40-7 |
Objective quality assessment of fish protein isolates and surimi using color machine vision and measurements of lipid oxidation products |
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 An important quality aspect of aquatic food products is lipid oxidation which can lead to undesirable appearance, odor and taste. Using non-destructive methods to detect and follow quality changes in aquatic food products would be of much benefit. The objective was to measure and compare quality changes of fish protein isolates (PI) made with low and high pH treatment and surimi, using color machine vision (CMV) and correlating results with lipid oxidation measurements. Ground muscle from croaker, mullet and spanish mackerel (SM) was used to make surimi and acid and alkali PI’s. Surimi and PI’s were placed in weighing boats and stored at 4°C (RH=95%). Images of surimi and PI were captured using CMV 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. Development of oxidation products (TBARS) was followed concurrently. Correlation between %color compositions and TBARS were performed using SAS. Results showed that samples differed in their color properties and that decrease in L* value was highest with mullet and SM. Alkali PI’s led to higher yellowness (b*) compared to acid PI’s and surimi for all species. There were significant differences in oxidative stability of samples (p<0.05) with alkali PI being most stable and acid PI least stable. This was because oxidation developed rapidly during the acid process. Color blocks and oxidation products over time gave high correlation for all species (R2=0.94 for Mullet, R2=0.97 for Croaker and R2=0.94 for SM). The alkali process is more successful than surimi in producing stable protein ingredients. The use of CMV gave good correlation with TBARS and could be a good method to non-destructively assess oxidative stability of aquatic food products.
Session 40, Aquatic Food Products: Surimi and proteins
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