92D-15 |
Quality changes in catfish protein isolates and surimi as assessed by color machine vision and lipid oxidation |
N. DEMIR, M. O. Balaban, and H. G. Kristinsson. Dept. of Food Science & Human Nutrition, Univ. of Florida, 359 FSHN Bldg., Newell Dr., PO Box 110370, Gainesville, FL 32611-0370 Protein ingredients can be successfully produced from fish muscle via acid and alkali-aided processing and surimi processing. Color and oxidative quality of these ingredients are of much importance. Using a non-destructive method suitable for non-uniform colors and surfaces such as color machine vision (CMV) to monitor quality changes would be of much benefit. The objective was to measure and correlate color changes and lipid oxidation with time in Catfish protein isolates (PI) and surimi using CMV and TBARS analysis. Surimi, acid and alkali PI were produced from catfish muscle. A variation of the acid and alkali process was used where one centrifugation step was omitted. Samples of surimi and PI were stored at 4°C (RH=95%) and images of the samples were captured using a video camera at 0, 3, 6, 9, 12 days. A color analysis software was used to calculate average L*a*b* values and % color composition of PI or surimi. Samples were concurrently analyzed for oxidation products (TBARS). Correlation between % color compositions and TBARS were done using SAS. Alkali processing gave a product of higher whiteness (L*) and lower yellowness (b*) compared to acid process due to removal of heme proteins. Omitting one centrifugation in the acid and alkali process had a negative impact on color in terms of b* value. The Alkali PI developed less oxidation than surimi and acid PI. Canonical correlation was used to correlate TBARS and color data with storage time. Color blocks (C428, C429, C436, C437, C438, C501, C502, C509 and C510) and TBARS were highly correlated with storage time (R2=.89). Different processes to produce protein ingredients have different oxidative and color stabilities. CMV can be satisfactorily used to detect and quantify color changes in fish PI or surimi due to lipid oxidation.
Session 92D, Quality Assurance: General
|