Foods, Vol. 14, Pages 4336: Effects of Grass Carp Antifreeze Peptide on Freeze-Thaw Characteristics and Structure of Wet Gluten Protein
Foods doi: 10.3390/foods14244336
Authors:
Meizhu Dang
Bing Huang
Yangyang Jia
Yuanyuan Shao
Xingxing Mei
Chunmei Li
This study uniquely explores the impact of a novel natural antifreeze peptide derived from grass carp (GCAFP) on the freeze–thaw characteristics and structural stability of wet gluten protein, providing new insights into the development of natural cryoprotectants for frozen foods. The effects of GCAFP on the physicochemical and structural properties of gluten protein were investigated using differential scanning calorimetry (DSC), nuclear magnetic resonance imaging (NMR), rheology, and scanning electron microscopy (SEM). The results showed that the addition of 0.5% GCAFP significantly reduced the freezing temperature (Tf, from −8.50 ± 1.31 °C to −10.75 ± 2.49 °C) and expanded the melting temperature range (Tm,δ, from 3.60 ± 1.40 °C to 5.65 ± 0.12 °C), indicating improved freezing stability. After five weeks of frozen storage, the ice crystal melting enthalpy (ΔHm) of gluten protein in the GCAFP group increased by only 20.17 J/g, compared with 27.23 J/g in the control, representing a 6.35% reduction (p < 0.05). Similarly, after five freeze–thaw cycles, the freezable water fraction (Fw) and ΔHm were reduced by 5.19% and 1.55%, respectively, demonstrating that GCAFP inhibited water migration and ice recrystallization. Low-field NMR revealed that GCAFP maintained a higher proportion of bound water (T21) and decreased free water (T23), confirming its role in restricting water mobility. Rheological analysis showed that GCAFP preserved the viscoelasticity of gluten protein, maintaining higher storage (G′) and loss (G″) moduli than the control after five freeze–thaw cycles, thus mitigating the decline in network elasticity. Structural characterization indicated that GCAFP stabilized the α-helix and β-sheet contents, reduced glutenin macropolymer depolymerization from 24.85% to 18.95%, and strengthened hydrogen bonding within the protein matrix. Overall, GCAFP effectively protected wet gluten protein against ice crystal damage by maintaining water distribution, viscoelasticity, and secondary structure integrity, highlighting its potential as a natural antifreeze ingredient for frozen food applications.
Source link
Meizhu Dang www.mdpi.com
