Abstract:

The objective of this study was to investigate the effects of various pretreatment methods including blanching,
freezing, citric acid dipping and fructose syrup dipping on the quality of crispy Housui pear slices dried by decompression
flash drying in terms of color, hardness, brittleness, rehydration capacity, sensory score, total soluble solids, titratable
acid, total sugar, total phenol, total flavonoids and ascorbic acid as well as their microstructure. The results showed that
blanching pretreatment improved the sensory quality of the product. Freezing pretreatment yielded products with higher
contents of total phenols and ascorbic acid, but a lower hardness and less volume expansion. Critic acid dipping resulted
in greater hardness, the highest content of titratable acid, which was not very desirable according to the sensory evaluation.
Fructose syrup dipping increased the contents of soluble solid and total sugar, resulted in higher hardness and lower
brittleness, and therefore decreased the commercial value of the product. Comprehensive comparison, blanching pretreatment
method of Housui pear slices dried by decompression flash drying is suitable.

Key words: Housui pear, blanching, decompression flash drying, quality, sensory evaluation