The amino acid and chemical composition of seeds from three lesser known legume species and an African cereal with high Met + Cys contents is presented. Mesquite (Prosopis spp.): 41% protein, 2.5% Met + Cys. Djenkol bean (Pithecellobium lobatum): immature seeds, 32% protein, 2.8% Met + Cys; mature seeds, 16% protein, 3.9% Met + Cys. Tamarind seeds (Tamarindus indica): 18% protein, 3.5% Met + Cys. Acha (Digitaria exilis): 8% protein, 7.3% Met + Cys. Threonine is the first limiting amino acid for mesquite and tamarind while leucine is for Djenkol bean. The overall chemical scores are as follows: mesquite, 55; Djenkol bean, (immature) 31, (mature) 38; tamarind, 80. Tamarind seed protein has a very favorable amino acid balance and deserves further study. These legumes can not only complement cereals but supplement legumes with lower Met + Cys contents as well. The exceptionally high Met + Cys content of the cereal Acha makes it an excellent complement to legumes.

Dietary pectin at levels of 0, 3, 6 and 8% was fed ad libitum to rats for 8 wk to evaluate whether the bioavailability of vitamin E fed at 0.001% of the diet was affected by pectin. Rats fed 3% pectin were not different in any vitamin E parameters from those fed 0% pectin. By the end of the study body weights were significantly lower in the 6 and 8% pectin groups after adjusting for their nonsignificant trend of lower food intake. At wk 8, liver vitamin E levels were reduced in the 6 and 8% pectin group compared to values at the start of the study. Both groups had significantly higher red blood cell hemolysis compared to 0% pectin at 8 wk. Fecal fat excretion was not different among the diet groups, but weights of the small and large intestines were significantly increased in rats fed 6 or 8% pectin compared to those fed 0 or 3%. Our results show that 6 and 8 but not 3% dietary pectin decreased vitamin E availability in rats.

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To add data to the very limited information on winged bean tubers, samples from 26 varieties were analyzed for proximate analysis, tannin, trypsin inhibitor activity (TIA) and nonprotein nitrogen (NPN). The averages obtained were: crude fat, 0.96%, ash, 2.94%; acid detergent fiber, 16.56%; crude protein, 16.4%; carbohydrate, 57.72%; tannin, 5.32 mg/g tubers; trypsin inhibitor, 1033 TIU/g tubers. NPN constituted only a small percentage (16.2%) of the total nitrogen indicating that most of the nitrogen is protein. A significant proportion of NPN (76%) was ninhydrin positive, indicating free amino adds, peptides and possibly other amines. Tannin concentration was higher than those present in seeds. The presence of TIA necessitates heat processing before consumption.

The zinc requirement and signs of zinc deficiency of the young guinea pig were investigated. One-week-old Hartley guinea pigs were fed low-zinc, semipurified diets with either 30% EDTA-treated casein or 30% EDTA-treated soybean protein as the protein source. Zinc was supplemented as ZnCO3 at 0, 3, 6, 9, 12, and 60 ppm (casein diets) and 0, 5, 10, 15, 20, and 60 ppm (soybean protein diets). Specificity of zinc deficiency was determined by rapid growth response to zinc supplementation following a 4-week period of zinc depletion. Significant growth retardation and decreased feed efficiency were seen in guinea pigs fed casein diets with 3 ppm zinc or less added, or soybean diets with 5 ppm zinc or less added. Plasma zinc concentration was significantly decreased in guinea pigs fed soybean diets supplemented with 20 ppm zinc or less. Less dramatic trends of decreased plasma zinc level were seen when low-zinc casein diets were fed. Plasma alkaline phosphatase activity showed significant decreases when 9 ppm zinc or less was added to casein diets and when 20 ppm zinc or less was added to soybean protein diets. Zinc (12 ppm) added to casein diets and 20 ppm zinc added to zinc soybean protein diets supported maximal growth rate for the 3-week duration of the feeding trials.