Changes of Functional Properties of Acylated Fish Protein

Acyl화에 의한 어류 단백질의 이화학적 성질의 변화

Fish protein was acylated with acetic anhydride(AA), succinic anhydride(SA) and maleic anhydride(MA) in order to improve the functional properties of the protein. The surface hydrophobicity and functional properties of protein were measured to study the relationship between them. It was found that the extented acylation of nucleophilic groups such as amino and sulfhydryl groups of the amino acid residues of fish protein was higher than other groups when acylated with AA, and the degree of acylation was 89.5 % for amino groups and 72.2 % for sulfhydryl groups. The surface hydrophobicity of fish protein was decreased by succinylation and maleylation, whereas acetylation caused tittle change. The acylated fish protein concentrate(FPC) showed higher surface hydrophobicity than the acylated fish myofibrilla protein(FMP). Acylation with AA, SA and MA of fish protein resulted in a significant increase in protein solubility, emulsifier properties, foaming properties, water adsorption capacity and oil adsorption capacity. These properties of acylated FMP were more improved than those of acylated FPC. Decrease in protein hydrophobicity was highly correlated with increase in protein solubility, and emulsifier properties and foaming properties were largely dependent on the solubility as well as surface hydrophobicity. The water adsorption capacity of the protein was significantly affected by solubility. Surface hydrophobicity had greater influence on oil adsorption capacity, whereas it had tittle effect on water adsorption capacity.

단백질의 기능성을 높이고자 acetic anhydride(AA), succinic anhydride (SA) 및 maleic anhydride(MA)로 단백질을 acyl화 시켜 소수성과 기능성 변화를 측정하여 기능 특성과 소수성의 관계를 고찰한 결과, 단백질의 아미노산 잔기인 amino기와 sulfhydryl기의 acyl화에는 AA에 의한 수식율이 가장 높아 amino기의 89.5 % sulfhydryl기의 72.2 %가 수식되었으며 amino기가 sulfhydryl기 보다 쉽게 acyl화 되었다. Succinyl화 및 maleyl화에 의해 어류 단백질의 소수성은 감소 하였으나 acetyl화는 단백질의 소수성이 근육 단백질보다 높다. AA, SA 및 MA로 acyl화 되면 단백질의 용해도, 유화특성, 포말특성, 수분 흡수력 및 지방 흡수력이 크게 향상되었으며 근육 단백질이 농축 단백질보다 기능적 특성이 좋았다. 단백질의 소수성 감소와 용해도 증가는 높은 상관을 보였고 유화특성 및 포말특성은 단백질의 용해도와 깊은 관련이 있었으며 단백질의 소수성도 중요하였다. 단백질의 수분 흡수력은 용해도와 상관이 크나 소수성과는 큰 관계가 없었으며 지방 흡수력은 단백질의 용해도 보다는 소수성에 더 큰 영향을 받는다.