Fermentative Stabilization of Betanin Content in Beetroot and Its Loss during Processing and Refrigerated Storage

Abstract

Fermentation is an important processing technique that nutritionally, functionally and therapeutically enhances the quality of fresh produce apart from increasing the shelf life significantly. The present study used fermentation of beetroot by Lactobacillus plantarum and Lactobacillus delbrueckii with the intention to stabilize the betanin content and compared it with losses due to refrigerated storage and during the processing of beetroot. The betanin content was correlated with CIE color values. Refrigerated storage reduced 50% of the betanin content in 10 days, while steaming reduced 40%. Lower pH during heat treatment showed better betanin retention compared with higher pH. Fermentation of beetroot by either L. plantarum or L. delbrueckii at 4C was able to preserve betanin up to 10-15mg/100ml beetroot extract up to 32 days of refrigerated storage and ensured a safe, good quality product. Higher survival of lactic acid bacteria was seen in these samples after 32 days. Practical Applications Lactic fermentation of sugar-rich vegetables is an alternative processing method that removes the sugars, which often interfere in most processing. Fermentation offers a valuable tool to stabilize betanin in beetroot and ensure its retention during storage. Fermenting beetroot prior to pressing and extraction can ensure greater recoveries and stabilities of pigment components as shown in this study. Further, the pigments are also stable over a period of time. Understanding the mechanisms of preservation of vitamins, colors, minerals and identifying various other metabolites and nutrients in fermented foods will enable the food industry to adopt processing methods which are likely to retain maximum amounts of nutrients or enhance the nutritive value as compared with those present in fresh produce.