Effect of novel blanching methods on Infra-red drying characteristics and quality attributes of elephant foot yam

The present study evaluated the effect of various pre-treatments (Potassium metabisulphite (KMS), KMS+Ultrasonication (KMSUS), KMS+Microwave (KMSMW), KMS+Hot water (KMSHWB) followed by infrared drying on the quality of Elephant Foot Yam (EFY). KMSMW-treated samples showed the fastest drying rate and highest moisture diffusivity, whereas the KMS-treated sample had the highest weight gain (171.57 %) in rehydration (80 °C). KMSMW and KMSHWB-treated samples exhibited softer textures in rehydration compared to control. Pre-treated samples had higher water absorption capacity and lower oil absorption capacity compared to the control. Pre-treatments also influenced the amylose content and the highest amylose content was observed for KMSUS (21.25 %). Pre-treatments positively influenced the retention of bioactive compounds and reduced the calcium oxalate (117.37 mg/g to 64.09 mg/g). Among all the pre-treatments, KMSHWB showed higher retention of bioactive compounds viz., TPC (297.67 mg GAE/100 g), TFC (922.22 mg QE/100 g), DPPH scavenging activity (57.91 %), ABTS (1.42 mmol TE/100 g) and lowest calcium oxalate (64.09 mg/100 g).