骏枣变温干燥工艺优化及品质评价

为了明确灰枣不同枝龄二次枝果实品质差异性，比较同一树龄灰枣树不同枝龄二次枝的果实品质指标并对其进行因子分析和综合评价，为灰枣不同枝龄果实品质形成机理研究及科学整形修剪管理提供理论依据。该研究以新疆红枣主栽品种“灰枣”作为研究对象，测定枝龄不同的二次枝果实21项品质指标，对其进行因子分析，建立综合品质评价模型，并根据综合品质得分进行优良度排序。灰枣不同枝龄二次枝果实21项品质指标的变异系数（CV）均有所差异，其中P、Mn、Cu和总酸含量的变异系数均大于15.0%，其中果实P含量的CV最大，为19.2%；Vc、Ca和Fe含量及色差值b*的CV均在10.0%～15.0%之间；总黄酮和Zn含量、色差值L*和a*的CV均在5.0%～10.0%之间；其余品质指标的CV均小于5.0%。经因子分析提取特征根值大于1的3个公因子，其累计方差贡献率达100.00%，第1公因子（f₁）的贡献率为44.81%，主要由果实表面色差值L*、a*、b*、果实纵径、果实横径、果形指数、单果质量和Mg含量8个因子决定，主要反映了果实表面颜色、果实大小等果实外观品质指标。第2公因子（f₂）的贡献率32.21%，由蛋白质、总黄酮、可溶性固形物、总糖、K、总酸和Cu含量7个因子决定，主要反映了果实酸甜口感品质及部分矿质元素含量的高低水平。第3公因子（f₃）的贡献率22.99%，由P、Zn、Ca、Mn、Fe和Vc 含量6个因子决定，主要反映了大部分果实矿物质元素和Vc含量的高低水平。总之而言，灰枣4种枝龄二次枝果实综合品质优良度排序为3年生二次枝果实>4年生二次枝果实>2年生二次枝果实>1年生二次枝果实，在灰枣生产过程中，可以根据不同枝龄二次枝果实的不同优势，形成因地制宜的灰枣栽培模式，整形修剪中多留2年生以上的结果枝，应尽量减少1年生二次枝上结果。

Optimization of the variable temperature drying process and quality evaluation of Junzao jujube

Various modes are adopted in fruit tree cultivation, according to the growth and development of tree species and varieties, local climate, geography, water and soil resources, and human activities. There are also differences in shaping and pruning. The fruit quality and yield can depend mainly on the advantage ratio between nutrient sources and reservoirs in different parts of the tree crown. Taking 'Huizao' jujube as an example, there are different requirements in the renewal period of the fruiting branch group under cultivation modes. There are also great variations in the fruiting, yield, and fruit quality of secondary branches at different branch ages. In this study, an evaluation system was established for the pruning and fruit quality of 'Huizao' jujube. 21 quality indicators were also compared, such as biomass characteristic parameters, surface color difference values, and mineral element content of 1, 2, 3, and 4-year-old secondary branch fruits. The comprehensive quality model was proposed to rank the excellent degree, according to the comprehensive quality score. The results indicate that there was a significant difference in the variation coefficient (CV) of 21 fruit quality indexes. The CV values of the total P, Mn, Cu, and total acid content were all greater than 15.0%, among them the CV of total P content was the largest (19.2%); the CV of ascorbic acid content, Ca, Fe, and color difference value b* were between 10.0% and 15.0%, the CV of total flavonoids content and color difference value L* , Zn and color difference value a* were between 5.0% and 10.0%, the CV of other quality indexes were less than 5.0%. Three common factors with characteristic root values greater than 1 were extracted by factor analysis, where the cumulative variance contribution rate was 100.00%. The contribution rate of the first common factor was 44.81%, which was mainly determined by eight factors (the fruit surface color difference value L* , a* , b* , fruit longitudinal diameter, fruit transverse diameter, fruit shape index, single fruit weight and Mg content), indicating the fruit surface color, fruit size, and appearance quality indicators. The contribution rate of the second common factor was 32.21%, which was determined by the contents of protein, total flavonoids, soluble solids, total sugar, K, total acid and Cu, indicating the taste quality and level of some nutritional contents. The contribution rate of the third common factor was 22.99%, which was determined by the contents of total P, Zn, Ca, Mn, Fe and ascorbic acid, indicating the content of mineral elements and Vc in fruits. The comprehensive quality score of fruit on the secondary branch was ranked in the order of the three- > four- > two- > one -year-old secondary branch fruit. A suitable cultivation model was formed to balance the various advantages of the secondary branches with different ages. More than two-year-old branches should be left, whereas, the one-year-old secondary branches should be minimized as much as possible when pruning of 'Huizao' jujube.