Effect of Aminopeptidase Activity of Thermophilic Lactobacilli on Emmental Cheese Characteristics

• Published in: Journal of dairy science Vol. 77; no. 1; pp. 24 - 33
• Main Authors: Prost, Florence, Chamba, Jean Francois
• Format: Journal Article
• Language: English
• Published: Savoy, IL Elsevier Inc 01.01.1994; Am Dairy Sci Assoc; American Dairy Science Association
• Subjects: ACIDIFICACION; ACIDIFICATION; ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; aminopeptidase activity; AROMA; BACTERIA; Biological and medical sciences; bitterness; CONTENIDO DE NITROGENO; CULTIVOS INICIADORES; CULTURE STARTER; DIFERENCIAS BIOLOGICAS; DIFFERENCE BIOLOGIQUE; FLAVEUR; Food industries; FROMAGE; Fundamental and applied biological sciences. Psychology; LACTOBACILLUS HELVETICUS; MADURAMIENTO; MICROORGANISME THERMOPHILE; MICROORGANISMOS TERMOFILOS; Milk and cheese industries. Ice creams; MURISSAGE; ODEUR; OLOR; PEPTIDASAS; PEPTIDASE; PEPTIDE; PEPTIDOS; QUESO; TENEUR EN AZOTE; TEXTURA; TEXTURE; thermophiiic lactobacilli; NTG; aminopeptidase activity; thermophiiic lactobacilli; p-NA; bitterness; AP; Lactobacillus helveticus; Enzymatic activity; Aminopeptidases; Bitter taste; Bacteria; Lactobacillaceae; Emmental; Mutation
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(94)76924-1

Cheeses were made with Lactobacillus helveticus strain L1, which has high aminopeptidase activity, and two clones (L2, L3), selected for their lack of aminopeptidase activity. Strains L2 and L3 were obtained from L1 by mutagenesis. The differences observed in cheese were essentially due to the variation of the aminopeptidase activity, the only parameter varying according to treatments. The physicochemical analyses of cheeses showed no differences in acidification, moisture of curd, and casein degradation. Differences between ripened cheeses were observed only by sensorial analysis; cheeses made with aminopeptidase-deficient lactobacilli (L2, L3) were more stiff and more bitter than those made with L1. The mutants should not be considered as bitter peptide-producing clones, but rather as allowing an accumulation of this kind of peptides in cheeses. These results explain the bitterness in ripened cheeses made with some strains or species of Lactobacillus (e.g., Lactobacillus delbrueckii ssp. lactis) that have a very low aminopeptidase activity. Therefore, the aminopeptidase activity must be controlled when strains of lactic acid bacteria are intended for manufacture of cheese.