Effect of processing method on physico-chemical and functional properties of two fonio (Digitaria exilis) landraces

Abstract

In West Africa, landraces or local varieties of fonio are processed into many products by women using small processing units and marketed locally as well as exported to Europe and the United States. The objective of this study was to evaluate the effect of processing methods, namely parboiling, precooking and roasting on the physico-chemical and functional properties of two mainly preferred fonio landraces (Iporhouwan and Namba) by consumers. Results showed that the physico-chemical characteristics and most functional properties were significantly (P < 0.0001) affected by the processing methods. The lowest brightness (L*) values were obtained for parboiled fonio for the two landraces. However, parboiled fonio presented the best biochemical composition as compared to the dehusked, milled, precooked and roasted fonio samples. The protein contents of parboiled fonio samples were 6.06 % and 7.24 % for Iporhouwan and Namba landraces respectively. The values of peak viscosity, trough viscosity, breakdown, final viscosity and setback, were significantly higher for dehusked and milled fonio than for precooked, parboiled and roasted fonio with respect to both landraces. The milled fonio showed highest peak viscosity (2,668.5 cP) which was similar for the both tested landraces.

Effects of parboiling and other hydrothermal treatments on the physical, functional, and nutritional properties of rice and other cereals

“…For example, significant increases in riboflavin, thiamine, calcium, and phosphorous contents in parboiled rice have been reported (Bello et al., ). Similar results were reported in two parboiled fonio landraces, which comparatively contained higher ash, iron, and zinc contents after the hydrothermal treatment (Ballogou et al., ). However, for pressure and atmospheric cooked barley, there were significant losses of thiamine in both treatments and a significant loss of riboflavin only in pressure‐cooked kernels.…”

“…This has been reported by several authors, not only for rice (Mir et al., ) but also for einkorn wheat ( Triticum monococcum ) (Hidalgo et al., ), emmer wheat ( Triticum dicoccon Schrank ) (Messia et al., ), fonio ( Digitaria exilis ) (Ballogou et al., ), and other millets (Varadharaju & Ganesan, ).…”

“…Additionally, the protein bodies associated with the surface of the starch granules ruptured proportionally with the severity of steaming thus decreasing the extractability of globulins and glutelins (Raghavendra Rao & Juliano, ). In the case of hydro‐treated cereals such as emmer wheat (Messia et al., ), fonio millet (Ballogou et al., ), and oat (Shukla, Chaturvedi, Sharma, & Shukla, ), the heating temperature and time settings slightly increased protein contents compared to untreated grains. Other studies reported nonsignificant differences in protein contents of parboiled cereal grains like einkorn wheat (Hidalgo et al., ).…”

Effect of soaking medium on the physicochemical properties of parboiled glutinous rice of selected Laotian cultivars

“…soaking, steaming, and drying. [1][2][3] According to the recent statistics, 130 million tons of paddy is parboiled annually around the globe with about 3-4 million tons high-value parboiled milled rice being moved in world trade. [4] Parboiling was initially originated and is largely practiced in India.…”

Processing and quality of glutinous rice

“…Parboiling is hydrothermal processing of paddy and/or brown rice to improve the head rice yield, nutritional and organoleptic properties by using a three-stage process viz. soaking, steaming and drying (Kar et al 1999;Ballogou et al 2015;Kwofie & Ngadi 2017). According to the recent statistics, 130 million tonnes of paddy is parboiled annually around the globe with about 3-4 million tonnes of high-value parboiled milled rice being moved in world trade (Bhattacharya 2013).…”