Physicochemical properties of fruit of 16 saskatoon (Amelanchier alnifolia Nutt.) cultivars

Abstract

Physicochemical properties were assessed for the fruit of 16 saskatoon (Amelanchier alnifolia Nutt.) cultivars harvested in 1998–2000 from replicated trials at two sites (Saskatoon and Moonlake, SK). The cultivars included Bluff, Buffalo, Elizabeth (at Saskatoon only), Forestburg, Honeywood, JB30, Martin, Nelson, Northline, PAR 90, Parkhill, Pearson II, Pembina, Smoky, Success, and Thiessen. Fruit weight and total solids, soluble solids, pH, titratable acidity, anthocyanin content, and colour characteristics of the fruit juice extracts were measured. Fruit of Martin, Thiessen and PAR 90 had the highest fruit weights (mean = 1.63 g), and Success and Bluff the lowest (mean = 0.79 g). Total and soluble solids contents ranged among cultivars from 19.9% and 14.0 °Brix, respectively, for JB30, to 27.9% and 20.1 °Brix, respectively, for Pembina. Fruit pH ranged from 3.65 for Nelson to 4.18 for Parkhill and Smoky. Fruit of Nelson had a titratable acidity (0.63%) that was approximately twice that of Success, Pearson II, Forestburg, Honeywood, Smoky and Parkhill. The soluble solids to titratable acidity ratio (SS/TA) differed greatly among cultivars ranging from 27 for JB30 to 55 for Parkhill. The colour characteristics of the fruit juice extracts differed among cultivars in chroma and L values, but not in hue angle. Anthocyanin analysis by HPLC identified four peaks: cyanidin-3-galactoside, cyanidin-3- glucoside and two unknowns. Total fruit anthocyanin content ranged from 414 µg g-1 for Forestburg to 852 µg g-1 for Nelson. Correlations were found between anthocyanin content and fruit pH, titratable acidity, hue angle and L value. Key words: Amelanchier alnifolia, saskatoon, fruit composition, acidity, anthocyanin content