Lactobionic acid as a suitable food preservative for yacon juice

Yacon root is known for its antioxidant, prebiotic and insulin modulator benefits. However, like the root, yacon juice exhibits rapid enzymatic browning, requiring treatments such as acidification. Lactobionic acid (LBA) is a promising food ingredient, which contains not only preservative but also nutritional properties. The first goal of this study was to evaluate the influence of combined treatments (blanching, acid pretreatment) and LBA on refrigerated yacon juice (8 degrees C; 48 h). The analysis of pH, antioxidants, total polyphenols and color, were used to select the optimal combined conditions, which were steam blanching (10 min) + LBA 1%. Secondly, the LBA was compared with citric, malic, tartaric, and ascorbic acids (at 1% levels), where the kinetics of polyphenol oxidases were determined in refrigerated storage of the juice at 8 degrees C for 48 h. Results showed that LBA, malic and tartaric acids maintained the color of yacon juice and preserved bioactive compounds. LBA and malic acid prevented enzymatic browning with PPO reductions of 80.4% and 79.4%, respectively. This was the first time that LBA has been tested in a refrigerated juice showing significant potential for preservation of color and bioactive compounds in food products.