Application of Ultrasonication and Fermentation with Lactobacillus Casei Strain on the Safety Characteristics of Rice, Soy, Almond, Coconut, and Oat Drinks By-Products

Abstract

The by-products from the production of plant-based beverages still contain a large amount of nutritional and functional compounds that may be valuable for food, as well as animal feed industry. In order to promote efficient use of these by-products, the attention should be drawn to the safety characteristics of it. The effects of low frequency ultrasonication (US) and fermentation with Lactobacillus casei LUHS210 strain as physical and biotechnological treatments on improving safety characteristics of by-products from the processing of rice, soy, almond, coconut, and oat drinks were investigated. A higher ratio of L-(+)-lactic acid was produced during the fermentation of all by-products, comparing to D-(-)-lactic acid. Ultrasonication at 37 kHz, as well as fermentation effectively improved the microbiological safety of processed by-products. All by-products contained deoxynivalenol (DON), however mycotoxins concentrations were detected as low (< 48 μg/kg). Ultrasonication and fermentation reduced the concentration of DON (on average by 24%) only in soy by-products. After fermentation 15-acetyldeoxynivalenol was formed in all samples (< 12 μg/kg), except for soy by-product. In most of the cases, lower total concentrations of biogenic amines were observed in fermented by-products. When comparing untreated and fermented by-products, significant changes (p ≤ 0.05) were found in macroelements content. Ultrasonication at 37 kHz did not significantly influence the concentrations of macro- and microelements, while fermentation affected most of the essential microelements. Consequently, while ultrasonication and fermentation can enhance the safety of by-products, the specific effects must be taken into account on biogenic amines, mycotoxins, and micro- and macroelements.