Effect of Blanching Pretreatments on the Physicochemical and Drying Characteristics of Chui Jhal ( Piper chaba H.) Stem
Md Rahmatuzzaman Rana, Md Aminul Islam, Ashfak Ahmed Sabuz, Mehedi Hasan, Rowshon Ara
Abstract
The research aimed to determine the effect of blanching pretreatment before drying at different temperatures and the chui jhal stem's physicochemical quality. Blanching methods like hot water blanching (HWB) at 90 o C for 3 minutes, steam blanching (SB) for 5 minutes, and microwave blanching (MWB) at 600 watts for 120 seconds were applied before hot air drying at 50 o C, 60 o C, and 70 o C at a constant airflow velocity of 1.5 m/s and relative humidity 50%. Physical deterioration of pretreated samples was lower than untreated samples, affecting the amount of nutritional retention. MWB treated sample showed maximum shrinkage and contained low ascorbic acid and total polyphenol content, but preserved better color and capsaicin content. The shrinkage percentage was found lower in SB samples and HB samples, but the former retained more ascorbic acid, total polyphenol, and capsaicin relative to all pretreatment. The experimental data on moisture loss were fitted to select drying models, namely Lewis, Henderson, Pabis, and Page. The determination coefficient (R 2 ) and root mean square error (RMSE) values of all models were compared. The Page model was considered most suitable for describing the drying characteristics of chui jhal stem. The page model had a good fitting of data with a high R 2 value (>0.98), and low root mean square of error RMSE (<0.07). The percentage of nutrition retention was affected by blanching physical treatment, which affects the physical structure and various nutrient content and drying time.