Hunter's color value “a” in dried-persimmon of table and full ripe fruit was higher than that in unripe fruit. In case of soluble solid content, full ripe fruit was 50o Brix, the highest degree, while unripe fruit was 40o Brix, the lowest degree. PPO activation of unripe fruit was 4.7, which was higher than table-ripe fruit (0.7) and full ripe (1.0). Polyphenol oxidase activation remained even while drying, but there was no difference in PPO activation degree as drying period increased. Total phenol content of unripe fruit was 101.4, which was higher than table-ripe fruit (57.5) and full ripe fruit (67.4). Total phenol content level increased as drying period increased, which was based on fresh weight. Hardness of unripe and table ripe fruit continued to decrease until three weeks during softening. After that, hardness was high and it started drying. However, in full ripe fruit, hardness increased after two weeks and softening was fast during the drying period, and its weight reduction rate was lower than that of unripe and table ripe fruit.

Three potato cultivars, Sumi,Daejima and Namjak, were prepared as slices. They were dipped in distilled water for 20 seconds. The potato slices were packed in polyethylene bags and stored at 5℃. Browning degree, total phenol and chlorogenic acid contents and polyphenol oxidase (PPO) activity were measured. And the correlation analysis of browning parameters were conducted. The results were as follows. There were increase in browning degree, phenolic content and PPO activity during cold storage of potato slices with different cultivars. Among three cultivars, Sumi showed the highest browning degree, phenolic content and PPO activity and also showed the highest % increse of browning and PPO activity during cold storage. On the contrary, Daejima was the lowest. But Daejima showed the highest % increase in phenolic contents during cold storage. With Sumi, browning degree was significantly correlated with PPO activity and phenolic contents (p〈0.05). With Daejima and Namjak, a significant correlation was found between browning degree and PPO activity (p〈0.05). From the above results, enzymatic browning reactions of potato slices and factors affecting them were dependent on cultivar. Among the tested three cultivars, Daejima showed the lowest browning degree during cold storage and thus seems to be desirable for minimal processing.

밀가루 및 국수 면대의 색깔 변화에 영향을 미치는 요인을 분석하여 소비자가 선호하는 밝은 색택의 밀가루 및 국수 제조에 적합한 품종의 육성에 유용한 간편 분석법을 확립하고자 본 연구를 수행하였다. 국산밀 25 품종을 이용하여 종실 및 밀가루 특성과 저장기간 동안 국수 면대의 밝기 변화를 조사하였다. 종실의 PPO 활성은 천립중이 낮을수록, 종실 회분과 단백질 함량이 낮을수록 낮은 경향을 나타내었다. 종실의 PPO 활성은 총폴리페놀 함량(r=0.609**

Polyphenol oxidase (PPO) is implicated in discoloration of white salted noodles and other wheat based foods. PPO activity was evaluated to determine the effect on discoloration of noodle dough sheets prepared from 25 Korean wheat flours during storage and to screen experimental lines with low PPO activity in 52 Korean wheats. PPO activity was assayed with whole-seed and performed with L-dihydroxyphenylalanine (L-DOPA) as substrates. Absorbance by L-DOPA assay of 25 Korean wheats was from 0.285 to 1.368 at 475 nm. PPO activity was significantly related with grain characteristics, including 1000-kernel weight and grain colors. In flour characteristics, PPO activity positively correlated with ash and protein content (r = 0.658, P < 0.001 and r = 0.424, P < 0.05, respectively) and negatively correlated with L* value of flour (r = 0.412, P < 0.05). In the changes of color of noodle dough sheet, L* and b* values consistently decreased and a* value increased during storage. PPO activity negatively correlated with L* value of noodle dough sheet during storage (r = 0.566, P < 0.01 at 2 hr, r = 0.547, P < 0.01 at 24 hr, and r = 0.509, P < 0.01 at 48 hr). But, no significant relationship was found in between PPO activity, a* and b* values during storage. The 52 Korean wheat lines examined in this study were divided into 3 different groups, low (< 0.500), medium (0.501-0.999) and high level (> 1.000), on the basis of the level of PPO activity. Twenty two Korean wheat lines showed low level of PPO activity and Suwon 252, 277 and 280 showed lower PPO activity (< 0.200) than others.

본 연구는 적변 유발 세균에 의해 발생하는 적변삼과 polyphenol 및 polyphenol oxidase 활성과의 관계를 조사하였으며, 이는 다음과 같다. 1. 적변 유발 균주를 상처낸 건전 인삼 외피에 접종하여 무처리구와 비교하였을 때, 접종일수의 증가에 따라 Hue angle값이 접종 후 1일 101.2, 10일 95.9, 20일 90.1, 30일 60.9로 적색으로 변화되었다. 2. Lysobacter gummosus, Pseudomonas veronii 및 Agrobacterium tumefaciens 균주를 인삼의 상처부위에 접종하였을 때, 총페놀의 함량은 일수가 경과할수록 증가하였다. 3. Lysobacter gummosus, Pseudomonas veronii 및 Agrobacterium tumefaciens 균주를 상처낸 인삼에 접종하였을 때 페놀함량의 증가와 함께 효소의 활성이 증가하였으나 단백질당 PPO의 활성은 감소하였다.

The environment in which a given genotype is grown may influence its grain quality characteristics. When varieties are ~times evaluated over numerous environments, a variety environment interaction usually is observed, but the relative magnitude of environmental(E), genetic(G), and G ~times E effects on quality is unclear. In order to determine relative contribution of genotype, environment, and G ~times E interaction to the variations observed in grain quality characteristics, 18 Korean wheat cultivars and experimental lines were evaluated in two environments in 1998 and 1999. Correlation coefficients between grain quality and agronomic characteristics were also estimated. The analysis of variance for the optical density obtained by reaction bet- ween gliadin and anti-gliadin polyclonal antibody (AGPab) indicated that gliadin content measured by Enzyme-Linked Immunosorbent Assay(ELISA) was significantly in- fluenced by environment and cultivar differences. The significant differences of year and year ~times location were also found. The ratio of the variances associated with environmental effects to the variances associated with genetic effect gave relatively greater influence of environmental factor on gliadin content. The different protein content from same genotype grown in different environment might be associated with degree of storage protein accumulations. Significant relationships between ELISA and protein content, yield, ten spike weight, and ten spike number were detected. Polyphenol oxidase (PPO) activity was significantly influenced by year, location, cultivar and year ~times location. The variance in grain PPO activities among growing years appeared larger than the variation produced by the cultivar examined. This suggested that the growing environment contributed more to variability in grain PPO concentration.