolved through domestication by repeated propagation in closed and highly controlled environments over centuries. This makes them interesting for understanding eco-evolutionary dynamics governing microbial communities. While cheese starter cultures are known to be dominated by a few bacterial species, little is known about the composition, functional relevance, and temporal dynamics of strain-level diversity. Here, we applied shotgun metagenomics to an important Swiss cheese starter culture and analyzed historical and experimental samples reflecting 82 years of starter culture propagation. We found that the bacterial community is highly stable and dominated by only a few coexisting strains of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. lactis. Genome sequencing, metabolomics analysis, and co-culturing experiments of 43 isolates show that these strains are functionally redundant, but differ tremendously in their phage resistance potential. Moreover, we identified two highly abundant Streptococcus phages that seem to stably coexist in the community without any negative impact on bacterial growth or strain persistence, and despite the presence of a large and diverse repertoire of matching CRISPR spacers. Our findings show that functionally equivalent strains can coexist in domesticated microbial communities and highlight an important role of bacteria-phage interactions that are different from kill-the-winner dynamics.


Author(s):  
Sanaz Seyedjafarri

Background: Aflatoxin M1 is a highly toxic and carcinogenic compound which is found in milk and milk products and it is a hydorxylated metabolite of Aflatoxin B1. When the dairy animal digested AFB1 contaminated feed, it is changed to aflatoxin M1 and transferred to tissues and milk. Aflatoxin M1 is less carcinogenic than AFB1, but it is acutely hepatotoxic as AFB1. Liver is their main target organ in the body. It has been calculated approximately that 0.3- 6.2% of presented AFB1 in animal feed transferred as aflatoxin M1 in milk. Occurrence of AFM1 in milk and milk products is a big concern. Therefore, several countries have standardized the maximum levels of AFM1 in milk and milk products. Methods: In this experiment, the ability of yoghurt bacteria to degrade AFM1 levels in milk and yoghurt were analysed. The starter culture of yoghurt contains Streptococcus thermophilus and Lactobacillus delbrueckii subsp. Bulgaricus (1:1). The experiment is carried out in Glasgow Caledonian University, department of life science in 2010. Result: These bacteria showed the higher binding ability between 90- 100% in milk samples whereas no considerable reduction was observed in yoghurt samples. In some yoghurt samples, an increase of AFM1 level was detected but in overall, concentration of AFM1 was stable in yoghurt. Also, the fat content of milk and yoghurt did not have any negative or positive effect on the concentration of AFM1 in milk and yoghurt.


2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Xue Han ◽  
Zhe Yang ◽  
Xueping Jing ◽  
Peng Yu ◽  
Yingchun Zhang ◽  
...  

19Streptococcus thermophiluswith 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 ofStreptococcus thermophiluszlw TM11 were selected because its fermented milk had the highest exopolysaccharide content (380 mg/L) and viscosity (7716 mpa/s). ThenStreptococcus thermophiluszlw TM11 was combined withLactobacillus delbrueckiisubsp.bulgaricus3 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.


Yoghurt, a product prepared by fermentation of milk with bacterial cultures consisting of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus, has been popular for a long time, however, dehydrated yogurt is still uncommon. Freeze drying is well-known as an effective method to preserve the nutritional and sensory characteristics of the food product compared to other dehydration ways. This study developed a protocol to produce freeze-dried yoghurt fermented by commercial probiotic starter culture containing betacyanin – a bioactive component from red dragon fruit on laboratory scale. The freeze-dried red dragon yoghurt was produced by the following steps: (1) plain yoghurt preparation: Milk with 12% milk dry matte was heated at 95oC for 5 min, cooled down to 42oC, followed by the addition of commercial probiotic bacteria starter, then fermented for 3 hours until the pH reached to 4.6 and the milk coagulated (2) obtained yoghurt was mixed with 30 % red dragon fruit, molding in the tray (3) Freeze at -20oC and freeze-dried (4) packaging to obtain the final product. Betacyanin – well-known as a bioactive compound from red dragon fruit of the obtained products and viable bacteria remained during 30 days storage at room temperature.


2021 ◽  
Vol 30 ◽  
pp. 01015
Author(s):  
Ekaterina Pozhidaeva ◽  
Lyubov Golubeva ◽  
Anton Sadchenko ◽  
Yana Dymovskih

As a result of scientific and technological research, the ingredient composition and the feasibility of using complex bacterial starter cultures as part of fermented milk ice cream have been substantiated. The objects of the study were samples of mixtures for the production of fermented milk ice cream were considered, which included dairy and non-dairy components, including complex bacterial starter cultures: YF-L812 (Streptococcus thermophilus, Lactobacillus bulgaricus) - control sample and YO-PROX 777 (Streptococcus thermophilus, Lactobacillus delbrueckii ssp.bulgaricus), as well as pectin stabilizers “Grindsted Pektin LC 710” and “Cremodan SE 334” with a concentration of 0.1-0.7%. It was found that a prototype sample with starter culture YO-PROX 777 has increased values of dynamic viscosity compared with the control sample with similar stabilizers and their identical concentrations, which is evidence of the accumulation of exopolysaccharides in the fermented fermented milk mixture. A prototype of fermented milk ice cream has better shape stability during temperature control, the thawing rate is reduced by 1.6 times compared to the control. The degree of overrun of the prototype fermented milk ice cream is 37.6%, which is 1.2 times higher compared to the control.


2018 ◽  
Vol 46 (3) ◽  
pp. 201-209
Author(s):  
Denny Rizkinata ◽  
Danish Andrian ◽  
Steven Ryan Susanto Tan ◽  
Lucy Jap ◽  
Tjie Jan Tan

1998 ◽  
Vol 64 (6) ◽  
pp. 2147-2151 ◽  
Author(s):  
Deborah Low ◽  
Jeffrey A. Ahlgren ◽  
Diane Horne ◽  
Donald J. McMahon ◽  
Craig J. Oberg ◽  
...  

ABSTRACT Recent work by our group has shown that an exopolysaccharide (EPS)-producing starter pair, Streptococcus thermophilusMR-1C and Lactobacillus delbrueckii subsp.bulgaricus MR-1R, can significantly increase moisture retention in low-fat mozzarella (D. B. Perry, D. J. McMahon, and C. J. Oberg, J. Dairy Sci. 80:799–805, 1997). The objectives of this study were to determine whether MR-1C, MR-1R, or both of these strains are required for enhanced moisture retention and to establish the role of EPS in this phenomenon. Analysis of low-fat mozzarella made with different combinations of MR-1C, MR-1R, and the non-EPS-producing starter culture strains S. thermophilus TA061 andLactobacillus helveticus LH100 showed that S. thermophilus MR-1C was responsible for the increased cheese moisture level. To investigate the role of the S. thermophilus MR-1C EPS in cheese moisture retention, theepsE gene in this bacterium was inactivated by gene replacement. Low-fat mozzarella made with L. helveticusLH100 plus the non-EPS-producing mutant S. thermophilusDM10 had a significantly lower moisture content than did cheese made with strains LH100 and MR-1C, which confirmed that the MR-1C capsular EPS was responsible for the water-binding properties of this bacterium in cheese. Chemical analysis of the S. thermophilus MR-1C EPS indicated that the polymer has a novel basic repeating unit composed of d-galactose, l-rhamnose, andl-fucose in a ratio of 5:2:1.


1996 ◽  
Vol 63 (3) ◽  
pp. 467-473 ◽  
Author(s):  
Mirza I. Baig ◽  
Velore Prasad

SummaryFresh rennet-coagulated cottage cheese whey was vacuum concentrated to 400 g total solids kg−1, and part of this evaporated whey was acidified to pH 4·6 to prepare whey protein concentrate. Both products were used separately to replace non-fat dried milk in yogurt. Diacetyl concentration increased on fortification with whey protein concentrate, and acetaldehyde increased with evaporated whey. However, the use ofBifidobacterium bifidumas a supplementary starter culture in addition toStreptococcus thermophilusandLactobacillus delbrueckiisubsp.bulgaricusreduced the concentration of diacetyl and acetaldehyde. Incorporation of whey solids stimulated the growth ofStr.thermophilusandBifid. bifidumin yogurt but the count ofLb. bulgaricuswas reduced whenBifid. bifidumwas incorporated. Examination of the organoleptic properties of the yogurts showed that both forms of whey solids were satisfactory replacements for non-fat dried milk. Fortification by whey protein concentrate improved the textural properties. Supplementation byBifid. bifidumhad only a marginal effect on the flavour of the product.


2021 ◽  
Author(s):  
Vincent Somerville ◽  
Hélène Berthoud ◽  
Remo S. Schmidt ◽  
Hans- Peter Bachmann ◽  
Yi Hélène Meng ◽  
...  

AbstractUndefined starter cultures are poorly characterized bacterial communities from environmental origin used in cheese making. They are phenotypically stable and have evolved through domestication by repeated propagation in closed and highly controlled environments over centuries. This makes them interesting for understanding eco-evolutionary dynamics governing microbial communities. While cheese starter cultures are known to be dominated by a few bacterial species, little is known about the composition, functional relevance, and temporal dynamics of strain-level diversity. Here, we applied shotgun metagenomics to an important Swiss cheese starter culture and analyzed historical and experimental samples reflecting 82 years of starter culture propagation. We found that the bacterial community is highly stable and dominated by only a few coexisting strains of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. lactis. Genome sequencing, metabolomics analysis, and co-culturing experiments of 43 isolates show that these strains are functionally redundant, but differ tremendously in their phage resistance potential. Moreover, we identified two highly abundant Streptococcus phages that seem to stably coexist in the community without any negative impact on bacterial growth or strain persistence, and despite the presence of a large and diverse repertoire of matching CRISPR spacers. Our findings show that functionally equivalent strains can coexist in domesticated microbial communities and highlight an important role of bacteria-phage interactions that are different from kill-the-winner dynamics.


2019 ◽  
Vol 7 (9) ◽  
pp. 274 ◽  
Author(s):  
Dimitra Dimitrellou ◽  
Chrysoula Salamoura ◽  
Artemis Kontogianni ◽  
Despoina Katsipi ◽  
Panagiotis Kandylis ◽  
...  

The production of fermented milk using cow milk, goat milk and a mixture of them (1:1) was evaluated. The traditional yogurt starter culture was used—Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus, along with Lactobacillus casei ATCC 393. The objective was to monitor the viability of these cultures during the storage of fermented milk at 4 °C for up to 28 days. Storage significantly affected the viability of all microorganisms and especially L. bulgaricus. All microorganisms retained viable numbers higher than 7.5 log CFU g−1, even after 4 weeks of storage, which is important to confirm the probiotic character of the product. The use of goat milk significantly affected the pH and acidity of fermented milk. More specifically, the use of goat milk led to fermented milk with lower pH values and higher acidities than fermented milk with cow milk. The sensory evaluation ascertained the overall quality of fermented milk with a mixture of cow and goat milk, which scored similar values to the commercial sample.


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