ISOLATION OF β2-CHACONINE, A POTATO BITTERNESS FACTOR

The 4-rhamnoglucoside of alkaloid solanidine, β₂-chaconine, was isolated from a mixture of α-solanine with β₂-chaconine by fractionation from hot ethyl acetate. The mixture of the two glycoalkaloids is obtained by endogenous enzyme action in a homogenate of potato berries and blossoms within a 24–36 h incubation at 37° C, pH 6.00. The identity of β₂-chaconine was ascertained by m.p., [α]D° IR spectrum, TLC of sugar components and reference to partial acid hydrolysis products of α-chaconine.     

Infrared-temperature variability in a large agricultural field

Airborne thermal imagery of a large varying-terrain commercial barley field was acquired over a full growing season. The data were analysed to determine temperature variability within the field and the percentage of area within various size instantaneous fields of view (ifovs) that would be within ±1, ±2, ±3 and ±5°C of the mean. There appears to be no great advantage in utilizing a small ifov instead of a large one for remote sensing of crop temperature.     

Pittsburgh Labor Market Adjustments In The 1980S: Who Gained and Who Lost?

ABSTRACT: This research describes the distribution of changes in labor market outcomes for individuals in a region disrupted by severe economic restructuring. We use data from western Pennsylvania to compare individuals' 1990 labor market outcomes with those they would have expected had the economic characteristics of the region remained unchanged for the previous 10 years. The comparison between these outcomes provides a measure of the cumulative effect of all labor market changes. We compare the average differences across subgroups of the population to explore how various demographic groups of workers fared. Our analysis suggests that the dynamic forces of economic change have a cumulative effect that differs greatly across subgroups of the population. In particular, older and less educated workers face the largest losses in wages and earnings. As expected, dislocation from a job adds to these economic losses, but the results indicate that age and education have larger negative effects, regardless of dislocation status.     

Relative Bioavailability of Dietary Iron from Three Processed Soy Products

The relative bioavailability of iron from soy flour (SF), freeze-dried soy beverage (SB) and soy concentrate (SC) was determined utilizing a hemoglobin repletion bioassay. Weanling male rats were fed a low iron depletion diet (3.5 ppm Fe) for 4 wk. For the next 2 wk groups of rats were fed repletion diets containing 0, 6, 12, or 18 ppm added iron from ferrous sulfate, SF, SB, or SC. Slope ratio analysis revealed that the relative iron bioavailabilities from SC (92%) and SF (81%) were not different from the reference standard, ferrous sulfate added to a casein-based diet, whereas that from SB (66%) was significantly less (P<0.01) than the inorganic source of iron. Analysis of results at individual iron levels suggested an iron bioavailability of SC>SF>SB.     

Behaviour of partially cross-linked casein micelles under high pressure

High pressure (HP) treatment of a casein micelle suspension at 250 and 300 MPa leads to an initial rapid increase of its light transmission, as measured in situ , indicating micellar disruption. Subsequently, a much slower, partial reversal of the HP-induced increase in light transmission is observed, indicating re-association of micellar fragments. Partial internal cross-linking of the casein micelles by the enzyme transglutaminase prior to pressure treatment slows down both the disruption and the reassociation process considerably. It is proposed that covalent cross-linking provides the micelle with extra stability against pressure-induced disruption and also prevents a molecular reorganization process required to induce reassociation of micellar fragments during prolonged pressure treatment.