Peptide incorporation in frozen dough and steamed bread: Characteristics and structure-function relationship

Antarctic krill peptide (AKP), a bioactive compound, has garnered significant attention in recent years. This study aimed to explore the effects of varying levels of AKP addition (ranging from 0% to 2.0%, based on the flour, w/w) and different freezing time (0, 1, 2, 4, and 6 weeks) on the rheological properties, rheo-fermentation properties, water distribution, and microstructure of dough. The results revealed that the addition of AKP led to a reduction in the freezable water content, T2 relaxation time, and free sulfhydryl content of frozen dough. After 6 weeks of freezing, the viscoelastic properties of the dough with AKP were higher than those of the control. Additionally, the fermentation height of dough containing 1.5% AKP increased by 25.85% compared with the control, resulting in increased springiness and specific volume, and decreased hardness in the resulting steamed bread. Pearson correlation analysis showed a positive correlation between freezable water content and free sulfhydryl groups, while a negative correlation was observed with springiness. Furthermore, springiness showed a positive correlation with the DPPH free radical scavenging rate. These findings highlight the potential of AKP as a novel food cryoprotectant capable of significantly enhancing the quality and nutritional value of frozen wheat products.