Effect of coating with calcium nitrate in three concentrations (0.0, 0.5, and 1.0 wt%) on chemical and mechanical properties, and impact behavior of two apple cultivars (Golden delicious (GD) and Red delicious (RD)) during time (0, 2 and 4 months) was studied. Moisture content, pH, titratable acidity, °Brix, organoleptic properties, modulus of elasticity (E), yield stress, yield strain, and toughness were measured. The effect of impact loads was determined by measuring bruise volume (BV) and bruise susceptibility (BS). The results showed that pH and °Brix significantly increased while titratable acidity, E, yield strain, toughness and BV decreased during storage time. As Ca(NO3)2 concentration increased, titratable acidity, E, yield strain and yield stress increased and pH decreased (p<0.05). Highest and lowest value for °Brix was observed in GD treated with 1.0% Ca(NO3)2 after four months (13.31) and GD treated with 0.5% Ca(NO3)2 at first day (10.65), respectively. Maximum E obtained in GD treated with 1.0% Ca(NO3)2 on the first day (2130 kPa) and the GD sample treated with 1.0% Ca(NO3)2 showed the lowest BS after four months of storage (2.82 ml J-1), while the uncoated GD had the highest at first day (7.11 ml J-1).

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