The influence of γ-PGA on the quality of cooked frozen crayfish during temperature fluctuations

Abstract

The purpose of this study was to compare the influences of gamma-poly glutamic acid (γ-PGA) (1, 2, 3, and 4 %) to see which could outperform conventional cryoprotectant mixture (4 % sorbitol + 4 % sucrose) on cooked crayfish properties, such as physicochemical, textural qualities, oxidation reaction, water distributions, and microstructure integrity, during different freeze-thaw cycles. Crayfish quality characteristics improved significantly as γ-PGA concentration increased compared to control samples.Adding γ-PGA 4 % reduced the carbonyl content from 4.20 to 3.00 nmol/ mg protein during fluctuation-1 (F1), and from 4.15 to 2.80 nmol/ mg protein during fluctuation-2 (F2) compared to control samples. Furthermore, it increased the total sulfhydryl content from 4.15 and 4.76 to 6.19 and 6.47 mol/10⁵ g protein during F1 and F2 and after five freeze-thaw cycles (FTC). This suggests that this concentration was more effective at controlling protein changes than other concentrations. γ-PGA generally enhanced the water-holding capacity by preventing protein denaturation and limiting ice crystal recrystallization. As a result, microstructure stability was evident, texture degradation was avoided, and the crayfish's color was preserved.

Keywords: Crayfish; Dinitrophenyl hydrazine (PubChem CID261500); Dithiobis (2-nitrobenzoic acid) (DNTB) (PubChem CID11087); Ethanol (PubChem CID702); Ethyl acetate (PubChem CID8857); Frozen storage; Guanidine (PubChem CID3520); Hydrochloric acid (PubChem CID313); Quality; Sorbitol (PubChem CID5780); Sucrose (PubChem CID5988); Temperature fluctuations; Trichloroacetic acid (PubChem CID6421); γ- poly glutamic acid.