scholarly journals RESEARCHES CONCERNING THE BIOSYNTHESIS OF EXOPOLYSACCHARIDES IN THE FERMENTED DAIRY PRODUCTS WITH THE YOGURT CULTURE YF-L 811

Author(s):  
Ina Simiţaru ◽  
Rodica Segal

The exopolysaccharides produced by the lactic acid bacteria confer the possibility to obtain fermented dairy products of good quality, with desirable rheological properties, and diverse benefits for health. The capacity of lactic acid bacteria to produce exopolysaccharides is influenced by culture media and the conditions of growth. The purpose of this work was to study the thermophile yogurt culture YF-L 811, which contains Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus. The study was based on the capacity of the culture to produce exopolysaccharides in different temperature conditions and with different ingredients added in culture media. The amount of exopolysaccharides was correlated to viscosity of the yogurt.

2021 ◽  
Vol 26 (2) ◽  
pp. 2548-2559
Author(s):  
VIORICA CORBU ◽  
◽  
STEFANA PETRUT ◽  
TATIANA VASSU ◽  
DIANA PELINESCU ◽  
...  

During last decades, there is a growing interest for characterizing new microbial strains isolated from various sources (plants, soil and natural fermentative processes), in order to enhance industrial productivity. The aim of the present study was to assess the profile of cell growth parameters and biomass accumulation of 15 newly isolated yeast and lactic acid bacteria (LAB) strains from Romanian spontaneous fermented dairy products under different environmental stress conditions (chemical and physical). On this purpose, the yeast and LAB strains were characterized and identified using MALDI-TOF MS and selected for their biotechnological potential. Cell growth was evaluated in presence of extreme pH values, temperatures and different NaCl concentrations. All strains included in this study grew well under their optimal conditions; some of them preferred extreme parameters: acid / very alkaline pH, high temperatures or NaCl concentration The characterization of microbiota from Romanian spontaneous fermented dairy products might represent a great opportunity for the development of dairy industry using native microorganisms, preserving thus the Romanian biodiversity and cultural heritage.


2009 ◽  
pp. 87-94
Author(s):  
Dragana Pesic-Mikulec ◽  
Gordana Niketic

Yoghurt quality is particularly difficult to standardize because of the many forms, varieties, manufacturing methods, ingredients and consumer preferences that exist. Since these factors will always play an important role, it is unlikely that a uniform yoghurt quality concept will ever emerge, such as has been developed for other dairy products. There are a number of common denominators, however that have bearing on yoghurt quality. Since a number of producers are recognized within the broad category entitled yoghurt. This situation makes yoghurt an interesting, challenging, but also a confusing area to work in. The present investigation was undertaken to isolate from commercial yoghurt the strains involved in its manufacture and determine the characteristics of Streptococcus thermophilus and Lactobacillus delbrueckii subsp.bulgaricus. This study is concerned with the lactic acid bacteria (L.delbrueckii subsp. bulgaricus and S. thermophilus) growth in yoghurt from involving different procedures and with the determination of the number of lactic acid bacteria in dependence of the temperature and acidity in the period of storage. Predominant samples of yoghurt were with 11-107/ml lactic acid lactococci (44.28%).


2014 ◽  
Vol 4 (3) ◽  
pp. 199-206 ◽  
Author(s):  
Alexander Oleskin ◽  
◽  
Olga Zhilenkova ◽  
Boris Shenderov ◽  
Adelaide Amerhanova ◽  
...  

2019 ◽  
Vol 13 (02) ◽  
pp. 137-148 ◽  
Author(s):  
Chao Yang ◽  
Tao Yu

Introduction: Lactic acid bacteria (LAB) are commonly found in foods and are also natural intestinal inhabitants in humans and most animals. However, information regarding antimicrobial resistance and the transfer of resistance genes of LAB from fermented dairy products in China is limited. Methodology: In this study, LAB isolates (n = 82) of Lactobacillus (n = 43) and Streptococcus thermophilus (n = 39) were isolated from 51 commercial fermented food samples in China. All isolates were subjected to pulsed-field gel electrophoresis (PFGE), antimicrobial susceptibility, detecting resistance genes, as well as investigating the transferability of resistance genes. Results: The 43 Lactobacillus isolates yielded 24 PFGE patterns and the 34 isolates of S. thermophilus generated 32 different PFGE patterns. Among the 43 Lactobacillus strains, the most commonly observed resistance was that to streptomycin (83.7%) and gentamycin (83.7%). Among the 39 S. thermophilus strains, the most frequently observed resistance was that to streptomycin (92.3%), gentamycin (87.2%), ciprofloxacin (79.5%), and chloramphenicol (71.8%), whereas the lowest level of resistance was that against erythromycin (7.7%). Antimicrobial resistance genes for erythromycin (emrB), gentamycin (aac(6')-aph(2")), streptomycin (ant(6)), sulfamethoxazole (sulI and sulII), tetracycline (tetM and tetS) were detected in the 18 resistance LAB strains. Conjugation experiments showed that tetM from L. delbrueckii subsp. bulgaricus R6 and tetS from L. plantarum R41 were successfully transferred to L. monocytogenes by filter mating. Conclusions: LAB strains could potentially act as reservoirs of resistance genes and play an active role in the transfer of resistance to humans via the food chain.


2013 ◽  
Vol 3 (2) ◽  
pp. 92-96
Author(s):  
Nadim Chishty ◽  
Srinivasan R ◽  
Dinesh K. Kumawat ◽  
Yogesh Franklin ◽  
Anil Tripathi

Lactic acid bacteria (LAB) are a group of gram positive, non spore forming, cocci or rod shaped, catalase negative and fastidious organisms. They are considered as “GRAS” (Generally Recognized As Safe) organisms. A total of 86 bacterial isolates were isolated from different samples of raw milk, buttermilk and curd by using MRS agar and M17 agar. Lactic Acid Bacteria have similar nutritional and growth requirements, it becomes difficult and laborious to identify them by classical methods. Hence, molecular typing was attempted to find the diversity, 16S rDNA gene amplification was done using specific 16S rDNA primers and amplified gene products were digested with different restriction endonuclease enzymes. Further the 16S rDNA sequencing was carried out and the sequences were compared with the available gene sequences in NCBI website by using BLASTn. All isolates obtained from dairy products were accurately identified as Lc. lactis, Lb. plantarum, Leu. mesenteroides, E. durans, Lb. fermentum, Lc. garviae and Lb. casei. The predominant LAB were Lactobacillus casei and Leu. mesenteroides, which were isolated from all sampling sites. The results demonstrate that traditional fermented dairy products from different regions of Rajasthan have complex compositions of LAB species.


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