scholarly journals On the Nitrogen Nutrition of Silage Strains of Lactic Acid Bacteria

1966 ◽  
Vol 19 (1) ◽  
pp. 105 ◽  
Author(s):  
CJ Brady
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Free Amino Acids ◽  
Free Amino ◽  
Nitrogen Nutrition ◽  
Synthetic Medium ◽  
Post Harvest ◽  
Synthetic Media ◽  
Time Of Harvest

Consideration is given to the adequacy of the free amino acids in plant juices at the time of harvest as nitrogen substrate for strains of lactic acid bacteria isolated from silage. The requirements of several strains of the bacteria for free amino acids in synthetic media were compared with the concentration of these acids in the liquid phase of plants at the time of harvest; this comparison suggested that several amino acids, and particulady lysine, may at times be rate.limiting. Ethanolic extracts of plants, sampled before and after a period of post-harvest wilting, were assayed as nitrogen substrates for the bacteria. A marked response to additions of lysine, some response to arginine, and evidence of deficiency of other acids were noted. The importance of post-harvest proteolysis to the amino acid nutrition of the bacteria in the silage environment is discussed. Certain fractions of the plant extracts were found to promote early growth of the bacteria in the synthetic medium, and the distribution of this activity in different fractions is described.

Influence of thermophilic lactic acid bacteria strains on propionibacteria growth and lactate consumption in an Emmental juice-like medium

1999 ◽  
Vol 66 (1) ◽  
pp. 105-113 ◽  
Author(s):  
ANNE THIERRY ◽  
DELPHINE SALVAT-BRUNAUD ◽  
JEAN-LOUIS MAUBOIS
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Free Amino Acids ◽  
Free Amino ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Helveticus ◽  
The Media ◽  
Lactate Consumption ◽  
Thermophilic Lactic Acid Bacteria

Swiss-type cheeses such as Emmental are characterized by the successive development of thermophilic lactic acid bacteria (TLAB) and propionibacteria. The aim of this study was to determine whether the choice of TLAB strain influenced propionibacteria. TLAB and propionibacteria were cultured sequentially under the conditions prevailing in cheese. Firstly, 11 Emmental juice-like media were prepared by fermenting casein-enriched milk with pure or mixed cultures of TLAB (Lactobacillus helveticus, Lb. delbrueckii subsp. lactis and Streptococcus thermophilus), differing in their proteolytic activities. TLAB cells were then removed by microfiltration. Finally, five strains of Propionibacterium freudenreichii were grown on these media at 24°C under anaerobiosis and their growth characteristics and lactate consumption determined. The media mainly differed in their contents of peptides (1·9–5·3 g/kg) and free amino acids (1·0–5·6 g/kg) and the proportions of lactate isomers (42–92% of the L(+) isomer). Propionibacteria were significantly (P<0·05) influenced by TLAB strains (differences in doubling times of up to 20% and differences in lactate consumption after 600 h culture of up to 52%). The influence of TLAB was similar for all the propionibacteria tested, depended on the TLAB strains and could not be generalized to the TLAB species. Propionibacteria were stimulated by high peptide levels, low levels of free amino acids and NaCl, a low proportion of L(+)-lactate and other undetermined factors. However, variations due to TLAB were less than those between propionibacteria strains.

Accelerated ripening of Pecorino Umbro cheese

1998 ◽  
Vol 65 (4) ◽  
pp. 631-642 ◽  
Author(s):  
ALDO CORSETTI ◽  
MARCO GOBBETTI ◽  
EMANUELE SMACCHI ◽  
MARIA DE ANGELIS ◽  
JONE ROSSI
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Free Amino ◽  
Trichloroacetic Acid ◽  
Short Peptides ◽  
Accelerated Ripening ◽  
Total Free Amino Acids ◽  
Biochemical Analyses ◽  
Dipeptidase Activities

We have investigated accelerating the ripening of Pecorino Umbro cheese by adding crude cytoplasmic extract from Pseudomonas fluorescens, non-starter lactic acid bacteria (NSLAB) or cheese slurry. Microbiological and biochemical analyses and sensory evaluation were carried out on control and experimental cheeses over 28 d ripening. In the cheeses containing NSLAB or slurry, counts of mesophilic lactobacilli ranged from log 7·6 at day 1 to ∼log 8·6 cfu/g after 28 d ripening, ∼2 log cycles higher than in the control cheese. All the experimental cheeses contained higher levels than the control of total free amino acids and N soluble at pH 4·6 and in 120 g trichloroacetic acid/l. Compared with the control, higher aminopeptidase and dipeptidase activities were found in the cheeses containing NSLAB and slurry, and especially in those containing the Pseudomonas enzyme. The cheeses containing NSLAB or slurry were characterized by an accumulation of short peptides (Mr<2000) detected by FPLC. Although the cheese containing enzyme had an atypical flavour, the addition of mesophilic lactobacilli reduced from 60 to 28 d the ripening period of Pecorino Umbro cheese, without the appearance of off flavour.

scholarly journals Evaluation of the Effect of Auxiliary Starter Yeasts With Enzyme Activities on Kazak Cheese Quality and Flavor

2020 ◽  
Vol 11 ◽  
Author(s):  
Jing Xiao ◽  
Yu Chen ◽  
Jie Li ◽  
Xuewei Shi ◽  
Li Deng ◽  
...  
Keyword(s):  
Amino Acids ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Enzyme Activities ◽  
Free Amino Acids ◽  
Free Amino ◽  
Isoamyl Acetate ◽  
Pichia Kudriavzevii ◽  
Phenethyl Acetate ◽  
Cheese Production

To investigate the effect of yeasts on Kazak cheese quality and flavor, three isolated yeasts (Kluyveromyces marxianus A2, Pichia kudriavzevii A11, and Pichia fermentans A19) were used to ferment cheeses and designated as StC, LhC, and WcC, respectively. The cheese fermented with a commercial lactic acid starter without adding yeast was used as control named LrC. The results showed that the texture of cheese added with yeasts were more brittle. K. marxianus A2 contributed to the formation of free amino acids and organic acids, especially glutamate and lactic acid. Moreover, K. marxianus A2 provides cheese with onion, oily, and floral aromas. Furthermore, P. kudriavzevii A11 promotes a strong brandy, herbaceous, and onion flavor. Although no significant aroma change was observed in PfC, it promoted the production of acetic acid, isoamyl acetate, and phenethyl acetate. These results indicate that yeasts are important auxiliary starters for cheese production.

Changes in the free amino acids and the biogenic amine contents during lactic acid fermentation of different lupin species

2016 ◽  
Vol 51 (9) ◽  
pp. 2049-2056 ◽  
Author(s):  
Elena Bartkiene ◽  
Vadims Bartkevics ◽  
Janis Rusko ◽  
Vytaute Starkute ◽  
Daiva Zadeike ◽  
...  
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Biogenic Amine ◽  
Free Amino Acids ◽  
Free Amino ◽  
Lactic Acid Fermentation ◽  
Acid Fermentation

scholarly journals Characterization of the taste compounds in 20 pungent spices by high-performance liquid chromatography

2020 ◽  
Author(s):  
Yan Huang ◽  
Wen Duan ◽  
Junfei Xiao ◽  
He Liu ◽  
Chenchen Zhou ◽  
...  
Keyword(s):  
Amino Acids ◽  
High Performance Liquid Chromatography ◽  
Lactic Acid ◽  
Liquid Chromatography ◽  
Organic Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
High Performance ◽  
Total Free Amino Acids

AbstractHigh-performance liquid chromatography was used to determine the important taste compounds in 20 pungent spices commonly used in food, including seventeen free amino acids, four 5′-nucleotides and twelve organic acids. The equivalent umami concentration (EUC) and taste activity value (TAV) of the analyzed samples were calculated. The results showed that the content of total free amino acids ranged from 0.57 to 46.67 g/kg in 20 pungent spices. The content of total free amino acids in horseradish was the highest. The content of total 5′-nucleotides ranged from 0.80 to 4.30 g/kg, and chive contains the highest 5′-nucleotide content. Inosine 5′-monophosphate was detected in all 20 pungent spices. The content of total organic acids ranged from 9.37 to 339.58 g/kg. The total organic acids content of fieldmint was the highest (339.58 g/kg). Oxalic acid was detected in 18 pungent spices, except white pepper and chilli. The EUC of fieldmint (37.1 g MSG/100 g) was the highest in all 20 pungent spices, followed with peppermint (24.5 g MSG/100 g), and horseradish (18.4 g MSG/100 g). The TAVs of malic acid, lactic acid and 5′-AMP were higher than 1 in more than 10 spices. Lactic acid were higher than 1 in 13 spices, implying these compounds contributed greater to the flavor of pungent spices. The results of this work will provide references for the application value of pungent spices.

Hydrolysis of fat and protein in small cheeses made under aseptic conditions

1969 ◽  
Vol 36 (1) ◽  
pp. 65-76 ◽  
Author(s):  
B. Reiter ◽  
Y. Sorokin ◽  
A. Pickering ◽  
A. J. Hall
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Ph Value ◽  
Low Ph ◽  
The Other ◽  
Feeding Regime ◽  
Aseptic Conditions ◽  
Hydrolysis Of

SummaryAseptically drawn milk was made into small cheeses (100 g) under aseptic conditions. The influence of the cow's feeding régime on the composition of the cheese fat, and the hydrolysis of the cheese fat and protein by bacterial and native milk enzymes, was studied.In the absence of a strongly lipolytic bacterial cheese flora, the free fatty acid (FFA) content of cheese appeared to depend on several variables:1. The initial FFA content of the milk varied according to the mode of milking (the lowest was obtained by cannulation of the udder) and the feeding régime of the cow. When one of a pair of monozygotic twin cows was maintained on pasture and the other on winter feed (hay and concentrates), the cheese made from the milk of the latter contained less FFA than did that from the former.2. The major changes in the composition of the milk fat of the cows on winter regime were an increase of myristic and palmitic acids from 8 to 11% and 21 to 28%, respectively, and a decrease in stearic and oleic acid from 11 to 7·5% and 38 to 28%; minor changes in the other fatty acids were also observed.3. The milk lipase in raw milk cheese liberated substantially more FFA than did the weakly lipolytic lactic acid streptococci. Milk lipase was active at the low pH value of cheese, but was inactivated when the milk was pasteurized at 63°C for 30 min.4. Although rennet did not produce any amino acids in the mature cheeses it hydrolysed some of the cheese protein to nitrogen soluble in water (WS), trichloroacetic acid (TCA-S) or phosphotungstic acid (PTA-S). Some of the WS-N appeared to be utilized by the lactic acid streptococci. The native milk protease resisted the heat treatment used and liberated amino acids at the low pH value of cheese, but its contribution to the proteolysis was relatively less important than the contribution of the milk lipase to the fat breakdown in cheese.5. The free amino acids of the milk, which appeared in the whey, were not recovered in the cheese. The cheese made from unheated milk with δ-gluconic acid lactone contained low amounts of free amino acids apparently due to the action of milk protease. The proteolytic activity of the lactic acid bacteria increased the amino acid content appreciably.

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