Analysis Of Lime Treatment Of Maize Flour

Fig.1. Lime treatment of maize flour

Maize

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Cleaning

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Soak 1kg grain in 1 % lime water (10 g of lime in 1 l of water)

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Heat treatment at 85° C for 30 minutes

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Remove the vessel and leave it overnight (32 ±1° C)

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Wash 3-4 times to remove lime

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Dry in drier (60°C, 6 hrs)

(Moisture level should be 10-12%)

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Milling

Maize flour Maize semolina

Chemical characteristics

The untreated and lime treated maize varieties were pulverized, sieved using a BS 60 mesh sieve and evaluated for chemical constituents such as moisture content of the sample estimated by hot air oven method, protein was determined by available nitrogen in the sample by microkjeldhal method in Kjel plus (Pelican equipment, India), fat estimated by soxhlet extraction

Then the mixture was steeped overnight (15 hours) at ambient temperature of 32±1ºC. The resultant alkaline cooked maize grains were washed three times with excess (5 litre) tap water and then dried for 6 hours at 60ºC to a final moisture of 10-12 per cent and the grains. The study supported by Kulshrestha et al. (1992). Maize flour cooked with lime water was afforded the finest flour compared to plain water cooked maize as reflected by the optimum water absorption and the particle size index. Water absorption capacity of maize flour increased significantly after lime water treatment. The alpha-amylase susceptibility was highest in lime treated flour. The contents of total ash and crude protein of maize flour increased whereas those of crude fibre, fat and carbohydrates decreased after lime and heat treatments. Boniface and Gladys (2011) studied the effect of alkaline soaking followed by cooking on sorghum flour. The result indicated that alkaline cooking of sorghum flour significantly increased the protein content, water absorption capacity, oil absorption capacity, pH, hydroscopicity and significantly lower ash, tannins cyanide contents, phytate and trypsin inhibitor than control and water treated sorghum flour. Roy and Singh (2013) compared the untreated and lime treated maize flour and found that lime treated maize flour had high amount of

Sharma et al. (2002) reported that moisture content of five maize genotypes ranged from 8.21 to 8.79 per cent. Paes and Maga (2004) reported that the moisture content of four maize cultivars ranged from 9.15 to 11.88 per cent. The lower moisture content of lime treated maize might be drying of grain in the cabinet drier during lime treatment process at 60ºC for 2 hours.

Protein

The lime treated samples had the highest protein content compared to the untreated maize varieties, ranging from 12.72 to 12.63g/100g in CO1 maize and from 12.27 to 12.15g/100g in HQPM 7 maize respectively. Gupta (2001) found that the protein content of normal maize, processed defatted maize germ cake and maize germ were 12.63, 23.94 and 23.41 per cent respectively. Sharma et al. (2002) reported that the five maize genotypes had the protein content ranged from 8.6 to 10.23 per cent. Paes and Maga (2004) reported protein content of four maize cultivars ranged from 6.99 to 9.20 per cent. Guria (2006) reported that protein content of three maize varieties viz., QPM, S.A. Tall andDHM-2 were 10.15, 8.90 and 10.29 per cent respectively. Significant increase in protein content during lime treatment of sorghum has been reported by Bonface and Gladys (2011). The protein content of sorghum was increased from 19.77 to 21.69