Effects of the decontamination of a fresh tiger nuts' milk beverage (horchata) with short wave ultraviolet treatments (UV-C) on quality attributes

In this work, the feasibility of short wave ultraviolet radiation (UV-C) to achieve the physicochemical and microbiological stability of a tiger nuts' milk beverage was evaluated. Colour changes measured as total color difference and browning index were imperceptible even when the liquid was treated at high UV-C doses. Likewise, the fat content and its oxidation level remained unaffected. By contrast, the antioxidant capacity of treated samples decreased with increasing doses of UV-C. And in particular, the peroxidase activity decreased up to 85% at the highest UV-C dose applied. Notably, UV-C effectively inactivated up to 3-log(10) cycles of spoilage-related microorganisms (yeasts and moulds, mesophilic flora and psychrotrophic bacteria). Horchata's freshness determined according to pH values, was extended 2 to 4 days if samples were UV treated. In summary, UV-C showed its suitability to commercialization possibilities with a minimum impact on its physicochemical quality attributes. Industrial relevance: Jellification of starch hinders the use of thermal treatments to pasteurize fresh tiger nuts' milks: consequently those products are highly perishable and have to face severe commercialization restrictions. We proved that UV-C is a suitable minimal processing technology for this type of products, inactivating efficiently the main contaminant microorganisms, and thus increasing significantly the shelf-life. (C) 2011 Elsevier Ltd. All rights reserved.