关键词: 枣, 果实品质, 理化指标, 质构特征, 回归模型, 综合评价

Abstract:

【Objective】This study aimed to establish a standardized and objective evaluation method for the textural quality of jujube fruits through comprehensive analysis of sensory, textural, and physicochemical traits, so as to provide a solid theoretical basis for fruit quality evaluation and selective breeding of jujube germplasm resources.【Method】A total of 123 jujube germplasms with different utilization types were employed as experimental materials. Correlation analysis, principal component analysis (PCA), significance difference analysis and stepwise linear regression were performed on sensory, textural and physicochemical indices of jujube fruits. The core indicators affecting fruit quality were screened, and a digital comprehensive evaluation model for jujube fruit quality was subsequently constructed.【Result】Descriptive statistical analysis revealed extensive phenotypic variations in sensory, textural and physicochemical traits among different jujube germplasms. The coefficient of variation (CV) of sensory indices ranged from 22.13% to 47.80%, that of textural indices from 13.94% to 30.84%, and that of physicochemical indices from 3.95% to 46.68%; pulp moisture content possessed the minimum CV of 3.95%. Correlation analysis demonstrated that the comprehensive taste quality of jujube fruits was strongly correlated with cell wall component contents. PCA identified five core factors affecting fruit quality from 14 textural and physiological indices, including cell wall components, total phenols and flavonoids, total soluble sugars, pulp moisture content, and soluble protein. The respective contribution rates of the first four principal factors were 28.97%, 13.07%, 10.72%, 8.75%, 7.52%, respectively, with a cumulative contribution rate of 69.03% to the total phenotypic variation. The comprehensive score H of tested germplasms varied from -1.48 to 1.52. The top 5% of germplasms ranked by H value had scores varying from 1.18 to 1.52, while the bottom 5% germplasms ranged from -1.48 to -0.97. Germplasms with high H values exhibited dense fruit texture, low juice yield and thick peel in sensory performance; those with low H values showed crisp texture, high juice yield and thin peel. A significant correlation was detected between total sensory scores and comprehensive H values. Significance difference analysis indicated fresh-eating jujube germplasms exhibited crisp texture, thin-peeled and juicy; drying-type germplasms exhibited denser texture, thick-peeled and low-juice; dual-purpose (fresh and dried) cultivars had moderately dense flesh, medium-thick peel and abundant juice. Finally, stepwise linear regression established a predictive model for sensory score: Y=7.16×10^-16+0.26CSP+0.285HCE+0.207WSP+0.183ISP+0.229CE+ 0.132TPC+0.108SC+0.083SP, where Y represented the comprehensive sensory score. The model presented high precision with a determination coefficient of R² = 0.98.【Conclusion】In conclusion, the model constructed from textural and physicochemical parameters achieved favorable evaluation performance on jujube fruit texture quality and eliminates the subjective bias inherent in conventional sensory evaluation.

Key words: jujube, fruit quality, physicochemical indices, texture characteristics, regression model, comprehensive evaluation