Journal of Taiwan Agricultural Research

Author:Tsung-Yen Wu*, Shwu-Jene Tsai, and Li-Duhng Huang

Abstract:

      This experiment was to evaluate the effect of polysaccharide on the qualities of cauliflower during dehydration.  Cauliflower were pretreated with a mixture of polysaccharide (maltdextrin or β-cyclodextrin, 5 or 10%) and sucrose (5 or 10%), and then dehyrated using a dryer with condensation dehumidification.  The nutritional compositions and antioxidant activity of dry products as well as the quality characteristics after rehydration were determined.  The pretreatment of polysaccharides prevented rapid water loss and shrinkage from drying resulting in a better color performance for dry products.  However, the immersion in polysaccharide solution also resulted in a higher nutrient losses of dry caulifower than those of untreated ones, such as 31–40% losses in protein, crude fat and crude fber, 35–56% losses in most of macro and trace elements, and 25–50% reduction in total phenolics and antioxidant activity (ORAC).  The higher the concentrate of maltdextrin and β-cyclodextrin, the more the losses of element contents, total phenolics and antioxidant activity in dry caulifower.  When evaluating the characteristics of rehydrated products, caulifower pretreated with polysaccharide possessed better rehydration ratio and texture (freshness and chewing) after rehydration than control.  Overall, pretreatment with 5% maltdextrin and 5% sucrose was suggested for dehydration of caulifower since it performed the best qualities of dry and rehydrated products.  Conclusively, the condensation dehumidification drying technology combining with pretreatment of polysaccharide could be successfully applied in the production of dehydrated caulifower.

Key words:Dehydrated cauliflower, Condensation dehumidification dryer, Polysaccharide

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