Texture formation of dehydrated yellow peach slices pretreated by osmotic dehydration with different sugars via cell wall pectin polymers modification

In this study, texture of heat pump drying (HPD) yellow peaches pretreated by osmotic dehydration (OD) with different sugars (sucrose/Suc, isomaltooligosaccharide/IMO, glucose/Glc) were evaluated. Properties of pectin fractions, namely water soluble pectin (WSP), chelator soluble pectin (CSP) and sodium carbonate soluble pectin (NSP) from yellow peach slices were also determined. Results showed that IMO-HPD samples exhibited the highest hardness (22.218 +/- 1.661 N) and chewiness (6.741 +/- 0.729 N). WSP fractions from IMO-HPD samples showed the lowest degree of methylation (28.5 +/- 0.5%), illustrating IMO could catalyze the demethylation of homogalacturonan in WSP. Glc-HPD samples exhibited the highest resilience (35.732 +/- 2.748%), springiness (82.255 +/- 3.868%), and pectin content, in which the content of WSP, CSP, and NSP fractions were 88.55, 29.60, and 55.96 mg/g AIR, respectively. Both CSP and NSP extracted from Glc-HPD samples showed the smallest molar mass, namely 4.630 x 105 Da and 6.639 x 105 Da, respectively, contributing to the breakage of the linkage between CSP and NSP and the cell wall induced by the infiltration of Glc. Correlation analysis suggested that the degradation or conversation was the pivotal cause of texture formation of OD-HPD yellow peach slices. In conclusion, the interaction between osmosis solutes and pectin could significantly affect the texture formation of OD-HPD yellow peach slices, which would provide theoretical guidance for improving the texture properties of dehydrated fruits with OD pretreatments.

Automated summary

This study evaluated the texture of heat pump dried yellow peaches that were pretreated by osmotic dehydration with different sugars. The properties of pectin fractions from the yellow peach slices were also determined. The results showed that the texture properties were affected by the interactions between osmosis solutes and pectin. Osmotic dehydration with isomaltooligosaccharide resulted in the highest hardness and chewiness, while osmotic dehydration with glucose resulted in the highest resilience, springiness, and pectin content in the yellow peach slices.