Extraction and characterization of low methoxyl pectin from durian rind

• Main Author: Jong, Sze Hui
• Format: Thesis
• Language: English; English; English
• Published: 2023
• Subjects: T Technology (General)
• Online Access: http://eprints.uthm.edu.my/10847/

Durian is a tropical fruit in Southeast Asia. Durian rind, comprising 65-70% of durian total weight, may serve as a potential source of pectin, a gelling agent commonly used in the food and pharmaceutical industries. This study aims to optimize the pectin extraction from durian rinds and characterize its physicochemical and rheological properties. The factors affecting pectin extraction: durian rind parts and varieties, acid type and concentration, temperature, duration, and solid-to-liquid ratio (S:L) were screened and optimized based on yield, esterification degree (DE), and purity (AUA). Pectin was characterized by intrinsic viscosity, molecular weight, structural, thermal, morphological, and rheological analysis. The durian rind's white part has higher pectin yield than the rind with thorns, while variety D168 has lower yield than other varieties. The parts and varieties did not significantly affect DE and AUA. Pectin yield and DE deteriorated at higher acid concentrations (0.1, 1.0 M). Mineral acids (hydrochloric, sulphuric, and nitric acids) were more effective in extracting pectin of higher purity (AUA > 65%). Organic acids-extracted pectins (citric, acetic, and tartaric acids) had AUA < 65%, indicating poor purity. 0.001M sulphuric acid was selected for extraction optimization due to its good yield (9.13%) and purity (AUA = 66.72%) of lowmethoxyl pectin (LMP) (DE = 20.11%). According to response surface methodology, temperature was the most significant variable affecting yield and purity. DE was not pronouncedly affected by temperature (75 – 95 ℃), time (30 – 270 minutes), and S:L (1:20 – 1:60 g/mL). The optimal extraction conditions (93.3 ℃, S:L 1:50, 185 minutes) yielded 12.12% pectin with AUA = 77.01%, DE = 18.99%, intrinsic viscosity = 148.74 mL/g, and molecular weight = 42.12 kDa. The strongest gel was obtained with 3% (w/v) pectin at pH 3, showing better gel strength than commercial LMP. The gel showed good thermal stability throughout heating and cooling. Therefore, durian rind is a potential LMP source, which could be a gelling and thickening agent for weakacid- low-calorie food and pharmaceutical applications. Future studies could be done to explore durian rind pectin’s applications in the pharmaceutical and food industries