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ABSTRACT This article focuses on the study of textural and protein characteristics of crisp grass carp (CGC) and grass carp (GC) fillets. The higher texture profile analysis (TPA) texture characteristics of CGC are related to a higher content of myofibrillar, sarcoplasmic, stromal proteins, sulfur amino acids and hydrophobic amino acids. Raman spectroscopy further revealed that the secondary and tertiary structural changes in the two fish meat proteins relate to the differences in TPA texture characteristics of the fillets. Lower α-helix contents and higher β-sheet contents are closely correlated to the special mastication properties of CGC fillets. More importantly, the disulfide bond content is another factor that affects the texture of CGC fillets. Furthermore, differential scanning calorimetry revealed that the special mastication properties of CGC fillets result from the greater stabilization afforded by proteins. Overall, the results show that the special texture characteristics of CGC fillet correlates positively with the protein characteristics found in fish muscle tissue. PRACTICAL APPLICATIONS Textural characteristics are an important quality for seafood products, which affects acceptability and mechanical processing of fillets. Crisp grass carps (CGCs), broadbean-fed grass carp (GC), have special mastication. In previous studies, we have found that the differences of texture between both carp's muscles were highly significant. More importantly, the different texture correlated closely with their ultrastructures. Hence, CGC and GC muscles, as the objects for study, will be able to better reflect the relationship between texture and protein characteristics. The research aimed at revealing the mechanism of mastication in CGC muscle to resolve the mastication of CGC decreasing after freezing process. [ABSTRACT FROM AUTHOR]

ABSTRACT In the present study, the use of ultrasonic conditions for the extraction of oil from hempseeds was investigated. The results show that ultrasonic extraction (UE) requires a shorter operating time and results in less solvent consumption than solvent extraction (SE). The optimal conditions for UE are as follows: power output: 200 W; exposure time: 25 min; acting on-off ratio: 20:20 (s/s); and solvent-to-solid ratio: 7:1 (v/w). The gas chromatography-mass spectrometry analysis indicated that the composition of the hempseed oil that is extracted is not significantly (P ≤ 0.05), if at all, affected by UE. Additionally, the 2,2-diphenyl-1-picryhydrazyl scavenging activity during the UE is 13.5% higher than that obtained under SE in this test. Hempseed oil that is extracted by UE has a higher ultraviolet-absorbing capacity than the oil obtained by SE. These tests indicate that UE may be a new, acceptable and even potentially superior commercial oil extraction process for preserving the naturally occurring content of bioactive components that are found within the oil. PRACTICAL APPLICATIONS In this investigation, we found that hempseed oil extracted using ultrasonic-assisted techniques has unique ultraviolet-absorbing properties and better 2,2-diphenyl-l-picryhydrazyl radical-scavenging activity when compared with oil obtained by solvent extraction. It can be concluded that ultrasonic-assisted extraction is a potential method for producing better hempseed oil for food and cosmetic applications. [ABSTRACT FROM AUTHOR]