Brazil is amongst the ten countries that mostly waste food, with about 35% of agricultural production going to the trash. The agro-food processing is one of the activities which generate high amount of residues, with approximately 50% of raw material being discarded. The lack of information on the nutritional quality of agroindustrial byproducts does not enable its potential use in the manufacture of food products. In this context, the aim of this study was the chemical characterization of the by-products of industrial processing of fruits and vegetables and grain processing. The chemical elements Br, Ca, Co, Cr, Cs, Fe, K, La, Na, Rb, Sc e Zn were determined by instrumental neutron activation analysis. The proximate composition was evaluated by methods recommended by AOAC. The antinutritional factors, through the determination of phytic acid and tannins. The availability of nutrients in vitro for Ca, Fe, K and Zn and through the Caco-2 cells for Fe. Most samples contain high fiber and protein and low lipid content and calorific value. Rice bran, the peel of cupuaçu seed, the cupuaçu seed and the raspberry bagasse had the highest concentrations of phytic acid, between 19.9 and 10.7 mg g-1. The grape peel showed the highest amount of tannins (23.8 mg / g of catechin). The samples showed good in vitro availability for Ca and Zn, but the values for K and Fe were below 10% available for most samples. In the analysis of bioavailability through the Caco-2 cells system, the sample that showed the highest amount of ferritin was the peel of cucumber (ferritin 56.8 ng / mg protein). It could be observed that the by-products generally exhibit similar or larger amounts of the nutrient than the food usually consumed, and nutrients availability compatible with other plant origin food. The data suggest that the agroindustrial byproducts are potential ingredients for the food industry and can add nutritional value to new products. Future studies more specific to each by-product should be considered like sensory analysis and ways to increase the nutritional quality of by-products.