C. W. Weber

Effect of extrusion processing on the soluble and insoluble fiber, and phytic acid contents of cereal brans

The health benefits associated with dietary fiber have resulted in it now being used in virtually all food product categories, including many products which are manufactured using extrusion processing. The objective of the present study was to determine if extrusion processing affected phytic acid, and soluble and insoluble fiber contents. The effect of screw speeds of 50, 70, and 100% of maximum rotations per minute (% MRPM) on these components was investigated. A BI-EX Model DNDG-62/20D co-rotating intermeshing self-cleaning twin-screw extruder, manufactured by Bühlerag, CH-9240, Uzwil, Switzerland, was used to process wheat, oat and rice brans. It was found that extrusion did not affect the insoluble fiber content of wheat bran; however, a decrease in this component was observed in rice and oat brans. The effect on rice bran insoluble fiber was greatest at screw speeds of 50 and 70% MRPM. This occurred in oat bran at 50% MRPM. Soluble fiber content increased in all brans after extrusion, except ER100. For oat and rice bran soluble fibers, the greatest increase occurred at 50 and 70% MRPM, while for wheat bran this occurred at 70 and 100% MRPM. Extrusion did not affect the phytate content of the cereal brans.

The nutritional and chemical evaluation of Chia seeds

The chia plants are found in a group of annuals in the genera Salvia and Hyptis of the family Labiatae. Species of chia have been under cultivation for centuries in Mexico. Seeds from three Salvia and two Hyptis sources were collected and chemically analyzed for protein, oil, fiber, ash, moisture, and amino acids. The protein ranged in concentration from 19.0 to 26.5%, oil from 15.9 to 34.1%, fiber (ADF) from 22.1 to 33.4%, and total dietary fiber (TDF) from 47.1 to 59.8%. Threonine was the first limiting amino acid in chia seed, while lysine and leucine were the other limiting amino acids.

Extraction and fractionation of insoluble fiber from five fiber sources

Abstract Commercially processed wheat bran (WB), rice bran (RB), oat fiber (OF), tomato fiber (TF), and apple fiber (AF) were analyzed for proximate composition, soluble fiber (SF), insoluble fiber (IF) and total dietary fiber (TDF). IF was further fractionated into four fractions: cellulose, hemicellulose A and B, and lignin. Protein, IF, and TDF values were significantly different among the samples. Protein content ranged from 4.6% in OF to 24.9% in TF. SF values ranged from 1.5% in OF to 13.9% in AF. IF values varied from 46.7% in RB to 73.6% in OF. TDF ranged from 51.4% in RB to 75.1% in OF. Hemicellulose A to B ratio was high in all the samples except rice bran. WB had the highest total hemicellulose (44.0% of TDF) content followed by AF (38.4%), OF (38.3%), TF (36.5%), and RB (31.6%). Cellulose was 32.2, 26.6, 24.4, 20.8, and 19.7% of TDF in WB, OF, RB, AF, and TF, respectively. Lignin levels ranged from 5.2% in WB to 21.4% in OF.

The properties ofCucurbita foetidissima seed oil

Oils from the seeds of 15 different selections of the buffalo gourd,Cucurbita foetidissima, were characterized in terms of their physical and chemical properties, which indicate that this oil is similar to other common edible oils. Xanthophylls were the predominant carotenoid pigments present in the crude oil, ranging from 51~232 mg/kg oil. Linoleic acid, the predominant fatty acid, ranged from 39~77% with an average level of 61%. Although conjugated unsaturated acids are a significant component in some other xerophytic cucurbit oils, the levels of conjugated dienoic and trienoic fatty acids in this species are only 2.3 and 0.03%, respectively.

Lead concentrations of milk, blood, and hair in lactating women

SummaryLead was measured in the milk of 39 lactating women to determine if the concentration posed a toxicological hazard to nursing infants. Blood and hair of these women were also analyzed for lead to establish possible correlations with milk, and to indicate body burdens. The women were categorized as rural or urban residents so that all mean values of lead could then be correlated with their locations.The mean levels of lead in milk, blood, and hair were 3, 119 ng/ml and 2002 ng/g (ppb), respectively. Lead levels in milk were not considered high enough to pose any threat to the nursing infant. Furthermore, the levels in blood and hair were below values typically cited as average. The three biological parameters did not correlate significantly with each other or with the location of these women. Therefore, it does not appear that the women in this study have high body burdens of lead, or that the nursing infant is at any risk of lead exposure via milk.

Use and nutrient composition of traditional Navajo foods

Traditional foods of the Navajo were examined to determine the adequacy of their traditional diet. Descriptive data on the traditional foods were collected during six months of anthropological fieldwork. Samples of 92 foods were analyzed for proximate composition, eight minerals, and some for two vitamins. The present‐day use of these foods was assessed by administering a modified food frequency questionnaire to 86 Navajo women. Wild food plants were found to be infrequently used but nutritious, some had exceptionally high concentrations of vitamin A. Corn foods were more frequently used and had a high mineral content, especially when culinary ash was added. Sheep were often home‐butchered, and most parts still consumed. The results suggested that the Navajo would have been able to meet their nutritional requirements with traditional foods if sufficient amounts and proportions were consumed, and that increased use of some of the traditional foods today could mean improved nutrient intakes.

Variation in composition of Hopi Indian beans

Dry Phaseolus beans grown on the Hopi Indian reservation by traditional agricultural techniques were collected and compared with beans utilized by the Hopis but grown off the reservation. Species included P. vulgaris, P. acutifolius var. latifolius, P. coccineus and P. lunatus. Ethnobotanical information, morphological and chemical data were obtained. Beans grown on the reservation were generally but not always found to be superior in protein content, but no clear differences in protein quality could be attributed to bean types or field environments. Legumes are consumed at the same level (30 g/day/person) but native beans contribute less protein to the Hopi diet than during the 1930s, as a consequence of reduced diversity in varieties locally produced and consumed. Much variation occurs in mineral levels in Hopi beans, but the wide range in soil composition found in Hopi fields gave no clear correlation with bean composition.

Wild beans of the greater Southwest: Phaseolus metcalfei and P. ritensis.

Cocolmeca (thePhaseolus metcalfei group) are leguminous root perennials of the uplands (1,000–2,500 m elevation) of southwestern North America. Their cultural significance has been underestimated both within and beyond their natural range, where they have been utilized in prehistoric and historic times. Ambiguities in both scientific taxonomy and folk taxonomy obscure the fact that bothP. metcalfei andP. ritensis have been widely used as systemic medicine, food, in fermentation, as forage, and as glue. The use of the seeds as green and dried bean foods was historically extensive, but was abandoned due to changes in Indian subsistence patterns and in the availability of the plants themselves. Herb dealers today are responsible for transport of the roots as far north as the Navajo in Utah; it is suggested that cross- cultural merchants may have been responsible for their diffusion historically or even prehistorically. Bean seed from the two species contain 20.5–30.9% crude protein. Germ plasm conservation and screening are needed in order to evaluate further the potential of these species as cultivated food and forage crops for semiarid uplands.

The feral buffalo gourd,Cucurbita foetidissima

SummaryThe feral species,Cucurbita foetidissima, the perennial Buffalo gourd, has the potential of becoming a cultivated food crop, producing seeds rich in edible oil and protein. It also produces an extensive storage root system rich in starch. It has evolved in the arid regions of North America and is adapted to growing on arid to semiarid lands, which constitute much of the world’s land mass, lands now marginal for crop production.

In vitro mineral binding capacity of five fiber sources and their insoluble components for copper and zinc

Five fiber-rich food sources, wheat bran (WB), rice bran (RB), oat fiber (OF), apple fiber (AF), and tomato fiber (TF) and their isolated insoluble fiber fractions were evaluated in vitro for their binding capacity for zinc (Zn) and copper (Cu). Endogenous Zn concentrations of the fibers varied from 11.0 µg/g for OF to 136.0 µg/g for WB, whereas Cu concentrations ranged from 1.0 µg/g for OF to 14.0 µg/g for WB. In all the fibers, total Cu bound was significantly higher than Zn. Total Cu bound ranged from 3687 µg/g for OF to 8019 µg/g and 8073 µg/g for WB and AF, whereas, bound Zn levels varied from 1213 µg/g for OF to 7121 µg/g and 7166 µg/g for WB and RB, respectively. Significantly more Zn and Cu were bound by the fiber fractions than the whole fibers, probably due to the exposure of more binding sites on the polymers during the fractionation process. Generally, the fiber components of all five fibers showed Cu and Zn binding capacities decreasing in the order; hemicellulose A>lignocellulose>lignin>cellulose. A strong correlation was seen between the combined effects of protein, hemicellulose, and lignin contents of the fibers versus total Zn binding capacity and a lesser correlation with Cu.