Chemical, Physical and Sensory Characteristics of Winter-Hardy Tart Cherry and Plum Jams

Plums are popular fruits for the fresh market but are often preserved as jams or dried fruits. In contrast, tart cherries are primarily grown for preserves. Both fruit types, however, are climacteric with high respiration rates, which decreases their shelf life. Our objective was to analyze jams made from winter-hardy plum and tart cherry fruits that survive in USDA Z3-Z4 for their sensory profiles and physicochemical properties. Fresh fruit from six tart cherry and 21 plum genotypes were made into jams and compared with three commercial products for soluble solids, pH, titratable acidity, L*a*b CIELAB chromaticity coordinates, hue angles, chrome values and sensorial profiles. Two sensory evaluation panels were convened to evaluate jam color, spreadability, texture, fruit pieces, flavor, off flavor, sweetness, bitterness, overall quality and desire to purchase. 'Suda' tart cherry had the lowest soluble solids (47.13 degrees Brix) whereas 'Meteor' had the highest (65.5 degrees Brix). 'Superior' (47.53 degrees Brix) and 'Alderman' (48.73 degrees Brix) plums had the lowest soluble solids but 'LaCrescent' and the plum control had the highest levels (65.83 and 66 degrees Brix, respectively). The widest range in pH was among the plum jams (2.95, 'Underwood' to 3.56, 'Stanley') and the tart cherries fell within this range (3.08, 'Suda' to 3.19, 'Mesabi'). Both 'North Star' and 'Suda' tart cherries were the darkest in color (low L* values) along with eight plum genotypes and the plum control; 'Superior' plum and the apricot control had the highest L* values. Only spreadability, texture and bitterness varied significantly among the panels. 'Opal' and 'Superior' plums had significantly less fruit pieces than 'Bounty'. Sensory evaluation panelists determined that 'Underwood' plum jam had the highest off-flavor ratings. Jams were significantly different for red color rating with 'La Crescent' and 'Compass' plums being rated the least and most red in color, respectively. One hundred percent of the panelists said they would purchase 'North Star' tart cherry and 'Bounty' plum jams whereas 100% would not purchase 'Underwood' jam. Based on cultivar availability and the generated data, Prunus cerasus 'North Star' is the best winter-hardy tart cherry whereas P. salicina x P. americana 'Alderman' and 'Superior' plum hybrids rank highest for jam making.