The effects of different extraction solvents on the extraction yield and chemical composition of oils from by-products of marine shrimp Penaeus vannamei ( Pv ) and freshwater shrimp Procambarus clarkia ( Pc ) were investigated. Our results indicated that the ethanol and n-hexane mixture (4:1, v/v) was suitable solvent for simultaneous extraction of phospholipid and nonpolar lipids. By contrast, the ethanol and n-hexane mixture (4:1, v/v) and single ethanol were suitable solvents for the extraction of polyunsaturated fatty acids-rich (36.10%–42.78% of total fatty acids for Pv and 23.57%–25.58% of total fatty acids for Pc ) and phosphatidylcholine-rich (66.22–67.09 mol% of total phospholipids for Pv and 55.01–58.68 mol% of total phospholipids for Pc ) oils, but acetone was suitable solvent for the extraction of astaxanthin-rich oil (436.19 μg/g oil for Pv and 799.27 μg/g oil for Pc ). The findings will provide relevant information that can be used to improve the production of nutritional oils from shrimp by-products. Practical applications This study provides a theoretical basis for creating proper extraction processing to recover nutritional oils from shrimp by-products. For example, the ethanol and n-hexane mixture (4:1, v/v) was a suitable solvent for simultaneous extraction of phospholipid and non-polar lipids. By contrast, both of the ethanol and n-hexane mixture (4:1, v/v) and single ethanol were suitable solvents for the extraction of polyunsaturated fatty acids (PUFA)-rich and phosphatidylcholine-rich oils, but acetone was a suitable solvent for the extraction of astaxanthin-rich oil. Therefore, the oils extracted from shrimp by-products are rich in phospholipid, PUFA, and astaxanthin, which may be used as new functional food ingredients.
Jiayin Huang,Zhiheng Hu,Gaoshang Li,Yingchun Xiang,Jianchu Chen,Yaqin Hu
The objective of this study was to investigate the advantages of liquid nitrogen freezing (LNF) over normal contact freezing (NCF) and individual quickly freezing (IQF). The quality attributes of LNF on crayfish ( Procambarus clarkia ) were characterized by biochemical and structural properties. Compared with NCF and IQF, LNF presented lower total viable counts (TVC) value of 5.83 log(CFU/g), thiobarbituric acid (TBA) value of 0.74 mg/kg, total volatile basic nitrogen (TVB-N) content of 23.43 mg/100 g and α-glucosidase and β-acetyl glucosaminidase enzyme activities. SDS-PAGE patterns confirmed less protein denaturation in LNF. Meanwhile, texture parameters analysis indicated LNF held texture quality better, while scanning electron microscope patterns revealed that muscle fibers in LNF were more uniform. The mathematical models exhibited the significant correlation among biochemical and structural properties. Therefore, LNF was a promising freezing process for crayfish preservation, due to the formation of small intracellular ice crystals and maintenance of cell integrity. Novelty impact statement The LNF which was considered as a promising freezing method was applied in crayfish preservation. The preservation behavior of LNF was characterized and the related protective mechanism was illustrated. The mathematical models were established to clarify the inner relationship between freezing conditions and quality attributes.
危险品化学品经营许可证（带存储）