柑橘果实矿质元素、活性物质含量特征及综合评价

A comprehensive evaluation of mineral elements and active substances in citrus fruits

【目的】通过对不同柑橘品种矿质元素、酚类物质含量及抗氧化性能的分析,筛选高营养价值的柑橘资源。【方法】以13个柑橘品种为试验材料,分析果实的8种矿质元素、总黄酮、总酚含量及3种抗氧化性能指标,采用相关性、PCA及热图聚类分析等多元统计方法对果实营养成分进行综合评价。【结果】果肉和果皮中8种矿质元素含量的变异系数分别为11.10%~41.26%和15.62%~46.23%,平均含量在果肉中从高到低为K>Ca>P>Mg>Na>Fe>Mn>Zn,果皮中排序为K>Ca>P>Mg>Na>Mn>Fe>Zn。柑橘是高K低Na水果,其中Ca、Mn在果皮中的含量高于果肉,而P相反。总黄酮和总酚含量均以酸橙最高,茶枝柑次高。采用抗氧化能力综合评价法得到排名前3的柑橘品种依次为酸橙、高橙、塔罗科血橙。通过PCA分析,得到3个主成分,累积贡献率为77.939%。【结论】柑橘矿质元素分布存在空间特异性,不同品种酚类物质含量存在较大差异,以酸橙、青瓯柑、媛小春和塔罗科血橙的矿质元素、活性物质含量较高。研究结果为柑橘优良品种的筛选、培育及功能食品的开发提供数据支撑和参考。

【Objective】Mineral elements play an important role in the growth,development,and yield formation of fruit trees and are also essential nutrients for human health.Citrus fruits contain abundant mineral elements required by the human body,which can be used as one of the important indicators for evaluating nutritional quality.In addition,citrus fruits are rich in phenolic substances,which have antiinflammatory,antioxidant,and anti-tumor effects.However,there are currently few reports on the accumulation characteristics and comprehensive evaluation of mineral elements in different parts of newly cultivated and introduced citrus varieties.Meanwhile,as consumers increasingly pay attention to health foods,a large amount of data related to nutrition and antioxidant activity is needed to screen for excellent citrus germplasm.Therefore,this study aimed to analyze mineral elements,polyphenols,antioxidant properties,and their relationship in different citrus varieties and to screen citrus resources with high nutritional value.【Methods】Mature fruit samples of all varieties were collected from Zhejiang Citrus Research Institute under consistent cultivation and management conditions.All citrus fruits were thoroughly washed,wiped with gauze,and seeded.The peel and pulp of samples were dried in an oven at 40℃,crushed through a 60-mesh sieve,and stored at−80℃.Atomic absorption analysis was used to analyze mineral nutrients(K,Ca,Mg,Na,Fe,Mn,and Zn),while the P content was determined by spectrometry.Total flavonoid content,total phenolic content,and antioxidant capacity were also determined.Subsequently,correlation analysis,principal component analysis(PCA),and heat map cluster analysis were employed to comprehensively evaluate the fruit quality of different citrus varieties.The data were organized using Excel 2010,and principal component analysis and comprehensive analysis were conducted using SPSS 22.Correlation graphing and heat map cluster analysis were performed using Origin 2024.【Results】The total mineral element content in citrus pulp ranged from 10918.22 to 17042.22 mg·kg^(-1) and from 12612.91 to 19777.92 mg·kg^(-1) in the peel.The coefficient of variation of mineral elements ranged from 11.10%to 41.26%in pulp and from 15.62%to 46.23%in peel.Among the 13 citrus varieties,the total mineral element contents in pulp was in the order of Sour orange>Ougan>Green Ougan>Bendizao>Himekoharu>Yuhuanyou>Tarocco blood orange>Ponkan>Cocktail grapefruit>Gaocheng>Hongmeiren>Chazhigan>Miyagawa wase,and in the peel the order was Sour orange>Yuhuanyou>Himekoharu>Miyagawa wase>Hongmeiren>Gaocheng>Chazhigan>Cocktail grapefruit>Ougan>Green Ougan>Bendizao>Tarocco blood orange>Ponkan.The average mineral element contents among the 13 citrus varieties in pulp was in the order of K>Ca>P>Mg>Na>Fe>Mn>Zn,and the order was K>Ca>P>Mg>Na>Mn>Fe>Zn in the peel.K and Na accounted for 73.79%and 2.09%of the total analyzed mineral elements,respectively.The characteristics of citrus fruits were high in K and low in Na.From the perspective of mineral element distribution,the contents of Ca and Mn in the peel were higher than in the pulp,while P was the opposite.Except for Yuhuanyou,the Fe content in the peel was higher than in the pulp,while the K content was higher in the pulp except for Miyagawa wase and Chazhigan.The content of phenolic substances varied among varieties.Sour orange had the highest contents of total flavonoids and total phenolics,and those of Chazhigan were the second highest.The antioxidant activity was positively correlated with the contents of total phenolics and total flavonoids in citrus pulp.The top three antioxidant capacities among all the different varieties were Sour orange,Gaocheng,and Tarocco blood orange,and the lowest was Hongmeiren.The correlation analysis showed that P,K,Ca,Mg,and Fe were significantly positively correlated.Na showed a highly significant negative correlation with Ca and a significant negative correlation with K.Ca promoted the accumulation of total flavonoids,while P and Na had antagonistic effects on the accumulation of flavonoids and phenolics.Three principal components were obtained using PCA analysis with a cumulative variance contribution of 77.939%.The contents of K,Ca,Mg total flavonoids,and total phenolics were the key indicators for comprehensive nutritional evaluation of citrus fruit.The comprehensive evaluation model was established:F=0.508F_(1)+0.357F_(2)+0.135F_(3).The comprehensive scores of mineral elements and polyphenols in the 13 citrus varieties was in an order of Sour orange>Green Ougan>Himekoharu>Tarocco blood orange>Ougan>Chazhigan>Bendizao>Yuhuanyou>Gaocheng>Ponkan>Cocktail grapefruit>Hongmeiren>Miyagawa wase.The 13 citrus varieties were divided into 4 categories by cluster analysis.Sour orange was in the first group;Yuhuanyou was in the second group;Miyagawa wase was in the fourth group,and the other varieties were clustered into the third group.【Conclusion】There was spatial specificity in the distribution of mineral elements in citrus,and there were significant differences in the content of phenolic substances among different citrus varieties.Sour orange,Green Ougan,Himekoharu,and Tarocco blood orange were rich in mineral elements and active substances.