The rates of loss in vitamin B1 and B2 contents of enriched white bread in the process of bread making were respectively about 12.2-13.7% and 3.8-4.2%. Dividing into two parts of crumb and crust, vitamin B1 and B2 were little deformed in crumb, on the contrary considerably in crust. Furthermore from the experimental results, vitamin B1 was stable, but vitamin B2 was unstable in the storage of white bread. And then we have been observed that the influence of light on the stability of vitamin B2 was remarkable in each difference of quality and color of wrapping paper.
This experiment was carried out in October 1953 as a series of previous experiment (Jap. J. Nut. 13, 135, 1956). The experimental methods and conditions were the same in previous experiment. The results obtained were as follows. 1) The variation of the heat production due to the influence of the restlessness, which could not be avoid thoroughly while the subject is kept at basal metabolic condition during a tolerable long time, showed the rise of about 3 per cent at comfortable temperature 20°C in this experiment. At 30°C temperature, slight rising metabolism was seen at second hour, but the average heat production in two hours had no signifcant variation. At 40°C temperature, there was the rising metabolism of 7 to 8 per cent in consideration of the restlessness. In lightly clothed conditions at lower temperature below 10°C, the rising metabolism accompanied with involuntary chill and shivering showed the increase of 13 per cent above basal in two hours at 10°C, 44 per cent at 0°C and 85 per cent at -15°C. In this cold conditions, the tensely superficial respiration by the shivering and compensatively deep respiration were seen alternatively as shown in figure 5 to 8. In warmly clothed conditions at lower temperature below 10°C, the signifcant variation was not recognized in the basal heat production at 10°C, 5°C and 0°C, but at -15°C the increase of 30 per cent was seen in average for two hours (see table 1 and figure 1 to 4). 2) The variation of the skin temperature were the largest at the peripheral place such as the hand. foot and forehead, and at the stem such as breast and abdomen were little, even in lightly clothed conditions at 0°C and -15°C, as shown in table 2 and figure 9 to 11. In the warmly clothed condition, for 0°C and -15°C, slight fall of the skin temperatures were seen at the hand and foot.
In this report as a series of previous experiments (Report 1 and 2), experimental environmental temperatures were set at the range from 40°C to -20°C and the effects of these different temperatures on the basal heat production were studied by the same methods and experimental conditions as described in previous reports. And more, in this experiment the following method was attempted, i. e., subject's head was placed in the room kept at lower temperature (0°C or -16°C) and his body was placed in the comfortable room, instead of keeping the subject at warmly conditions in lower environmental temperatures by varying the clothing conditions. Results obtained were as follows. 1) The heat productions at higher 40°C in this experiment did not show any signifcant variation above the basal metabolism, though the rising metabolism was seen, at the corresponding temperatures in previous summer and autumn experiments. And also, the rising metabolism at lower 10°C and -20°C temperatures in winter was lower than the heat production at 10°C and -15°C in autumn experiment. These inclination suggest that one's physiological status in winter has much tolerance or adaptability to the wide range from higher to lower environmental temperatures. 2) The basal heat production showed no signifcant variation when the head was placed in the room kept at 0°C or -16°C and the body was layed at comfortable room. This data show theoretically that there is no variation in the basal metabolism even at cosiderable lower environmental temperature such as -16°C, if the body is completely kept at comfortable temperature. 3) The skin temperature measured at lower temperature in this experiment showed the tendency of smaller variation at the sole and hand, as compared with the previous experiments in summer and autumn.