Author

Sovann Kin

Advisor

Schilling, M. Wes

Committee Member

Smith, Brian

Committee Member

Behrends, M. Jason

Committee Member

Silva, L. Juan

Committee Member

Nannapaneni, Ramakrishna

Date of Degree

5-1-2011

Document Type

Dissertation - Open Access

Abstract

Catfish fillets that were enhanced with salt and various phosphate treatments through vacuum tumbling or multi-needle injection were evaluated for yield, protein exudate (only tumbling), surface color, pH, cooking loss, tenderness, purge loss and shelf-life. An agglomerated sodium phosphate blend (AGSP) was the optimum treatment for both vacuum tumbling and multi-needle injection and was further utilized in conjunction with potassium lactate (PL) and/or potassium acetate (PA) through vacuum tumbling to determine their effect on the quality, shelf-life and sensory characteristics of enhanced catfish fillets. In addition, the combination of AGSP and PA+PL that maximized shelf-life was further utilized in conjunction with liquid or wood smoking to evaluate the quality and inhibition of L. monocytogenes growth in ready-to-eat (RTE) smoked catfish fillets. All phosphate treatments increased (P<0.05) tenderness, but AGSP that contained mono-, tri-, and polyphosphates increased (P<0.05) pH and yield and decreased (P<0.05) yellowness in both tumbling and injection systems when compared to the control treatment. In addition, AGSP decreased (P<0.05) protein exudate when fillets were tumbled and increased (P<0.05) solution pick-up when injected. Psychrotrophic plate counts (PPC) for all phosphate treatments were similar to the control at each storage time and reached 7 log CFU/g by day 7 of storage; however, when AGSP was used in conjunction with PA+PL, PPC and sensory spoilage scores of raw catfish fillets were lower (P<0.05) than the control at each storage time. Marinating with a combination of 0.25% PA and 0.58% PL increased shelf-life (P<0.05) to between 10 and 14 days when compared to the control which had a shelf-life between 7 and 10 days. In addition, consumers preferred (P<0.05) fried catfish fillets that were treated with AGSP with and without PA+PL when compared to non-marinated controls with respect to appearance, flavor and overall acceptability. In conclusion, AGSP optimized yield and improved the quality of refrigerated catfish fillets, and extended shelf-life three days over other treatments when combined with PA+PL. This combined treatment also enhanced sensory properties of fried catfish fillets and had a synergistic effect with wood smoke constituents that inhibited the growth of L. monocytogenes on RTE smoked catfish fillets.

URI

https://hdl.handle.net/11668/14986

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