Modification of Functional, Antioxidant, and Anti-Allergic Properties of Fermented Silkworm Pupae Protein During In Vitro Gastrointestinal Digestion.

Silkworm pupae protein (SPP) is a promising alternative protein, but its application is limited by allergenicity and suboptimal functionality. Here, SPP was fermented with Lactiplantibacillus plantarum Z4 and subjected to in vitro gastrointestinal digestion to evaluate the stability and bioaccessibility of its functional properties. Fermentation increased the degree of hydrolysis, α-helix content, surface hydrophobicity, and free sulfhydryl content, indicating structural rearrangement. Emulsion stability was improved, whereas foaming capacity, foam stability, and emulsifying activity were unchanged. Fermentation also enhanced antioxidant activity and reduced allergenicity-related responses. After digestion, both unfermented and fermented samples showed higher antioxidant activity and lower allergenicity-related responses, while fermented digests generally showed greater antioxidant activity and lower IgE-inhibition activity than the corresponding unfermented digests. These findings suggest that Z4 fermentation acts as a pre-digestion modification strategy that improves SPP functionality, and gastrointestinal digestion provides a physiologically relevant evaluation of the bioaccessibility of its functional properties.