명태육의 식품가공적성과 이용성을 높이기 위해 pronase에 의한 명태단백의 가수분해조건과 fruit-와 stem-bromelain에 의한 plastein의 합성 반응조건을 검토하였다. Pronase 가수분해 최적조건인 반응pH 7.0, 반응온도 $40^{circ}C$, 기질 g당 효소첨가량 1,000units 및 반응시간 4시간에서 89% 분해도를 보이는 명태단백의 가수분해물을 제조하였다. Plastein은 pH가 각각 5.0(stem-bromelain)과 7.0(fruit-bromelain)으로 조정된 기질 30% 용액에 bromelain 1%를 가하여 $40^{circ}C$, 24시간 진탕반응하여 합성하였다. 이 최적조건에서 합성된 plastein은 각각 22.6과 20.8 아미노산 잔기를 가진 펩타이드로 구성되어 있었으며 관능검사에 의해 반응초보다 크게 쓴맛이 제거되는 결과를 나타내었다.
In order to enhance the processing quality and utility of alaska-pollack meat, the optimum conditions for the preparation of pronase hydrolysate and the synthesis of plastein were investigated. The optimum temperature and pH for the hydrolysis of alaska-pollack by pronase were $40^{circ}C$ and pH 7.0. The reaction time and enzyme concentration were 4 hr and 1,000 units per g of substrate. Under the above optimum conditions alaska-pollack was hydrolyzed by pronase yielding a hydrolytic degree of about 89%. Pronase hydrolysate was employed as substrate for plastein synthesis. The 30% pronase hydrolysates were adjusted to pH 7 for fruit-bromelain and pH 5 for stem-bromelain, and then plastein were synthesized by 1% bromelain at $40^{circ}C$ for 24 hr. The plasteins synthesized by fruit- and stem-bromelain were consisted of peptides having average peptide length of 22.6 and 20.8 under the optimum synthetic conditions. The plastein synthesis reaction reduced considerably the bitterness of pronase hydrolysate.
