Food fortification using fruit-processing by-products and their derived bioactive compounds: opportunities, challenges, and future perspectives

Food fortification has emerged as a sustainable strategy to address global micronutrient deficiencies by improving nutritional quality of food. Alongside conventional fortification, increasing attention has been directed toward food-to-food fortification using naturally derived ingredients that can provide nutritional and functional components. Fruit processing generates substantial quantities of by products such as peels, seeds, kernels, and pomace which contain vitamins, minerals, dietary fibers, and phytochemicals. Recent research has demonstrated that these fruit-derived wastes possess considerable functional and nutraceutical potential, exhibiting antioxidant, antimicrobial, antidiabetic, and anti-inflammatory properties in experimental studies. Their incorporation into food systems offers a promising approach for enhancing nutritional quality while simultaneously supporting sustainable waste management. This review critically examines the potential of fruit-processing by-products and their derived ingredients as complementary fortifying materials in food systems. A structured literature search was used to synthesize evidence according to by-product type, major bioactive and nutritional components, food matrix, incorporation level, nutritional and technological effects, sensory response, processing stability, bioaccessibility, safety, and industrial relevance. Particular emphasis is placed on the effects of drying, baking, extrusion, storage, and gastrointestinal digestion on the stability and accessibility of bioactive compounds. The available evidence indicates that fruit by-products can enhance dietary fibre, phenolic content, antioxidant capacity, and other functional attributes of bakery, cereal, dairy, and beverage products; however, the magnitude of these effects depends strongly on the by-product, processing conditions, incorporation level, and food matrix. Sensory acceptability, raw-material variability, contaminant risks, regulatory requirements, and techno-economic feasibility remain important constraints to industrial application. Overall, fruit by-products represent promising complementary ingredients for food-to-food fortification and circular food systems, but their potential should be evaluated based on matrix-specific nutritional, technological, sensory, safety, and bioaccessibility evidence rather than being considered direct substitutes for conventional micronutrient fortificants.