Proximate composition and carotenoids composition of Halocynthia aurantium in the Okhotsk Sea

Abstract

In the Okhotsk Sea, Halocynthia aurantium caught along with scallops have been discarded as bycatch. In order to avoid discarding H. aurantium and promote its use as a process material, we analyzed the proximate composition and carotenoids composition in its muscle. We also investigated the relationship between composition change in the muscle and gonad maturity. The results showed the following: (1) From summer to autumn, the moisture and ash contents decreased gradually; in contrast, the protein, lipid, and glycogen contents increased. (2) The protein, lipid, and glycogen contents showed a negative correlation with moisture. (3) The proportion of individuals with developed ovaries increased from summer to autumn. (4) These results suggested that proximate composition changes in the muscle were related to seasonal variations as well as gonad maturation. (5) Carotenoids in muscle showed no clear trend compared with proximate composition. (6) The main carotenoids were identi fied as β-carotene, alloxanthin, astaxanthin, mytiloxanthin, pectenolone, halocynthiaxanthin, and their fatty acid esters. (7) From these results, H. aurantium muscle contains several useful carotenoids, and therefore may be used as a functional food.