THE 2013 STATE OF THE WORLD'S QUINOA
CHAPTER 3.1: Traditional processes and Technological Innovations in Quinoa Harvesting, Milling and
The growth in global demand for quinoa has fostered a production increase in its areas of origin, as well as the introduction of this plant species in other regions. The increased production is mainly of varieties and ecotypes that are rich in saponin, a substance that needs to be removed from the surface of the grain prior to consumption, because of its anti-nutritional properties and undesirable organoleptic qualities.
In the light of this situation, various industrial-scale innovations have been carried out in the harvest and post-harvest phases (which include shearing or cutting, placing in sheaves or arcs, threshing, winnowing and cleaning of grains, drying, selection, storing, milling, manufacturing of high value added products, and direct use of the product), to replace traditional practices that were generally conceived for small-scale production.
Successful production of high commercial quality grains depends to a large extent on what occurs at harvesting. At this stage, timely introduction of mechanised systems such as dryers, winnowers, threshers, brushes, and combined threshing and sifting equipment on medium and large-sized farms has demonstrated various advantages over traditional manual practices. These methods help to reduce impurities, as well as damage and loss of grains, while also requiring less labour, which is often scarce in the farming areas.
These systems were introduced and improved to mitigate the intrinsic, negative environmental impacts. Where milling is concerned, improvements have been made to traditional saponin removal methods, leading to the development and use of industrial-scale appropriate equipment and technology. The most commonly used methods are combined methods, which guarantee the nutritional quality and morphological stability of the grain, as well as a final saponin content well below international standards. With these systems, saponins are removed in 2 stages: hulling and washing, followed by spinning and drying of the grains. In the optimised processes, up to 95% of saponins are eliminated in the hulling machine, and the rest is washed away with water.
The volumes of water needed are however still quite high, generally above 5 m3/t of quinoa processed, and the runoff generated is contaminated with saponins. Impurities such as gravel, twigs, unripe, broken or different coloured grains are removed using sieves, sorters, spreaders, and magnetic or optical systems. All these systems are almost always supplemented by manual work.
Market forces, combined with more stringent environmental standards, better prices, and the paucity of water resources in production areas, will continue to drive the development of increasingly efficient and innovative equipment and technology. The trend is moving towards dry saponin removal methods that not only do not require water, but make it possible to collect all of the saponins, which fetch good prices on the market because they can be used in various areas of the industrial sector. A number of interesting artisanal models for dry processing of quinoa have been put forward, but they require further experimentation before they can brought up to the industrial scale.
Quinoa based foods have been a part of the diet of Andean populations for centuries and due to its nutritional qualities, quinoa is now used in other areas in a wide variety of derived products alone (flour, flakes, popped seeds) or in blends with cereals, oleaginous seeds, and other foods (mixed flour breads, noodles, extruded products and gluten-free pasta). It is hoped that the expansion of the quinoa market will lead to the development of other derived products such as protein concentrates and isolates, oils, starches, and high value-added saponin derivatives.