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Food and Feed Uses
Food and Feed Uses
Pages 46-56
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From page 46... ...
In QPM kernels, it is the glutelins that predominate, making up about 40 percent of the total protein. This is the crucial nutritional advantage because glutelins are 18 times richer in both lysine and tryptophan than are prolamines (figure 6.2)
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From page 47... ...
With the proportion of glutelins increasing at the expense of prolamines, the overall lysine content in the endosperm protein rises from 2.6 percent in common maize to about 4 percent in QPM. Additionally, another amino acid, tryptophan, also increases substantially -- an important factor because, as noted, tryptophan is both an essential amino acid and the biological precursor of the B-vitamin, niacin.
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From page 48... ...
The more equal balance between these two amino acids is of possible nutritional benefit: some researchers believe that it boosts the production of niacin, thereby also helping to overcome pellagra. Further, the change from prolamines to glutelins raises the amount of usable protein.
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From page 49... ...
protein-as-energy value of 4.7 percent, which makes it unable to fulfill the requirements of a 1-year-old. VITAMINS QPM's niacin content is no higher than that of common maize, but, as just discussed, it has more tryptophan, a compound that the human body converts into niacin for itself.
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From page 50... ...
ANIMAL TRIALS WITH OPAQUE-2 MAIZE In the 1960s and 1970s, nutritional research with rats, pigs, and chicks showed that opaque-2 maize was a dramatically better feed than ordinary maize. The results are generally transferable to QPM because opaque-2 and QPM differ mainly in kernel texture and field performance; nutritional compositions are essentially identical.
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From page 51... ...
Opaque-2 maize alone is not adequate for piglets, growing pigs, or lactating sows. For them, it must be supplemented with protein or amino acids to produce maximum performance.5 In Colombian trials, piglets fed solely on opaque-2 maize remained healthy and vigorous, while piglets fed solely on common maize developed a protein-deficiency disease and, after 110 days, began to die.
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From page 52... ...
• For adult males, 300 g of opaque-2 maize provides 93 percent of the daily protein requirement (and 40 percent of the daily calorie requirement)
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From page 53... ...
The nitrogen-balance index (a good estimate of the biological value of proteins) was 0.72 for opaque-2 maize, and 0.80 for milk, suggesting that the protein in opaque-2 maize had a biological value equivalent to 90 percent of that in milk.10 Nitrogen-balance studies conducted in Colombian children 24-29 months of age who were recuperating from calorie-protein malnutrition concluded that: fed common maize, the children lost 54 mg of nitrogen per kg per day; fed opaque-2 maize, they lost only 8 mg of nitrogen per kg per day; and fed milk, they gained 2 mg of nitrogen per kg per day.
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From page 54... ...
These trials indicate that only differences in protein and carbohydrate digestibilities separate QPM from milk as a food for catch-up growth in malnourished infants.13 FAMILY USE For all its newness, QPM should require no change in the family's habits. People already using common maize should find QPM indistinguishable in appearance and feel.
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From page 55... ...
As much as 20 percent QPM can be added to wheat flour without seriously affecting the loaf value and crumb quality of leavened breads. More than 25 percent, however, decreases the ease of rolling and reduces loaf volume.14 QPM has outstanding promise in unleavened foods such as tortillas and corn chips (table 6.3)
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From page 56... ...
LIVESTOCK FEED People indirectly consume vast amounts of maize in the form of animal products such as meat and eggs. This is especially so in the industrialized nations where maize is used to feed poultry and pigs.
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