Wet milling comparison of quality protein maize and normal maize. uri icon

abstract

  • Quality protein maize (QPM) experimental hybrids and normal maize possessing different physical and chemical properties were studied as the raw material for wet milling. Maize samples were steeped for 36 h in a 600-ml solution containing 15 g kg(-1) lactic acid and 0.5 g kg(-1) SO2 followed by 12 h in a second 600-ml solution containing 5 g kg(-1) lactic acid and 1 g kg(-1) SO2. The steeped grain was then wet milled and the yields and purity of fractions were analysed. Water-soluble solids, kernel size, quality protein, total dietary fibre and ash content were higher in QPM samples than in normal maize. Water-soluble solids were positively correlated to kernel size (r = 0.97, P < 0.05), test weight (r = 0.83, P < 0.05) and density (r = 0.57, P < 0.05). Total fraction recovery for the five hybrids tested ranged from 921 to 955 g kg(-1), with the highest values corresponding to QPM hybrids. QPM hybrids yielded slightly higher starch content than normal maize. Gluten yields of QPM-HO (high oil) presented the highest values. The lysine contents of kernel gluten and milling solubles were highest for QPM hybrids. QPM contained more palmitic acid than the other hybrids. The H-137 normal maize and QPM yellow dent-HO contained more oleic and linolenic acids than the other samples, and the QPM white-C (corneous) contained more linoleic acid than QPM-HO and normal maize.

publication date

  • 1996
  • 1996