Influence of blanching and guar gum pretreatments on total phenolic content and antioxidant activity of cabinet-dried white bitter gourd Momordica charantia L.

Currently, the global food industry is experiencing a shift in consumer preference towards natural sources of antioxidants derived from edible fruits and vegetables. In view of this, white skinned bitter gourd with bioactive properties has great potential. Additionally, guar gum has the characteristic ability to form strong hydrogen bonds with water molecules, thereby reducing shrinkage during dehydration. Thus, the present investigation was carried out to study the influence of blanching and guar gum pretreatment on the retention of the total phenolic content (TPC) stability and antioxidant activity (AA) of white Momordica charantia L. when cabinet dried at 60±5 °C. The results are indicative of a significant (P values of < 0.05) impact of using guar gum along with blanching before dehydration of white Momordica charantia. The findings obtained clearly show the positive impact of guar gum on the stability and retention of TPC (Folin Ciocalteau) and AA (percentage of 2,2-diphenyl-1-picrylhydrazyl DPPH scavenging activity) in the dried product in comparison to the untreated control. Water Blanching + 1% Guar gum (T5) and 2%Salt Blanching + 0.2% Potassium meta bisulphite + 1%Sodium carbonate + 1% Guar gum (T16) showed higher AA [20.29% (T5) and 40.13% (T16)] and TPC [30.8 (T5) and 39.5 (T16) GAE per 100 g of dried weight (DW)]. Therefore, the application of guar gum as a pretreatment with blanching turns out to be beneficial for higher retention of TPC and AA, thereby maintaining product quality as a whole.