scholarly journals Redox Potential: Monitoring and Role in Development of Aroma Compounds, Rheological Properties and Survival of Oxygen Sensitive Strains During the Manufacture of Fermented Dairy Products

Author(s):  
F. Martin ◽  
B. Ebel ◽  
C. Rojas ◽  
P. Gervais ◽  
N. Cayot ◽  
...  
2009 ◽  
Vol 76 (5) ◽  
pp. 1311-1319 ◽  
Author(s):  
Sybille Tachon ◽  
Johannes Bernhard Brandsma ◽  
Mireille Yvon

ABSTRACT The redox potential plays a major role in the microbial and sensorial quality of fermented dairy products. The redox potential of milk (around 400 mV) is mainly due to the presence of oxygen and many other oxidizing compounds. Lactococcus lactis has a strong ability to decrease the redox potential of milk to a negative value (−220 mV), but the molecular mechanisms of milk reduction have never been addressed. In this study, we investigated the impact of inactivation of genes encoding NADH oxidases (noxE and ahpF) and components of the electron transport chain (ETC) (menC and noxAB) on the ability of L. lactis to decrease the redox potential of ultrahigh-temperature (UHT) skim milk during growth under aerobic and anaerobic conditions. Our results revealed that elimination of oxygen is required for milk reduction and that NoxE is mainly responsible for the rapid removal of oxygen from milk before the exponential growth phase. The ETC also contributes slightly to oxygen consumption, especially during the stationary growth phase. We also demonstrated that the ETC is responsible for the decrease in the milk redox potential from 300 mV to −220 mV when the oxygen concentration reaches zero or under anaerobic conditions. This suggests that the ETC is responsible for the reduction of oxidizing compounds other than oxygen. Moreover, we found great diversity in the reducing activities of natural L. lactis strains originating from the dairy environment. This diversity allows selection of specific strains that can be used to modulate the redox potential of fermented dairy products to optimize their microbial and sensorial qualities.


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 20 (1) ◽  
Author(s):  
Kamil Rashidi ◽  
Bahman Razi ◽  
Mina Darand ◽  
Azadeh Dehghani ◽  
Parisa Janmohammadi ◽  
...  

Abstract Background Previous studies have suggested that the consumption of probiotic fermented dairy products (PFDP) may have a protective effect on respiratory tract infections (RTIs). However, the results of studies are inconclusive. We aimed to systematically investigate the effect of PFDP on RTIs by performing a meta-analysis of randomized controlled trials (RCTs). Methods PubMed and Scopus databases were systematically searched up to October 2020 to identify eligible RCTs. Meta-analysis outcomes were risk of incidence of upper (URTIs ) and lower (LRTIs ) respiratory tract infections. A random-effects model was used to pool the relative risks (RR) and corresponding 95 % confidence intervals (CI) for outcomes following conception of PFDP. Results A total of 22 RCTs, with a total sample size of 10,190 participants, were included in this meta-analysis. Compared with placebo, consumption of PFDP had a significant protective effect against RTIs in the overall analysis (RR = 0.81, 95 %CI: 0.74 to 0.89) and in children (RR = 0.82, 95 %CI: 0.73 to 0.93), adults (RR = 0.81, 95 %CI: 0.66 to 1.00), and elderly population (RR = 0.78, 95 %CI: 0.61 to 0.98). The significant decreased risk of RTIs was also observed for URTIs (RR = 0.83, 95 %CI: 0.73 to 0.93), while, this effect was marginal for LRTIs (RR = 0.78, 95 %CI: 0.60 to 1.01, P = 0.06). The disease-specific analysis showed that PFDP have a protective effect on pneumonia (RR = 0.76, 95 %CI: 0.61 to 0.95) and common cold (RR = 0.68, 95 %CI: 0.49 to 0.96). Conclusions Consumption of PFDP is a potential dietary approach for the prevention of RTIs.


2015 ◽  
Vol 4 (5) ◽  
pp. 222-225
Author(s):  
K. G. Li ◽  
G. P. Pogossian ◽  
A. K. Moldagulova ◽  
E. E. Bekenova ◽  
A. Abdikadirova ◽  
...  

  Lactobacilli are essential and important biological objects used in food pro-duction and medicine. One of the sufficient problems is fast, reliable and highly specific identification of lactobacilli in the scientific research and cur-rent production control. We represent two species-specific real-time PCR in the present study to discriminate L. rhamnosus and L. casei basing on the unique peptidoglycan-hydrolase genes p40 and p75 respectively. PCR pri-mers and probes were designed to provide high specificity discrimination via high temperature of PCR annealing stage. High efficiency of the reactions is provided by the size of amplified DNA fragments minimization. Reliable re-producibility of the target sequences amplification and fluorescence detec-tion provide a basis for the future creation of industrial test-systems for op-erational control in the production of fermented dairy products.


2021 ◽  
Vol 104 (4) ◽  
pp. 3766-3778
Author(s):  
Carmen G. Manzanarez-Quín ◽  
Lilia M. Beltrán-Barrientos ◽  
Adrián Hernández-Mendoza ◽  
Aarón F. González-Córdova ◽  
Belinda Vallejo-Cordoba

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