Development of Pectin from Durian Rind for Application as Functional Ingredient and Cryoprotective Agent in Frozen Foods

Durian rind pectin, a sustainable polysaccharide sourced from agricultural waste, offers a valuable avenue for converting by-products into functional ingredients. This research investigated pectin extracted from Monthong durian (Durio zibethinus) at pH 2 and pH 4.5, comparing its cryoprotective, antioxidant, and anti-inflammatory properties with commercial pectin. FTIR analysis confirmed characteristic carboxyl groups, with peak shifts indicating higher DE at lower pH. Pectin whiteness decreased with increasing pH. DSC analysis showed that pectin at pH 2 reduced ice content to 46.42% compared with 51.12% in commercial pectin and 52.35% in sucrose, while unfreezable water increased to 23.23% compared with 18.53% and 17.65%, respectively. Scanning electron microscopy showed a smooth surface for the extracted durian rind pectin. Bioactivity assays showed significant antioxidant activity; pectin at pH 2 displayed the greatest effect. Additionally, both the pH 2–extracted pectin and the commercial pectin exhibited potential anti-inflammatory activity, reducing nitric oxide (NO) production in RAW 264.7 macrophages without detectable cytotoxicity. These results suggest that durian rind pectin extracted at pH 2 holds considerable promise for retarding ice crystal growth and exhibiting both antioxidant and anti-inflammatory effects.