本文主要对浏阳豆豉自然发酵工艺过程中豆豉的理化、微生物指标、滋气味的变化规律进行研究。在湖南某豆豉厂取样，采用可培养方法测定细菌和真菌数量的变化，并检测不同阶段的总酸、氨基酸态氮、蛋白质及水分的变化、电子舌测定滋气味变化。结果表明：在浏阳豆豉生产过程中，制曲时细菌总数在发酵4 d达到最大值3.8×1011 CFU/g，霉菌总数的最大值为1.5×105 CFU/g，总酸和氨基酸态氮的变化趋势相似，成品中总酸达到2.15%，氨基酸态氮到1.37%。总氮在发酵过程中变化不大，水分变化与工艺有关。成品中蛋白质含量达到40.08%，水分含量在发酵过程中一直在减少，成品中只有14.30%。电子鼻的主成分分析图能显著区分发酵过程中各组分样品；电子舌稳定有效地检测出不同发酵阶段豆豉的味觉差异，主要体现在苦味、鲜味、丰富度和咸味上。发酵17 d苦味、鲜味强度最大，堆积发酵4 d咸味和丰富度强度最大。

Dynamic changes in physicochemical indexes, microbiological indicators, and flavor during natural fermentation of Liuyang douchi were studied. Samples were obtained from the Liuyang Tianmashan Lobster Sauce Factory. Culture-based methods were used to determine changes in the bacterial and fungal counts, and total acid, amino acid nitrogen, protein, and water content were measured. The results indicated that during the production of Liuyang douchi, the total bacterial count reached a maximum (3.8×1011 CFU/g) on the fourth day, and the maximum fungal count was 1.5×105 CFU/g. Changes in total acid and amino acid nitrogen showed similar trends, and the content of total acid and amino acid nitrogen in the finished product were 2.15% and 1.37%, respectively. The total nitrogen content changed slightly during the fermentation process. The protein content in the finished product was 40.08%. The moisture content showed a downward trend during the fermentation and reached 14.30% in the finished product. Principal component analysis of the data obtained using an electronic nose could distinguish samples taken at different stages of the fermentation process. The electronic tongue could stably and efficiently detect differences in taste of the lobster sauce at various stages of the fermentation, mainly reflected in the bitterness, umami, richness and saltiness. The maximum intensities of bitterness and umami were found after 17 d of fermentation, and the maximum intensities of saltiness and richness were found after four days of fermentation.

国家自然科学基金项目31571819