Effect Of Variety, Storage And Ripeness Of Apples (Malus Domestica Borkh.) On Physical And Chemical Parameters Affecting Applesauce Rheological Properties

Abstract

Over 3 harvest years (2009, 2010 and 2011), rheological properties of applesauce in relation to fruit ripening and sauce physical and chemical parameters were assessed. Ten varieties were used to obtain single-variety applesauce (Ben Davis, Cortland, Crispin, Empire, Golden Delicious, Idared, Jonagold, McIntosh, Rhode Island Greening, Rome Beauty) by hot and cold-break methods. The effect of storage and fruit ripening were studied using different post-harvest conditions:  Cold storage (1-4 °C at 95% relative humidity) for up to 8 months. Sauce was prepared monthly for collection of at least 5 experimental points.  Varying storage temperatures for assessing the benefit of controlled post -harvest fruit ripening - 10 and 21 °C for up to 30 days. Sauce was prepared every 3-7 days for collection of at least 5 experimental points.  Controlled atmosphere (CA) storage (1-3% O2 and 1-4% CO2 at 1-4 °C). Apples out of CA storage were held at 10 °C for up to 35 days. Sauce was prepared every 3-7 days for collection of at least 5 experimental points and results were compared to those of freshly harvested apples subjected to controlled post-harvest fruit ripening. Apples were evaluated for ripeness (firmness, pH, acidity, soluble solids); and applesauce for rheology (USDA consistency, yield stress, consistency index and serum capillary viscosity) and physical and chemical parameters - particle size distribution (PSD), mean particle size (MPS) and particle size distribution span (PSDS); moisture, calcium, starch, alcohol insoluble residue (AIR), total soluble pectin (TSP) and pectin degree of methoxylation (PDM). Results were analyzed by ANOVA and significant differences among means determined by Tukey's test (p [LESS-THAN OR EQUAL TO]0.05). Harvest year, variety, storage condition, fruit ripeness and their interaction were significant factors for sauce consistency. Differences in rheological parameters are explained by differences in MPS (500-1200 [mu]m) and PSDS (0.9-2.25); starch (0.01-0.78%), AIR (1.5-5.5%) and TSP (0.11-0.75%) contents; and PDM (33-95%). Best consistency applesauce was achieved with smaller MPS ([LESS-THAN OR EQUAL TO] 800 [mu]m), larger PSDS ([GREATER-THAN OR EQUAL TO] 1.5) and/or higher AIR ([GREATER-THAN OR EQUAL TO] 2.5%), TSP ([GREATER-THAN OR EQUAL TO] 0.25%) and lower PDM ([LESS-THAN OR EQUAL TO] 60%). Differences in chemical parameters of sauce between harvest years might be related to weather conditions affecting apple composition.