89B-30 |
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T. OKADA and M. T. Morrissey. Dept. of Food Science & Technology, Oregon State Univ., OSU Seafood Research Lab., 2001 Marine Dr., Rm. 253, Astoria, OR 97103-3420 The sardine (Sardinops sagax) fishery is a new industry in the Pacific Northwest and is having strong economic impact. However, market choices are limited and sardines are usually frozen and exported to Asian countries for bait. To increase utilization of sardine for human consumption, including high omega-3 sardine oils, new methods such as the pH shift method are being investigated. Oil extraction methods were studied and compared with a heat processing method for lipid recovery and quality. Minced sardines were mixed with deionized water (9:1, v/v), and pH was adjusted to the pI of sardines (5.5) with several acids including: HCl, citric acid, citric acid and 1.5% calcium citrate, tartaric acid, and tartaric acid with 1.5% calcium tartrate. After extraction of oil by centrifugation, acid value was determined by AOCS method, and lipid components were measured by thin layer chromatography. Fatty acid composition was analyzed by gas chromatography, and thiobarbituric acid (TBA) was measured periodically. Extracted oil by adjusting pH with citric acid and 1.5% calcium citrate showed the highest lipid recovery (40.06%) followed by extracted oil by citric acid alone (37.67%). Both methods showed a higher recovery than heat-process extraction (35.51%). There were no significant differences in acid value and lipid components. Heat-process extracted oil contained less total fatty acids (754.5mg/g oil) resulted in lower total omega-3 fatty acids (265.4gmg/g oil) compared to pH-shift methods (average of 963.4mg/g oil total fatty acid and 353.8mg/g oil total omega-3 fatty acids). Heat-process extracted oil showed higher TBA value (12.24) while the lowest TBA value (9.45) was found in extracted oil by adjusting pH with citric acid and 1.5% calcium citrate. This study showed the potential of using the pH-shift method for oil extraction and producing high quality oil from sardines.
Session 89B, Aquatic Food Products: Surimi, gels and by-products
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |