Proteolysis and biogenic amine formation in sterilized Edam-type curd slurry inoculated with probiotic strains

Abstract

Edam-type curd slurry inoculated with 1% Lactococcus lactis subsp. lactis KF147 as control and further added with Propionibacterium shermanii PS-4 + Bifidobacterium bifidum DSM 20082 (1:1), P. shermanii PS-4 + Lactobacil- lus acidophilus ATCC4356 or P. shermanii PS-4 + B. bifidum DSM 20082 + Lacto- bacillus acidophilus ATCC4356 (1:1:1), at a rate of 1%, were studied for their effect upon biogenic amine and proteolysis pattern during incubation at 30C for 21 days. Results showed no significant influence of any combination of probiotic microorganisms on total solids, salt and fat of Edam-type curd slurries, but some effect on pH and soluble nitrogen fractions; presence of P. shermanii + B. bifidum + Lactobacillus acidophilus led to the highest concentration (7.9%) of water-soluble nitrogen by the end of incubation. When inoculation included B. bifidum, a significant decrease in total biogenic amines (from 447 to 37 mg/ kgDW) was observed by 21 days - with histamine decreasing from 84 to 25 and tyramine from 359 to 6 mg/kgDW.