39B-32

D. IRADI and J. Montecalvo. Department of Food Science and Nutrition, California Polytechnic State University, 261 Agricultural Sciences Bldg., San Luis Obispo, CA 93407

The wine industry is facing continuing challenges in by-product disposal as the amount of grapes for wine making continually increases. Few studies have focused on the utilization of wine grape seeds as functional food ingredients. Wine grape seeds may offer the potential of flavonoid (Flavan-3-ol, tannins, anthocyanins and anthocyanidins) protein complexes that may have positive health benefits. Recent studies have shown that wine phenolic may have protective effect for coronary heart disease. Therefore products produced from wine processing by-products may also offer this potential.

Therefore, the object of this study was to develop and optimize isolates produced from defatted grape seed flour and determine their comparative functional properties. Commercial soy isolates and concentrates were used throughout the study as controls and for comparative evaluation.

Seeds of Cabernet Sauvignon were used throughout the study. Seeds were treated with a 1.1 -% solution of NH₄OH, rinsed and air-dried at 110°F for 12 hours to a final moisture content of 5.6%. Seeds were then milled into a 40 mesh flour and defatted with petroleum ether to yield a defatted grape seed flour.

Protein concentrates (PC) were made by extraction at pH 11(1-10 wt./wt.),centrifuged, supernatants adjusted to p117 and freeze-dried. Protein isolates (P1) were produced by adjusting the pH of the protein extract after centrifugation from 11 to 4.5 and freeze-drying. Preparation of PC and PI products resulted in light tan color with percent protein contents of 68.08% and 90.82% respectively.

Comparative emulsification capacity showed that grape seed PC-39.04 ml. oil/ 100 mg. protein and PI, 30.96 were comparable to a commercial soy isolate of 35.18. Comparative emulsification activity (EA) indicated that PC’s and PI 58.01 and 55.68% were lower compared to soy isolate of 82.12%. Emulsion stability of grape seed PC and PI was also found to be lower, 58.42% and 63.86% compared to soy isolate, 74.26%.

The results of this study indicate that protein concentrates and protein isolates produced from grape seed flours may offer significant potential as functional food ingredients. Continuing research is being conducted on phenolic compound binding to PC’s and PI and further functionality evaluation.