The continually growing global population presents environmental issues and compromises food security. Although food production and preservation have improved with the advent of new technologies, about one third of the food produced is currently lost or wasted. While food waste is produced in households and food service providers, food loss is generated at all stages of the food chain supply. At the processing stage, food byproducts are inherently generated and still contain precursors of valuable edible ingredients that can be processed instead of undergoing land disposal or animal feed. Enzymes are proteins that catalyze a wide variety of reactions including the conversion of carbohydrates, lipids, and proteins that are present in food byproducts. Moreover, enzymes can operate with mild energy inputs and can discriminate their target substrate from other substances in a mixture preventing the formation of side products. Despite the advantages that enzymes offer to sustainably valorize food byproducts, the conditions in which they elicit catalytic activity without potential risk of denaturation are not the same as those occurring in real processing conditions. Nonetheless, the immobilization of enzymes on solid materials presents a viable solution to improve the stability of enzymes in addition to facilitate their recovery and reuse. This technology involves the use of materials for the confinement of enzymes or the fixation of enzymes on the surface. To prepare reusable and robust biocatalysts (immobilized enzymes) that preserve catalytic activity in real processing conditions, several factors must be considered in the preparation of the biocatalyst. Such factors include the use of a recoverable insoluble material with sufficient surface area to achieve high enzyme loads, a stable form of attachment or encapsulation to prevent enzyme loss, the preservation of the active structure of the enzyme, and unobstructed diffusion of substrate and products inwards and outwards the active site. Hierarchical materials hold promise to perform well as enzyme supports due to their high surface area per unit volume, the creation of protective microenvironments within cavities, and their density or sufficiently large overall size to facilitate their recovery from a reaction mixture. Therefore, the goal of this dissertation was to use hierarchical materials as supports of _-galactosidase to valorize lactose from deproteinized whey. First, we demonstrated the relevance of self-assembly conditions of cooper phosphate hierarchical microflowers for the simultaneous immobilization of _-galactosidase. As we observed that _-galactosidase desorbed after immobilization, the surface of calcium phosphate microflowers was functionalized to enable a stable attachment of _-galactosidase, which resulted in a reusable biocatalyst with retained activity over a period of 10 days under constant agitation. Lastly, we used this biocatalyst to produce lactulose (a sugar with prebiotic activity) from lactose to provide an alternative valuable use to deproteinized whey. Overall, this work demonstrated how hierarchical biocatalysts can be applied in the valorization of food byproducts to improve the sustainability of food production and reduction of food loss.