207. Protein metabolism and acid production by the lactic acid bacteria in milk. Influence of yeast extract and chalk

1939 ◽  
Vol 10 (1) ◽  
pp. 20-34 ◽  
Author(s):  
M. Braz ◽  
L. A. Allen
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Proteolytic Activity ◽  
Yeast Extract ◽  
Protein Metabolism ◽  
Acid Production ◽  
Single Species ◽  
Soluble Nitrogen ◽  
Protein Breakdown ◽  
Protein Nitrogen

Though the lactic acid bacteria are recognized primarily as saccharolytic, several workers have recorded observations on their slow proteolytic activity. Von Freudenreich(1) was the first to record the fact that cultures of these organisms in milk, to which chalk had been added to neutralize the acidity, formed appreciable amounts of soluble nitrogen, and these findings were confirmed by Orla-Jensen (2), Barthel(3), and Barthel & Sandberg(4). Anderegg & Hammer (5), in a study of a large number of strains ofStr. Lactis, found an increase in soluble nitrogen in some cases and a decrease in others, while occasionally the same strain differed in different tests. In general, cultures which clotted rapidly were more inclined to proteolysis than those which were slower in forming acid.Str. citrovorusandStr. paracitrovorusdid not cause protein breakdown. Addition of 0·3% peptone to the milk tended to retard proteolysis or to increase negative values while addition of chalk resulted in more extensive proteolysis. Barthel & Sadler (6) found that starters consisting of mixed cultures of streptococci produced more extensive proteolysis than single species, indicating a symbiotic effect. Sherwood & Whitehead (7) tested the proteolytic powers of several strains ofStr. cremorisin chalk milk cultures and found some active and some comparatively inactive. Two strains appear to have formed surprisingly large amounts of non-protein nitrogen. In general they found that acid-producing power was linked with proteolytic power.

scholarly journals The influence of compression level and inoculation on biochemical changes in lucerne silages

2011 ◽  
Vol 56 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Nenad Djordjevic ◽  
Goran Grubic ◽  
Bojan Stojanovic ◽  
Aleksa Bozickovic
Keyword(s):  
Acetic Acid ◽  
Lactic Acid ◽  
Chemical Composition ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Ammonia Nitrogen ◽  
Soluble Nitrogen ◽  
Acetic Acid Production ◽  
Protein Nitrogen ◽  
True Protein

The effect of different levels of compression (A1 = 420 gdm-1, A2 = 560 gdm-1) and inoculation (B1 = no inoculant, B2 = with inoculant) on changes in chemical composition, proteolysis and quality of lucerne silage was investigated in this paper. Based on the results of chemical analysis we found that in silages with more compressed material there was a reduction in the amount of ammonia nitrogen, soluble nitrogen and acetic acid, and increased content of protein nitrogen (?true?protein) and production of lactic acid (p<0.05). With the inoculation of the ensiling material the production of ammonia nitrogen and acetic acid was reduced but the content of lactic acid and acidity was increased (p<0.05). The interaction of both investigated factors (A?B) induced a decrease in the proteolysis degree, increase of lactic acid production and decrease in acetic acid production, and decrease in pH values (p<0.001) in investigated silages. The investigated factors had less influence on the chemical composition of lucerne material, and the significant variations were observed in fat and NFE contents. On the basis of this investigation the degree of compression is the most important parameter in ensiling technology. With the adequate compression and reduction of air in the starting material, the aerobic phase is reduced and the activity of proeolytic enzymes is decreased. In practice the special attention should be given to factors on which directly or indirectly the level of compression of ensiled material depends: wilting, cutting, object selection and/or selection of machines used for compression.

161. Studies in Cheddar cheese. VI. The degradation of milk proteins by lactic acid bacteria isolated from cheese, alone, with sterile rennet and with whole rennet

1937 ◽  
Vol 8 (2) ◽  
pp. 238-244 ◽  
Author(s):  
J. G. Davis ◽  
W. L. Davies ◽  
A. T. R. Mattick
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Amino Nitrogen ◽  
Milk Proteins ◽  
Cheddar Cheese ◽  
Protein Breakdown ◽  
Protein Nitrogen

It has been shown by experiments in milk that the enzymes of commercial rennet in conjunction with the lactic acid bacteria occurring in Cheddar cheese can bring about protein breakdown similar in extent to that found in the ripe cheese as far as the non-protein nitrogen is concerned. The amino nitrogen produced is, however, much less than in cheese. This may be ascribed to the higher pH of cheese as compared with that of the milk cultures, since acidity adversely affects the peptidases present. Attention is drawn to the differences between the conditions.

scholarly journals Hardening Properties of Cheeses by Latilactobacillus curvatus PD1 Isolated from Hardened Cheese-Ddukbokki Rice Cake

2021 ◽  
Vol 9 (5) ◽  
pp. 1044
Author(s):  
Jeong A Kim ◽  
Geun Su Kim ◽  
Se Mi Choi ◽  
Myeong Seon Kim ◽  
Do Young Kwon ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Acid Production ◽  
Lactobacillus Casei ◽  
Leuconostoc Mesenteroides ◽  
The Other ◽  
Rice Cake ◽  
Two Samples ◽  
High Protease Activity

Hardening of cheese is one of major issues that degrade the quality of Home Meal Replacement (HMR) foods containing cheese such as Cheese-ddukbokki rice cake (CD, stir-fried rice cakes with shredded cheese). The quality of cheese, such as pH, proteolytic, and flavor properties, depends on various lactic acid bacteria (LAB) used in cheese fermentation. The hardening of cheese is also caused by LAB. In this study, various LAB strains were isolated from CD samples that showed rapid hardening. The correlation of LAB with the hardening of cheese was investigated. Seven of the CD samples with different manufacturing dates were collected and tested for hardening properties of cheese. Among them, strong-hardening of cheese was confirmed for two samples and weak-hardening was confirmed for one sample. All LAB in two strong-hardening samples and 40% of LAB in one weak-hardening sample were identified as Latilactobacillus curvatus. On the other hand, most LAB in normal cheese samples were identified as Leuconostoc mesenteroides and Lactobacillus casei. We prepared cheese samples in which L. curvatus (LC-CD) and L. mesenteroides (LM-CD) were most dominant, respectively. Each CD made of the prepared cheese was subjected to quality test for 50 days at 10 °C. Hardening of cheese with LC-CD dominant appeared at 30 days. However, hardening of cheese with LM-CD dominant did not appear until 50 days. The pH of the LC-CD was 5.18 ± 0.04 at 30 days, lower than that of LM-CD. The proteolytic activity of LC-CD sample was 2993.67 ± 246.17 units/g, higher than that of LM-CD sample (1421.67 ± 174.5 units/g). These results indicate that high acid production and high protease activity of L. curvatus might have caused hardening of cheese.

Screening for antimicrobial and proteolytic activities of lactic acid bacteria isolated from cow, buffalo and goat milk and cheeses marketed in the southeast region of Brazil

2015 ◽  
Vol 83 (1) ◽  
pp. 115-124 ◽  
Author(s):  
Fabricio L Tulini ◽  
Nolwenn Hymery ◽  
Thomas Haertlé ◽  
Gwenaelle Le Blay ◽  
Elaine C P De Martinis
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Proteolytic Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Fermented Milk ◽  
Antimicrobial Activities ◽  
Penicillium Expansum ◽  
Streptococcus Uberis ◽  
Sds Page

Lactic acid bacteria (LAB) can be isolated from different sources such as milk and cheese, and the lipolytic, proteolytic and glycolytic enzymes of LAB are important in cheese preservation and in flavour production. Moreover, LAB produce several antimicrobial compounds which make these bacteria interesting for food biopreservation. These characteristics stimulate the search of new strains with technological potential. From 156 milk and cheese samples from cow, buffalo and goat, 815 isolates were obtained on selective agars for LAB. Pure cultures were evaluated for antimicrobial activities by agar antagonism tests and for proteolytic activity on milk proteins by cultivation on agar plates. The most proteolytic isolates were also tested by cultivation in skim milk followed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the fermented milk. Among the 815 tested isolates, three of them identified asStreptococcus uberis(strains FT86, FT126 and FT190) were bacteriocin producers, whereas four other ones identified asWeissella confusaFT424,W. hellenicaFT476,Leuconostoc citreumFT671 andLactobacillus plantarumFT723 showed high antifungal activity in preliminary assays. Complementary analyses showed that the most antifungal strain wasL. plantarumFT723 that inhibitedPenicillium expansumin modified MRS agar (De Man, Rogosa, Sharpe, without acetate) and fermented milk model, however no inhibition was observed againstYarrowia lipolytica. The proteolytic capacities of three highly proteolytic isolates identified asEnterococcus faecalis(strains FT132 and FT522) andLactobacillus paracaseiFT700 were confirmed by SDS–PAGE, as visualized by the digestion of caseins and whey proteins (β-lactoglobulin and α-lactalbumin). These results suggest potential applications of these isolates or their activities (proteolytic activity or production of antimicrobials) in dairy foods production.

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 Effects of the Addition of Non-Starter Lactic Acid Bacteria on Free Amino Acid Production During Cheese Ripening

2018 ◽  
Vol 24 (2) ◽  
pp. 299-309 ◽  
Author(s):  
Risa Saiki ◽  
Tatsuro Hagi ◽  
Takumi Narita ◽  
Miho Kobayashi ◽  
Keisuke Sasaki ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Amino Acid ◽  
Lactic Acid Bacteria ◽  
Free Amino Acid ◽  
Acid Production ◽  
Free Amino ◽  
Amino Acid Production ◽  
Cheese Ripening
Sign in / Sign up

Export Citation Format

Share Document