scholarly journals A Relation between Exopolysaccharide from Lactic Acid Bacteria and Properties of Fermentation Induced Soybean Protein Gels

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 90
Author(s):  
Xiaoyu Yang ◽  
Jiao Feng ◽  
Qianqian Zhu ◽  
Rui Hong ◽  
Liang Li
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Water Distribution ◽  
Soybean Protein ◽  
Production Capacity ◽  
Gel Properties ◽  
Texture Profile ◽  
Protein Gel ◽  
Protein Gels ◽  
Α Helix

Exopolysaccharide (EPS) producing lactic acid bacteria (LAB) is considered to be an effective texture improver. The effect of LAB strains (different EPS production capacity) on physicochemical properties (texture profile, water distribution, rheological properties, and microstructure), protein conformation, and chemical forces of soybean protein gel was investigated. Correlations between EPS yield and gel properties were established. Large masses of EPS were isolated from L. casei fermentation gel (L. casei-G, 677.01 ± 19.82 mg/kg). Gel with the highest hardness (319.74 ± 9.98 g) and water holding capacity (WHC, 87.74 ± 2.00%) was also formed with L. casei. The conversion of β-sheet to α-helix, the increased hydrophobic interaction and ionic bond helped to form an ordered gel network. The yield was positively correlated with hardness, WHC, A22, viscoelasticity, and viscosity, but negatively correlated with A23 (p < 0.05). The macromolecular properties of EPS (especially the yield) and its incompatibility with proteins could be explained as the main reason for improving gel properties. In conclusion, the EPS producing LAB, especially L. casei used in our study, is the best ordinary coagulate replacement in soybean-based products.

Isolation and Screening of Lactic Acid Bacteria Strains With Antibacterial Properties From The Vagina of Healthy Cows

2021 ◽  
Author(s):  
Chao Cheng ◽  
Linchong Zhang ◽  
Yanru Fu ◽  
Yanzhong Li ◽  
Xiaohong Ma ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Cell Biology ◽  
Acid Production ◽  
Antibacterial Properties ◽  
Production Capacity ◽  
Strong Acid ◽  
Isolation And Identification ◽  
Vaginal Epithelial Cells ◽  
Bacteriocin Genes

Abstract Background Lactic acid bacteria with probiotic and antibacterial properties were isolated from the vagina of healthy cows. The purpose of the study is to isolation and screening of lactic acid bacteria strains with antibacterial properties from the vagina of healthy cows, which could be used to treat cow vaginal inflammation. Results Isolation and identification of eight dominant lactic acid bacteria strains from 55 isolates was performed using classic microbiology methods and fermentation engineering. Eight strains were selected that had no spores and capsules, exhibited strong acid production capacity (pH <4.5) and had a rapid acid production (time ≤12 h) at the lowest pH. These strains were screened using fermentation engineering, pharmacology, cell biology and molecular biology methods. Lactobacillus johnsonii (SQ0048) had the lowest pH (4.32) and shortest acid-producing time (8 h). L. johnsonii (SQ0048) could produce hydrogen peroxide, inhibit the growth of Staphylococcus aureus and Escherichia coli and adhere to the vaginal epithelial cells of cows. The average number adhering to each cell was 304±2.67. Bacteriocin genes were detected in L. johnsonii (SQ0048), and the bacteriocin gene of a positive clone of this strain was 100% similar to that of Lactobacillus johnsonii NCC 533 (NC_005362.1). Expression of the bacteriocin genes had inhibitory activity against S. aureus and E. coli. Conclusions These advantages indicate that SQ0048 is a promising candidate for use in antimicrobial preparations.

scholarly journals Clustering of Streptococcus thermophilus Strains to Establish a Relation between Exopolysaccharide Characteristics and Gel Properties of Acidified Milk

Foods ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 146 ◽  
Author(s):  
Georg Surber ◽  
Susann Mende ◽  
Doris Jaros ◽  
Harald Rohm
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Streptococcus Thermophilus ◽  
Starter Cultures ◽  
Extracellular Polysaccharides ◽  
Gel Properties ◽  
Fermentation Time ◽  
Thread Length ◽  
Acid Gel ◽  
Fermented Dairy

In situ produced extracellular polysaccharides (EPS) from lactic acid bacteria are generally known to affect the texture of fermented dairy products; however, the interplay between EPS and product properties is still poorly understood. The aim of this study was to establish a relationship between concentration and properties of EPS, and gel formation of milk analysed by noninvasive Multispeckle Diffusing Wave Spectroscopy. Twenty Streptococcus thermophilus strains were classified with respect to EPS concentration (8–126 mg GE/kg) and ropiness (thread length: 15–80 mm). Five groups identified by cluster analysis demonstrate the high strain-to-strain variability even within one species of lactic acid bacteria. Results from acidification and gelation experiments averaged per cluster indicate that fermentation time and gel stiffness is higher for strains that produce ropy EPS. A further increase in gel stiffness was detected for strains that also produced cell-bound EPS, which underlines the importance of both ropy and cell-bound EPS for improving acid gel properties. The results may be helpful for a proper selection of EPS-producing starter cultures.

Screening and Identification of Biosurfactant-Producing Lactic Acid Bacteria

2019 ◽  
Vol 23 (2) ◽  
pp. 85-92
Author(s):  
Yujun Dong ◽  
Guowei Shu ◽  
Chunji Dai ◽  
Meng Zhang ◽  
Hongchang Wan
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Surface Activity ◽  
Animal Health ◽  
Production Capacity ◽  
Application Of Surfactants ◽  
Standard Curve ◽  
Surfactant Production ◽  
Expanding Circle ◽  
Screening And Identification

Abstract Biosurfactant attracts people’s attention because of its advantages of green and low toxicity. Lactic acid bacteria are beneficial to human and animal health. In order to make the application of surfactants safer, SDS standard curve was established, 65 strains of Lactic acid bacteria were used as screening source, and oil expanding circle was used as index to screen the strain with strong surfactant production capacity. The results showed that the standard curve of SDS was Y=34.82+(-1495.97) X1+33.11X2, and all strains had the ability to produce surfactants. Surface activity varied with bacteria. The concentration of surface activity ranged from 111.15mg/L to 736.23 mg/L. The concentration of BS in supernatant of LB6, 49, F70, 20 and Y1 strains was selected for screening. The concentration of BS in supernatant was 561.01~935.77 mg/L, and the concentration of BS on cell surface was 401.67~1076.94 mg/L. Considering the highest BS-producing strain is F70, the result of 16SrDNA showed that the strain is Pediococcus acidilactici F70. This experiment provides basic data for the production of surfactants by Lactic acid bacteria.

Spoilage of Sous Vide Cooked Salmon (Salmo salar) Stored Under Refrigeration

2010 ◽  
Vol 17 (1) ◽  
pp. 31-37 ◽  
Author(s):  
P. Díaz ◽  
M.D. Garrido ◽  
S. Bañón
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Water Activity ◽  
Profile Analysis ◽  
Microbiological Quality ◽  
Quality Parameters ◽  
Texture Profile ◽  
Physical Chemical ◽  
Sous Vide ◽  
Aerobic And Anaerobic

The spoilage of Sous Vide ‘SV’ cooked salmon stored under refrigeration was studied. Samples were packaged under vacuum in polyamide—polypropylene pouches, cooked at an oven temperature/time of 80 °C/45 min, quickly chilled at 3 °C and stored at 2 °C for 0, 5 or 10 weeks for catering use. Microbial (aerobic and anaerobic psychrotrophs, lactic acid bacteria, molds and yeasts and Enterobacteriaceae), physical—chemical (pH, water activity, TBARS, acidity, L*a*b* color, texture profile analysis and shear force) and sensory (appearance, odor, flavor, texture and overall quality) parameters were determined. SV processing prevented the growth of aerobic and anaerobic psychrotrophs, lactic acid bacteria, molds and yeasts and Enterobacteriaceae. There were no relevant changes in pH, water activity, TBARS, CIELab color associated with cooked salmon spoilage. Instrumental texture data were contradictory. Slight decrease in lactic acid levels was found. In contrast, the SV cooked salmon suffered considerable sensory deterioration during its refrigerated storage, consisting of severe losses of cooked salmon odor and flavor, slight rancidity, discoloration associated with white precipitation, and moderates softness, and loss of chewiness and juiciness. No acidification, putrefaction or relevant rancidity was detected. The sensory spoilage preceded microbiological and physical—chemical spoilage, suggesting that microbiological quality alone may overestimate the shelf life of SV cooked salmon.

scholarly journals Potential of Lactic Acid Bacteria Isolated From Different Forages as Silage Inoculants for Improving Fermentation Quality and Aerobic Stability

2020 ◽  
Vol 11 ◽  
Author(s):  
Melisa Puntillo ◽  
Mónica Gaggiotti ◽  
Juan Martín Oteiza ◽  
Ana Binetti ◽  
Ariel Massera ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Production Capacity ◽  
Maize Silage ◽  
Acetic Acid Production ◽  
Plant Materials ◽  
16S Sequencing ◽  
Aerobic Stability ◽  
Fermentation Capacity ◽  
Silage Inoculants

We aimed at isolating lactic acid bacteria (LAB) from different plant materials to study their crossed-fermentation capacity in silos and to find strains able to confer enhanced aerobic stability to silage. A total of 129 LAB isolates were obtained from lucerne (alfalfa), maize, sorghum, ryegrass, rice, barley, canola, Gatton panic, Melilotus albus, soy, white clover, wheat, sunflower, oat, and moha. Four Lactiplantibacillus plantarum subsp. plantarum strains (isolated from oat, lucerne, sorghum, or maize) were selected for their growth capacity. Identity (16S sequencing) and diversity (RAPD-PCR) were confirmed. Fermentative capacity (inoculated at 104, 105, 106, 107 CFU/g) was studied in maize silage and their cross-fermentation capacity was assessed in oat, lucerne, sorghum, and maize. Heterofermentative strains with the highest acetic acid production capacity conferred higher aerobic stability to maize silages. Regardless the source of isolation, L. plantarum strains, inoculated at a rate of 106 CFU/g, were effective to produce silage from different plant materials. From more than 100 isolates obtained, the application of a succession of experiments allowed us to narrow down the number of potential candidates of silage inoculants to two strains. Based on the studies made, L. plantarum LpM15 and Limosilactobacillus fermentum LfM1 showed potential to be used as inoculants, however further studies are needed to determine their performance when inoculated together. The former because it positively influenced different quality parameters in oat, lucerne, sorghum, and maize silage, and the latter because of its capacity to confer enhanced aerobic stability to maize silage. The rest of the strains constitute a valuable collection of autochthonous strains that will be further studied in the future for new applications in animal or human foods.

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