Preparation of shrimp shells chitosan and use it in extending eggs shelf life

Abstract

This study aimed to examine the performance of chitosan prepared from chitin. By treating the shrimp shells with 3.5% sodium hydroxide then with 1 N hydrochloric acid. The chitin produced was used to prepare two types of chitosan by treating it with concentrated solution of sodium hydroxide 50% with heating at 100c°for 4 hr. (type A) and 20 hr. (type B). The molecular weights of samples A and B as determined by viscometer were 1155 and 720 KDa. The performance of the two chitosans was examined in preserving eggs quality and extending its shelf life after coating them with 2%of chitosan and keep it at 25C°for 4 week. The results indicate that both samples showed better performance than control (non-coated eggs and eggs coated with 1% acetic acid) as A and B contributed in preserving albumen and yolk quality, whereas, Hough Unit of coating sample decreased from 100 (in the 1st day) to (76.3, 76.8), respectively after 4 wk of storage while the control (non coated eggs and 1% acetic acid coated eggs) was (68.2, 67.9), respectively. The yolk index decreased from 0.6 (in 1st day) to 0.27 and 0.28 for eggs coated with chitosan A and B, respectively and to 0.21 and 0.22 for none coated and 1% acetic acid coated eggs respectively after 4 week of storage. A and B coated samples contributed in decreasing the albumen pH increasing which increased from 7.9 ( in the first day) to 10.4 and 10.8, respectively as compared to 11 for the control. B sample was the best compared to A sample and control in preventing decreasing weight losses which were (5.51, 6.12, 6.33, 7.69) %, respectively. Therefore A and B coated eggs showed high activity to improve the internal quality of eggs and to extend its storage period.