Assessment of acid production efficiency and aroma volatile compounds by immobilized fermentation of different carriers on sugarcane original vinegar

Abstract

Sugarcane original vinegar (SOV) is a healthy beverage worldwide. Almost all the countries or regions in the world have their own kinds of vinegar with special aromas and flavors, which come from the relative raw materials, microorganisms and production processes with vinegar. It is rich in phenolic substances, such as vanillin, coumarin, chlorogenic acid, caffeic acid, ferulic acid, p-coumaric acid, 10 types of luteolin in celery, cinnamic acid, and kaempferol, among which the vanillin, coumarin, chlorogenic and caffeic acids are relatively high (sugarcane original vinegar >5 mg/L, sugarcane vinegar drink >2 mg/L). This study assessed the influence of acetic acid fermentation from sodium alginate, corncobs and rice husk on SOV by immobilized fermentation processes. Volatile organic compounds were determined by solid-phase microextraction (SPME) and gas chromatography (GC-MS). During the first and second fermentation stages, the rice husk carrier enhanced the fermentation process at 24 h as compared to corncobs and sodium alginate. Fermentation with different immobilized carriers revealed 95–115 types of organic volatile compounds, with the relative content of each compound monitored through the area normalization method, representing 98% of the total peak area. The free fermented sugarcane vinegar has found 24 specific compounds. Fifty-seven aroma compounds were identified at different degrees by the ROAV method during fermentation with different immobilized carriers. The key flavor compound was isoamyl acetate and the modified flavor was phenylethyl alcohol. Isoamyl acetate was identified as significant aroma compound in SOV for the first time. Using plant sources as immobilized carriers to ferment fruit vinegar can effectively improve the aroma and acid production efficiency of vinegar. This study enriched the knowledge of the compounds and flavors of SOV and assisted in upgrading the production quality of vinegar.