Evaluation of ethanol and citric acid to increase beetroot drying performance and quality

Hot air is the most popular method for drying foods, but its performance remains a barrier in industrial scale. Beetroot is an important crop worldwide and drying is an important tool to increase foods’ shelf-life, incorpo-rate into food applications and produce dried vegetable snacks. The objective of this work was to evaluate the use of ethanol and citric acid solutions as pretreatments for the drying of beetroot. Beetroot slices were subject-ed to four different treatments before the drying proce-dure (60ºC), as follows: no wet pretreatment; wet pre-treatment; ethanol solution; and citric acid solution pretreatment. The impact on color, betalain content, and structure of beetroot slices were evaluated. Modi-fied Page model was selected to evaluate drying rates. Ethanol and citric acid solution impacted on plant tis-sue structure. Pretreatment with alcohol solution implied on increasing the drying performance of beetroot slices. Soaking beetroot slices into citric acid solution did not change drying rates compared to samples without any treatment but increases when comparison is made with samples soaked into water solution. Beetroot slices pre-treated with citric acid presented better color parameters and when they were pretreated with ethanol preserved betalain amounts after drying. Ethanol shows up as promising pretreatment for beetroot drying, enhancing process performance and maintaining quality parame-ters, meanwhile citric acid does not have great impact.