Effect of pre-cooking times on enzymes, properties, and melanosis of Pacific white shrimp during refrigerated storage

Kusaimah Manheem,Nandhsha Faithong,Soottawat Benjakul,Kongkarn Kijroongrojana,Wonnop Visessanguan

doi:10.1186/2008-6970-5-1

Abstract

Abstract Pre-cooked shrimp have gained interest due to their attractive color and flavor. However, shrimp without sufficient pre-cooking have faced melanosis, particularly during the extended storage. This leads to the rejection by consumers and the market. Therefore, pre-cooking with appropriate time would be a means to tackle such a problem. The objective of this study was to investigate the effect of pre-cooking times on enzyme activities, properties, microstructure, and melanosis of Pacific white shrimp (Litopenaeus vannamei). Pacific white shrimp were subjected to pre-cooking at 80°C for various times (0 to 120 s). The residual activities of polyphenoloxidase (PPO) and protease decreased with increasing pre-cooking times (p < 0.05). Nevertheless, the increasing pre-cooking time resulted in more cooking loss. With cooking time above 60 s, a cooking loss of 9.85% was obtained (p < 0.05). Marked decreases in the relative PPO and protease activities were observed within the first 30 s of pre-cooking, and negligible activities were detected after 120 s. The microstructure study revealed that the muscle fibers of pre-cooked shrimps were less attached with concomitantly higher shrinkage of the sarcomere, compared with those of the raw counterpart. Shrimps pre-cooked with longer time showed a lower development of black spots as evidenced by a lower melanosis score throughout storage of 7 days at 4°C. Therefore, a pre-cooking time of 30 s at 80°C was sufficient to lower PPO and protease activities with the minimized cooking loss and melanosis during refrigerated storage.

Highlights

Hybridization is a process that involves the crossbreeding of two animals or plants from the different taxa, to produce a new species (Dunham et al 1987)
At 1 h 40 min after fertilization (AF), eggs developed to the 4-cell stage (Fig. 2b); and later at 2 h 15 min AF, the eggs developed to the 6-cell stage (Fig. 2c)
This study revealed the first record of natural spawning in hybrid TGGG in captivity, since its first report on the successful sex differentiation and gonad maturation by Luin et al (2013)

Summary

Introduction

Hybridization is a process that involves the crossbreeding of two animals or plants from the different taxa, to produce a new species (Dunham et al 1987). Hybridization is a powerful tool that offers the hope of producing aquatic organisms with valuable traits, where the offspring carries the characteristics of hybrid vigor or positive heterosis. Hybrid groupers have taken the Asian aquaculture industry by storm since 2006, with the first production of hybrid TGGG, a crossbreed between tiger grouper (Epinephelus fuscoguttatus) and giant grouper (E. lanceolatus). This novel hybrid grouper has gained immediate popularity from aquaculturists and seafood consumers, owing to its production success and premium organoleptic properties, which has led to high commercial value

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