In order to determine the effect of trehalose as a total or partial replacement of sucrose in osmotic dehydration on the quality of candied strawberry, the changes in the solid growth rate, water loss rate, water activity, free sugar content, water state, texture and color of candied strawberry were studied when the osmotic dehydration was performed using a mixture of trehalose at varying levels ranging from 0% to 40% and sucrose (the total mass was 40% of that of strawberry). The results showed that with increasing trehalose proportion, the solid gain rate decreased linearly while the water activity and the trehalose content increased linearly. However, the relationships of trehalose levels with the transverse relaxation times and peak areas for three water states and color parameters were all fitted to a quadratic function, indicating that the interaction between trehalose and sucrose is mainly manifested in the freedom of water and color. In addition, excessive addition of trehalose increased the individual differences in the texture of candied strawberry. At addition levels of 35% and 40%, the variation coefficients of viscous force were 174% and 67%, respectively, which were higher than those at the other addition levels (17%–46%). The research results provide a reference for the application of trehalose in candied strawberry.

In order to illustrate the chemical pathway of the browning of preserved strawberry during storage, commercial preserved strawberries were stored at 37, 25 or 4 ℃ and evaluated for color parameters and the contents of ascorbic acid, total phenol, three free sugars, five free amino acids and 5-hydroxymethyl furfural (5-HMF), and correlation and cluster analyses were performed as well. The results showed that for each temperature, the color parameters L*, a*, and b* of preserved strawberry all decreased with storage time, and the total color difference ΔE was 11.42–33.33 after 90 days of storage, suggesting that the color of preserved strawberry changed obviously during storage. Additionally, the contents of ascorbic acid, total phenol, free sugars, and free amino acids decreased in varying degrees, while 5-HMF content increased linearly. The correlation analysis showed that ΔE was significantly correlated with all color and chemical parameters except glutamine content (P < 0.05, P < 0.01, P < 0.001), indicating that the browning may result from a combination of ascorbic acid degradation, polyphenol oxidation and Maillard reaction. Using cluster analysis, the samples stored at higher temperature and for a longer period of time were distinguished from others, suggesting that the influence of storage temperature and period on the browning degree cannot be neglected. In conclusion, during storage, ascorbic acid, total phenol, free sugars and free amino acids are involved in the browning of preserved strawberry, despite the asynchrony. The results of this study provide a rationale for browning control of preserved strawberry.