33G-10 |
|
N. PANSAWAT1, P. E. Koehler2, R. D. Phillips2, F. K. Saalia2, and R. R. Eitenmiller2. (1) Department of Product Development, Faculty of Agro-Industry, Kasetsart University, Bangkok, 10900, Thailand, (2) Dept. of Food Science & Technology, Univ. of Georgia, 317 Food Science Bldg., Athens, GA 30602-7610 Since n-3 fatty acids are accepted functional food components, an extruded product with enhanced n-3 fatty acids content was developed. To determine effects of extrusion on n-3 fatty acids and vitamin E in a fish powder, rice flour and menhaden oil formulation. A mixture of 25% fish protein concentrate, 73.2% rice flour and 1.8% menhaden oil was formulated to provide approximately 300mg n-3 fatty acids/ 28 g (dry basis). A mixed tocopherol preparation was added at 0.005% of the fat content as an antioxidant. The formulation was extruded with an APV Baker twin screw extruder (25:1 L/D) at 125-145 °C, 150-300 rpm screw speed and at 19-23% feed moisture. Response surface methodology showed the effects of barrel temperature, screw speed and feed moisture content on n-3 fatty acid and vitamin E. Second order polynomial equations modeled the extrudate properties as functions of process variables. Eicosapentaenoic acid (C20:5n-3; EPA) and docosahexaenoic acid (C22:6n-3; DHA) and vitamin E were analyzed by GC and normal phase HPLC, respectively. ANOVA for the predictive model showed that the linear effects of temperature and screw speed, the quadratic effects of temperature and the cross-product terms of moisture and screw speed were significant (P<0.05) for EPA. Retention of EPA was greatest at the more extreme conditions of moisture and screw speeds. Greatest EPA retention (93.4%) was found at 135 °C, 300 rpm, 19% moisture and 145 °C, 150 rpm, 23% feed moisture (93.7%). Retention of DHA and EPA+DHA showed similar trends but no significant effects (P³0.05). Vitamin E retention ranged from 54-76%. However, none of the extrusion variables were significant (P³0.05) in the model with respect to vitamin E retention. n-3 Fatty acids can be incorporated into an extrusion formulation with excellent retention. Decreases in added vitamin E during extrusion indicates loss due to its activity as an antioxidant.
Session 33G, Nutraceuticals & Functional Foods: Lipid and probiotic functional foods
|