Diversity in growth and protein degradation by diary relevant lactic acid bacteria species in reconstituted whey.

M. PESCUMA; E. HEBERT; E. BRU; G. FONT DE VALDEZ; F. MOZZI

Journal of Dairy Research

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2012 vol. 79 p. 201 - 208

0022-0299

The high nutritional value of whey makes it an interesting substrate for the development of fermented 8 foods. The aim of this work was to evaluate the growth and proteolytic activity of sixty-four strains of 9 lactic acid bacteria in whey to further formulate a starter culture for the development of fermented 10 whey-based beverages. Fermentations were performed at 37 °C for 24 h in 10 and 16% (w/v) 11 reconstituted whey powder. Cultivable populations, pH, and proteolytic activity (o-phthaldialdehyde 12 test) were determined at 6 and 24 h incubation. Hydrolysis of whey proteins was analysed by Tricine 13 SDS-PAGE. A principal component analysis (PCA) was applied to evaluate the behaviour of strains. 14 Forty-six percent of the strains grew between 1 and 2 Δlog CFU/ml while 19% grew less than 15 0·9 Δlog CFU/ml in both reconstituted whey solutions. Regarding the proteolytic activity, most of the 16 lactobacilli released amino acids and small peptides during the first 6 h incubation while streptococci 17 consumed the amino acids initially present in whey to sustain growth. Whey proteins were degraded 18 by the studied strains although to different extents. Special attention was paid to the main allergenic 19 whey protein, β-lactoglobulin, which was degraded the most by Lactobacillus acidophilus CRL 636 20 and Lb. delbrueckii subsp. bulgaricus CRL 656. The strain variability observed and the PCA applied in 21 this study allowed selecting appropriate strains able to improve the nutritional characteristics (through 22 amino group release and protein degradation) and storage (decrease in pH) of whey.