In order to detect foreign fats in lard, differential thermal analyses were carried out by raising the temperature from 0°C, using lard, beef tallow, horse fat, mutton tallow and hardened lard, and mixed with beef tallow, horse fat or hardened lard in 5, 10, 20, 40, 60 or 80% amount.
1) The samples were melted at 60°C, rapidly cooled to 0 in 30 minutes, tempered at 20°C for 24 hours, and the temperature gradually raised at the rate of 3°C/min.
2) Lard showed two and beef tallow showed three endothermic peaks, and scattering of peak temperature was small among the same species. Mutton tallow showed the same curve as beef tallow, and their peak temperature was about the same but horse fat did not show any clear peak.
3) Presence of 10% beef tallow in lard can be easily detected because of the peak on lowtemperature side characteristic to beef tallow, and this was more sensitive than the Bomer number. The amount of beef tallow mixed in lard can be known from the shape of the curve and ratio of peak height. The same would probably be true in the presence of mutton tallow.
4) Presence of more than 10% of horse fat also showed the same tendency as that of beef tallow, but the presence of 1040% of horse fat cannot be discriminated from that of beef tallow. However, consideration of the ratio of peak height will make it posible to discriminate between beef tallew and horse fat.
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