Effect of Protein Hydrolysate from Antarctic Krill on the State of Water and Denaturation of Lizard Fish Myofibrils during Frozen Storage.

Abstract

Protein hydrolysates were prepared from Antarctic krill and two types of shrimp by enzymatic treatment using protease. Hydrolysates prepared from the krill were added to lizard fish myofibrils, and changes in the amount of unfrozen water in myofibrils during freezing were analyzed by differential scanning calorimetry. Ca-ATPase activity of myofibrils was measured concurrently and the results were compared with those using hydrolysates from shrimp. The amount of unfrozen water increased after addition of the hydrolysates and decreased moderately during frozen storage. When hydrolysates were not added to myofibrils, the amount of water rapidly decreased during frozen storage. The decrease in ATPase activity during frozen storage followed that of unfrozen water, indicating a close correlation between ATPase activity and the amount of unfrozen water. These results suggest that the denaturation of myofibrils may be suppressed by the addition of hydrolysates, since the hydrolysates appeared to increase the amount of unfrozen water.

Effect of proteolytic squid protein hydrolysate on the state of water and denaturation of lizardfish (Saurida wanieso) myofibrillar protein during freezing

“…Although the Mf with SPH showed biphasic time-dependent denaturation, it proceeded more slowly, suggesting the suppressive effect of SPH against freezeinduced denaturation of Mf. This finding corresponds well with the reports of Noguchi and Matsumoto (1975) and Zhang et al (2002) who postulated that peptides and protein hydrolysates might prevent freeze-induced denaturation of fish muscle protein.…”

Effect of Squid Protein Hydrolysate on Freeze-Induced Denaturation of Lizardfish (Saurida wanieso) Myofibrillar Protein

“…Although Mf with SPH showed a biphasic timedependent denaturation pattern, it proceeded very slowly, which suggested the suppressive effect of SPH against the freeze-induced denaturation of Mf. This finding corresponds well with the reports of Noguchi et al (1975) and Zhang et al (2002) in which these authors postulated that peptides and protein hydrolysates might have a preventive effect against freeze-induced denaturation of fish muscle protein. The Mf with Na-glu showed a onestep denaturation pattern, revealing that Na-glu strongly suppressed the freeze-induced denaturation of Mf.…”

“…Measurement of Mf Ca-ATPase activity Mf Ca-ATPase activity was measured according to the method of Arai et al (1970) and Zhang et al (2002) in order to determine the protective effect of SPH and Na-glu against freeze-induced denaturation of Mf. The Ca-ATPase activity of the frozen Mf was expressed as the ratio of the specific activity before freezing (relative %).…”

“…The amount of unfrozen water in Mf was measured according to the method of Wakamatu and Sato (1979) and Zhang et al (2002) using a differential scanning calorimeter (DSC) (model SSC-5200, Seiko Electronic Industry, Inc., Tokyo), to assess changes in the state of water in Mf after addition of SPH or Na-glu and the stability of Mf during long-term frozen storage. The results were compared by means of one-way analysis of variance using Excel Statistical Analysis 2000 (Shakai-Joho Service Co., Tokyo).…”

“…The folding and the structural stability of protein during drying and frozen storage are extensively controlled by addition of a variety of anti-denaturants such as sugars, amino acids, organic acids, phosphates, and polyalcohols (Matsumoto et al, 1985;Park & Lanier, 1987;Nozaki et al, 1991). Currently, enzymatically degraded materials from various ingredients, such as fishery by-products and residues from the seafood processing industries, are considered as potential natural suppressors for freeze-induced denaturation and stabilizers of protein molecular structure (Darmanto et al, 1997;Zhang et al, 2002). However, functional protein from squid by protease treatment has not been reported yet for the purpose of food preservation and product development although squid contributes an important global source of protein, and its chemical constituents and nutritive value are worthy of mention.…”