Role of Enterococci in Cheddar Cheese: Proteolytic Activity and Lactic Acid Development1

1975 ◽  
Vol 38 (1) ◽  
pp. 3-7 ◽  
Author(s):  
JANE P. JENSEN ◽  
G. W. REINBOLD ◽  
C. J. WASHAM ◽  
E. R. VEDAMUTHU
Keyword(s):  
Lactic Acid ◽  
Proteolytic Activity ◽  
Statistical Difference ◽  
Cheddar Cheese ◽  
Protein Breakdown ◽  
Streptococcus Faecalis

Eight lots of Cheddar cheese were manufactured by using two strains of Streptococcus faecalis and Streptococcus durans in combination with a commercial lactic culture. Each lot consisted of a control vat of cheese, manufactured with lactic starter only, and an experimental vat of cheese containing the lactic starter and one of the enterococcus strains. Combinations of two curing temperatures (7.2 and 12.8 C) and two early cooling treatments (air vs. brine cooling) were used for cheeses from each vat to determine the effects of these handling procedures, as well as of enterococcus addition, on proteolysis and lactic acid development. These characteristics were monitored from milling to up to 6 months of curing. Cheeses manufactured with S. faecalis exhibited more protein breakdown than did the control cheeses and those made with S. durans, the latter two being nearly identical in the extent of proteolysis. More proteolysis was consistently observed in those cheeses cured at 12.8 C. No statistical difference was observed inproteolytic activity between air- and brine-cooled cheeses. Cheeses made with S. durans had a higher final percentage of lactic acid than did controls and cheeses made with S. faecalis. Cheeses manufactured with enterococci exhibited a more rapid initial production of lactate. Cheeses cured at 12.8 C had greater percentages of lactic acid compared with those cured at 7.2 C. Air-cooled cheeses also developed significantly higher levels of lactic acid than did brine-cooled cheeses.

Role of Enterococci in Cheddar Cheese: Organoleptic Considerations1

1975 ◽  
Vol 38 (3) ◽  
pp. 142-145 ◽  
Author(s):  
JANE P. JENSEN ◽  
G. W. REINBOLD ◽  
C. J. WASHAM ◽  
E. R. VEDAMUTBU
Keyword(s):  
Lactic Acid ◽  
Fatty Acid ◽  
Citric Acid ◽  
Free Fatty Acid ◽  
Cheddar Cheese ◽  
Streptococcus Faecalis ◽  
Growth And Survival ◽  
Respective Control ◽  
Significant Difference

Eight lots of Cheddar cheese were manufactured with two strains each of Streptococcus faecalis and Streptococcus durans and subjected to combinations of two early cooling treatments (air vs. brine cooling) and two curing temperatures (7.2 and 12.8 C). The enterococcus cultures were used as supplemental starters in combination with a commercial lactic culture. These cheeses were analyzed for microbiological growth and survival, proteolysis, lactic acid development, free fatty acid appearance, and citric acid utilization—each being compared with a control cheese made without enterococci. Results were presented in three previous articles. This series is concluded with the results of organoleptic ana1ysis of the cheeses. Cheeses made with S. faecalis were either comparable to or less desirable than their respective control cheeses. Those made with S. durans, however, were in all instances more desirable than their controls. Cheeses cured at 7.2 C were always given the better scores, but there was no statistically significant difference between air- and brine-cooled cheeses.

LIPOLYTIC AND PROTEOLYTIC ACTIVITY OF ENTEROCOCCI AND LACTIC GROUP STREPTOCOCCI ISOLATED FROM YOUNG CHEDDAR CHEESE1

1970 ◽  
Vol 33 (9) ◽  
pp. 365-372 ◽  
Author(s):  
A. M. Dovat ◽  
G. W. Reinbold ◽  
E. G. Hammond ◽  
E. R. Vedamuthu
Keyword(s):  
Acetic Acid ◽  
Proteolytic Activity ◽  
Lipolytic Activity ◽  
Cheddar Cheese ◽  
Streptococcus Faecalis ◽  
Screening Techniques ◽  
Ph Values ◽  
Plate Counts

Lipolytic and proteolytic screening techniques were applied to cultures isolated from young Cheddar cheese manufactured in 10 Iowa cheese plants. Twenty-one cultures were selected for study. These included 16 enterococci and 5 lactic group streptococci. These strains were examined for lipolytic activity when grown in skimmilk, cream, and skimmilk containing tributyrin; changes in proteolysis index, plate counts, and pH in skimmilk incubated at 7, 15, 21, and 32 C also were determined, And, combinations of enterococci and lactic streptococci were studied. One-half of the Streptococcus durans strains frequently produced as much as 10 times more acetic acid than the others; the five strains of lactic streptococci consistently produced the lowest quantities of acetic acid. Compared with enterococci, except for Streptococcus faecalis var. liquefaciens, the lactic streptococci were more proteolytic, produced lower pH values, and had less viability at 15, 21, and 32 C. Enterococci other than S. faecalis var. liquefaciens were not proteolytic. All cultures showed tributyrinase activity; enterococci were the most active. Combining enterococci and lactic streptococci produced anomalous results.

ROLE OF ENTEROCOCCI IN CHEDDAR CHEESE: GROWTH OF ENTEROCOCCI DURING MANUFACTURE AND CURING1

1973 ◽  
Vol 36 (12) ◽  
pp. 613-618 ◽  
Author(s):  
Jane P. Jensen ◽  
G. W. Reinbold ◽  
c. J. Washam ◽  
E. R. Vedamuthu
Keyword(s):  
Cheddar Cheese ◽  
Rapid Decrease ◽  
Growth Patterns ◽  
Population Differences ◽  
Streptococcus Faecalis

Eight lots of Cheddar cheese were manufactured to determine the microbiological response of two strains each of Streptococcus faecalis and Streptococcus durans when used as supplemental starters in combination with a commercial lactic culture. Each lot consisted of a control vat of cheese manufactured with the lactic starter only, and an experimental vat of cheese containing the lactic starter and one of the enterococcus strains. Combinations of two curing temperatures ( 7.2 and 12.8 C) and two early cooling treatments (air vs. brine cooling) were used for cheeses from each vat to determine environmentally-induced variability. Growth patterns were monitored throughout the manufacture period up to the end of pressing, and during curing up to 6 months. Enterococcus populations showed little or no decrease when the cheeses were being pressed, whereas populations in control cheeses decreased over the same period. During curing, control cheeses cured at 7.2 C showed marked population decreases over the 6 months; those cured at 12.8 C showed a rapid decrease followed by an upsurge in population. Populations of S. faecalis in the experimental cheeses decreased only slightly, and S. durans showed almost no decrease. Generally, cheeses cured at 7.2 C showed the greatest numerical survival and there appeared to be no population differences caused by early cooling treatment.

scholarly journals Role of the Sortase A in the Release of Cell-Wall Proteinase PrtS in the Growth Medium of Streptococcus thermophilus 4F44

2021 ◽  
Vol 9 (11) ◽  
pp. 2380
Author(s):  
Ahoefa Ablavi Awussi ◽  
Emeline Roux ◽  
Catherine Humeau ◽  
Zeeshan Hafeez ◽  
Bernard Maigret ◽  
...  
Keyword(s):  
Cell Wall ◽  
Lactic Acid ◽  
Lactic Acid Bacterium ◽  
Proteolytic Activity ◽  
Growth Medium ◽  
Cell Envelope ◽  
Streptococcus Thermophilus ◽  
Sortase A ◽  
Cellular Density

Growth of the lactic acid bacterium Streptococcus thermophilus in milk depends on its capacity to hydrolyze proteins of this medium through its surface proteolytic activity. Thus, strains exhibiting the cell envelope proteinase (CEP) PrtS are able to grow in milk at high cellular density. Due to its LPNTG motif, which is possibly the substrate of the sortase A (SrtA), PrtS is anchored to the cell wall in most S. thermophilus strains. Conversely, a soluble extracellular PrtS activity has been reported in the strain 4F44. It corresponds, in fact, to a certain proportion of PrtS that is not anchored to the cell wall but rather is released in the growth medium. The main difference between PrtS of strain 4F44 (PrtS4F44) and other PrtS concerns the absence of a 32-residue imperfect duplication in the prodomain of the CEP, postulated as being required for the maturation and correct subsequent anchoring of PrtS. In fact, both mature (without the prodomain at the N-terminal extremity) and immature (with the prodomain) forms are found in the soluble PrtS4F44 form along with an intact LPNTG at their C-terminal extremity. Investigations we present in this work show that (i) the imperfect duplication is not implied in PrtS maturation; (ii) the maturase PrtM is irrelevant in PrtS maturation which is probably automaturated; and (iii) SrtA allows for the PrtS anchoring in S. thermophilus but the SrtA of strain 4F44 (SrtA4F44) displays an altered activity.

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.

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.

Role of Lactic Acid Probiotic Bacteria in IBD

2017 ◽  
Vol 23 (16) ◽  
Author(s):  
Ravichandra Vemuri ◽  
Rohit Gundamaraju ◽  
Rajaraman Eri
Keyword(s):  
Lactic Acid ◽  
Probiotic Bacteria

γ-Valerolactone-Introduced Controlled-Isomerization of Glucose for Lactic Acid Production over Sn-Beta Catalyst

2021 ◽  
Author(s):  
Xinpeng Zhao ◽  
Zhimin Zhou ◽  
hu luo ◽  
Yanfei Zhang ◽  
Wang Liu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Lactic Acid ◽  
Dft Calculations ◽  
Acid Production ◽  
Density Functional ◽  
Lactic Acid Production ◽  
Hydrothermal Conversion ◽  
Functional Theory ◽  
Environment Friendly

Combined experiments and density functional theory (DFT) calculations provided insights into the role of the environment-friendly γ-valerolactone (GVL) as a solvent in the hydrothermal conversion of glucose into lactic acid...

scholarly journals Biocomposites of Epoxidized Natural Rubber/Poly(lactic acid) Modified with Natural Fillers (Part I)

2021 ◽  
Vol 22 (6) ◽  
pp. 3150
Author(s):  
Anna Masek ◽  
Stefan Cichosz ◽  
Małgorzata Piotrowska
Keyword(s):  
Tensile Strength ◽  
Lactic Acid ◽  
Natural Rubber ◽  
Epoxidized Natural Rubber ◽  
Poly Lactic Acid ◽  
Uv Aging ◽  
High Elasticity ◽  
Natural Fillers ◽  
Natural Additives

The study aimed to prepare sustainable and degradable elastic blends of epoxidized natural rubber (ENR) with poly(lactic acid) (PLA) that were reinforced with flax fiber (FF) and montmorillonite (MMT), simultaneously filling the gap in the literature regarding the PLA-containing polymer blends filled with natural additives. The performed study reveals that FF incorporation into ENR/PLA blend may cause a significant improvement in tensile strength from (10 ± 1) MPa for the reference material to (19 ± 2) MPa for the fibers-filled blend. Additionally, it was found that MMT employment in the role of the filler might contribute to ENR/PLA plasticization and considerably promote the blend elongation up to 600%. This proves the successful creation of the unique and eco-friendly PLA-containing polymer blend exhibiting high elasticity. Moreover, thanks to the performed accelerated thermo-oxidative and ultraviolet (UV) aging, it was established that MMT incorporation may delay the degradation of ENR/PLA blends under the abovementioned conditions. Additionally, mold tests revealed that plant-derived fiber addition might highly enhance the ENR/PLA blend’s biodeterioration potential enabling faster and more efficient growth of microorganisms. Therefore, materials presented in this research may become competitive and eco-friendly alternatives to commonly utilized petro-based polymeric products.

Sign in / Sign up

Export Citation Format

Share Document