Pre-fermentation juice treatments offer alternative to sulfiting.

Hard cider is made by the yeast fermentation of apple juice and represents a small but growing portion of the market for alcoholic beverages. This market niche offers an alternative utilization of apples as a special value-added product.

National organic standards restrict the use of sulfites in hard cider, requiring alternative processing methods to produce a high-quality product. The objective of research at Cornell University was to evaluate the effects of various pre-fermentation juice treatments on the quality of hard cider and evaluate them as an alternative to sulfite treatments.

Extracted apple juice was treated with ultraviolet light (14 mJ per [cm.sup.2]), microfiltration (0.45[micro]m) and pasteurization (71 C for 6 seconds and 85 C for 60 seconds) to eliminate unwanted microorganisms prior to the fermentation process. Total plate, yeast and mold, wild yeast and lactic acid bacteria counts were measured before and after treatments.

After fermentation, the researchers bottled samples with a cold sterilant and kept them refrigerated. Then the investigators analyzed the samples for pH, acidity, turbidity, color, total phenol, alcohol level and for the types of acids they contained. A sensory panel set out to detect perceived differences and to express preferences among the treated samples.

Pasteurization eliminated most microorganisms in the juice, even when a mild pasteurization of 71 C for 6 seconds was used. Filtering and sulfiting lowered all yeast and bacterial counts. Ultraviolet light eliminated most lactic acid bacteria but was not as effective against wild yeast. All treatments had significantly different results from the natural control fermentation, but not from each other.

Ciders produced from juice treated by pasteurization, ultraviolet light or microfiltration were similar to sulfited cider, with only slight differences in their chemical composition and sensory attributes. So it appears these techniques could be used as alternative juice treatments to sulfiting prior to fermentation, and could possibly be the first steps in organic cider production.

Further information. Olga I. Padilla-Zakour, Department of Food Science and Technology, New York State Agricultural Experiment Station, 630 West North St., Geneva, NY 14456; phone: 315-787-2259; fax: 315-787-2284; email: oip1@cornell.edu.

The FDA has approved the use of ultraviolet light to reduce harmful bacteria in juice products. However, not all juice producers use this technology, which promises to preserve the juice's delicious taste and nutrients.