When looking for certain millets to purchase online recently, I found in some cases I had the option of raw or parboiled grains. Parboiling is a process of boiling and drying that I’ve heard of over the years, but which I never fully figured out.
Turns out that the process has some notable effects on nutrients (mostly positive) and physical characteristics of grains (more resistant to breakage in processing).
Of what I found in some quick online research, here are a couple of articles to pass on: one is general, and the other a more technical description of research on parboiled proso and pearl millets. For the second, I’ve included the abstract.
Pragyani Bora, Sanaa Ragaee, Massimo Marcone, “Effect of parboiling on decortication yield of millet grains and phenolic acids and in vitro digestibility of selected millet products,” Food Chemistry, Vol. 274,
2019, Pages 718-725, ISSN 0308-8146,
https://doi.org/10.1016/j.foodchem.2018.09.010.
https://www.sciencedirect.com/science/article/pii/S0308814618315760
Abstract: Parboiling is a common method used in rice processing to improve milling yield and physicochemical properties. The current study evaluates parboiling as a pre-treatment step in millet decortication and its impact on phenolic profile and in vitro digestibility of two traditional millet products, steam-cooked couscous and porridge, made from pearl (Pennisetum glaucum) and proso (Panicum miliaceum) millets. Parboiling increased decorticated yield of pearl and proso millet by 37% and 28% respectively. It resulted in significant (P < 0.05) rise in free and bound phenolic contents and DPPH (2,2-diphenyl-1- picrylhydrazyl) radical scavenging activity of the millet products. This method significantly (P < 0.05) changed starch digestion fractions of both products thereby reducing expected glycemic index (eGI) while the in vitro protein digestibility of products decreased by 14–17%. Parboiling could be an effective way to improve millet decortication yield as well as produce millet products with higher phenolic acids antioxidant activity and lower GI.
Keywords: Parboiling; Pearl millet; Proso millet; Phenolic; DPPH activity; In vitro digestibility
Don Osborn, PhD
(East Lansing, MI, US - +1 202-621-3911)
North American Millets Alliance
