Changes in headspace volatile attributes of apple cider resulting from thermal processing and storage

One attribute that frequently reflects a product's organoleptic impact is its aroma. In research presented here, a Fox-3000 Electronic Nose was used to determine and compare the aromatic profiles of samples of apple cider subjected to various thermal treatments. Initial results have indicated that exposure to temperatures of up to 90 degreesC for approximately 28 s acts to stabilize the aromatic properties of apple cider over a 7-day period. In contrast, there are significant changes in the aromatic profiles of fresh apple cider having no such thermal treatment over the same time period. A comparison of samples thermally treated at 60, 70, and 80 degreesC to non-processed cider showed minimal statistical difference on the basis of similarity indices obtained after 24-h of storage of the samples at 4 degreesC. Treatment at 90 degreesC showed significant differences from the unprocessed samples in the same test sequence. After storage for 7-days, samples that were thermally treated exhibited minimal differences from each other, however, were quite different from the non-processed sample on the basis of similarity index analysis. GC analysis was done to confirm potential differences between the samples measured using the electronic nose. Sensory testing is required to determine whether these differences affect the overall quality perception by consumers. (C) 2002 Elsevier Science Ltd. All rights reserved.