Changes of Dietary Fiber of Onion during Storage

Abstract

The change of content and component of dietary fiber in onion (Allium cepa L.) during storage was studied. The relationship between dietary fiber content and hardness of onion was also researched. Dietary fiber was determined by two different methods. Fresh onions were dried to about 92% moisture suspending in the shade and stored at 0°C for 5 months. The following results were observed; The value of total dietary fiber by the PR0SKY's method was 1.2-1.3 times higher than that by KAINUMA'S modified method, and there was correlation between these values. A negative correlation existed between the total dietary fiber content and penetration force, as the onions with higher total dietary fiber content being harder. The dietary fiber changed during storage. For example, the dried-onion (after suspension) concluded higher pectin and cellulose, and the pectin in stored-onion at 0°C changed to insoluble.