Quinoa : an ancient grain for modern applications

Awareness of the several agronomic, environmental, and health benefits of quinoa has led to a constant increase in its production and consumption not only in South America - where it is a native crop – but also in Europe and the United States. However, producing wheat or gluten-free based products enriched with quinoa alters some quality characteristics, including sensory acceptance. Several anti-nutritional factors such as saponins are concentrated in the grain pericarp. These bitter and astringent substances may interfere with the digestion and absorption of various food components. Developing processes to decrease or modify the bitterness of quinoa can enhance palatability and thus consumption of quinoa. In this context, the main approaches adopted to counteract the negative characteristics of quinoa and enhance its use in human nutrition will be presented. Attention will be paid on the effects of sprouting on both nutritional and sensory traits of quinoa seeds, with regard to saponins. Moreover, the possibility of using sprouted quinoa as an ingredient in wheat-based bread will be assessed with the aim of improving the technological performance of quinoa-enriched baked products. Overall, the results of highlighted that quinoa seeds underwent relevant physical changes during sprouting. The maximum intensity of the macromolecular modifications can be seen after 48 h of sprouting, although the activities of the hydrolytic enzymes responsible for most of the observed molecular changes are already present at 12 h. Endogenous proteases seem to have an impact on the capacity of proteins to interact with nutritionally relevant metals, including copper and zinc. The impressive increase in α-amylase activity occurring in the early stages of sprouting results in progressive nicking of starch molecules, with a very noticeable impact on the pasting properties of residual starch fractions in the sprouted material. Molecular changes on starch and protein upon sprouting affected the functional properties of the related flours, giving bread with increased bread volume and crumb softness. Finally, sprouting can be proposed as an alternative method to washing or pearling to decrease the amount of saponins starting from 24-48h of process, while decreasing bitterness and astringency in cooked seeds, flour, and bread.