Ground Color as a Peach Maturity Index

Abstract

Abstract Changes in peach ground color were analysed over the periods of growth, maturation, and ripening for an early, mid-season, and late maturing cultivar. Color was measured with a tristimulus colorimeter in Hunter “L”, “a”, “b” coordinates. Ground color progressions over time were similar for the 3 cultivars. All color coordinates increased during the 3 weeks prior to harvest, with the “a” coordinate showing the largest rate of change with time. Ground color also was compared with a trial series of 6 uniformly spaced color references. High correlations between color reference selection and measured “a” value demonstrated the feasibility of a ground color reference maturity index even when color matches were not exact. Effects of packing house operations on ground color were investigated. Removal of fuzz by brushing had little effect on measured color, whereas wetting of the brushed surface caused a distinct decrease in lightness (“L” value) but little change in chromaticity (“a” and “b” value).