Study on Deterioration of Margarine. II.

Abstract

Preparing 5 (almost 1/2 lb) samples, for each of 8 kinds of bakery margarine from the market, observation was made on appearance, moisture, P.O.V., A.V, and color of the surface and the inside every month for 5 months. Moisture measurement shows what is hard and fragile in structure has a high rate of moisture reduction, and what is soft has a low rate. But inside observation shows any minor change during the whole period, showing a little change with hard one. All the samples show an increase in P.O.V. which is in proportion to linoleic acid content in general, because they contain no milk ingredient. There is a little difference between the surface and the inside, same as well in the first report. Oxidation is found to take place at the inside almost at the same level as is on the surface. Most samples show very small increase in A.V. since they have no hydrolysing element such as mold and coconut oil. And the difference between the surface and the inside is considerably small. All the samples discolor on the surface. The surface color become heavier only in the first month, but then after, sharp discoloration occurres, and the difference in color value between the surface and the inside grows increasingly wider. Compared with household margarine which almost did not discolor, the average value of the difference for bakery margarine is 7.0 against 0.9 for household margarine, when expressed the difference value between the surface and the inside in the 5th month figures.