Relation between proteolysis and astringent off-flavor in milk

Pasteurized skim milk was treated with 10 proteinases from psychrotrophic bacteria and with plasmin, the naturally occurring milk proteinase, and evaluated organoleptically for astringency. At comparable levels of digestion (extent of proteolysis equivalent to approximately 0.5 micromole/ml of glyci...

Full description

Saved in:
Bibliographic Details
Published in:Journal of dairy science 1993-09, Vol.76 (9), p.2521-2527
Main Authors: Harwalkar, V.R, Cholette, H, McKellar, R.C, Emmons, D.B
Format: Article
Language:English
Subjects:
AROMA
Biological and medical sciences
CASEINA
CASEINE
CHROMATOGRAPHIE
CROMATOGRAFIA
FLAVEUR
Food industries
Fundamental and applied biological sciences. Psychology
LAIT
LAIT ECREME
LECHE
LECHE DESNATADA
Milk and cheese industries. Ice creams
PLASMINA
PLASMINE
PROTEOLISIS
PROTEOLYSE
PSEUDOMONAS FLUORESCENS
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Pasteurized skim milk was treated with 10 proteinases from psychrotrophic bacteria and with plasmin, the naturally occurring milk proteinase, and evaluated organoleptically for astringency. At comparable levels of digestion (extent of proteolysis equivalent to approximately 0.5 micromole/ml of glycine), milk samples treated with plasmin and 5 psychrotrophic proteinases produced varying astringencies. All of the treated samples were extracted by 2:1 (vol/vol) mixtures of chloroform: methanol, and the isolated compounds were analyzed by fast protein liquid chromatography on an anion-exchange column and urea-PAGE. Both methods of analysis showed increased concentrations of gamma-casein only in the extracts from astringent samples. The samples treated with psychrotroph proteinase that were not astringent apparently were digested nonspecifically into smaller peptides. Thus, astringent off-flavor has been linked to the production of gamma-caseins, which are specific C-terminal breakdown products of beta-casein (cleavage of peptide bond between residues 28 to 29, 105 to 106, and 107 to 108); treatment of purified beta-casein with plasmin also produced astringent compounds
ISSN:0022-0302
1525-3198
DOI:10.3168/jds.S0022-0302(93)77587-6