Influence of pretreatment conditions on the texture and cell wall components of carrots during thermal processing

Diced carrots (Daucus carota var. Nerac) were subjected to different pretreatment conditions. The pretreated carrots were subsequently thermally processed in an oil bath (100 degrees C) and in a static retort (equivalent processes [F. del 6 min] at 115 degrees C, 120 degrees C, and 125 degrees C). Changes in texture were analyzed as well as changes in the degree of methylation (DM) of pectin. From all the pretreatment conditions tested, high-pressure pretreated carrots (400 MPa, 60 degrees C for 15 min) exhibited the highest resistance to texture loss. The textural properties were significantly improved when calcium infusion was combined with low-temperature blanching condition (60 degrees C for 40 min). A significant reduction in the DM of carrot pectin was observed for all pretreatment conditions that resulted in a reduced texture loss after thermal processing. A strong negative correlation (r <= -0.90) exists between the changes in the degree of methylation of carrot pectin and the observed changes in texture.