Exploring Plant Agro-Industrial By-Products as a Source of Fibrous Food Ingredients: A Review of Extraction Methods and Technological Properties.

The agro-industrial sector generates a large amount of by-products, and researchers have been seeking new ways to use them, especially those of plant origin. The concept of biorefinery and circular bioeconomy aims to enhance and maximize the use of organic ingredients, emphasizing the use of renewable and sustainable materials. Many by-products are rich in both macro and micronutrients, making them attractive for reuse and the development of new products. Plant fibers, composed of sclerenchyma cells, are an important example and are classified according to their origin. The use of food processing by-products as a source of fiber has great potential to reduce waste and improve nutritional value. Industrial interest in plant fibers is growing, making them a viable alternative to traditional ingredients. These fibers, originating from agro-industrial by-products, have proven profitable for food enrichment. This review examines the current state of the art in recovering and applying fibrous by-products, highlighting methods for obtaining them, their technological properties, and potential future applications. Furthermore, the conditions for modifying agro-industrial waste are analyzed, and the importance of understanding the original fibrous matrix is emphasized to select the most suitable transformation process, thereby ensuring a high-quality final product.