• vacuum impregnation;
  • pectinmethylesterase;
  • firmness;
  • strawberry;
  • fruits

ABSTRACT: Vacuum impregnation allows replacing the occluded air present in fruits by a solution. Apples, strawberries, and raspberries were infused in a solution of pectinmethylesterase (PME) and calcium chloride (CaCl2) either by using this technology or by classical infusion. The vacuum pretreatment limited the loss in fruits firmness following pasteurization. The influence of PME and CaCl2concentrations in the vacuum impregnation solutions on the calcium content, the PME activity and the firmness of pretreated strawberries was studied: the firmness of strawberries was maximal after impregnation in solutions containing a threshold concentration of PME and/or calcium. The synergistic action of PME and calcium used in the vacuum impregnation solution was significant.