Effect of Enzymatic Fish Protein Hydrolysate from Fish Scrap on the State of Water and Denaturation of Lizard Fish (Saurida wanieso) Myofibrils during Dehydration

Abstract

Fish protein hydrolysate (FPH) was prepared from scraps of 5 marine species, in order to utilize by-products effectively by protease treatment. Protein was the major component of the FPH ranging 82-86%. The effects of 5% FPH (dried weight/wet weight) on the state of water and the denaturation of lizard fish Saurida wanieso myofibrils were evaluated by desorption isotherm curves, Ca-ATPase activity, and differential scanning calorimetry (DSC) during dehydration. The myofibrils with FPH showed a decreased water activity (Aw), while they exhibited significantly higher Ca-ATPase activity compared to myofibrils without FPH (control). The myofibrils with FPH had higher amount of unfrozen water than the control. These results suggest that the FPH suppressed dehydration-induced denaturation, which seems to be attributable to the stabilization of the hydrated water surrounding the myofibrils.Keywords: fish protein hydrolysate, Ca-ATPase activity, water activity, unfrozen water, lizard fish, myofibrils, dehydration Fishery wastes have been converted by proteolytic hydrolysis into a more marketable and functional form, which is called fish protein hydrolysate, FPH (Hall & Ahmad, 1992;Hoyle & Merritt, 1994;Barzana & Garcia-Garbaly, 1994;Liceaga-Gesualdo & Li-Chan, 1999). Recently, the functional properties of enzymatic hydrolysate from various foods, such as fishery products (Suetsuna et al., 1988;Iwamoto et al., 1991;Sugiyama et al., 1991;Yokoyama et al., 1992;Liceaga-Gesualdo & Li-Chan, 1999;Hall & Ahmad, 1992) and residue from seafood processing (Miyake, 1982;Murata et al., 1991), have been studied. Further, FPH has the potential to meet the expanding demand for natural protein sources, and it has already been used to enrich food products as a food ingredient, and also as a nutritional supplement for human consumption (Whitaker, 1986;Rutman & Heimlich, 1974;Ballester et al., 1977).Dehydration is widely used as a method for fish and fishery products preservation. The quality of a fishery product generally deteriorates due to the decrease of water holding capacity and solubility of proteins during dehydration (Migita et al., 1956;Suzuki, 1971), because water is closely associated with maintenance of the structure and function of proteins (Kauzman, 1959;Nemethy & Scheraga, 1962;Kavanau, 1965). To prevent such undesirable changes, the addition of sugars, amino acids, organic acids, phosphates and functional proteins has been recommended by many food scientists (Hall & Ahmad, 1992, Hanafusa, 1973Akiba, 1973;Matsuda, 1973;Nakano & Yasui, 1976;Nozaki et al., 1993).In this study, we evaluated the effects of fish protein hydrolysate prepared from scraps of 5 marine species on the state of water and denaturation of lizard fish myofibrils during dehydration. Lizard fish meat has been used as a material to prepare high quality fish jelly products in fish processing industries in Nagasaki. Therefore, we used this species in our study. Materials and MethodsMaterials Scraps of 5 marine species, viz., horse mackerel (Trachurus japonicus...

Concentration Dependent Effect of Enzymatic Fish Protein Hydrolysate on the State of Water and Denaturation of Lizard Fish (Saurida wanieso) Myofibrils during Dehydration

“…Results and Discussion P/-opel'ties of FPH Details of the proximate composition, amino acid analysis, and molecular weight distribution of the FPH of horse mackerel, chub mackerel, and white croaker were described in our previous report (Khan et a/., 2003a), and the properties of the three FPH are described briefiy here. The major components of the FPH were peptides (85.1 1-85.8alo).…”

“…paper (Zhang et a/., 2002b;Khan et al, 2003a). The general components of myofibril specimens were moisture 87.…”

“…As we described earlier (Khan et al, 2003a) an attempt was made to prepare FPH from fish scrap of three marine species and to compare the protective effect of dehydration-induced denaturation on fish myofibrils. We intended in this work to classify the concentration dependent protective effect of FPH on dehydration-induced denaturation of myofibrils.…”

“…( 1 99 1 ) with a slight modih~cation, which is described in our previous paper (Khan et a/., 2003a). ash, and sugar substances were determined by the methods of heat drying (l05'C). Kjeldahl, Soxhlet, ashing in furnace (550'C), and phenol-sulfuric acid, respectively.…”

“…However, fish protein hydrolysates (FPH) are the subjects of an expanding demand as natural proteln sources with good functional properties for the enrichment of food products (Whitaker,1 986). Therefore, we described earlier the preparation of FPH derived from h~ve marine species: white croaker (white meat), horse mackerel and flying fish (medium meat), chub mackerel and sardine (red meat) for color function, and their suppressive effects have been compared with lizard fish myofi~brils at the concentration of 5.00/0 FPH during dehydration (Khan et a!., 2003a). But the effects of the five FPH on the myofibrils were more or less similar, and their proximate components and amlno acid components were almost the same among the h~ve species.…”