Physicochemical Characteristics of Natural Fruit and Vegetable Fermentation Broth and Monitoring of Its Fermentation Process

Abstract

The natural fermentation broth of fruits and vegetables is the fermentation broth obtained from the natural fermentation process of fruits and vegetables. The raw fermentation broth is produced by anaerobic fermentation of fruits and vegetables, so as to form a fermentation beverage with complex components, which can promote digestion and absorption, alleviate constipation and beautify the face. Fruit fermentation can be used not only as a drink, but also as a substitute for highly active dry yeast. It can be added into bread to make natural yeast bread with good flavor and long shelf life and other baking products. It has broad market application prospects. In this paper, physical and chemical indexes (soluble solids content, alcohol content, total acid content) and microbial indexes of natural fermentation products on sale and self-made fermentation broth of fruits and vegetables were determined, and the morphology, size and color of yeast colony in fermentation broth were observed. In order to find the suitable fermentation time, the fermentation processes of two kinds of compound fermentation broth of fruits were monitored continuously and dynamically. The results showed that the contents of soluble solids, alcoholicity, total acid content and yeast count were significantly different among different natural fermentation liquors of fruits and vegetables due to different raw materials, formulations and fermentation time. The content of soluble solids in compound natural fermentation broth 1 (orange + apple + lemon) was reduced from 13.1% to 4.0% and the pH was decreased from 4.2 to 3.1, then slowly increased to 3.3 during the 40-day fermentation at 28°C, while the content of soluble solids in compound natural fermentation broth 2 (apple + pear + lemon) decreased slowly from 12.4% to 8.5% and the pH decreased from 4.4 to 2.9 at the same fermentation temperature and time.