The pasteurization is employed for extending shelf-life and keeping the quality of products constant. However the pasteurization undesirably accelerates the oxidation of beer which renders volatile compounds concerning off-flavor. The pasteurization conditions was optimized to avoid off-flavor of beer during pasteurization. Under the isothermal condition, thermal destruction kinetics such as D and Z value of Lactobacillus brevis which is reported the most common beer spoilage, was determined. The binomial data (detected or non-detected of off-flavor) was treated with logistic regression to estimate off-flavor development (OFD) times. The temperature dependence of OFD times was established in terms of Arrhenius relationships. Optimized pasteurization temperature and time were found at which OFD times was not detected. The constraint for optimization was that the pasteurization degree should be larger than 5 decimal reduction time. The optimization was conducted through mathematical simulation using kinetics and temperature-dependent models for microbial death and OFD times. The optimized results were validated by the corresponding experimentations, which met the requirements that the concentration of Lactobacillus brevis was 5-Log reduction and the OFD times not detected.

Off-flavor in foods and in raw materials is quite concerning, as it could signify deeper-rooted problems. Methods of reduction of "off-flavors" in traditional food such as Cheonggukjan and Kimchi, and in raw materials of soybean paste were studied by means of a literature review. It was found that the major components of "off-flavor" were due to butyric acid, valeric acid, alkylpyrazines, ammonia, and sulfides for Cheonggukjang, and for Kimchi were sulfur containing components such as methyl allylsulfide, dimethyl disulfide, diallyl disulfide, methyl allyl trisulfide, methyl 2-propenyldisulfide, dipropenyldisulfide. There is a demand for a scientific and systematic approach in overcoming the "off-flavor" problem. Nutritional aspects and safety should be considered. Several methods have been attempted, such as masking, binding, improving cooking process, inhibiting rancidity, and controlling the growth of micro-organism. Methods of masking were the most frequently ones used for the reduction of "off-flavor", and in some cases, othertechniques were additionally applied. The masking method would be useful in the reduction of "off-flavor" in traditional Korean foods, i.e. Cheonggukjang, Kimchi, as well as in new product development.

필름 포장 상태로 유통되는 콩나물의 주요 상품성 저하 원인 중 하나인 이취의 종류 및 발생 조건 등을 구명하고자 수행된 실험 결과를 요약하면 다음과 같다. 1. 콩나물은 저장 온도가 높을 수록 호흡속도가 증가하여 O2 의 빠른 소모와 높은 농도의 CO2 축적 및 알콜취, 이취의 발생 촉진을 가져왔다. 2. 알콜취는 이취에 앞서 발생하였으며 EtOH은 이취와 유사한 시점에서 GC를 이용한 검출이 가능하였다. 3. 이취의 발생 한계 O2 농도는 1~2% 수준으로, 알콜취의 발생 한계 O2 농도는 4~2% 수준인 것으로 나타났다. 4. 이취 기체 내에는 다양한 종류의 aldehyde류 및 fatty acid류가 동정되었다.