Digestion Resistance of Soybean 7S Protein and Its Implications for Reinforcing the Gastric Mucus Barrier

J Agric Food Chem. 2022 Jul 20;70(28):8776-8787. doi: 10.1021/acs.jafc.2c02603. Epub 2022 Jul 8.

Abstract

Previous studies have found that soybean protein, especially soybean 7S protein (β-conglycinin), exhibits digestion resistance, but the mechanism of digestion resistance and its implications for human health are still unclear. Here, we show that the extracted soybean 7S protein contains both oligomer globulins and amyloid aggregates, while the gastric digested soybean 7S protein only contains amyloid aggregates and thus exhibits digestion resistance. An animal experiment shows that un-digestible soybean 7S protein effectively prevents aspirin-induced acute gastric mucosa damage. The impacts of un-digestible soybean 7S protein on gastric mucus barrier properties are investigated using quartz crystal microbalance with dissipation (QCM-D), Langmuir monolayer, and multiple particle tracking (MPT). Results show that these un-digestible protein aggregates can penetrate into gastric mucus, increase the viscosity and compactness of the mucin layer, and reinforce the gastric mucus barrier properties. The findings are helpful to understand that high consumption of non-fermented soybean foods is associated with a decreased risk of gastric cancer.

Keywords: amyloid aggregates; digestion resistance; gastric cancer; mucus barrier properties; soybean 7S protein.

MeSH terms

  • Animals
  • Antigens, Plant / chemistry
  • Aspirin / adverse effects
  • Digestion
  • Gastric Mucosa* / drug effects
  • Gastric Mucosa* / pathology
  • Globulins* / chemistry
  • Glycine max / chemistry
  • Mucus / chemistry
  • Quartz Crystal Microbalance Techniques
  • Seed Storage Proteins* / chemistry
  • Soybean Proteins* / chemistry

Substances

  • Antigens, Plant
  • Globulins
  • Seed Storage Proteins
  • Soybean Proteins
  • Aspirin