A Novel Procedure for Preparing Mango Jellies with Higher Antioxidant Capacity and Reduced Sugar Content

This study investigated the impact of two different temperature regimes (high and low) on the chemical composition, antioxidant activity, and antidiabetic properties of mango jellies. Total phenolic content (TPC) and antioxidant capacity were assessed using the conventional 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and the recently developed direct current (DC) polarographic method. Jellies prepared under low-temperature conditions contained higher TPC levels (82.0 ± 2.0 mg gallic acid equivalents (GAE)/kg jelly) and exhibited stronger antioxidant activity (65.0 ± 2.2 ascorbic acid equivalents (AAE)/100 g jelly by DPPH; 12.40 × 10^-6 mol reduced Hg(II)/g jelly by DC polarography). Antidiabetic evaluation revealed that the low-temperature jelly significantly inhibited both α-amylase and α-glucosidase activity. Thermal analysis further confirmed distinct structural behavior between low- and high-temperature products. This novel processing approach-combining mild heating (55 °C), vacuum treatment, and reduced sugar content (40%) without pectin addition-proved effective in preserving bioactive compounds and functionality. Notably, this is the first report applying DC polarography to assess antioxidant capacity in fruit jellies, highlighting its potential as a robust tool in functional food research.