采用感官分析结合色度仪、气相色谱-质谱联用仪、电子舌、扫描电镜对蒸制过程中黄精“色、香、味、形”进行描述。利用尺寸排阻凝胶色谱、离子色谱、傅里叶红外光谱分析多糖的分子质量分布、单糖组成、多糖结构。结果发现：蒸制过程中，黄精由黄白变为黑褐色，苦味值、甜味值降低，于五次蒸制出现苦味；内部于第二次蒸制出现孔隙，组织结构由致密变得疏松多孔。黄精生品中的多糖分子量集中在12.8 ku左右；九蒸九制工艺使黄精多糖的分子量分布范围增大，出现分子量大于670 ku和分子量2 000 u左右的组分。经第一次蒸制，黄精多糖的单糖组成出现D-核糖、半乳糖醛酸两种单糖，葡萄糖醛酸、岩藻糖分别于第三、四次蒸制后消失。红外光谱显示，0~9次蒸制黄精的多糖均在3 410 cm-1、2 930 cm-1处均有较强的糖类特征吸收峰，1 200~1 000 cm-1、880 cm-1处吸收峰提示多糖中吡喃糖及β-糖苷键的存在。通过研究九蒸九制过程中黄精理化品质形成及多糖变化规律，为黄精九蒸九制工艺标准化、质量标准制定提供参考。

Sensory evaluation combined with colorimeter, gas chromatography-mass spectrometry, electronic tongue and scanning electron microscope were used to describe the "color, aroma, taste and shape" of Polygonatum sibiricum root. The molecular weight distribution, monosaccharide composition and structure of the polysaccharides were analyzed by size exclusion gel chromatography, ion chromatography and Fourier transform infrared spectroscopy. The results showed that during the steaming process, the Polygonatum sibiricum root changed from yellowish white to dark brown. The bitterness score and sweetness score decreased, and the bitterness appeared after being steamed five times. Internal pores appeared during the second steaming, with the tissue structure changing from dense to loose and porous. The molecular weight of polysaccharide in the raw Polygonatum sibiricum root was about 12.8 ku. The molecular weight distribution of the Polygonatum sibiricum root polysaccharides increased after the nine-steam-nine-dry-bask process, leading to the presence of fractions containing components with molecular weights greater than 670 ku and around 2 000 u. D-ribose and galacturonic acid were found in the monosaccharides from the Polygonatum root steamed once, whilst the glucuronic acid and fucose disappeared after the third and fourth steaming, respectively. The IR spectra showed relatively strong characteristic absorption at 3 410 cm-1 and 2 930 cm-1 for the polysaccharides from the Polygonatum root steamed for 0~9 times, and the absorption peaks at 1 200~1 000 cm-1 and 880 cm-1 indicated the occurrence of pyranose and β-glycosidic bonds in the polysaccharides. Investigations on the development of the physicochemical quality of Polygonatum root and the changing trend of its polysaccharide during the nine-steam-nine-bask process allow us to provide a reference for the standardization of nine-steam-nine-bask process and the establishment of quality standards.

高值中草药系列产品研发（BB30500075）