Abstract: Firmness of processed canned foods including fruits and vegetables has been markedly improved by subjecting the fruit or vegetable to a low temperature blanching step at a temperature in the range of 125.degree. F. to 160.degree. F. and preferably from about 140.degree. F. to 155.degree. F. prior to conventional sterilization. Determination of blanch temperature conditions to produce optimum firmness in the processed food is made by first obtaining firmness values of specific foods at various blanch and hold temperatures and thereafter plotting the rate of firmness increase (Newtons/minute) against blanch temperatures. Preferred conditions, which vary for different foods, are obtained from individual plots for each food. Synergistic improvement of firmness results by combining the low temperature blanching with food grade acid (pH) and/or calcium salt additions.

Abstract: The improved firmness obtained in frozen vegetables by a two-step blanch prior to freezing consisting essentially of a lower temperature blanch to activate pectin methyl esterase in the vegetable to increase firmness followed by a higher temperature blanch to inactivate enzymes thereby to prevent the development of off flavors during frozen storage is retained when the frozen vegetables are canned and heat sterilized. The firming effect is accentuated when the food grade calcium salt is added or when a food grade acid is added to reduce the pH below 4.5. The greatest firming effect is obtained when both a food grade acid and a food grade calcium salt are added.

Abstract: Firmness of processed canned vegetables has been markedly improved by subjecting the vegetable to a low temperature blanching step at a temperature in the range of 125.degree. F. to 160.degree. F. and preferably from about 140.degree. F. to 155.degree. F. prior to conventional sterilization. Determination of blanch temperature conditions to produce optimum firmness in the processed food is made by first obtaining firmness values of specific foods at various blanch and hold temperatures and thereafter plotting the rate of firmness increase (Newtons/minute) against blanch temperatures. Preferred conditions, which vary for different foods, are obtained from individual plots for each food. Synergistic improvement of firmness results by combining the low temperature blanching with food grade acid (pH) and/or calcium salt additions.