Physicochemical and functional properties of pectin from Premna microphylla Turcz leaves cultivated in Taiwan

This study evaluated Premna microphylla Turcz leaves as a potential source of pectin for industrial applications. Alcohol-insoluble solids (AIS) were obtained through alcohol precipitation, yielding 77.67% AIS with a pectin content of 28.55%. Various extraction methods, including water, ammonium oxalate, hydrochloric acid and sodium hydroxide, were employed to extract pectin from AIS.

Water extraction produced the highest yield at 25.60% with a 42.49% pectin content. The degree of esterification for water-extracted pectin was 44.52%, classifying it as low methoxyl pectin and demonstrating effective DPPH (i.e. 2,2-diphenyl-1-picrylhydrazyl) radical scavenging. AIS (2%) exhibited superior gelling capacity, whereas pectin extracted using 2% sodium hydroxide showed notable gelation properties. Additionally, pectin extracted with 2% ammonium oxalate had a remarkable water-holding capacity of 91.12%. Rheological analysis indicated liquid-dominant behaviour, with the G″ value consistently exceeding G'.

These findings suggest that pectin extracted using sodium hydroxide is more suitable for use as a thickening agent, whereas AIS-derived pectin at a 2% concentration demonstrates potential as a gelling agent. This study offers valuable insights into the characteristics of pectin from P. microphylla Turcz leaves, supporting its application in edible pectin-based formulations and functional products, thereby promoting the value-added utilization of this underexplored botanical resource. © 2025 Society of Chemical Industry.