44-5 |
Optimization of factors for the production of polyunsaturated fatty acid (PUFA) concentrates from Mackerel (Scomber scombrus) tissues |
C. P. ZUTA, Food Science and Agricultural Chemistry, Macdonald Campus, McGill University, 21 111 Lakeshore Rd, Ste Anne de Bellevue, QC H9X 3V9, Canada, B. K. Simpson, L. Chan, Centre for Indigenous Peoples' Nutrition (CINE), McGill University (MacDonald Campus), 21 111lakeshore Rd, Ste Anne de Bellevue, QC H9X 3V9, Canada, and L. Phillip, Animal Science, Macdonald Campus, McGill University. The suitability of mackerel oil for production of PUFA concentrates using urea complexation was studied, as a means of developing value-added products from an underutilized fish species. Although urea complexation is cheap and simple, information is required on optimum ranges and interaction between input factors. Additionally, fish oil as starting material requires stabilization by antioxidants. The objectives of the study were to determine optimum input levels for production of PUFA concentrates by urea complexation and level of a-tocopherol that provides the most protection against oxidation. Freshly extracted oil samples (peroxide value, 1.3 meq kg, acid value, 0.6 mg/g) with four concentrations of a-tocopherol: 50 ppm, 100 ppm, 250 ppm and 500 ppm were kept in the dark in uncapped containers at 30 C and sampled regularly. Peroxide value (PV), conjugated diene (CD) and thiobarbituric acid reactive substances (TBARs) were determined. A three-factor 2-level response surface design was used to identify optimum input variable levels. These were: Temperature (-7.0 C - 7.0 C), fatty acid-urea ratio (1:0.9 –1:6.1) and time (18 h-34 h). Quantitation was done by GC-Fid analysis of methyl esters. Responses were measured as increment in concentration of EPA and DHA over initial levels. 100 ppm of a-tocopherol had least oxidation. Higher a-tocopherol levels had significantly higher PV, CD and TBAR values above controls and were prooxidant. The induction period occurred between 8 and 12 days for all samples with significant increase in PV, CD and TBARs values beyond 8 days. The most effective range of factors for optimal yield of EPA and DHA was determined from response surface plots. Temperature and Urea-fatty acid ratio were the key effectors. Oxidation could be lowered with a-tocopherol but it is concentration dependant. The ratio of fatty acid-urea and temperature of complexation would influence levels and kinds of fatty acids concentrated.
Session 44, Seafood Technology: Safety
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