Ultrafiltration of fruit juice and wine.

摘要

The possible effect of oxidation (processing with or without sulfur dioxide ({dollar}pm{dollar}SO{dollar}sb2{dollar})) and of pre-ultrafiltration treatment of juices with fining agents and enzymes on flux, and on juice color, composition and stability was investigated. White Riesling juice was ultrafiltered with a Romicon system operated with a nominal molecular weight cut-off (MWCO) of 10,000 daltons. In addition, UF White Riesling juices processed {dollar}pm{dollar}SO{dollar}sb2{dollar}, were stored for 2 months (1985 vintage) and 12 months (1984 vintage) at 2{dollar}spcirc{dollar}C and 20{dollar}spcirc{dollar}C, and evaluated by a trained panel using descriptive analysis. Pre-UF treatment with enzymes and fining increased flux. Up to 99% of protein, 90% of pectin, 84% of color and low variable phenolics were retained. UF juices processed with minimum oxidation and stored for 12 months had lower intensity aroma (apple/apple cider, sweet, and honey/caramel) and overall intensity flavor by mouth descriptors than those processed with oxidation. Storage at 20{dollar}spcirc{dollar}C in comparison with 2{dollar}spcirc{dollar}C, significantly increased the intensity of the vegetative aroma in the 12-month-old juices.; White Riesling (WR) and Gewurztraminer (GEW) wines were ultrafiltered with Romicon and Millipore pilot-scale systems, respectively. The effect of ultrafiltration (UF), membrane nominal MWCO from 10,000-50,000 daltons, and VCR on composition and wine stability was investigated. The effect of (1) pilot-scale UF processing and Bentonite fining on WR and GEW wines, and (2) commercial-scale UF processing on GEW wine was sensorially evaluated by a trained panel using descriptive analysis. UF processing significantly reduced color (A{dollar}sb{lcub}420rm nm{rcub}{dollar}), total phenol, protein and heat/cold test (HCT) haze of both WR and GEW wines. The panel detected significant differences among the treatments in several of the aroma descriptors for both WR and GEW wines. However, the panel did not detect any significant differences for the flavor-by-mouth descriptors. A consistent decrease of the intensity of most of the significant aroma descriptors across treatments (Intensity ratings: control unfiltered {dollar}>{dollar} bentonite fined {dollar}>{dollar} ultrafiltered) was detected for both wines. Commercial processing of GEW wine by UF did not have any significant effect on the aroma and flavor-by-mouth descriptors evaluated. (Abstract shortened with permission of author.)