Antioxidant activity and emulsifying properties of Dendrobium officinale polysaccharides with distinct structural
Cunchao Zhao1, Weiqian Wang2, Fanrui Li2
1School of Food Science and Engineering, South China University of Technology, Guangzhou, Guangdong 510640, China; College of Food Science and Technology, Yunnan Agricultural University, Kunming 650201, China; Yunnan Plateau Characteristic Agricultural Industry Research Institute, Kunming 650201, China; Yunnan Key Laboratory of Precision Nutrition and Personalized Food Manufacturing, Yunnan Agricultural University, Kunming 650201, China; Key Laboratory of Development and Utilization of Food and Medicinal Resources, Ministry of Education, Yunnan Agricultural University, Kunming 650201, China.
Abstract:
This study compared six extraction techniques, hot water, acid-assised, ultrasound-assisted, microwave-assisted, UV/H₂O₂-assisted, and enzyme-assisted on the structural, antioxidant, and emulsifying properties of Dendrobium officinale polysaccharides (DOPs). Molecular weights ranged from 1155.239 kDa (DOPs-hwe) to 3.139 kDa (DOPs-ee). DOPs-hwe showed the highest uronic acid content (4.52 %) and excellent emulsifying ability (89.2 % activity, 81.5 % stability). In contrast, DOPs-ae and DOPs-ee exhibited stronger antioxidant activity, with DPPH scavenging rates of 52.36 % and 58.05 % (15 mg/mL), linked to lower molecular weights and higher carboxyl group contents (0.58-0.66 mmol/g). FTIR and Congo red analyses confirmed differences in triple-helix conformations. SEM imaging revealed morphological diversity, from dense (DOPs-hwe) to porous (DOPs-ee). Monosaccharide composition varied across extraction methods. Emulsifying performance was mainly influenced by hydrophobic and steric interactions. These findings provide a useful reference for selecting suitable extraction approaches to tailor DOP functionality for specific applications in food, cosmetic, and pharmaceutical industries.
