Fruit waste (FW), mainly from agroindustry, is currently left behind in landfills despite its rich composition. The bioactive compounds (e.g., oils, polyphenols), carbohydrates, and lignin present in this biomass type require comprehensive characterization (i.e., identification and quantification) before they can be used as raw materials in biorefineries. This review collected information from scientific papers on FW compositional analysis methods and characterization data; the information needs to be compiled in a systematic, standardized, and comprehensive way to understand and quantify the true potential of FW as feedstocks for biorefineries. The information gathered in this review allowed us to identify the biomass fractions that could be valorized further depending on the kind of FW (peels, seeds, or seed vessels, and pomace or mixed residues). Fruit waste differs from conventional lignocellulosic biomass due to the presence of higher amounts (>5%) of extractives – pectin, and starch. This review describes current compositional analysis methodologies to identify possible strengths and weaknesses that could affect the adequate selection of valorization platforms. As no current methodology allows the composition of FW to be described thoroughly, this work identifies procedures applicable to biorefineries that use FW. Possible improvements are suggested to fill methodological gaps in the quantification of samples with large amounts of extractives and pectin. The standardization of methods for FW's quantification is fundamental for the adequate integration of different valorization platforms into biorefineries. It is essential to consider all the substances present in FW to exploit fully their potential for new value-added molecules, including oils, polyphenols, and pectin.

In the last few years, healthy foods have increasingly attracted consumers' interest, leading to an increase in sales worldwide. Using by-products from the agroindustry to produce healthy/fortified foods is a promising approach since peels and seeds of fruits have significant amounts of bioactive compounds. In this sense, this work evaluated the possibility to add fractions recovered from residues of orange, lime, and peach palm in a food product. First, the proximate, ultimate, and chemical composition of the residues was determined to identify the main substances that could be valorized. Then, the selected high-value-added molecules extracted from fruit residues were used to formulate a high-fiber brownie. A Box-Behnken experimental design was used to determine if fat replacement, flour replacement, and the addition of encapsulated extracts influenced the food product's color, texture, and humidity which were determined from the analysis of the texture profile of the samples. It was possible to identify with the help of an electronic tongue a formulation with similar properties to a commercial brownie but with enhanced functional properties due to the novel ingredients added, which could potentially improve consumers' health.