Abstract:

To explore the best pretreatment and storage conditions for Apostichopus japonicas, biochemical characteristics,
nutritional composition and sensory quality of Apostichopus japonicas with and without intestine as well as subjected to
blanching were measured during storage in 0 ℃ ice-water bath and a comparison with Apostichopus japonicas without
intestine refrigerated at 0 ℃ for differences in tissue structure was carried out as well. The results showed that during storage
in 0 ℃ ice-water bath, with the extension of storage time, nutrient loss, total volatile basic nitrogen (TVB-N) and the total
number of microbes of three samples of processed A. japonicus presented an ascending trend and sensory quality declined.
Tissue structures of A. japonicus without intestine changed obviously both in 0 ℃ ice-water bath and in a refrigerator at
0 ℃, but there was a big difference between them. During the whole period of 0 ℃ ice-water bath storage, volatile basic
nitrogen (TVB-N) contents of all three samples of processed A. japonicus were below standard. Total bacterial count of A.
japonicus with intestine exceeded the standard on the 18th day of storage, while that of A. japonicus without intestine on the
ninth day was higher than the standard. Blanched A. japonicus had minimal loss of nutrients. There was no significant
difference in collagen loss between A. japonicas with and without intestine. Meanwhile significant differences in total
sugar dissolubility on the sixth day as well as in trichloroacetic acid (TCA) soluble oligopeptide dissolubility on the
21th day were found. In respect of sensory quality, A. japonicus with intestine smelled unpleasant on the 18th day and
indicated severe skin ulceration on the 21th day of storage, while the unpleasant smell and serious skin ulceration of A.
japonicas without intestine appeared on the 12th and18th days, respectively, along with less tight and elastic body wall
tissue. The sensory quality of blanched A. japonicus remained unchanged throughout the storage period. Both blanched
A. japonicus and A. japonicuss with intestine showed no obvious changes in tissue structure. But A. japonicas without
intestine formed many collagen fragments with the extension of storage time. A. japonicas without intestine in 0 ℃
ice-water bath exhibited relatively smaller changes in tissue structure than when refrigerated at 0 ℃, which indicated
that water bath environment was beneficial to A. japonicus storage. Conclusion: Blanching without the removal of
intestine and 0 ℃ ice-water bath storage are better for A. japonicas.

Key words: Apostichopus japonicus, storage, nutrient content, sensory evaluation, biochemical characteristics, tissue structure