Comprehensive evaluation of oil quality of 98 varieties with different maturity levels from the Bailongjiang River Valley area in Longnan, China

This study analyzed oil content, fatty acid composition, and key active components (squalene, β-sitosterol, α-tocopherol, and total polyphenols) in 98 olive germplasms from China’s Longnan region across three maturity stages (I, II, III). Results revealed a broad range in oil content, increasing with maturity. I: 28.00-60.20%; II: 32.50-64.60%; III: 34.10-64.80%. Oleic acid (C18:1) was the predominant fatty acid, The content of squalene varies significantly and increases, while the mean value of β -sitosterol remains stable with the increase of maturity.Whereas α-tocopherol and total polyphenols exhibited greater variability. Comprehensive evaluation identified the top five varieties for oil quality. I: K2> FS17> Nikiskii > Gai> Lyuan Manzanilla de Sevilla. II: Agiou orous >FS17> Nikiskii > Megaritiki> Gai; III: Agiou orous > FS17> Nikiskii > Lyuan Manzanilla de Sevilla > Megaritiki. Cluster analysis classified germplasms into three distinct categories, with Group I serving as core germplasm suitable for bulk commodity oil production while Group II represents ideal material for cultivating highly stable specialty oils and fats. Germplasms in Group III represent a valuable resource for developing hypoglycemic and lipid-lowering functional oils. This study establishes a foundation for olive breeding, cultivation promotion, and processing in Longnan, China.