Near-infrared (NIR) methods to determine kiwifruit field harvest date and maturity parameters in cool store

Kiwifruit is conventionally graded on the basis of external appearance (huh shape, fruit size, absence of physical defects). Other parameters which could meet consumers expectations such as sugar content, acidity, as well as flesh firmness, are traditionally determined in a destructive manner on a limited sample of fruit. Although it is known that fruit on a single vine are characterised by a high degree of heterogeneity, harvesting and assessment of the potential cold-storage life of the ffuit is determined using a sample which is assumed to be representative of all of the harvested fruit. Recently it has been shown that the standard method of assessing average soluble solids content for fruit from kiwifruit vines will over-estimate this value on 95% of all occasions. Non-destructive evaluation methods using near-infrared spectrometer (NIRS) in conjunction with a reliable sampling procedure has been tested on several different fruit and vegetables as well on kiwifruit, with the aim of highlighting parameters which could estimate maturity. This study reports on preliminary results obtained with an NIR (near-infrared) instrument on kiwifruit to establish harvesting dates as well as maturity changes in the field and cool store.