Extruded snacks from industrial by-products: A review

Background: Within the context of circular economy, there is an emergent need to convert food processing by-products into useful ingredients, thanks also to the recent technological advances in processing techniques. Extruded cereal-based snacks are popular products, however many snacks on the market are currently high in salt, fat and sugar, with an overall low nutritional value. Scope and approach: With the growth of healthy and sustainable diets and with consumers better understanding the links between diet, health and the environment, there is an opportunity to develop novel healthy and eco-friendly extruded snacks. Within this context, food industry by-products, such as fruit and vegetable pomace and bagasse, oilseed cakes, brewers spent grains, cereal brans and whey, could be used as excellent sources of nutritionally enhancing and eco-friendly compounds. This review summarizes the research published within the last five years on cereal-based snacks produced using food by-products. Key findings and conclusions: The production of extruded snacks with food by-products will need novel technologies that limit heat damage, both during drying of the food by-product and the extrusion process. The percentage of by-product inclusion and the particle size of the by-product added require further investigation. The economic sustainability and the environmental impact of snacks produced with food by-products should be explored in a more holistic approach. Current research is focussed mainly on reformulation strategies rather than sensory or consumer aspects. These gaps needs to be addressed and future research on extruded snacks from by-products should be more multidisciplinary, covering technical, sensory, consumer, economic and sustainability aspects.