No abstract

Ascorbate uptake by muscle tissue of live channel catfish was affected by ascorbate concentrations (1000, 2000, and 3000 ppm), pH (5, 6, and 7) and duration of exposure (8, 16, and 24 hr.). The most favorable conditions for ascorbate absorption were exposure to 3000 ppm ascorbate at pH 5 for 24 hr. The increased muscle ascorbic acid concentration was 4-fold higher than that of the control group (10 ppm). The ability of live channel catfish to absorb dissolved ascorbate via gills and/or intestines and distribute the antioxidant into muscle tissue provides a new approach to introduce water-soluble antioxidants to aquacultured fish species.

Channel catfish were treated with ascorbate via metabolic absorption and vacuum tumbling. R e fillets were subjected to varying periods (0, 1.5, 3, 4.5, and 6 months) offrozen storage at -6C. When muscle ascorbic acid levels were increased two fold by both methods, lBA-RS values were significantly lower than that of the control after 6 months of storage. Vacuum tumbledjillets with muscle ascorbic acid that increased by four fold were found to be the least stable to oxidation. The possible fate of the ascorbic acid in the fish tissue was discussed.

Live channel catfish were exposed to 0.3 % sodium ascorbate solution at pH 5. Ascorbic acid concentration in the fillets was found to increase from 13 ppm initially (control group) to 51 pprn and 43 pprn for j s h exposed to ascorbate for 8 and 24 h, respectively. For the group offish exposed to 8 h of ascorbate followed by 16 h of dechlorinated water, pH 7, the fillets contained 27ppm ascorbic acid. Fish which were exposed to water (without ascorbate) at pH 5 for 24 h showed a comparable ascorbic acid level in fillets to those fillets from the control group. Ihe absorption of ascorbate via gills and/or intestines and distribution to required sites within the muscle tissue could serve to increase the stability of the fish fillet during subsequent processing and storage. Introduction of water-soluble antioxidants to aquaculturedjish species by this approach requires firther exploration.