可食椰衣纤维椰子果皮苦涩味道缺失与酚类和糖类物质含量的关系

【目的】测定可食椰衣纤维椰子果皮中酚类和糖类物质含量，分析其苦涩味道缺失的生理原因，为该种质的深入研究及创新利用提供参考依据。【方法】采用高效液相色谱技术测定可食椰衣纤维椰子和海南本地高种椰子（对照）2份材料的椰果外果皮与中果皮在其3个生长时期（幼果期、嫩果期和老果期）的酚类及糖类物质含量，并分析酚类和糖类物质含量与果皮苦涩味道缺失的关系。【结果】在外果皮中，可食椰衣纤维椰子的儿茶素和单宁含量在嫩果期和老果期均显著低于对照（P<0.05，下同），且2种酚类物质在嫩果期的含量约为对照的50.0%，绿原酸含量在老果期也显著低于对照。在中果皮生长期间，可食椰衣纤维椰子的儿茶素含量均显著低于对照，而绿原酸含量仅在嫩果期显著低于对照，单宁含量在二者间则无显著差异（P>0.05，下同）；其中，嫩果期的儿茶素和绿原酸含量分别是对照的14.3%和19.7%。可食椰衣纤维椰子外果皮在3个生长时期的果糖、葡萄糖和蔗糖含量均与对照无显著差异，而嫩果期中果皮的果糖、葡萄糖和蔗糖含量均显著高于对照，约是对照的1.5、1.7和1.9倍。相关分析结果表明，外果皮中葡萄糖和蔗糖含量与儿茶素含量呈显著负相关，绿原酸与3个糖组分含量间均呈极显著负相关（P<0.01，下同）；中果皮中儿茶素与蔗糖含量呈显著负相关，单宁与3个糖组分含量间均呈极显著负相关。【结论】可食椰衣纤维椰子果皮中，儿茶素、单宁及绿原酸等酚类物质含量的降低和果糖、葡萄糖及蔗糖等糖类物质含量的增加，可能是造成该种质果皮苦涩味道缺失的重要原因之一。

Relationship between the absence of bitter and astringency for edible fiber coconut pericarp and the content of phenols and saccharides

【Objective】Determination of phenols and sugars contents in edible fiber coconut (EFC), explore the physiological reasons for the absence of bitter and astringency in the pericarp of EFC and provide relevant data for the studying and utilization of EFC.【Method】The contents of phenols and sugars in exocarp and mesocarp of coconut fruit at three growth stages(young, tender and mature fruit) were determined by high-performance liquid chromatography technology (HPLC) with EFC as material and Hainan local variety as control. The relationship between the content of phenols and saccharides and the lack of bitter peel was analyzed.【Result】The results showed that:in the exocarp, thecatechin and tannin content in the tender fruits and mature fruits of EFC was significantly lower than that of the control material(P<0.05, the same below), the two phenols contents at tender fruit period were about 50.0% as much as the control. And the content of chlorogenic acid of EFC was also significantly lower than that of the control material in the maturefruits. In the mesocarp, the content of catechin of EFC was significantly lower than that of the control material at three growth stages, whilethe content of chlorogenic acid was significantly lower than that of the controlonlyin the tender fruits, and there was no significant difference in the tannin content between the EFC and control(P>0.05, the same below). The contents of catechin, chlorogenic acid in the EFC young fruitswere about 14.3% and 19.7% of the control, respectively. In the exocarp, there was no significant difference in fructose, glucose and sucrose contents between EFC and control materials at three growth stages. In the mesocarp, the three sugars contents in the tender fruits were significantly higher than those of the control, they were as 1.5 times, 1.7 times and 1.9 times as that of the control, respectively. The results of correlation analysis showed that glucose and sucrose contents in the pericarp were significantly negatively correlated with catechin content, while chlorogenic acid was extremely significantly negatively correlated with the content of the three sugar components (P<0.01, the same below). There was significant negative correlation between catechin content and sucrose content in mesocarp, while there was extremely significant negative correlation between tannin content and the three sugar components.【Conclusion】The reducing of the content of phenolic substances(catechin, tannin and chlorogenic acid) and the increase of the content of saccharide(fructose, glucose and sucrose) in the mesocarp of EFCmight be one of the important reasons for the absence of bitter and astringency taste in EFC.