In this study, soybean is used to produce soymilk according to various extracting methods and heating time. Specifically, the soy slurry is being filtered before being heated, or heated before being filtered. Following that the soymilk produced is freeze-dried to be powdered, and then, the quality characteristics of the powdered soymilk are mutually compared to determine the applicability of various food additives. The freeze-dried soymilk powder shows 2.03~6.35% of moisture content, and in

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... s of unit quantity, retained more proteins, which suggests that the ratio of protein extraction is higher than any other nutrients. Accordingly, the protein coefficient is significantly higher in soymilk powder being heated and processed than in raw soybeans. In particular, protein coefficient is the highest in the soymilk which is heated for 20 minutes before being filtered (SHBF20). The longer the heating time was, the trypsin inhibitor (TI) tended to be far less active. Such an inactivation seems to be more apparent in the "SHAF" soymilk powder than "SHBF" soymilk powder. Because protein had to be denaturated by heating for soymilk, the nitrogen solubility index (NSI) of soymilk powder is decreased considerably, while the protein digestibility, water absorption, emulsification and foaming activity all increase. Oil absorption tends to decrease slightly. As discussed above, the soymilk heated for 10 minutes after being filtered (SHAF10) and the soymilk heated for 20 minutes before being filtered (SHBF20) show optimum processing conditions for soymilk powder. 서 론 콩(大豆, soybean, Glycine max(L.) Merrill)은 1년생 콩과 작 물로서, 콩 가공제품 중 가장 많이 이용되고 있는 두유(豆乳, soymilk)는 기원전 2세기에 중국에서 처음으로 제조되어 왔 으며(Liu KS 1997), 콩에 있는 수용성 물질 즉, 고형분과 단백 질을 주로 추출하여 이용한 가공제품이다. 한편, 두유는 두부 등과 같은 콩 가공품을 제조하기 위한 중간물질로 사용되기 도 하며, 여러 종류의 생리활성물질(phytochemicals)을 갖고 있으며, 콜레스테롤도 거의 없어(Chen S 1989) 우리나라를 비 롯한 세계 여러 나라에서 천연적인 건강식품으로서 가치를 인정받게 되어, 이의 품질 향상을 위한 연구가 많이 진행되어 왔으며, 또한 두유를 이용한 2차 가공품도 개발․이용되고 있다(Yang 등 2013). 콩 단백질은 저비용의 식물성 단백질로, 동양에서는 콩 자 체를 식용하는 것 외에 여러 가지 다양한 형태로 전환되어 사용되어 왔으나, 서양에서는 콩기름과 사료용으로 대두박만 을 이용해 왔을 뿐이다(Liu 등 1995; Wilson LA 1995). 그러나 식품산업이 발전하면서 다양한 식품 가공 제조에 콩가루(soy flour), 탈지대두(defatted soy meal), 농축대두단백(soy protein concentrate), 분리대두단백(soy protein isolate), 조직대두단백 (texturized soy protein) 등 콩 단백질 제품들(soy protein product) 김 용 선 한국식품영양학회지 90