Agro-food industry byproducts into value-added extruded foods

• Food industry co-products were converted into shelf-stable extruded products.
• Co-products were utilized as a source of nutrients and bioactives.
• Liquid whey was concentrated and utilized into extruder barrel in lieu of water.
• The natural color and bioactives are preserved in the final product.
• The process adds value to the industrial waste streams.

Food industry co-products, fruit pomace and liquid whey, were converted into shelf-stable, puffed products by using low-shear, low-temperature supercritical fluid extrusion. Co-products were utilized as a source of dietary fiber, phytochemicals, and milk nutrients in extruded products. Liquid whey was concentrated and pumped directly into extruder barrel in lieu of water while processing cereal formulations fortified with finely ground fruit pomace. The resulting extruded products were very light in weight with 0.21–0.35 g/cm3 density and contain14 g dietary fiber, 93 mg gallic acid equivalent polyphenols, and 652 mg vitamin C equivalent antioxidants in 100 g products. The natural fruit color is retained in the final product, indicating the preservation of color pigments and the associated bioactive compounds. About 84% of the total phenolics and 74% of the antioxidants of apple pomace were preserved in the final extrudates. The utilization of the agro-industry waste streams offers effective preservation and utilization of the nutritionally attractive byproducts as a source of functional ingredients in extruded products while adding value to the industrial waste streams.