Comprehensive Quality Evaluation, Key Flavor Characterization, and Geographical Origin Discrimination of Quinces from Major Production Areas in Xinjiang

This study aimed to investigate regional differences in the quality and flavor of quinces (Cydonia oblonga Mill.) from major production areas in Xinjiang and to establish a robust method for the geographical origin discrimination of this fruit. Quinces from six representative production regions (Kashi city, Zepu county, Korla city, Bole city, Shache county, and Cele county) were systematically analyzed for appearance, nutritional composition, antioxidant activity, and volatile flavor compounds. Based on these attributes, a comprehensive quality evaluation system was developed. Significant differences (P < 0.05) in physicochemical and nutritional indices were observed among quinces from different production regions. Samples from Cele county exhibited the highest titratable acidity (46.90 g/L) and total antioxidant capacity (T-AOC, 205.43 μmol/g). Headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) identified 88 volatile compounds. The total ester content in samples from Zepu county was the highest among these production regions. Based on odor activity values, 12 key aroma-active compounds were identified, among which damascenone was found to be a potential common key aroma compound. Orthogonal partial least squares-discriminant analysis (OPLS-DA) effectively differentiated quinces from different geographical origins. Variable importance in projection (VIP) analysis further identified 5 and 14 key differential markers from the peel and pulp, respectively, which were primarily associated with color indices, total phenolics, damascenone, aldehydes, and esters. The integrated multi-dimensional evaluation system and the discriminant model established in this study provide a theoretical basis for the quality grading, geographical indication protection, and targeted product development of Xinjiang quince resources.