Effects of pasteurisation and storage conditions on folate retention and microbiological quality of beetroot juice

Abstract

This study investigates how pasteurisation and storage conditions affect folate content, microbial quality, and physicochemical properties in beetroot juice. Fresh beetroot juice was extracted, packed in amber and transparent glass bottles, then pasteurised at 90 °C for 15 s, immediately cooled, and stored at either 4 °C or ambient temperature for 75 days. pH, total soluble solids (TSS), acidity (%), folate concentration, total plate count (TPC), and yeast and mould count were analysed. Folate content was measured using a UV spectrophotometer. Results indicated that folate content decreased by 10.71% during pasteurisation and all microbes were destroyed. A significant decrease (p < 0.05) in TSS was observed post-pasteurisation, while TA decreased and pH increased. The average folate loss in all bottles was 39.86% as it decreased from 72.87 µg/100 g to 43.82 µg/100. Beetroot juice stored at 4 °C in amber bottles significantly (p < 0.05) preserved folate content compared to ambient temperature in transparent bottles. The juice pH of juice in transparent bottles stored at ambient temperature significantly increased (p < 0.05), while TA and TSS decreased; others showed only minor changes. These findings offer practical guidance for optimising the preservation of folate in beetroot juice through careful processing and storage practices.