Due to increasing awareness of food sustainability and security among consumers and food manufacturers, the valorization of food products has gained huge interest among researchers with the aim to diversify the product range, including those processed from the by-products. From the United Nations (UN) Environment Programme’s Food Waste Index Report 2021, the wastage of foods reaches 931 million tonnes each year. To align with the UN Sustainable Development Goals, which aim to halve food waste by 2030, food wastage reduction, especially from fruits and vegetables that have a short shelf life, can be processed into a stable value-added product. Hence, the application of various drying methods on fruits, vegetables, and their by-product were conducted as measures to decrease or avoid possible wastage. In this article, the applications of sun drying, solar drying, convective air drying, hybrid drying, spray drying, drum drying, vacuum drying, freeze-drying, and refractance window drying as means of food valorization strategy and impacts on the physical, chemical, microbiological, and nutritional properties are compiled and reviewed. In addition, bio-drying processes were also presented to reduce the generation of food waste and environmental impact.

Historically, the application of thermal heating in food processing could be dated back to the invention by Nicholas Appert (1749–1841) which is nowadays known as canning and is able to preserve food products stored in glass bottles for an extended period

Purpose: This review provides an overview of the applications of Bambara groundnuts in various food products. The genetic diversity, physical properties and chemical compositions of the crop are also elucidated.Design/methodology/approach: This paper critically reviewed the physicochemical properties and applications of Bambara groundnuts from recent literature.Findings: Bambara groundnut (Vigna subterranea) is a drought-tolerant crop from West Africa that contains not only carbohydrates and fats but is also high in protein. The cultivars of Bambara groundnut can be distinguished by the colours of seeds, which range from red, blue-eye, brown and black-eye. Bambara groundnuts contain carbohydrate (57–67%), protein (15–25%), fat (4–8%), fibre (1.4–1.5%) and ash (2.9–4%). As a percentage of protein, the essential amino acids, lysine, methionine and cysteine are relatively high in Bambara groundnuts. Meanwhile, linoleic, palmitic and linolenic acids are the fatty acids present in this crop.Practical implications: Several studies have shown that Bambara groundnuts can be used as fat substitutes, emulsifiers, water binders, bulking agents and thickeners due to its water and oil absorption properties, gelling, pasting, emulsifying and foaming abilities. Bambara groundnuts are used in the development of many intermediate or final products like flour blend, cookies, bread and fermented milk. It has a positive impact on the overall proximate, functional, mineral and amino acid profiles of the food products.Originality/value: Despite its high nutrient density, Bambara groundnuts are an underutilised legume due to unavailability and lack of knowledge among consumers on its benefits. There is a need to promote the use of Bambara groundnuts as a future food.