Abstract: A strain of producing fragrant yeast —— Hansenula anomala Y16 was used as the tested strain, which was isolated from the traditionally fermented Jiangshui (Tianshui, Gansu). After being high-density fermented, the preparation technology of its aroma-enhancing yeast starter was optimized by using Plackett-Burman test, steepest ascent test and response surface methodology (RSM). The results showed that the cell density of Y16 could reached 9.2×1010 CFU/mL after high-density culturing. And the optimum centrifugation conditions for collecting Y16 fermentation broth was being centrifuged at 1 600 g for 10 min, after that the centrifugal sedimentation rate of living cells was 95.5%. While the optimal combination of protective agent for the yeast starter was 11% skim milk powder, 9% sucrose and 12% trehalose, and under this condition, the yeast survival rate of lyophilizing inoculum was up to 91.54%. This flavoring starter prepared by the above process still had good storage stability after the storage period of 3 months. In addition, the result of simulated fermentation test of Jiangshui showed that the product had good flavor. The research result could provide a source of aroma-enhancing starter for Jiangshui industrial production.

Key words: Jiangshui, direct vat aroma-enhancing yeast starter, preparation technology, vacuum freeze-drying, Hansenula anomala

摘要： 以一株分离自甘肃天水传统酿造浆水中的产香酵母——异常汉逊酵母（Hansenula anomala）Y16为供试菌株，经高密度发酵后，采用Plackets-Burman试验、最陡爬坡实验及响应面法（response surface methodology，RSM），对其直投式增香酵母冻干菌剂的制备工艺进行优化。结果表明，经高密度增殖培养后，酵母Y16细胞浓度可达9.2×1010 CFU/mL；收集Y16发酵液的最佳离心条件：Y16发酵液经1 600 g离心10 min，离心沉降活细胞率为95.5%；冻干保护剂最佳组合配方：11%脱脂奶粉，9%蔗糖，12%海藻糖，在该条件下，冻干菌剂中酵母存活率为91.54%。经上述工艺制备的增香发酵剂保存3个月仍具有较好的贮藏稳定性。此外，浆水模拟发酵试验的结果表明，浆水风味优良。研究结果为浆水工业化生产提供了良好的增香发酵剂来源。

关键词: 浆水, 直投式增香发酵剂, 制备工艺, 真空冷冻干燥, 异常汉逊酵母