Three kinds offish frame protein hydrolysates （PPH, APH and FPH） were prepared from fish frame of red drum （ Sciaenops ocellatus ） by papain, alkaline proteinase and flavorzyme treatment. The hydrolysates were mai...Three kinds offish frame protein hydrolysates （PPH, APH and FPH） were prepared from fish frame of red drum （ Sciaenops ocellatus ） by papain, alkaline proteinase and flavorzyme treatment. The hydrolysates were mainly composed of peptide （83.5 % -84.6% ） and displayed different molecular weight distribution pattern. The protective effects of hydrolysates on the freeze-induced denaturation of myofibrillar protein （Mf） from bighead carp （Aristichthys nobilis） mince during storage at -20℃ for 12 weeks were investigated. The hydrolysate （5 % dried weight/wet weight） reduced the freeze-induced denaturation of Mf as evidenced by the lowered decrease in Ca-ATPase activity and reactive sulfllydryl contents as well as the impeded increase in surface hydrophobicity. Microscopic photographs indicated that the hydrolysates inhibited the growth of ice crystal in fish mince, and then prevented the aggregation of Mf during frozen storage. The protective effects of hydrolysates on freeze-induced denaturation of Mf were influenced by the molecular weight distribution. PPH had strongest cryoprotective ability among three hydrolysates.展开更多
A non invasive ultrasonic method is used to detect whether or not the frozen fish has suffered a partial or total accidental thawing. The time of flight and the peak to peak amplitude of the ultrasonic signals backsca...A non invasive ultrasonic method is used to detect whether or not the frozen fish has suffered a partial or total accidental thawing. The time of flight and the peak to peak amplitude of the ultrasonic signals backscattered by fish are recorded during thawing. The comparison of the evolution curves and images corresponding to first and second thawing shows indicators of accidental thawing. The monitoring of thawing process showed that its assessment can be reduced to the measurement of the water content lost by fish. The attempt to replace the original water lost by fish in first thawing is analyzed. The influence of the transducer frequency on fish thawing evaluation is tested.展开更多
文摘Three kinds offish frame protein hydrolysates （PPH, APH and FPH） were prepared from fish frame of red drum （ Sciaenops ocellatus ） by papain, alkaline proteinase and flavorzyme treatment. The hydrolysates were mainly composed of peptide （83.5 % -84.6% ） and displayed different molecular weight distribution pattern. The protective effects of hydrolysates on the freeze-induced denaturation of myofibrillar protein （Mf） from bighead carp （Aristichthys nobilis） mince during storage at -20℃ for 12 weeks were investigated. The hydrolysate （5 % dried weight/wet weight） reduced the freeze-induced denaturation of Mf as evidenced by the lowered decrease in Ca-ATPase activity and reactive sulfllydryl contents as well as the impeded increase in surface hydrophobicity. Microscopic photographs indicated that the hydrolysates inhibited the growth of ice crystal in fish mince, and then prevented the aggregation of Mf during frozen storage. The protective effects of hydrolysates on freeze-induced denaturation of Mf were influenced by the molecular weight distribution. PPH had strongest cryoprotective ability among three hydrolysates.
文摘A non invasive ultrasonic method is used to detect whether or not the frozen fish has suffered a partial or total accidental thawing. The time of flight and the peak to peak amplitude of the ultrasonic signals backscattered by fish are recorded during thawing. The comparison of the evolution curves and images corresponding to first and second thawing shows indicators of accidental thawing. The monitoring of thawing process showed that its assessment can be reduced to the measurement of the water content lost by fish. The attempt to replace the original water lost by fish in first thawing is analyzed. The influence of the transducer frequency on fish thawing evaluation is tested.
