From waste to application: uses of leftover rice proteins

The leftover protein from rice husks has great potential in being used for alternative purposes. (Source: Flickr)

The leftover protein from rice husks has great potential in being used for alternative purposes. (Source: Flickr)

Recent efforts are being made to take advantage of the rice proteins leftover from starch processing by incorporating them into nutritional supplements and cosmetics.

Rice is a big food staple in the world: its worldwide consumption in 2015 is estimated to be around 484.6 million metric tons (1). Because producers are mainly interested in the starch from the rice grain, they end up disposing the leftover protein crusts. In trying to reduce the additional expense caused by such waste, researchers are taking note of the benefits of rice proteins: they contain all essential amino acids and serve as a desirable alternative to people who are allergic to milk and soy-derived proteins (2).

Researchers at the Fraunhofer UMSICHT in Oberhausen are working on developing an efficient process in breaking up and drying the rice proteins as part of their BIORICE project (3). The proteins are first broken up into fragments called peptides. These peptides then undergo size-exclusion chromatography for purification. Because such technique does not use chemicals, the end product is free from contamination. Currently, researchers are able to mass-purify protein samples up to 20 liters.

After purification, peptides go through freeze-drying and spray-drying processes to complete their transformation into fine powder form. Freeze-drying is a dehydration technique in which a vacuum removes the moisture which is then frozen onto the condenser. Although gentle, the use of freeze-drying for industrial setting is impractical because of the long loading time and the expensive cost (3). Hence spray-drying is used in which the peptides are sprayed with a stream of hot air. The disadvantage is that researchers have to compromise speed with potential damage to the peptides.

The date of liberal application of rice proteins in cosmetics and nutritional supplements is undetermined: challenges remain to keep the peptides stable and tolerable for long shelf-lives. Further tests are also needed to confirm their potency in the human body.

References

  1. U.S. Department of Agriculture. (2015, May). Total global rice consumption 2015. Retrieved from http://www.statista.com/statistics/255977/total-global-rice-consumption/
  2. Greenfield, Ben. (2013, June 6). Secrets of the Superhuman Food Pyramid: Benefits of Organic Rice or Pea Protein Powder. Superhuman. Retrieved from http://superhumancoach.com/benefits-of-organic-rice-or-pea-protein-powder
  3. Fraunhofer-Gesellschaft. (2015, October 1). Proteins from rice: raw materials instead of waste.ScienceDaily. Retrieved from www.sciencedaily.com/releases/2015/10/151001095801.htm

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