Effect of Fermentation on the Protein Digestibility and Levels of Non-Nutritive Compounds of Pea Protein Concentrate
1Department of Food and Bioproduct Sciences, University of Saskatchewan, 51 Campus Dr., Saskatoon, SK, S7N 5A8, Canada
2Department of Human Nutritional Sciences, Department of Food Science, Department of Animal Science, Canadian Centre for Agri-Food Research in Health and Medicine, Richardson Centre for Functional Foods and Nutraceuticals, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
Received: 30 July 2017
Accepted: 28 February 2018
pea protein concentrate, fermentation, non-nutritive compounds, protein digestibility, protein quality
In order to determine the impact of fermentation on protein quality, pea protein concentrate (PPC) was fermented with Lactobacillus plantarum for 11 h and total phenol and tannin contents, protease inhibitor activity, amino acid composition and in vitro protein digestibility were analyzed. Phenol levels, expressed as catechin equivalents (CE), increased on dry mass basis from 2.5 at 0 h to 4.9 mg CE per 1 g of PPC at 11 h. Tannin content rose from 0.14 at 0 h to a maximum of 0.96 mg CE per 1 g of PPC after 5 h, and thereafter declined to 0.79 mg/g after 11 h. After 9 h of fermentation trypsin inhibitor activity decreased, however, at all other fermentation times similar levels to the PPC at time 0 h were produced. Chymotrypsin inhibitor activity decreased from 3.7 to 1.1 chymotrypsin inhibitory units (CIU) per mg following 11 h of fermentation. Protein digestibility reached a maximum (87.4 %) after 5 h of fermentation, however, the sulfur amino acid score was reduced from 0.84 at 0 h to 0.66 at 11 h. This reduction in sulfur content altered the in vitro protein digestibility-corrected amino acid score from 67.0 % at 0 h to 54.6 % at 11 h. These data suggest that while fermentation is a viable method of reducing certain non-nutritive compounds in pea protein concentrate, selection of an alternative bacterium which metabolises sulfur amino acids to a lesser extent than L. plantarum should be considered.
*Corresponding author: +13069665030