Journal of the Faculty of Fisheries and Animal Husbandry, Hiroshima University Volume 8 Issue 2
1969-12-30 発行

肉および肉製品の風味成分に関する研究II. : 豚の皮下脂肪および赤肉の低沸点成分

A study on the flavor components of meat and meat products II. : Low-boiling compounds in barrow's subcutaneous fat depot and fresh lean pork
Kami, Takayasu
Otaishi, Satoru
Hayashi, Shuichi
Roast meat (Back and loin), 5.65 kg, was obtained from the right side of a Middle Yorkshire barrow of seven-month-old, weighing 100 kg. This was separated into the subcutaneous fat depot and fresh lean pork to examine the low-boiling compounds.

(1) A portion of the subcutaneous fat depot weighing 2.64 kg was heated with an equal volume of distilled water at lOO"C for 2% hours under constant stirring. The distillate collected in the watercooled trap was adjusted to pH 3 with 2N-phosphoric acid and was extracted with isopentane. The head space vapor of the isopentane soluble fraction, was taken out from the material-storing tube, and was examined in FID-equipped gas chromatograph. From the isopentane insoluble fraction, 2,4-dinitrophenylhydrazone. 3,5-dinitrobenzoate, phenylthiourea, methyl ester and mercury cyanide complex were prepared, which were analyzed by the gas chromatography, TLC and IR etc. The following compounds were thus identified as: isooctane, n-octane, acetaldehyde, propionaldehyde, n-butyraldehyde, isovaleraldehyde, isoheptyraldehyde, glyoxal, acetone, methyl isopropyl ketone, methyl isobutyl ketone, diacetyl, methanol, isopropanol, sec-butanol, tert-butanol, n-pentanol, lerl-pentanol, isononanol, isodecanol, n-propyl mercaptane, isoamyl mercaptane, ammonia, isopropyl formate, ethyl acetate, n-propyl acetate, acetic acid, propionic acid, n-butyric acid, isobutyric acid, n-valeric acid and isoheptanoic acid.

(2) Fresh lean pork, 1.84 kg, was distilled by steam and analyzed in the same manner as mentioned above. Only two small peaks were detected by the gas chromatography from the head space vapor of the isopentane soluble fraction, but the result obtained by the analysis of derivatives from the isopentane insoluble fraction was the same as that of the subcutaneous fat, lacking only n-butyraldehyde and isopropanol. Thus, the difference between the low-boiling compounds of the subcutaneous fat and the lean pork is not qualitative but only quantitative.

(3) It was observed by thin layer chromatography of isopentane extracts that lean pork is rich in triglycerides and cholesterol esters, while subcutaneous fat is rich in unsaturated fatty acids. The nitrogen content of the subcutaneous fat was about five times higher than that of the lean pork.