61B-5 |
Factors affecting the formation of lipid oxidation compounds in spray-dried bovine plasma proteins |
K. M. PARCHER1, T. D. Boylston1, and I. A. Nnanna2. (1) Department of Food Science & Human Nutrition, Iowa State University, 2312 Food Sciences Building, Ames, IA 50011-1061, (2) Proliant, Inc., 2325 North Loop Dr., Ames, IA 50010 Bovine plasma proteins (BPP) are an economical source of high quality proteins that enhance gel strength and improve the emulsion capacity of foods. However, usage of BPP is limited by off-flavors formed through lipid oxidation reactions in spray-dried plasma. The objectives of this research were to determine the effects of antioxidant addition and heat treatment on lipid oxidation reactions, so that processing treatments may be designed to improve flavor characteristics of BPP. In two separate studies, factors affecting the formation of lipid oxidation compounds in BPP were investigated. The first considered antioxidant addition (TBHQ, PG, BHT, rosemary) and spray-dryer type (gas-fired or electric). The second examined how spray-dryer residence time (0 and 20 min), and storage time (0 and 8 weeks) affected antioxidant (TBHQ and rosemary) treated BPP. BPP were reconstituted and analyzed as suspensions and heat-set gels. Volatile compounds were quantified using solid-phase microextraction (SPME) headspace analysis and GC/MS. Lipid oxidation products were the primary flavor compounds present, with hexanal accounting for 60% of the total volatiles. Control BPP suspensions from the gas-fired spray-dryer had significantly higher contents of hexanal than did the BPP suspensions from the electric spray-dryer. Hexanal contents were significantly lower with the addition of TBHQ and PG for the gas-fired spray dried samples; antioxidant addition had no effect on the electric spray-dried samples. Increased spray dryer residence time contributed to a rise in volatile compound formation. TBHQ, but not rosemary, was effective in reducing hexanal and total volatile contents. Gas-fired spray dryers, increased residence time and storage all contributed to increased formation of lipid oxidation compounds and off-flavor development. Selection of the appropriate antioxidant and control of the heat intensity during spray drying does reduce the formation of lipid oxidation compounds and can increase the utilization of BPP in food systems.
Session 61B, Food Chemistry: Flavor and aroma chemistry
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