Quality Improvement of Short-Time Micro-Flow Water Treatment on the Flesh of Juvenile Hybrid F1 Fish Cultured in Ponds

Abstract

Hybrid F1 is a novel hybrid of Erythroculter ilishaeformis (♀) and Ancherythroculter nigrocauda (♂). Current studies have focused on the genetic features, evaluation of fillet quality, farming techniques, and so on. Meanwhile, few studies have addressed enhancing fillet quality. Traditional intensive pond aquaculture is the major culture method in China. A large amount of excreta and feed residuals remaining in the aquaculture water bodies restricts the critical nutrients, flesh texture, and taste of the fillet. In this study, juvenile hybrid F1 cultured in ponds was obtained from the seed farm (Wuhan Xianfeng Aquaculture Technology Company Limited, Wuhan, Hubei) as the study subject. The fish was treated with short-term micro-flow water (1.2 BL/s) to improve muscle quality. The effects of treatment time (0, 4, 8, and 12 d) on muscle quality in juvenile hybrid F1 flesh were investigated following short-term micro-flow water treatment by assessing the color, muscle fiber, texture, nutrient composition, and the contents of amino acid and fatty acid. The color of the samples was determined by a CR-400 automatic chromaticity meter (Konica Minolta, Japan), wherein the color was expressed by L, a*, and b*. The skin yellowness values were significantly higher at treated 8 d and 12 d, while the short-term micro-flow water treatment significantly influenced muscle redness (P 0.05, the same below). The amino acid content presented the highest values of glutamic acid, followed by proline, and the lowest values in cystine among the 17 amino acids detected in the fillet of juvenile hybrid F1. The amino acid composition was assayed by a Hitachi L-8900 automatic amino acid analyzer. The amino acids EAA/TAA of all groups were about 40%, and the amino acids EAA/NEAA was over 60%, which were high-quality proteins complied with the Food and Agriculture Organization of the United Nations and the World Health Organization (FAO/WHO) standards. Umami flavors are closely related to the composition and ratio of umami amino acid. The content of total amino acids and essential amino acids showed a decreasing trend under the influence of micro-flow water. The total of delicious amino acid treated at 4 d were significantly higher than those of juvenile hybrid F1 treated at 8 d and 12 d. The TAA content and total EAA content did not dramatically change. The essential amino acid index (EAAI) is used to indicate how close the essential amino acid content is to the standard protein. EAAI were 77.33%, 74.91%, 76.56% and 76.75%, respectively. The fatty acid composition was assayed using gas chromatography (Agilent 7890A, USA). Nineteen kinds of fatty acids were detected in the muscle of juvenile hybrid F1, including 5 kinds of saturated fatty acids, 6 kinds of monounsaturated fatty acids, and 8 kinds of polyunsaturated fatty acids, respectively. The micro-flow water significantly affected the fatty acid content in muscle. The content of cis-15-tetracosenoic acid (6.85 mg/100 g), eicosatrienoic acid (41.05 mg/100 g), and arachidonate (53.84 mg/100 g) was significantly higher than that in the other groups after treatment for 8 d. Meanwhile, the content of α-linolenic acid (48.05 mg/100 g), monounsaturated fatty acid (MUFA) (1 336.43 mg/100 g), and n-6 polyunsaturated fatty acids (524.43 mg/100 g) were higher than that in the other groups at 4 d and 12 d. This study indicated that short-term micro-flow water treatment improves the color of skin and meat, and the meat texture at 8 d while ensuring the quality of the flesh. The short-term micro-flow water treatment can help to provide new ideas to improve the quality of aquatic products cultured in ponds.

Keywords

• hybrid f1
• micro-flow water treatment
• texture
• muscle quality