Table 3.

Studies carried out by various researchers on antinutrient reduction method and their effect on processing method.

Processing method	Millets	Experimental condition	Experimental outcomes	Effect of processing method	Disadvantages	References
Parboiling	Finger millet	70°C at 10 to 24 h	Reduces phytic acid content by 20 to 30%. Facilitates efficient separation of the endosperm from the bran. Increase in residual starch content.	Maximum grain recovery with lower nutrient loss. Reduces phytic acid levels and facilitates the separation of the endosperm from the bran. Decreases the glycemic index while enhancing residual starch content.	Altered texture and cooking quality. Sensory change. Energy intensive. Nutrient specificity and loss.	(31, 32)
Dehulling/ Decortication	Pearl	30 ± 2°C for 14 h	Protein content increased. Decrease phytic acid content from 943 to 380 mg/100 g (59.5% reduction).	Removal of husk from millets. Millets are usually dehulled or decorated by using a mortar and pestle or mill stone, resulting in fatigue during processing operations.	Significant Nutrient loss. Incomplete antinutrient removal. Variable efficacy. Grain breakage.	(33)
Heating	Proso	Pan and microwave cooking	Elevated carbohydrate content but reduced fat content. Protein content in pan and microwave cooking was increased and decreased, resp.	Change of fat content, smell, texture, color, nutrient composition, flavor depends on heating method.	Loss of heat sensitive nutrients. Thermal stability of certain anti-nutrients. Reduced protein digestibility and mineral. Mineral losses. Negative effects on organoleptic properties. Time and energy consumption.	(101)
	Little	Pan and microwave cooking.	Elevated carbohydrate content but reduced fat content. Protein content in pan and microwave cooking was increased and decreased, resp.			(101)
	Pearl	Roasting 150 °C for 5 min.	Enhanced the proportion of all polyphenols that are bio-accessible for native and roasted sample by 73.2 to 78.1%. Elevated bio-accessible flavonoid.			(102)
		Microwave heating	Decreased bio-accessible of phenolic content.
	Kodo	Boiling 95 to 100 °C for 25 min.	Elevated water absorption capacity and porosity. Decreased starch yield.			(103)
Soaking	Pearl	Soaking for 24 h	Protein content elevated due to release of stored nitrogen grains. With sprouting fat and crude fiber increases. Sprouting reduces Co, Cr, Cu, Zn, Fe, Na, K.	Increases the grains’ capacity to absorb moisture and enhances the bioavailability of zinc quickly and uniformly. Inhibition of trypsin action. At 25 °C, over a 12-h period, reductions were observed in several antinutritional factors: trypsin inhibitor activity (TIA), oxalates, polyphenols, and saponins decreased by 33%, tannins by 20%, and phytate levels declined from 39.47 to 24.17%.	Loss of water-soluble nutrients. Limited and variable effectiveness. Time consuming process. Risk of souring. Lack of control on process parameters.	(30, 104–106)
Germination	Foxtail	Germinated for 46.5 h	Protein content increased (13.37 g/100 g) compared to raw (10.60 g/ 100 g). Increase minerals like Fe, Mg, Ca, Na. The fat content is reduced from 3.86 to 2.78 g per 100 grams.	Reduces antinutritional content and increases the mineral biodiversity. Substantially decreased amylase activity, trypsin inhibitor, phytates by 54% and tannin by 65%.	Time intensive process. Risk of spoilage and mold growth. Loss of dry matter and nutrients. Variable effectiveness across antinutrients. Potential for antinutrients resynthesis. Decline of bio accessibility of some compounds. Potential loss of water-soluble nutrients.	(30, 54, 55)
		Germination at room temp.	Protein, dietary fiber and phenolic content increased by 29.72, 58.02 and 77.42%.			74,
	Kodo	38.75 °C for 36 h	The mineral content, protein, and dietary fiber increase, while total carbohydrate levels decline.			(107)
	Pearl millet	Sprouting at 72 h for room temperature.	Decrease fat and Ash content. After germination iron and calcium content increases.			(108)
Fermentation	Pearl var	Lactobacillus Plantarum	After 96 h of fermentation, the protein content increased from 8.7 to 20.54% in the sample with a starter culture and to 20.21% in the naturally fermented sample. Reduces carbohydrate with increase of soluble sugar. The lipid content decreased significantly from 10.34 to 0.34% in the starter culture sample and to 0.74% in the naturally fermented sample.	• Enhances the biological value (BV), net protein utilization (NPU), and some vitamins. • Enhances dietary value and flavor. • A decrease of 20, 52, and 32%, respectively, in phytates, tannins, and trypsin inhibitors.	Time consuming. Risk of contamination. Variable quality and consistency. Sensory changes. Incomplete removal of all nutrients. By product accumulation.	(109, 110)
	Foxtail	Fermentation followed heat moisture treatment.	Crude protein content improves. Total carbohydrate level decrease. Increases nutritional quality of starch.			(54)
		Fermentation using L. paracasei Fen032 strain.	The crude protein content increased by 20.51% in the fermented sample. The total carbohydrase content decreased by 74.02%.			(111)