4726954 Lipolytic enzyme derived from a aspergillus microorganism having an accelerating effect on cheese flavor development

1988 ◽  
Vol 6 (2) ◽  
pp. 253
Keyword(s):  
Lipolytic Enzyme ◽  
Cheese Flavor ◽  
Flavor Development

scholarly journals Heterologous Production of Methionine-γ-Lyase from Brevibacterium linens in Lactococcus lactis and Formation of Volatile Sulfur Compounds

2009 ◽  
Vol 75 (8) ◽  
pp. 2326-2332 ◽  
Author(s):  
Sean B. Hanniffy ◽  
Mark Philo ◽  
Carmen Peláez ◽  
Michael J. Gasson ◽  
Teresa Requena ◽  
...  
Keyword(s):  
Lactococcus Lactis ◽  
Sulfur Compounds ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Volatile Sulfur Compounds ◽  
Brevibacterium Linens ◽  
Cell Extracts ◽  
Cheese Flavor ◽  
Flavor Development ◽  
Volatile Sulfur

ABSTRACT The conversion of methionine to volatile sulfur compounds (VSCs) is of great importance in flavor formation during cheese ripening and is the focus of biotechnological approaches toward flavor improvement. A synthetic mgl gene encoding methionine-γ-lyase (MGL) from Brevibacterium linens BL2 was cloned into a Lactococcus lactis expression plasmid under the control of the nisin-inducible promoter PnisA. When expressed in L. lactis and purified as a recombinant protein, MGL was shown to degrade l-methionine as well as other sulfur-containing compounds such as l-cysteine, l-cystathionine, and l-cystine. Overproduction of MGL in recombinant L. lactis also resulted in an increase in the degradation of these compounds compared to the wild-type strain. Importantly, gas chromatography-mass spectrometry analysis identified considerably higher formation of methanethiol (and its oxidized derivatives dimethyl disulfide and dimethyl trisulfide) in reactions containing either purified protein, whole cells, or cell extracts from the heterologous L. lactis strain. This is the first report of production of MGL from B. linens in L. lactis. Given their significance in cheese flavor development, the use of lactic acid bacteria with enhanced VSC-producing abilities could be an efficient way to enhance cheese flavor development.

scholarly journals Overexpression of Lactobacillus caseid-Hydroxyisocaproic Acid Dehydrogenase in Cheddar Cheese

2004 ◽  
Vol 70 (8) ◽  
pp. 4814-4820 ◽  
Author(s):  
Jeffery R. Broadbent ◽  
Sanjay Gummalla ◽  
Joanne E. Hughes ◽  
Mark E. Johnson ◽  
Scott A. Rankin ◽  
...  
Keyword(s):  
Aromatic Amino Acids ◽  
Cheddar Cheese ◽  
Flavor Compounds ◽  
Gas Chromatography Mass Spectrometry ◽  
Keto Acid ◽  
Acid Dehydrogenase ◽  
Keto Acids ◽  
Cheese Flavor ◽  
Enhanced Expression ◽  
Flavor Development

ABSTRACT Metabolism of aromatic amino acids by lactic acid bacteria is an important source of off-flavor compounds in Cheddar cheese. Previous work has shown that α-keto acids produced from Trp, Tyr, and Phe by aminotransferase enzymes are chemically labile and may degrade spontaneously into a variety of off-flavor compounds. However, dairy lactobacilli can convert unstable α-keto acids to more-stable α-hydroxy acids via the action of α-keto acid dehydrogenases such as d-hydroxyisocaproic acid dehydrogenase. To further characterize the role of this enzyme in cheese flavor, the Lactobacillus casei d-hydroxyisocaproic acid dehydrogenase gene was cloned into the high-copy-number vector pTRKH2 and transformed into L. casei ATCC 334. Enzyme assays confirmed that α-keto acid dehydrogenase activity was significantly higher in pTRKH2:dhic transformants than in wild-type cells. Reduced-fat Cheddar cheeses were made with Lactococcus lactis starter only, starter plus L. casei ATCC 334, and starter plus L. casei ATCC 334 transformed with pTRKH2:dhic. After 3 months of aging, the cheese chemistry and flavor attributes were evaluated instrumentally by gas chromatography-mass spectrometry and by descriptive sensory analysis. The culture system used significantly affected the concentrations of various ketones, aldehydes, alcohols, and esters and one sulfur compound in cheese. Results further indicated that enhanced expression of d-hydroxyisocaproic acid dehydrogenase suppressed spontaneous degradation of α-keto acids, but sensory work indicated that this effect retarded cheese flavor development.

scholarly journals Cooperation between Lactococcus lactis and Nonstarter Lactobacilli in the Formation of Cheese Aroma from Amino Acids

2003 ◽  
Vol 69 (2) ◽  
pp. 734-739 ◽  
Author(s):  
Agnieszka Kieronczyk ◽  
Siv Skeie ◽  
Thor Langsrud ◽  
Mireille Yvon
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Carboxylic Acids ◽  
Lactococcus Lactis ◽  
Cheese Flavor ◽  
Major Process ◽  
Flavor Development ◽  
Cheese Aroma

ABSTRACT In Gouda and Cheddar type cheeses the amino acid conversion to aroma compounds, which is a major process for aroma formation, is essentially due to lactic acid bacteria (LAB). In order to evaluate the respective role of starter and nonstarter LAB and their interactions in cheese flavor formation, we compared the catabolism of phenylalanine, leucine, and methionine by single strains and strain mixtures of Lactococcus lactis subsp. cremoris NCDO763 and three mesophilic lactobacilli. Amino acid catabolism was studied in vitro at pH 5.5, by using radiolabeled amino acids as tracers. In the presence of α-ketoglutarate, which is essential for amino acid transamination, the lactobacillus strains degraded less amino acids than L. lactis subsp. cremoris NCDO763, and produced mainly nonaromatic metabolites. L. lactis subsp. cremoris NCDO763 produced mainly the carboxylic acids, which are important compounds for cheese aroma. However, in the reaction mixture containing glutamate, only two lactobacillus strains degraded amino acids significantly. This was due to their glutamate dehydrogenase (GDH) activity, which produced α-ketoglutarate from glutamate. The combination of each of the GDH-positive lactobacilli with L. lactis subsp. cremoris NCDO763 had a beneficial effect on the aroma formation. Lactobacilli initiated the conversion of amino acids by transforming them mainly to keto and hydroxy acids, which subsequently were converted to carboxylic acids by the Lactococcus strain. Therefore, we think that such cooperation between starter L. lactis and GDH-positive lactobacilli can stimulate flavor development in cheese.

scholarly journals Cheese Flavor Development Using Direct Acidified Curd

1972 ◽  
Vol 55 (6) ◽  
pp. 744-749 ◽  
Author(s):  
S. Singh ◽  
T. Kristoffersen
Keyword(s):  
Cheese Flavor ◽  
Flavor Development

Microbial Non-Coagulant Enzymes Used in Cheese Making

2018 ◽  
pp. 204-221
Author(s):  
Ekaterini Moschopoulou
Keyword(s):  
Cross Linking ◽  
Peptide Bonds ◽  
Cheese Making ◽  
Cheese Ripening ◽  
Cheese Texture ◽  
Cheese Flavor ◽  
Flavor Development ◽  
Microbial Lipases ◽  
Bacteria And Fungi ◽  
Almost All

In this chapter, the use of microbial non-coagulant proteases, microbial lipases, and microbial transglutaminase in the cheese making procedure is discussed. Microbial proteases and lipases have been used for over 30 years to accelerate cheese ripening and consequently to enhance the cheese flavor development by increasing proteolysis and lipolysis level in a shorter time. They are commercially produced by bacteria and fungi species. Transglutaminase is a relative new enzyme, which catalyzes the cross-linking of peptide bonds and helps to improve the cheese texture and to increase the cheese yield. Today, cheeses from almost all cheese categories are produced using these enzymes.

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