Factors affecting skin resistance measurements in pipfruit

The accuracy and applicability of different methods for estimating resistance to gas diffusion through the analysis of the efflux of preloaded inert gas out of a fruit were critically assessed. The inert gas neon was introduced as a good replacement for the non-inert gas ethane. A sensitivity analysis was carried out to determine the importance of the different parameters and indicated the importance of the internal free space volume and of the fruit surface area. Experiments with fruit of two apple and two pear cultivars confirmed that the results obtained with non-linear regression were more accurate. The largest resistance to gas diffusion was found in 'Doyenne du Comice' pears, followed by 'Conference' pears and 'Braeburn' apples, and the lowest value was found for 'Jonica' apples. Storage duration did not influence the resistance to gas diffusion except for 'Doyenne du Comice' pears where a significant increase in resistance to gas diffusion during storage was found. Harvest date had no influence on resistance to gas diffusion. (C) 2002 Elsevier Science B.V. All rights reserved.