83A-15 |
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P. ZHOU and J. M. Regenstein. Dept. of Food Science, Cornell Univ., Stocking Hall, Ithaca, NY 14853-7201 Gelatin is an important functional food biopolymer. Gelatins from cold-water fish, due to their lower hydroxyproline content, usually have poor gelling ability and cannot gel at 10 °C, the standard temperature for bloom determination. Alaskan pollock, a cold-water fish, is an important fishery resource and accounts for over 1/3 of the US domestic fish catch. In previous research, an optimization was applied to the extraction procedure to obtain a pollock skin gelatin (PSG) with improved gel properties. The objective of this study was to determine the chemical and physiochemical properties of PSG, and compare it with gelatins from other sources. Alaskan pollock skin was pretreated with 0.1 M Ca(OH)2 and 0.1 M acetic acid at 2 ºC, then extracted with distilled water at 50 ºC for 3 h and freeze-dried. Gel strength was determined by the bloom method; viscosity using a Cannon-Fenske viscometer at 60 °C; molecular weight distribution by SDS-PAGE; hydroxyproline by the Woessner method; and the gel melting point using a heating rate of 0.2~0.4 °C/min. PSG contained about 7% hydroxyproline, which is similar to other cold-water fish gelatins (CFG), but lower than warm-water fish gelatins (WFG) and mammalian gelatins (MG). The major protein fractions in PSG were the a, b, and other oligomers. The gel strength of PSG was about 100 bloom at 10 °C, and increased much faster with decreasing temperature than WFG and MG. The gel melting point of PSG was 20 °C, lower than WFG and MG. However, the viscosity of PSG was about 120 mps, much higher than all the other gelatins. These results suggest that because of the low hydroxyproline content and larger polymers, the physiochemical properties of PSG are different from WFG and MG, which may provide unique opportunities for the use of pollock gelatin in the food industry.
Session 83A, Aquatic Food Products: Byproducts, mince and surimi
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