Maize, or corn, is processed commercially by 2 main processes, wet or dry milling. More recently, it is being processed by dry grinding for ethanol production. Defatted maize germ cake is a byproduct of the corn oil industry and is mostly used for animal feed. However, this low-cost ingredient may have potential utilisation in human foods.

The maize kernel contains 5-14% of maize germ, depending on the variety and grain size. The germ is high in protein content, dietary fibre and minerals, with the proteins mainly comprising albumin and globulin with a balanced content of most essential amino acids. In particular, the lysine content is more than twice that in wheat flour. The nutrient-dense composition of defatted maize germ flour could have potential as an ingredient or fortifying agent in various foods such as bread, cookies and cakes.

The functional properties of flours also contribute to the final quality of a processed product. Defatted maize germ protein meal or flour has good water retention and fat binding capacity, which helps stabilise emulsions by absorbing or binding excess water, thus giving a higher yield of end products. Texture is one of the major quality for consumers to judge quality, freshness and eating quality. Flow and deformation behaviour of doughs are also important functional characteristics.

A study by Siddiq et al.¹, evaluated the functional and rheological properties of wheat flour blends with defatted maize germ flour (5-25%). The bulk density, water and oil absorption capacities, emulsion/foaming capacity and stability, colour, least gelation concentration, viscosity and dough compression were determined. The addition of defatted maize germ flour to wheat flour improved functional and rheological properties. In particular, it increased water and oil absorption and emulsion capacities and significantly increased apparent viscosity and dough hardness. Defatted maize germ flour thus has potential use as a value-added ingredient in bakery products.
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¹ Siddiq, N; Nasir, M; Ravi, R; Dolan, KD; Butt, MS (2009). Effect of defatted maize germ addition on the functional and textural properties of wheat flour. International Journal of Food Properties 12 (4) 860-870.

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