Four lactating Holstein cows were used in a 4 X 4 Latin Square design to determine the effects of postruminally administering sodium caseinate and/or glucose on milk production, milk composition, nitrogen utilization, amino acid utilization by the lactating mammary gland and glucose turnover rate. An 8.5% increase in milk yield and a 13.3% increase in milk protein production were obtained during infusion of sodium caseinate. No significant production responses were attributed to abomasal infusion of glucose. Arterial concentrations of most essential amino acids were increased during infusion of sodium caseinate. Uptake of phenylalanine, methionine and lysine by the mammary gland most closely paralleled their output in milk. The relative concentrations of methionine, lysine and phenylalanine in arterial plasma were considerably less than their concentrations in milk which resulted in a large percentage extraction of these amino acids by the mammary gland. If the availability of essential amino acids to the mammary gland, per se, was limiting the synthesis of milk protein, methionine, lysine and phenylalanine may have been the three amino acids most limiting. Measurements of glucose entry rate showed a trend toward increased glucose flux when either glucose, sodium caseinate or glucose plus sodium caseinate were infused abomasally. The similarity in glucose entry rates obtained during infusion of glucose and sodium caseinate suggest that the increase in milk production was not due totally to increased glucose flux resulting from sodium caseinate infusion.

Consumption of soy foods has been weakly associated with reduced colon cancer risk. Colon cancer risk is influenced by estrogen exposure, although the mechanism through which this occurs is not defined. Conversion of estradiol (E2) to estrone (E1) may be protective in the colon. We hypothesized that dietary phytoestrogens, or E1, would reduce colon tumorigenesis via an estrogen receptor (ER)-dependent mechanism. Ovariectomized ERalphaKO or wild-type (WT) female mice were fed diets containing casein (Casein), soy protein without isoflavones (Soy-IF), soy protein + genistein (Soy+Gen), soy protein + NovaSoy (Soy+NSoy) or soy protein + estrone (Soy+E1) from weaning. Colon tumors were induced with azoxymethane. Tumor incidence was affected by diet but not genotype. Colon tumor incidence was lower in ERalphaKO and WT mice fed the Soy+E1 diet compared with those fed the casein or Soy-IF diets. Mice fed Soy+NSoy had a lower tumor incidence than mice fed casein, but not Soy-IF. Genistein did not affect tumor incidence. Soy protein, independently of phytoestrogens or E1, significantly reduced relative colon weight, tumor burden and multiplicity. Relative colon weight was lower (P=0.008) in mice fed Soy+E1 than in the other soy-fed groups. Tumor incidence in this group was lower than in the casein and soy-IF-fed groups and tended to be lower than in the others (P=0.020). Hence, soy protein and NSoy protect mice from colon cancer, and E1 further reduces colon tumorigenesis in mice, independently of ERalpha.

Based on the protective effects of cooked dry bean consumption in a human intervention study, we evaluated which fraction of cooked dry beans is responsible for its cancer-preventive effects. Cooked navy beans (whole beans), the insoluble fraction (bean residue) or soluble fraction of the 60% (vol:vol) ethanol extract of cooked navy beans (bean extract), or a modified AIN-93G diet (16.6% fat including 12.9% lard) as control diet were fed to 160 male obese ob/ob mice after 2 azoxymethane injections. In comparison to control-fed mice, dysplasia, adenomas, or adenocarcinomas were detected in fewer mice on either bean fraction diet (percent reduction from control: whole beans 54%, P = 0.10; bean residue 81%, P = 0.003 ; bean extract 91%, P = 0.007) , and any type of colon lesions, including focal hyperplasia, were found in fewer mice on each of the 3 bean diets percent reduction from control: whole bean 56%, P = 0.04; bean residue 67%, P = 0.01; bean extract 87%, P = 0.0003. These results suggest that both the soluble and the insoluble fraction of the extract contribute to the cancer-protective effect of cooked navy beans.

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Cereal Chem. 77(2):237-240Okara is the residue left after soymilk or tofu production. In North America, okara is used either as animal feed, fertilizer, or landfill. The purpose of this study was to use wet okara to produce and enrich extruded cereal products and to study the effects of extrusion on the dietary fiber and isoflavone contents. Wet okara was combined with soft wheat flour to produce two different formulations (33.3 and 40% okara) and extruded using four combinations of two screw configurations and two temperature profiles. Various physicochemical properties, dietary fiber by enzymatic-gravimetric method, and isoflavone content by HPLC were analyzed. The radial expansion ratio decreased as fiber content increased. On the other hand, both bulk density and breaking strength increased as fiber content increased. Combining okara with soft wheat flour resulted in increased protein, dietary fiber, and isoflavone contents compared with soft wheat flour alone. Extrusion of the formulations resulted in decreased insoluble fiber (≤25.5%) and increased soluble fiber (≤150%) contents of extrudates. Extrusion decreased the total detectable isoflavones (≤20%) and altered the distribution of the six detected isoflavones.