Evaluation Of Six Corn (zea mays) Hybrids For Wet-Milling And Starch Quality

Abstract

The objective of this study was to evaluate six flint yellow corn (Zea mays) hybrids grains namely SHM5, SHM6, SHM9, SHM10, SHM11, and SHM13 for starch production and quality .The grains were analyzed for proximate composition, starch was extracted through wet-milling process. Parameters measured include: Water absorption of the grains, fractions of the wet-milling process, also the quality of the starch was determined according to it´s content of moisture, ash, protein, amylose as well as viscosity and colour. The results indicated significant variations among the tested hybrids in most of the studied characters. Grain, protein content varied from11.4 %(SHM9) to 12.2% (SHM13), fat content 3.9% (SHM9) to 4.9% (SHM10), moisture content 7.5% (SHM10) to 8.3% (SHM5), ash content 1.2%(SHM13) to 1.4% (SHM10), fiber content 1.7%(SHM10) to 2.7% (SHM5) and carbohydrate 71.5%(SHM5) to 73.3% (SHM9). The water absorption of the grains ranged between 55% (SHM10) and 64% (SHM9). Variations were also detected in the fractions of the wetmilling process; the extracted starch was 41% (SHM10) to 45% (SHM5), fiber and germ as well as horny endosperm 14% (SHM13) to 20.5% (SHM10) and extracted protein 20% (SHM5) to 24.5% (SHM6). Starch, moisture content varied from 5.5% (SHM10) to 7.2% (SHM13), ash content 0.12% (SHM13) to 0.22% (SHM10) and protein content 0.18% (SHM10) to 0.24% (SHM13). Furthermore the amylose content of the extracted starch ranged between 13.6% (SHM11) and 30.5% (SHM6). Starch had falling number ranging between 274Sec (SHM10) to 347 Sec (SHM13), and a yellow colour value varying from 1.4 (SHM10) – 1.7 (SHM6, SHM11). The relationship between the amylose content and falling number is a positive and moderate one, while the relationship between the amylopectin content and falling number of the starch is a negative and weak. These results indicated that the hybrid (SHM5) is the best one for starch extraction and quality followed by (SHM9).