1.Pomology Institute,Shanxi Agricultural University;2.Shanxi Key Laboratory of Germplasm Improvement and Utilization in Pomology,Taiyuan 030031
National Science and Technology Resource Sharing Service Platform Project (NHGRC2021-NH12-1); China Agriculture Research System (CARS-30-5-02；CARS-30-ZZ-22)
糖和酸是构成果实风味的重要物质，系统鉴定评价枣品种资源果实的糖酸风味，比较不同资源间的糖酸风味构成差异，建立枣品种资源果实糖酸风味评价体系，对资源高效利用具有重要意义。以210份枣资源脆熟期果实为试材，测定可溶性固形物、可滴定酸以及糖组分含量，并进行相关性分析。结果如下：(1) 10项指标的变异系数范围在9.81%~34.70%，其中可溶性固形物、甜度值和总糖的变异系数较小。蔗糖的范围最宽，最大值和最小值相差83.54倍。果糖、葡萄糖、蔗糖、总糖、可滴定酸、甜度值、固酸比和糖酸比等8项指标服从正态分布，可溶性固形物和甜酸比不服从正态分布。(2) 果糖、葡萄糖、蔗糖与总糖含量均呈极显著正相关，果糖与葡萄糖含量呈极显著正相关，总糖、可溶性固形物和甜度值间都呈极显著正相关，可滴定酸与固酸比、糖酸比和甜酸比间都呈极显著负相关，固酸比、糖酸比、甜酸比两两之间都呈极显著正相关。(3) 因子分析共提取3个主因子，累积贡献率为91.781%。结合各项指标的聚类分析，筛选出果糖、蔗糖、可溶性固形物、可滴定酸和固酸比5项评价枣果实糖酸风味的指标。(4) 基于5项评价指标进行聚类分析，将210个枣品种分为5个类群，根据各类群不同指标的含量特征，分别定义为低蔗糖型、高酸型、果糖优势型、居中类型和蔗糖优势型，其中蔗糖优势型包含的种质最多。可用果糖、蔗糖、可溶性固形物、可滴定酸和固酸比5项指标对枣果实糖酸风味进行评价，不同品种资源脆熟期枣果实以蔗糖优势型为主，不同类群果实风味不同，生产中可根据不同类群资源的糖酸指标特点进行针对性应用。
Sugars and acids are important components that contribute to the flavor of fruits. In this study, we systematically identified and evaluated the sugar-acid flavor indexes of jujube variety resources, and analyzed the compositional differences in sugar-acid flavor among different resources. Finally, an evaluation system for sugar-acid flavor in jujube fruit were established. The results are of great significance for efficient utilization of resources. A total of 210 jujube varieties fruits at the crisp ripening stage were used as experimental materials. The contents of soluble solids, titrable acids, and sugar components were measured, and correlation analysis was performed. The results were as follows: (1) The coefficient of variation ranged from 9.81% ~ 34.70% for the 10 indexes, with smaller coefficient for soluble solids, sweetness value, and total sugar. Sucrose showed the widest range, with a difference of 83.54 times between the maximum and minimum values. Eight indexes, including fructose, glucose, sucrose, total sugar, titrable acid, sweetness value, solid-acid ratio and sugar-acid ratio, followed a normal distribution, while soluble solid and sweet-acid ratio did not follow a normal distribution. (2) The results of correlation analysis showed that fructose, glucose and sucrose were significantly positive correlated with total sugar content. There was a significant positive correlation between fructose and glucose content. There was a significant positive correlation between total sugar, soluble solid and sweet value. Titrable acid was significanlty negatively correlated with solid-acid ratio, sugar-acid ratio and sweet-acid ratio. The solid-acid ratio, sugar-acid ratio and sweet-acid ratio were significantly positive correlated with each other. (3) Factor analysis extracted three main factors with a cumulative contribution rate of 91.781%. Combined with the cluster analysis of various indexes, five indexes, including fructose, sucrose, soluble solid, titrable acid and solid-acid ratio, were selected to evaluate the sugar-acid flavor of jujube fruit. (4) Based on the five evaluation indexes, cluster analysis divided the 210 jujube varieties into five groups. According to the different indexes profiles, these clusters were defined as low sucrose type, high acid type, fructose dominant type, intermediate type and sucrose dominant type, with the sucrose dominant type containing the largest number of varieties. The evaluation of sugar-acid flavor in jujube fruit can be performed using the five indexes of fructose, sucrose, soluble solid, titrable acid and solid-acid ratio. Sucrose dominant type was the main type of fruits in different varieties. Different types of fruits have different flavors. In production, targeted applications can be developed based on the sugar and acid indexes of different varieties resources.