Effect of Osmotic Solution Characteristics on the Texture of Osmotic Dehydrated Yellow Peach

In order to study the effect of osmotic solution characteristics on the texture of osmotic dehydrated yellow peach, changes in osmotic solution characteristics and the texture quality of ‘Baby Gold 8’ yellow peach slices were investigated during osmotic dehydration. After ultrasound or vacuum pretreatment, fresh-cut yellow peach slices were impregnated in a 30 °Brix sucrose, isomaltose, fructose or glucose solution (25 ℃) and sampled at time 0.5, 1, 2, 3, 4 and 5 h for analysis. The properties of osmotic solutions were evaluated in terms of total solid soluble (TSS) content, osmotic pressure, pH and turbidity. Results showed that the different initial osmotic solutions had the same total soluble solid (TSS) content; however, their turbidity, osmotic pressure, and pH were significantly different. At the initial stage of osmotic dehydration (0–2 h), a markedly decreasing trend in TSS content and osmotic pressure was observed, which could be accelerated by either pretreatment. At the late stage, both TSS content and osmotic pressure decreased slowly. The pH of osmotic solutions declined to a level close to that of fresh yellow peach fruit (4.30 ± 0.32) after 0.5 h, and then was not significantly change. As mass transfer occurred, the turbidity increased first rapidly and then slowly. Moreover, both hardness and chewiness fell significantly (P < 0.05). Correlation analysis indicated that the texture quality was positively correlated with osmotic pressure, TSS content and pH but negatively correlated with turbidity. Therefore, the texture of osmotic dehydrated yellow peach slices can be improved by controlling the characteristics of osmotic solution and adopting appropriate pretreatments.