30B-10 |
Process development for manufacturing apple/red beet juice blends |
O. I. PADILLA-ZAKOUR1, H. Nasri, S. Valois, and T. A. Gibson. (1) Department of Food science & Technology, Cornell University, W. North Street, NYSAES, Geneva, NY 14456 Red beets are canned whole, sliced or diced. Since larger beets are only fit for dicing there is a need to find simple alternative uses for small processors. There is interest in juices due to steady increase in per capita consumption. Juices provide convenience and health benefits from daily consumption of fruits and vegetables. Beets blend well with apples due to sweetness and low acidity. Blending allows for production of natural acid products with just pasteurization, instead of typical canning. Our objective was to develop a simplified method for small-scale production of an apple/beet juice needing only pasteurization to assure shelf-stability. Different methods of juice blend production were evaluated to determine best overall method for simplicity, yield and quality, including blanching beets prior to juice extraction, enzymatic treatment of beet mash (5 enzymes), and mixing apple and beet before and after pressing. Blending juices at 70% apple/30% beet was sufficient to achieve a pH below 4.0, but a mixture of 75% apple was preferred (better flavor). Final blends were hot-filled at 85°C and evaluated in duplicates for pH, acidity, soluble solids, color (spectrophotometer), total phenols and preference rating (9-point hedonic scale). Results were analyzed by ANOVA and Duncan's test. Finished samples presented minor variations in pH (3.7-3.8), acidity (0.38-0.43%) and soluble solids (11.4-12.0°Brix). Differences were due to color, total phenols, yield and sensory attributes. Blanching resulted in significantly higher yield (63% compared to 51%), better color and noticeable cooked off-flavor. Enzymatic treatment improved yield to 72% only when beets were blanched. Best overall method was no-blanching, no-enzyme and mixing apple and beet mash before juice extraction, although sensory tests showed preference for enzyme treated samples. A simple method to manufacture shelf-stable 75% apple/25% beet juices of acceptable quality was developed. Small juice producers, including cider mills, can follow this procedure.
Session 30B, Fruit & Vegetable Products: Sensory, Product Development, Fresh-Cut, and Storage
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