Impact of freeze-drying on bioactive compounds of yellow passion fruit residues

Fruit production and processing result in a large amount of residues, which are usually discarded or underused. Passion fruit residues are source of fibers and other bioactive substances, which are antioxidant, protect cells against oxidative stress, and have pharmaceutical and food properties. This paper investigates the effects of freeze-drying on bioactive compounds of yellow passion fruit residues (Passiflora edulis f. flavicarpa). It was analyzed the following compounds: Pectin, total phenolics, total flavonoids, citric acid, and ascorbic acid, and also the effect of freezing techniques (in freezer or liquid nitrogen) on moisture removal and product quality. The results indicated the best freeze-drying conditions for yellow passion fruit residues considering the preservation of the main compounds. Practical applicationConcerning processed fruits, the yellow passion fruit (Passiflora edulis f. flavicarpa) has had great importance due to the quality of its juice and its great amount of minerals and vitamins. However, the processing of this fruit results in a substantial amount of residues, which may represent 65-70% of the fruit weight. These residues are usually discarded, causing environmental impact and loss of raw material and energy. Yellow passion fruit residues contain high levels of bioactive compounds, such as pectin, vitamins, minerals, polyphenolic antioxidants, and dietary fibers. This study investigated the freeze-drying of passion fruit residues. It was analyzed the effect of operating conditions on bioactive compounds content in the samples and determined the most suitable process conditions.