Abstract: Intelligent post-fermentation of Pixian broad-bean paste (PBP) was carried out using the equipment independently designed by our group and the quality of the finished product was evaluated. One-factor-at-a-time experiments were performed to examine the effects of stirring frequency, light and environmental humidity on amino nitrogen, soluble nitrogen, total acidity, reducing sugar and characteristic flavor components. The optimum fermentation conditions were determined as follows: stirring for one minute per day, no light,?28 ℃ and natural indoor humidity. The results showed that PBP produced by intelligent fermentation had lower level of salinity, but higher moisture content, color value and total acidity than did naturally fermented PBP. Moreover, the consumption rate of reducing sugar, the production rate of amino nitrogen and soluble nitrogen and the contents of organic acid and free amino acids were higher in PBP produced by intelligent fermentation, which produced most characteristic aroma compounds (except aldehydes) but less varieties of aroma compounds and accumulated excess amounts of acid, causing an overall imbalance in the flavor profile. In spite of this, PBP produced by intelligent fermentation was superior in other quality indicators and a shorter fermentation cycle. Thus, controlling acid accumulation to optimize the intelligent post-fermentation process can provide data support for promoting the industrialization of intelligent fermentation.

Key words: Pixian broad-bean paste; intelligent fermentation; natural fermentation; contrastive?analysis