问题
问答题 简答题
试述花色素苷的理化特点?
答案
参考答案:
随着pH值变化,颜色发生变化的色素大多为花色素;花色素对SO2特别敏感,SO2起褪色保护的作用;与金属离子的作用(加明矾、组织结构软化,加Ca硬化与脆化);花青素对光照很敏感,尤其在维生素C条件下,产生褐色沉淀。
试述花色素苷的理化特点?
参考答案:
随着pH值变化,颜色发生变化的色素大多为花色素;花色素对SO2特别敏感,SO2起褪色保护的作用;与金属离子的作用(加明矾、组织结构软化,加Ca硬化与脆化);花青素对光照很敏感,尤其在维生素C条件下,产生褐色沉淀。
选用方框中所给词的适当形式填空,完成句子。 | |
2. The children ______ in their father's shop when things are busy.. 3. They _______ all the milk, they need to buy some.. 4. The machine doesn't work, they ______ urgent repairs now. 5. We must not let them _______ such fine trees just to build a road. |