Evaluating Brewers' Spent Grain Protein Isolate Postprandial Amino Acid Uptake Kinetics: A Randomized, Cross-Over,...

Area of Science:

• Food Science
• Nutritional Biochemistry
• Sustainable Food Systems

Background:

• Brewers' spent grain (BSG) is a major byproduct of the brewing industry, presenting an opportunity for valorization.
• Upcycling BSG into valuable protein ingredients aligns with food waste reduction and sustainable food system goals.

Purpose of the Study:

• To evaluate the nutritional value of upcycled barley/rice proteins (BRP) derived from BSG.
• To compare the postprandial amino acid (AA) uptake kinetics of BRP with pea proteins (PP) and whey protein (WP).

Main Methods:

• A randomized, cross-over, double-blind controlled trial involving twelve participants.
• Participants consumed 20g of BRP, PP, or WP during three separate visits with washout periods.
• Postprandial blood samples were analyzed for free amino acid concentrations to determine uptake kinetics.

Main Results:

• Upcycled barley/rice proteins (BRP) demonstrated an estimated total amino acid (TAA) uptake of 69% relative to whey protein (WP) and 87% relative to pea proteins (PP).
• The time to reach maximum amino acid values was comparable across all three protein sources.
• BRP showed higher postprandial responses for methionine and tryptophan but lower responses for lysine, histidine, and isoleucine compared to PP.

Conclusions:

• Upcycled barley/rice proteins (BRP) exhibit comparable postprandial total amino acid uptake kinetics to pea proteins (PP).
• The amino acid profiles suggest a complementary relationship between BRP and PP.
• Blending BRP and PP could be a strategy to optimize protein quality for health benefits.