彩色马铃薯块茎中花色苷分布差异及取样方法探讨

为考察花色苷在马铃薯块茎中的含量分布差异，探讨兼具代表性和经济性的科学取样方法。试验选取颜色不同的三个彩色马铃薯品种（系）:黑金刚、品系21-1和剑川红作为试验材料，从块茎大小、薯块纵向、横向三个角度分析了马铃薯花色苷的含量差异。结果表明:同株采收的马铃薯，大、中、小薯间花色苷含量存在显著性差异（P<0.05），差异程度受品种（系）因素影响；同一块茎中，花色苷含量沿横向分布存在显著性差异（P<0.05），横向分布上薯皮中花色苷含量显著高于薯肉。其中，剑川红薯皮中花色苷含量约是薯肉中的7倍，黑金刚薯皮中花色苷含量约是薯肉中的2.5倍，品系21-1薯皮中花色苷含量比薯肉中高1.5倍；在纵向分布上，花色苷含量亦存在显著性差异（P<0.05）。其中，黑金刚与21-1的块茎顶部和脐部花色苷含量显著高于中部，剑川红的块茎顶部花色苷显著高于中部和脐部；部分取样对整体的代表性方面:分别以块茎纵切后按取对角2份、随机取1份和取整薯三种方式取样，花色苷在三种取样方式下测定结果差异不显著（P?0.05），表明通过纵切取少部分薯块样本即可满足对整体块茎花色苷含量水平的有效定量；样品打浆与样品研磨相比，显著降低了块茎花色苷的含量测定结果（P<0.05），不适用于研究分析。因此，纵切取对角的取样方式适用于马铃薯花色苷含量检测时块茎取样。

Anthocyanin Distribution and Sampling Method in Colored Potato Tubers

In order to investigate the difference of anthocyanin distribution in potato tuber and explore the most applicable method for sampling economically and scientifically, three colored potato materials, ‘Heijingang (variety)’, ‘21-1 (line)’ and ‘Jianchuanhong (variety)’ with various pigment accumulation were selected for the analysis of the tuber anthocyanin content depend on the size (large, middle and small) and length (longitudinal and the lateral) of the tuber, as well as the angle (transversely, vertically and diagonally) from where the tuber was cut for sampling. The results showed that the distribution of the potato anthocyanins in the same species was significantly different due to the material and size differences (P<0.05). In the same tuber, the allocation of anthocyanins was of significant difference along the horizontal area, which was significantly higher in the potato flesh (P<0.05). Specifically, the anthocyanins level in the skin of ‘Jianchuanhong’ was about 7-fold higher than the flesh, while it was 2.5-fold and 1.5-fold higher in ‘Heijingang’ and ‘21-1’ respectively. By comparison, in the longitudinal distribution, anthocyanins contents in the top and umbilical regions of the ‘Heijingang’ and ‘21-1’ were both significantly higher than the middle part, whereas the top of the ‘Jianchuanhong’ was significantly higher than the middle and the umbilical area (P<0.05). Relatively, the three methods utilized to cut the tubers from three angles did not reflect significant differences in terms of the anthocyanin quantification (P?0.05), showing that sample lesser amount of the tuber through the diagonal cut might be a much more efficient and economical way for the potato pigment analysis. Lastly, this study also compared the analytical effects between tuber grinding and pulping, demonstrating that the pulping method could cause the anthocyanin loss drastically (P<0.05), which was not an appropriate way for the potato tuber pigment quantification. Thus, cutting the potato tuber from a morphologically diagonal angle with lesser amount would be a quite favorable approach for the lab detection of potato tuber anthocyanins.