89B-25 |
|
J. W. PARK and S. Thawornchinsombut. Dept. of Food Science & Technology, Oregon State Univ., OSU Seafood Research Lab., 2001 Marine Dr., Rm. 253, Astoria, OR 97103-3420 A low sodium, surimi-based product can be developed by a reduction of ionic strength (IS) of alkali-treated fish protein isolates using a washing process. These low IS fish proteins could form a gel at proper pH without adding salt. Our aim was to develop low sodium gels from near zero IS fish proteins (N0FP). Response surface methodology (RSM) was used to optimize pH and protein concentration of gel preparing conditions to obtain desirable gel qualities. N0FP was prepared from Alaska pollock surimi. The pH of homogenates (1:9 ratio of surimi:deionized water) was adjusted to pH 11.0. Proteins were then recovered at pH 5.5. Protein pellet was washed twice (1:9 and 1:4 ratios of pellet to deionized water) to reduce the IS to 0.63 mM (NaCl). Cryoprotectants (8% sucrose and sorbitol (1:1)) and 0.3% sodium tripolyphosphate were added. Final pH and water content of N0FP were ≈ 6.0 and 76-78%, respectively. To prepare gel, N0FP was adjusted to the desired pH (7.3-9.5) and moisture content (82 to 88 %) as designed by RSM. The pH and moisture content (MC) of the gel were the independent variables selected to optimize gel qualities. A two-factor central composite rotatable design with uniform precision and 5 replicates at the center point was selected to study 3 responses; breaking force (BF), deformation (DF), and water retention ability (WRA). The pH and concentrations of proteins significantly affected the BF and DF of the gels (p < 0.05). However, pH had a little effect on WRA. Region of maximal responses for BF, DF, and WRA were high pH-low MC, low pH-low MC, and high MC, respectively. RSM is a useful tool to determine how a specific response is affected by changes in the level of the factors over the specified levels of interest.
Session 89B, Aquatic Food Products: Surimi, gels and by-products
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |