Effect of blanching and dehydration on rheological, structural, functional and physicochemical properties of okra

In this study, the effect of dip blanching-DB, steam blanching-SB (2 and 4 min), and microwave blanching-MB (180, 450, and 750 W) on the physicochemical, functional, bioactive, and structural characteristics of okra were studied. Compared with the unblanched sample, blanching led to a significant change in the color and water activity of okra. The results regarding functional properties indicated that water and oil absorption capacity and rehydration ratio improved during MB and samples showed the shear thinning behaviour as the shear rate increased. The retention of bioactive compounds following the trend of MB > SB > DB. Fourier-transform infrared spectroscopy also confirms the maximum retention of phytocompounds in MB. The scanning electron microscopy and X-ray diffraction revealed that the blanched sample had a porous, and less crystalline surface, which was responsible for changes in functional properties. The results are suggestive that MB okra powder has potential to serve as a techno-functional food ingredient for industrial applications.

Automated summary

This study investigated the effects of different blanching methods (dip blanching, steam blanching, and microwave blanching) on the physicochemical, functional, bioactive, and structural characteristics of okra. Blanching significantly changed the color and water activity of okra. Microwave blanching improved water and oil absorption capacity and rehydration ratio. The retention of bioactive compounds followed the trend of microwave blanching > steam blanching > dip blanching. The results suggest that microwave blanched okra powder has potential as a techno-functional food ingredient for industrial applications.