Buchbesprechungen

Ohne Zusammenfassung     

THE SYSTEM MAGNESIUM OXIDE-BORIC OXIDE*

Equilibrium In the system has been investigated for compositions from 0.6 to 75 weight per cent MgO. Three intermediate compounds are present. MgO⋅B₂O₃ melts incongruently at 988°C. to form 2MgO⋅B₂O₃ and a liquid containing more than 99% B₂O₃. The other two compounds melt congruently: 2MgO⋅B₂O₃ at 1340°C. and 3MgO⋅-B₂O₃ at 1366°C. At 1142°C., a region of liquid immiscibility extends from 0.6 to 36.0% MgO. Temperatures are accurate within =5°C. Conflicts between these results and those of Toropov and Konovalov (see footnote 8) are discussed.     

Stability values of fats by the active oxygen method and by storage in glass vials

Summary The stability of lards containing various antioxidants was determined by the active oxygen method and by storage in glass vials at 21° C. In many instances there was general agreement in the results, but no constant relationship was found. The difference between the results of the rapid test and those of the storage tests seemed to be greatest when tocopherol concentrate and lecithin were added to lard. In most instances where antioxidants were used, the protection indicated by the rapid stability test was higher than that found in the storage test. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, United States Department of Agriculture.     

The effect of fat on the gastric responses to foods

Summary 1. In eight series of triplicate tests on persons in good health and with normal secretory responses who were fed test meals of foods cooked with fat, the day to day variations in gastric evacuation times ranged from 0 to 30 minutes with an average deviation from the mean of ±17 minutes. 2. Experiments with meals of foods in which moderate quantities of fats were incorporated intimately by either baking or frying according to good culinary procedure revealed no relationship between the fat contents of the foods and the times required for complete evacuation of the foods from the subjects’ stomachs. 3. The experiments indicated a parallelism between the protein contents of the test meals and the gastric evacuation times. 4. No significant differences were observed between the influences of a hydrogenated vegetable fat and of butter upon the rates of evacuation from the subjects’ stomachs of meals of potatoes in which these fats had been incorporated intimately by good culinary technic. Within the limits of error of the experimental procedure, French fried and Lyonnaise potatoes containing moderate amounts of fat were evacuated from the stomachs as rapidly as boiled potatoes. 5. Gastric emptying times for meals of doughnuts did not differ significantly from gastric evacuation times for meals of bread and butter supplying equivalent amounts of fat. 6. The addition to a test meal of glucose in water of either hydrogenated vegetable fat or butter fat in amounts equivalent to two-thirds the weight of the glucose retarded the evacuation of the glucose meal from the stomach. 7. Excess fat, added to potatoes by pan-frying in hydrogenated vegetable fat or butter to the extent of making the potatoes “greasy,” such as may occur in poor culinary practice, prolonged the emptying time of the stomach beyond the period for boiled potatoes. 8. An explanation has been suggested for this retardation of the emptying of the stomach effected both by digestible fats added to glucose solutions and by foods containing fats in excess of that which is incorporated intimately in these foods by good culinary methods. This paper was presented before the meeting of the American Oil Chemists’ Society, Chicago, Illinois, October 27, 1944. This work was supported by a grant from Lever Brothers Company, Cambridge, Massachusetts.