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S. WIBOWO, J. A. Torres, V. D. Savant, and G. Velazquez de la Cruz. Dept. of Food Science & Technology, Oregon State Univ., Food Process Engineering Group, 100 Wiegand Hall, Corvallis, OR 97331-6602 Chitosan (Chi) has been proposed for protein recovery; however, alginate complexes (Chi-Alg) are more effective. Optimizing Chi-Alg dose and treatment time can further increase effectiveness. Molecular weight (MW) and degree of deacetylation (DD) may also improve adsorption Objective was to improve protein recovery from surimi wash water (SWW). SWW was treated with 20, 40, 100 and 150 mg Chi(84% DD)-Alg complex/L SWW for 0.5, 1 and 24 h. Six chitosan samples differing in MW and DD were tested at 20, 40 and 100 mg Chi-Alg/L SWW for 1 h. In all studies, the Chi:Alg mixing ratio was 0.2 and flocculation (20C) was aided by agitation for 5 min. Turbidity was measured according to EPA protocols and proteins by the modified Lowry method. FTIR analysis was used to confirm protein adsorption by the Chi-Alg complex. Turbidity, protein determinations and qualitative FTIR analysis confirmed SWW protein adsorption which depended on Chi-Alg concentration and time. Turbidity was affected by concentration only. No significant differences in adsorption were found between 1 and 24 h. 100 mg Chi-Alg complex/L SWW for 1 hr achieved 83% protein adsorption and 97% turbidity reduction. Chitosan with 94, 93 and 75% DD showed 73-75% protein adsorption while 84% DD chitosan had higher values (74-83%). Chi with 94% DD showed the highest protein adsorption (79-86%) and turbidity reduction (85-92%). Chitosan with high MW resulted in higher protein adsorption. FTIR analysis of SWW solids recovered by Chi-Alg revealed all three amide bands observed in the same region for untreated SWW confirming SWW protein adsorption by Chi-Alg. The flocculation of SWW proteins by 100 mg Chi-Alg/L SWW for 1 h or lower concentration for longer time appear an effective SWW treatment.
Session 63, Aquatic Food Products: Quality, processing, antioxidants and surimi
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