宁夏菜心不同部位发酵理化品质及挥发性风味物质的分析

为探究宁夏菜心湿态发酵的可行性，该研究通过对宁夏菜心基部茎、顶端茎、叶子以及菜心整体进行乳酸菌接种发酵，解析发酵前后微生物、有机酸、亚硝酸盐、抗氧化能力、生物胺以及挥发性风味物质的变化规律。研究表明，发酵后菜心各部位总有机酸含量升高、亚硝酸盐含量降低、抗氧化能力降低和生物胺含量降低，基部茎、叶子、整颗菜心的挥发性性风味物质种类含量均升高；菜心叶子经发酵后亚硝酸盐含量和生物胺含量分别降解了0.30和22.78 mg/kg，DPPH自由基清除率62.06%，总有机酸含量3 212.70 mg/100 g，挥发性风味物质种类丰富，检出48种化合物，相对含量为123.68 g/g。与其他发酵组相比，叶子发酵组的理化指标和挥发性风味物质含量均处于较优水平。以上研究表明宁夏菜心可作为泡菜发酵的原材料，且较优发酵部位是叶子，该研究为菜心的湿态发酵奠定基础。

Analysis of the Physicochemical Qualities and Volatile Flavor Compounds of the Different Parts of Fermented Ningxia Brassica parachinensis L.

In order to explore the feasibility of wet fermentation of Ningxia Chinese flowering cabbage, the basal stems, apical stems, leaves and the whole of Ningxia Brassica parachinensis L. were fermented with lactic acid bacteria, respectively. The changing trends of microorganisms, organic acids, nitrite, antioxidant capacity, biogenic amines, and volatile flavor substances before and after fermentation of Ningxia Brassica parachinensis L. were analyzed. The results indicated that the contents of total organic acids for all the fermented samples increased, their nitrite concentration, biogenic amine content and antioxidant capacity all decreased, and both the number of species and the contents of volatile flavor substances in the basal stems, leaves and whole Ningxia Brassica parachinensis L. increased. After fermentation, the nitrite and biogenic amine contents of leaves decreased by 0.30 and 22.78 mg/kg, respectively. and the DPPH free radical scavenging rate and total organic acid content of the fermented leaves were 62.06% and 3 212.70 mg/100 g, respectively. The volatile flavor compounds were abundant, and 48 compounds were detected (with a relative content of 123.68 g/g). Compared with the other fermentation groups, the physico-chemical indexes and contents of volatile flavor substances of the fermented leaves were at superior levels. The above results showed that Ningxia Brassica parachinensis L. could be used as the raw material for kimchi fermentation, and the leaf was the most suitable site for fermentation. This research laid a foundation for wet fermentation of Brassica parachinensis L.