Comprehensive evaluation system for quality characteristics of olive (Olea europaea L.) in Longnan, China

Abstract

Olive (Olea europaea L.), which originated from the Mediterranean region, has been cultivated in Longnan City, China, for several decades and demonstrated a remarkable adaptation to the local environment. Despite the social and economic importance of olive cultivation, a comprehensive evaluation of olive quality remains lacking to date. Thus, this study aimed to compare and characterize 20 quality-related indices across 20 olive cultivars grown in China by using Pearson correlation, principal component, and hierarchical clustering analyses. All the tested indices exhibited significant variations among the 20 olive cultivars. Five principal component factors were extracted to establish a comprehensive quality evaluation model represented by Y = 0.398Y₁+0.286Y₂+0.140Y₃+0.105Y₄+0.071Y₅. Based on their comprehensive scores, the 20 olive cultivars were categorized into four distinct groups. The cultivars Cornicabra, Picholine Languedoc, Koroneiki, Picual, Yuntai14, and Coratina were classified within the excellent-quality group. The core quality parameters for olives in Longnan City included moisture content (MC), peroxide value (PV), oil content (OC), ratio of monounsaturated and polyunsaturated fatty acids (MUFA/PUFA), ratio of oleic and linoleic acids (C18:1/C18:2), total polyphenol content (TPC), and oxidative stability (OS). This study may serve as a basis for evaluating olive quality and advancing standardized quality classification. It also promotes high-value development and utilization within the olive industry, particularly for the development of functional foods and innovation in lipid-based products.