Characteristics of viable Brevibacterium linens cells, methionine and cysteine in milkfat-coated microcapsules

Abstract

The potential for microencapsulation of viable Brevibacterium linens with methionine or cysteine in milkfat to produce sulphur compounds was examined in this study. More than 80 per cent of B. linens cells were encapsulated and then numbers inside capsules increased about three-fold during 48 h at 26d`C under anaerobic conditions before a slow decline. Most of micro-organisms (7 × 10<sup>7</sup>/ml) were still viable in the capsules after 15 days. More than 90 per cent of cysteine and methionine were encapsulated and 90, 80 and 60 per cent of the encapsulated amino acids were maintained in the capsules at 4, 12 and 26d`C, respectively, after 24 h. Most of the cysteine was oxidized to cystine during microencapsulation but still available to micro-organisms whereas methionine remained in the reduced form. Partition coefficients of methionine and cysteine to milkfat were 0.117 and 0.275, respectively, indicating that most of these substrates would be available to cells of B. linens in the capsules.