ボーマー数について (第7報)
析出グリセリドの示差熱分析
1968 年 17 巻 12 号 p. 665-670
詳細
1968 年 17 巻 12 号 p. 665-670
For the purpose of detecting foreign fats in lard, differential thermal analysis of crystallized glycerides from acetone by the Bömer method was carried out.
1) The DTA curve of the crystallized glyceride itself by the dilution method showed each one fusion peak at 6365°C for lard, at 5860°C for beef tallow, at 60°C for mutton tallow, and at 59°C for hardened lard. It is impossible to judge the mixing ratio from this point alone.
2) The crystallized glyceride was melted, cooled rapidly, and then heat-treated at 18°C. By doing this treatment, lard showed three endothermic peaks at 48, 55, and 66°C, and one exothermic peak at 58°C. Beef tallow showed a large endothermic peak at 61°C and a small exothermic peak at 47°C, exhibiting a DTA curve entirely different from that of lard.
Mutton tallow showed a curve quite similar to that of beef tallow, and hardened lard showed two endothermic peaks, a gentle slope peak at 44°C and a sharpe one at 56°C, and one exothermic peak at 47°C. There could be seen no any change of these peaks according to the duration of heattreatment.
3) Presence of more than 10% of beef tallow in lard can be detected from changes in DTA curve and, further, estimation of the mixing ratio is believed possible from the characteristics of the curve in the rough mixing range of 1060%.
4) Presence of 1080% of hardened lard in the lard makes difficult the judgement, whether the foreign fat is beef tallow or hardened lard, from only result of Bömer number. Whereas it is believed possible to estimate the rough mixing ratio from DTA curve.
