第1个回答 2022-10-21
防腐剂就是可以减慢微生物生长(eg. 霉菌)或化学变化(eg. 苹果切开后变啡)引起的腐坏。 减慢微生物生长的原理: 改变生长环境，令微生物生长减慢，甚至死亡(eg.改变pH)，或利用对微生物有害的物质(eg. SO2)直接使微生物死亡 减慢化学变化的原理: 通常是减慢食物中的酶与空气产生化学反应的速度(eg. 醋能减少苹果的酶与空气反应) 天然防腐剂: 就是非人造的防腐剂(eg. 醋、盐、糖)
The green persevatives are salt
sugar & vinegar . Take vinegar for example
it is the high content of acetic acid inhibit the growth of bacteria so when any germs try to colony on the food
the acetic acid just stop the multipication of the bacteria . In this way the food can be kept for a long time . As for sugar or salt
they are hygroscopic that they can absorb water even from the cells of plants & animals . For a dry peice of meat
it can kept for a long time just like a salted fish or egg . Water is required for breeding living things !