Evaluation of the Effect of 1-MCP Treatment on Flesh and Surface Color of Selected European and Asian Plum Fruit Using Machine Vision

The aim of this work was to evaluate how 1-methylcyclopropene (1-MCP) treatment affects appearance of plum fruit. Fruit of 'Angeleno' and 'Topend' cultivars were treated with 625 ppb gaseous 1-MCP at 1 degrees C for 24 h after harvest. Samples without treatment, called control, and those subjected to the treatment were stored at 1 degrees C for 8 weeks (Topend) and 10 weeks (Angeleno). The subgroup of initial samples and those withdrawn from cold storage were also measured after 7 d storage at 20 degrees C. According to measured parameters of ethylene, CO2 production, firmness, and total soluble solids content, there was a clear difference between 1-MCP- treated and control samples for both cultivars. Color attributes of hue angle and saturation changed significantly during storage, especially for flesh color measured on fruit cut in half. The comparison revealed that saturation responded more sensitively to changes. Firmness correlated significantly with color attributes, and flesh saturation reached the highest value of Pearson's correlation of r = 0.608 (p < 0.01) and Spearman's rank correlation of rho = 0.636 (p < 0.01). The specific plum color was also evaluated with a normalized blue value, which obtained significant linear correlation with firmness (r = -0.7414, p < 0.001). There was significant difference between cultivars in terms of surface color and its correlation with firmness as Pearson's correlation obtained r = 0.833 (p < 0.001) for 'Topend' and r = 0.556 (p > 0.05) for 'Angeleno'.