TY - JOUR

T1 - Simulated gastrointestinal digestion of protein alginate complexes

T2 - effects of whey protein cross-linking and the composition and degradation of alginate

AU - Madsen, Mikkel

AU - Ronne, Mette E.

AU - Li, Ruifen

AU - Greco, Ines

AU - Ipsen, Richard

AU - Svensson, Birte

PY - 2022

Y1 - 2022

N2 - Alginate and whey protein are common additives in food production improving storage stability, texture and nutritional value. Alginate forms complexes with whey protein and inhibits proteolysis by pepsin and trypsin, but the influence of alginate protein complexation on digestion is poorly understood. This study shows that whey protein cross-linking by microbial transglutaminase dramatically decreased particle size (2-fold) and viscosity of alginate protein complexes. The INFOGEST in vitro simulated gastrointestinal digestion of whey protein was increased by cross-linking (16%) and suppressed by alginate, most pronounced with high mannuronic acid and least with high guluronic acid content. Sizes of alginate whey protein particles increased during gastric digestion, whereas for cross-linked whey protein complexes the size initially increased, but returned to their initial size at the end of gastric digestion. While alginate is not degraded by human enzymes, a few gut bacteria were recently found to encode lyases and other enzymes metabolizing alginate. Alginate lyase added to the intestinal phase enhanced digestion (9%) as controlled by alginate composition and enzyme specificity. Thus we provide evidence that use of hydrocolloids and processing of protein strongly influence digestion and should be considered when using food additives.

AB - Alginate and whey protein are common additives in food production improving storage stability, texture and nutritional value. Alginate forms complexes with whey protein and inhibits proteolysis by pepsin and trypsin, but the influence of alginate protein complexation on digestion is poorly understood. This study shows that whey protein cross-linking by microbial transglutaminase dramatically decreased particle size (2-fold) and viscosity of alginate protein complexes. The INFOGEST in vitro simulated gastrointestinal digestion of whey protein was increased by cross-linking (16%) and suppressed by alginate, most pronounced with high mannuronic acid and least with high guluronic acid content. Sizes of alginate whey protein particles increased during gastric digestion, whereas for cross-linked whey protein complexes the size initially increased, but returned to their initial size at the end of gastric digestion. While alginate is not degraded by human enzymes, a few gut bacteria were recently found to encode lyases and other enzymes metabolizing alginate. Alginate lyase added to the intestinal phase enhanced digestion (9%) as controlled by alginate composition and enzyme specificity. Thus we provide evidence that use of hydrocolloids and processing of protein strongly influence digestion and should be considered when using food additives.

KW - VITRO GASTRIC DIGESTION

KW - IN-VITRO

KW - CRYSTAL-STRUCTURE

KW - ACID

KW - LYASE

KW - FOOD

KW - SUPPLEMENTATION

KW - FRACTIONATION

KW - STABILITY

KW - GELS

U2 - 10.1039/d2fo01256a

DO - 10.1039/d2fo01256a

M3 - Journal article

C2 - 35848445

VL - 13

SP - 8375

EP - 8387

JO - Food & Function

JF - Food & Function

SN - 2042-6496

IS - 16

ER -