Vacuum impregnation of firming agents in red raspberries.

Background: Red raspberries are a delicate and highly perishable fruit with a fragile pulp tissue. In this study we used vacuum impregnation (VI) methods to incorporate pectin and calcium chloride into whole red raspberries to improve their firmness. Specifically, we impregnated low methoxyl pectin (LMP) at 10 g of pectin kg of solution and calcium chloride (CaCl ·2H O) at 30 g calcium kg of pectin, and on the other side pectin methylesterase (PME) at 10 g of enzyme kg of solution, and (CaCl ·2H O) at 10 g of calcium kg of solution, into whole red raspberries.