We have shown previously that sorghum is highly digestible in the rat. However, other workers have shown that sorghum is much less digestible than wheat, maize, and rice in young children. Because the rat does not show these digestibility differences, we developed an empirical pepsin digestion method, furst reported in 1981, which simulates the digestion values found in children. In this report the method has been improved and used to analyze wheat, maize, rice, millet, and sorghum and certain processed samples of millet and sorghum. The pepsin digestion values parallel those found in children for wheat, maize, rice, and sorghum. In addition, a processed sorghum product that gave a high digestion value in children also gave a high value with the in vitro pepsin method.Sorghum [Sorghum bicolor (L.) Moench] is an important source of calories and protein for a large segment of the human population in the semiarid tropics.In a previous publication (1), the apparent digestibility of the proteins in four (cooked) sorghum gruels varied from 76.5% to 83.0% (average, 80.4%) in young rats. The same four sorghum flours, when cooked and fed to children of age 6-27 months, gave an average apparent digestibility value of only 46%, compared with values of 81%, 73%, and 66% for wheat, maize, and rice, respectively (2). Because the rat gave values for cooked sorghum that were the same as those MacLean et al. (2) found for cooked wheat in the child, we developed an empirical in vitro pepsin method (1) that more closely simulates MacLean's values in children. In this report we present improvements in our original method and data on the pepsin digestibility of the major cereals. We also include data on processed sorghum and millet products [sorghum and millet nasha (fermented baby foods) and extruded decorticated sorghum].MATERIALS AND METHODS found on the grain in Sudan), was added, and the mixture was incubated at 30'C for 12 hr. The slurry was fed to a laboratory drum dryer or was freeze-dried, and the dry residue was used for digestibility studies.Pepsin. The pepsin used was porcine pepsin 1:10,000 (Sigma). It had an activity of 1,200-2,000 units/mg of protein (A28) (3).Modified Pepsin Method (Residue Method). Ground cereal samples (200 mg) prepared with a Udy grinder and 0.4-mm screen were suspended in 35 ml of a solution of pepsin (1.5 mg/ml) in 0.1 M phosphate buffer (pH 2.0); the mixture was incubated with gentle shaking at 370C for 2 hr. Incubation for 3 hr raises all values about 10% above the 2-hr values; incubation for 1 hr lowers all values about 10% below the 2-hr values. Therefore, time of incubation is critical in the assay. After incubation the suspension was centrifuged (12,000 x g for 15 min at 40C), and the residue was suspended in 10 ml of 0.1 M phosphate buffer (pH 2.0) and centrifuged as before. The low-pepsin moist residue was freed from the walls of the centrifuge tube with a spatula and dumped in the center of Whatman filter paper no. 3 on a 43-mm Buchner funnel. Suction (aspirator) was applied, an...

The purpose of this study was to compare in vitro digestibility, protein distribution patterns, and amino acid composition of pearl millet with other major cereals, Digestibility values for the pearl millet varieties were higher than that of sorghum and comparable to that of maize. In contrast to sorghum, digestibility of pearl millet and maize did not decrease significantly upon cooking. Protein distribution patterns of uncooked pearl millet and shifts in the different fractions as a result of cooking also resembled that of maize and not sorghum. The amino acid profile of pearl millet is more favorable than that of normal sorghum and normal maize and is comparable to the small grains, wheat, barley, and rice. On the basis of these findings, it appears that pearl millet is a nutritious and well-digested source of calories and proteins for humans.Pearl millet (Pennisetum typhoides) ( laboratory (7, 8). However, for the total amino acid profile assays, several cereals including maize (Zea mays), barley (Hordeum vulgare), wheat (Triticum aestivum), and rice (Oryzae sativa) were compared with the same pearl millet and sorghum varieties listed above.Whole-grain proteins were sequentially extracted into five fractions following the Landry-Moureaux method as described in detail by Misra et al. (9). Samples (1 g) of finely ground, defatted, cooked and uncooked flour were suspended in 10 ml of a 0.5 M NaCl solution and stirred for 60 min at 40C. The mixture was then centrifuged and the extract saved.The residue was treated again with the same amount of saline and stirred for another 30 min. The extraction was repeated for the third time for 30 min. Finally, the residue was extracted with the same volume of water for another 15 min, and this process was repeated once again for 15 min. The five extracts were then combined to give fraction I. The residue was then treated with 10 volumes of 70% isopropyl alcohol at 20TC for three 30-min periods as outlined by Misra et al. (9) to give fraction II. The residue was then reserved for isolation of fraction III, etc. Fraction I contains the albumins and globulins, free amino acids and small peptide fragments, and any other saline-soluble compounds. Fraction II contains the prolamins, and fraction III contains prolamin-like proteins that are soluble in alcohol after the disulfide bonds of the protein have been reduced with 2-mercaptoethanol. Fraction IV, which contains proteins soluble in an alkali borate buffer containing 2-mercaptoethanol, has some of the characteristics of glutelin and may be classified as glutelin-like. Fraction V contains the true glutelin, which is a complex, high molecular weight mixture of proteins that can be solubilized only by treatment with a reducing agent and a detergent, NaDodSO4, at alkaline pH. Nitrogen was determined by the micro-Kjeldahl method using the Technicon analyzer.Both uncooked flour and cooked (1:10 ratio of flour to water in a boiling water bath for 20 min) pearl millet and sorghum samples were digested with pepsin by the me...

Published information indicates that rice, maize, and wheat. proteins are much more digestible in children than sorghum proteins are (6681% compared with 46%). However, this digestibility difference cannot be demonstrated with the weanfing rat, which gave digestibility values of 80% for cooked and 85% for uncooked sorghum gruels. Therefore, a search was made for a laboratory system sensitive to the digestibility differences between sorghum and other cereals. We foundthat porcine pepsin in vitro shows these digestibility differences. Using pepsin, we have found that uncooked sorghum proteins have a high digestibility (78-100%), which drops .to a range of 45-55% after cooking. Two fermented sheet-baked sorghum products (kisra and abrey) from Sudan gave pepsin digestibility values of 65-86%. In contrast, unfermented cooked gruels made in our laboratory from the same flours used for the kisra and abrey gave pepsin values of only 44-56%. Therefore, fermentation improves pepsin digestibility of sorghum. The digestibility values of other sorghum-based foods prepared in the semiarid tropics need surveying. Those with high pepsin digestibility values hopefly should be more digestible (in children) than are the cooked sorghum gruels. studied to date by human nutritionists.Sorghum [Sorghum bicolor (L.) Moench] is one of the four major cereal grain crops grown for human consumption in the world. It is an important source of calories and protein for a large segment of the human population in the semiarid tropics.The published information available on the apparent digestibility of sorghum proteins indicates that. they are less digestible than those of other cereals. Kurien et aL (1) found that the proteins in rice fed to seven boys age 10-11 yr were 75% digestible; replacement of the rice with sorghum lowered the apparent digestibility to 55%. Similar results were obtained by Daniel et aL (2) in young girls fed a sorghum diet. Graham and MacLean (3) fed two normal and two high-lysine sorghum cultivars supplied by our laboratory to children age 6-27 mo. The mean apparent digestibility value of the cooked sorghum gruels was only 46%, compared with 81% for wheat, 73% for maize, and 66% for rice.Because only a limited number of digestibility tests can be carried out with children, we have developed a laboratory system giving digestibility values similar to those found in children.In this report, samples of the same sorghum cultivars used by Graham and MacLean (3) were cooked as gruels and fed to young weanling rats; they digested the sorghum gruel proteins much more efficiently than did the children in Graham and MacLean's study. A pepsin method previously used to study the digestibility of proteins in high tannin sorghum by Chibber et aL (4) was tested. This method gave values similar to those found in the literature for humans and has been used to study factors affecting the digestibility of sorghum proteins. MATERIALS AND METHODSGrain samples of the same low-tannin cultivars sent to Graham were used in the pepsin ass...

Based on the negative relationship between lignin and digestibility, one of the most effective means of increasing forage digestibility is by reducing lignin content. Our objective was to chemically induce a brown‐midrib (bmr) mutation in pearl millet, Pennisetum americanum (L.) Leeke, and evaluate the resulting mutants for lignin content and similarity to existing bmr mutants in other species. Seeds from two inbred pearl millet lines derived from Tift 23D2B1/2 ✕ PI 185642 were treated with either ethyl methyl sulfonate or diethyl sulfate, planted, and selfed in 1984. In 1985 a single plant in one head row exhibited a brown‐midrib phenotype, and was selfed. The bmr pearl millet was compared to selfed normal plants from the same head row along with bmr and normal sorghum, Sorghum bicolor (L.) Moench., and maize, Zea mays L., in 1986 at two locations. Plants were harvested at anthesis and analyzed for apparent in vitro dry matter digestibility (IVDMD), permanganate lignin, alkali‐labile phenolics, and other quality parameters. Lignin concentration in bmr pearl millet was 40 g kg−1 compared to 50 g kg−1 for its normal counterpart, and IVDMD was 726 g kg−1 for the bmr genotype compared to 659 g kg−1 for the normal genotype. The differences in phenolic monomer concentrations between normal and bmr pearl millet were more like those in sorghum than maize. Based on IVDMD, lignin and phenolic monomer analyses, we concluded that bmr pearl millet was similar phenotypically to bmr mutants in sorghum. This trait has excellent potential for improving the quality of forage pearl millet.