Characterization and epiphytic microbial load changes of a fresh vegetables purple smoothie during shelf life

© 2018 International Society for Horticultural Science. All rights reserved. The food industry offers fresh smoothies to increase the intake of fruit and vegetables. However, such elaborates have the disadvantage of accelerated metabolic degradative reactions which causes a quick quality deterioration. In this work, an optimum composition of a fresh vegetables purple smoothie (cucumber, beet, broccoli, purple cabbage and red grapes) was developed after sensory analyses and physicochemical quality attributes. The initial pH was 4.23 and total soluble solids content was 12.9 °Brix. The smoothie quality was preserved by mild thermal treatment (3 min; 85°C) while fresh blended, non-treated samples were used as controls. All samples were stored in darkness at 5 and 10°C up to 37 days. Total soluble solids content and pH slightly decreased throughout storage. Just after heat treatment, the epiphytic microbial load analyzed (mesophiles, psychrophiles and yeasts and moulds) was decreased by 1-2 log cycles. Storage temperature was the most important factor to prevent the microbial growth. Samples at 5°C generally showed ¿2 log cycles less than those stored at 10°C the end of incubation, regardless of the heat treatment applied. Mesophilic and psychrophilic microbial populations showed a similar behavior, being less than 8 log cycles in all samples throughout storage.