Freeze-Thawing Treatment as a Simple Way to Tune the Gel Property and Digestibility of Minced Meat from Red Swamp Crayfish (Procambarus clarkiix).

Tao Ye,Lin Lin,Yun Wang,Jianfeng Lu,Xing Chen,Zhi Zheng,Zhina Chen,Yajun Zhu

doi:10.3390/foods11060837

Abstract

The effects of freezing methods, including rapid freezing (RF) or slow freezing (SF), combined with thawing methods, e.g., water immersing thawing (WT) or cold thawing (CT), on the meat yield, drip loss, gel properties, and digestive properties of meat detached from red swamp crayfish were investigated. RF greatly reduced the freezing time compared to SF, and the thawing time of frozen crayfish was obviously shortened by WT in comparison to CT. RF and CT improved the meat yield but increased the drip loss, probably as a result of the greater protein denaturation or degradation. A soft and flexible gel was obtained by SF-CT, while a hard one was achieved by RF-WT. An SEM analysis showed that SF resulted in rough and irregular microstructures with larger pore sizes. Freeze-thawing led to an increase in the β-sheet content at the expense of α-helix and variations in the microenvironment of tyrosine and tryptophan residues in protein molecules of the gels, which was more pronounced in the SF-CT group. Moreover, freeze-thawing could cause enhanced protein digestibility but reduce the antioxidant activity of gels. These findings underline the promise of the freezing-thawing treatment in tuning the gel-based meat products of crayfish.

Highlights

Aquatic products are among the most important foods consumed worldwide due to their presence of high-value proteins, essential micronutrients, and desirable sensory properties [1]
Our preliminary experiments proved that freeze-thawing was effective for the shelling of crayfish
The freezing methods, SF and RF, allowed the core temperature to decrease from −1 ◦C to −5 ◦C in 156.33 and 2.17 min, respectively (Figure 1D), indicating that SF and RF in the current study belonged to typical slow freezing and rapid freezing, respectively

Summary

Introduction

Aquatic products are among the most important foods consumed worldwide due to their presence of high-value proteins, essential micronutrients, and desirable sensory properties (delicious taste and unique aroma) [1]. These valuable food ingredients are highly perishable after harvest, their preservation becomes crucial for the aquatic processing industry [2]. As a common unit operation of food processing, can effectively reduce the water activity, inhibit microbial growth and enzyme activity, and retard the quality deterioration, thereby extending the shelf-life of aquatic products [3,4]. The ice crystals formed by freezing are disruptive to muscle fibers and cells of seafood, and they can induce protein denaturation, resulting in thawing drip loss and the deterioration of protein functional properties [5,6]. Data from previous research suggested that a freeze-thawing treatment prior to peeling was beneficial to improving meat yield and organoleptic quality, as well as reducing the energy or labor consumption required for the complete removal of the shell from the meat [8]

Methods

Results

Conclusion