A strain of Saccharomyces cerevisiae BY-366 was isolated to produce a strong sucrose hydrolyzing enzyme. After entrapment of yeast cell invertase with alginate, enzymatic properties of immobilized cells were investigated. The results are as follows. 1. The optimum pH of invertase in immobilized cells and non immobilized cells was 6.0 and 5.0, and pH stability of invertase in immobilized cells and non immobilized cells was 6.0 and 5.0, respectively. 2. Activation energy of immobilized cells was 4.7㎉/㏖. 3. The immobilized preparation exhibited high resistance to heat and urea induced denaturation. 4. The bead size less than 2㎜ in diameter was desirable. 5. In spite of repeated use, the enzyme activity of immobilized cells was inhibited slightly in batch reaction, and a small column of the immobilized preparation could hydrolyze relatively high concentration of sucrose almost quantitatively to more than 6 days.
A strain of Saccharomyces cerevisiae BY-366was found to produce a strong sucrose-hydrolyzing enzyme Using this strain, the optimal culture conditions for the production of invertase were investigated. The results are as follows : 1. For enzyme production, optimal temperature, initial pH and critical concentrations of sucrose and raffinose were 30℃, 5.0 and 3.0%, respectively. 2. Enzyme production was reached maxium by organic nitrogen source, 0.3% yeast extract plus 0.5% bactopeptone. 3. It was appeared the presence of 0.1M Mn^2+ and Fe^2+ ion was essential factors, on the other hand, 0.1M Ag^+ and Hg^2+ ion almost block in yeast growth and enzyme production. 4. Invertase productivity was reached maxium within 3days on stationary culture with medium-composed of sucrose 3%, bactopeptone 0.5%, yeast extract 0.3%, K_2HPO_4 0.1%, MgSO4·7H_2O 0.05%.
Experiments were performed using sweet potato starch-wheat composite flours to study the rheology and baking properties of bread with composite flours and to test sensory characteristics. Doughs were prepared from mixtures containing wheat flour and 10, 20, and 30% of sweet potato starch(SPS). Standard methods were used to evaluate the rheology and characteristics of wheat composite flour. The results were as follows : 1. The water absorption, developing time and stability measured by farinograph tended to decrease as SPS contents increased. 2. As the contents of SPS increased, the maximum viscosity of the composite flour by amylograph increased, yet gelatinization temperature was slightly low. 3. In the extensograph, extensibility decreased but the ratio of resistence to extensibility increased in proportion to the contents of SPS. 4. In the quality scoring of the bread, WF, WF + SPS 10%, WF + SPS 20% and WF SPS 30% were 84, 80, 77, 73, respectively. Specific volume and crumb characteristics of bread became inferior as SPS contents increased.
숙근(宿根)안개초(草)의 조직배양(組織培養)에 있어 배지(培地)에 첨가하는 agar농도(濃度) 및 auxins의 농도(濃度)가 vitrification에 미치는 영향(影響)을 조사(調査)한 결과(結果)는 다음과 같다. 1. 초장(草長), 생체중(生體重), 분지수(分枝數)는 agar농도(濃度)가 높아질수록 감소(減少)되는 경향(傾向)이었으며 auxins의 효과(效果)는 미약(微弱)하였다. 그러나 초장신장(草長伸長)에 있어서 IAA 1.0ppm+NAA 0.5ppm 및 IAA 2.0ppm+NAA 1.0ppm 첨가구에서는 그 결과(結果)가 매우 양호(良好)하였다. 2. 발근소요일수(發根所要日數)에 있어서는 auxins의 첨가효과(效果)가 적었다. 그러나 근(根)의 생육(生育)에 있어서는 IAA 1.0ppm+NAA 0.5ppm 및 IAA 2.0ppm+NAA 1.0ppm 첨가구에 있어서 분화(分化)된 근(根)의 생장(生長)이 매우 양호(良好)한 경향(傾向)이었다. 3. 건전주율(健全株率)에 있어서는 agar농도(濃度)가 높아질수록 증가(增加)하는 경향(傾向)이었으나 배지(培地)가 너무 경화(硬化)되면(1.5%) 지상부(地上部) 및 지하부(地下部)의 생육(生育)이 극(極)히 저조(低調)하였다. 4. 이상(以上)을 종합(綜合)해 보면 숙근(宿根)안개초의 조직배양시(組織培養時) 외부환경(外部環境)에 대(對)한 적응력(適應力)이 높은 강건한 묘(苗)의 육성(育成)을 위해서는 agar농도(濃度) 1.2%로 한 MS배지(培地)(RM1962)에 IAA 1.0ppm+NAA 0.5ppm 첨가배지(培地)를 사용(使用)하는 것이 바람직하다고 생각된다.