Flour made from fruit by‐products: Characteristics, processing conditions, and applications

The disposal of fruit and vegetable by‐products has drawn the attention of several sectors worldwide, not only due to the concern over environmental impacts but also due to high ratios of nutrients and bioactive compounds that are found in these nonedible parts. These by‐products still have great technological potential, because they can be processed and transformed in cosmetics, pharmaceuticals, food, and other products and biomaterial with high added value. The most common form of incorporating them into food is flour. Drying operations enable waste to keep higher concentration of nutrients, less susceptibility to be attacked by microorganisms (due to low humidity), lower storage volumes, and longer shelf‐life. The process of transforming residue into flours can be carried out by different equipment whose goal is to remove moisture. Afterwards, dry products pass through mills to reduce particle size. Then, standardization of granule size is recommended. In the conversion steps, processing conditions are particularly important because they should not cause any loss of nutrients, bioactive compounds, and antioxidant activity to the final product. In view of the need to control production steps, this review aimed at compiling information on the theme found in the literature and at highlighting existing gaps to show the scientific community the importance of studying the factors that affect the quality of dehydrated final products. Practical applications The disposal of fruit by‐products attracts the attention of several segments, not only due to the concern with environmental impacts worldwide but also due to the high levels of nutrients and bioactive compounds that are still present in these inedible parts that are not properly used. This review provides nutritional and technological information on fruit residues and their potential for application in food. The most common way of inserting these products in food matrices is through flour, but this process is not just about removing moisture from the product, several factors need to be studied and controlled aiming at the minimum of nutritional and technological losses, reduction of antinutritional factors that may be present in the residues, reduced development of microorganisms, and enzymatic activity, and for these reasons, this review was constructed, to bring the main scientific findings in the literature that reports studies on these subjects to the scientific community.