Relationship of Soluble Solids, Alcohol-insoluble Solids, Fruit Calcium, and Pectin Levels to Firmness and Surface Pitting in ‘Lambert’ and ‘Bing’ Sweet Cherry Fruit1

Firmer ‘Lambert’ and ‘Bing’ sweet cherry fruit ( Prunus avium L.) was associated with higher soluble solids (SS), higher concentration of alcohol-insoluble solids (AIS), and pectinase-soluble pectic substances and less crop, surface pitting, and lower concentration of water-soluble pectic substances. Fruit Ca and ethylene diamine-tetraacetic acid (EDTA) soluble pectic substances were not associated with fruit firmness. Total pectic substances were lower in AIS extracted with 70% ethanol held at 70°C for 1 hour as compared with AIS extracted with 70% ethanol at room temperature plus 80% ethanol in 5% HCI (v/v) for an additional hour. The major differences between the 2 methods were less EDTA and more pectinase pectins in 70°C ethanol-extracted AIS.