51A-40

D. Lemerise, DoD Combat Feeding Program, US Army Natick Soldier Center, Kansas Street, Natick, MA 01760, A. SENECAL, and S. Constantinides, Food Science and Nutrition, University of Rhode Island, 530 Liberty Lane, West Kingston, RI.

Seafood products are composed of relatively high numbers of unsaturated fatty acids which makes them particularly susceptible to lipid oxidation and subsequent rancidity. Current research efforts on the use of antioxidants have been conducted on raw, frozen and minced fish with few studies involving pre-cooked fish and none on ready-to-eat, shelf stable cooked fish products.

The objective of this study was to determine the effectiveness of a natural herbal antioxidant extracted from Rosmarina officialis (Rosemary) when applied to a ready-to-eat, shelf stable catfish being developed by the military.

Frozen catfish fillets were thawed, washed and cut into 40-60 gram pieces. The shelf stable catfish was produced by a one minute dip in vinegar for 1 minute, frying in oil for five minutes at 175ïC, cool to room temperature, re-dipped in vinegar for 1 minutes, drain, packaged in 8 oz trilaminated foil pouches, sealed under atmospheric conditions, and stored for 56 days at 22ïC. Herbalox® Type P (water miscible) and Herbalox® Type O (fat soluble) antioxidants were applied at three concentrations each to the catfish at different times during processing Thiobarbituric acid (TBA) and headspace oxygen analysis were conducted.

Results showed Herbalox® P appeared to have the greatest antioxidant activity, particularly when applied prior to frying. Peak TBARS at day 14 for similar concentrations of antioxidants were 40, 50 and 47% lower pre-frying, and 27, 44, and 33% post frying than controls. All samples displayed significant differences (P<0.05) from the control in % oxygen headspace. Herbalox® O showed not significant differences when compared to the controls. Combination of antioxidant treatments reduced TBARS by 70% compared to control on day 14, and was significantly lower than any individual antioxidant treatments.

These results demonstrate that the addition of water miscible rosemary extract antioxidants have the potential for suppressing oxidation in shelf stable catfish.