초록
말쥐치육 단백질의 가수분해물로 합성한 plastein을 식품단백질원으로서 고도이용 가능성을 구명하기 위하여 그의 기능성을 FPC 및 egg albumin과 비교 검토하였으며, 아울러 SEM에 의한 plastein 형상도 관찰하였다. 용해도는 plastein이 FPC 보다 용해도가 월등히 높았고, Glu-papain plastein은 pH변화에 관계없이 용해도가 $95\%$이상으로 높았으나 Leu-papain plastein의 용해도는 매우 낮았다. 가열시간이 길어짐에 따라 FPC는 용해도가 감소하는 경향을 보였으나 Glu-papain plastein은 가열시간에 관계없이 용해도가 $81\%$이상이었다. 분산성은 Glu-papain plastein과 protease plastein이 egg albumin의 그것과 비슷하였으나 ekfms plastein은 다소 분산성이 낮았다. 보수력은 FPC가 egg albumin보다 낮았으며, 지방흡수력은 Leu-papain plastein이 1.88ml/g으로 가장 높았고, 다른 plastein은 egg albumin의 그것과 비슷하였다. 유화성은 Leu-papain plastein이 $61.2\%$로 가장 높았으나 Glu-papain plastein은 $50.7\%$로 가장 낮았다. 유화안정성도 이와 같은 경향이었다. 포말성은 Leu-papain plastein과 Glu-papain plastein이 각각 $373\%,\;360\%$로 egg albumin의 $130\%$ 보다 우수하였다. 포말안정성은 모든 plastein이 50시간 이후에 소실되어 egg albumin의 36시간에 비해 높았다. 점도는 모든 plastein이 egg albumin에 비해 낮았다. SEM을 통해 본 plastein의 형상은 처리한 효소 종류에 따라 다소 차이를 보였으며, Glu-papain plastein과 Leu-papain plastein은 다른 plastein에 비해 특이한 부드러운 형상을 나타내었다.
Plasteins were synthesized from a peptic filefish protein hydrolysate by papain, $\alpha-chymotrypsin$ and protease(from Streptomyces griceus) under the optimum conditions of previous paper. L-glutamic acid diethylester and L-leucine ethylester were incorporated into plastein during the plastein reaction by papain. The structural changes of freeze-dried filefish meat, peptic hydrolysate, FPC and plasteins were observed by Scanning Electron Microscopy(SEM). The functional properties of plasteins also were measured. The solubility of plasteins was higher than that of FPC and the Glu-plastein had $95\%$ solubility in the range of pH 3-10. The dispersibility of Glu-plastein and protease plastein was similar to that of egg albumin, but those of the other plasteins were lower. The water holding capacity of plasteins was lower than that of egg albumin and C. Lipid absorption of Leu-plastein was tile highest, holding 1.80 ml/g, and that of the other plasteins was similar to that of egg albumin. The emulsifying activity of Leu-plastein was the highest, holding $61.2\%$, and that of Glu-plastein was the lowest, holding $50.7\%$. The emulsifying stability of plasteins was similar to that of the emulsifying activity. The emulsifying capacity of Leu-plastein was 384 ml/g(the highest), but that of Glu-plastein and $\alpha-chymotrypsin$ plastein was 248 ml/g(the lowest). The Leu-plastein shelved the highest foaming capacity, $373\%$. The foaming capacity of other plasteins was higher than that of egg albumin. The foaming stability of plasteins was superior to that of egg albumin. The viscosity of plasteins was lower than that of egg albumin. The microstructure of $\alpha-chymotrypsin$ plastein by SEM wassimilar to that of papain plastein, but other plasteins showed differences in their microstructure. The microstructure of Glu-plastein had a smooth shape.