Development of protein-enriched biscuit based on oat-milk byproduct fortified with chickpea flour

Oat milk by-product (OMB) is the insoluble fraction filtered out after the production of oat milk and is generally considered as food waste. However, the OMB contains abundant nutrients such as protein, fiber, and phytochemicals, which is a promising food ingredient. This study aims to utilize OMB as main food material to develop a high-protein biscuit and evaluate the fortification of chickpea flour on the physical parameters, chemical composition, and antioxidant capacity of OMB biscuits. Biscuits made from pure OMB flour showed high nutritional value by presenting high content of protein, dietary fiber, β-gluten, total polyphenol, and antioxidant capacity evaluated by ABTS+* and DPPH*. Enrichment of chickpea flour in OMB biscuits further increased the content of protein, total sugar, carbohydrates, TPC, antioxidant capacity, as well as improved the surface appearance. Incorporation of chickpea flour did not significantly impact the spread ratio and hardness of OMB biscuits, but increased the weight loss. Among them, the formulation O-4 (oat 55.6 g/100 g: chickpea 46.5 g/100 g) presented the highest protein content as well as a preferable appearance. This study provides a sustainable way of converting oat milk by-products into a high-protein food ingredient, which reduces the environmental burden and generates economic value for food industry.