FURTHER STUDIES ON CANADIAN LARD: PHOSPHORUS CONTENT, COLOR, AND STABILITY

A modified colorimetric procedure showed that phosphorus content of Canadian lard (12 dry rendered samples and 21 wet rendered samples) was generally less than 0.001%, and did not appear to be definitely related to method of rendering or to keeping quality. Color of lard was conveniently measured with the Evelyn photoelectric colorimeter; photoelectric transmission values were most closely related to Lovibond color values in the yellow region. Lovibond color could be predicted only approximately from transmission. No association of color with processing conditions or with keeping quality was found. The criterion of an indicator change by volatile fatty acids in the Swift stability test rather than the attainment of an arbitrary peroxide value by the fat gave a closer association of Swift stability test values with organoleptic storage life of lard.

CHARACTERISTICS OF CANADIAN LARD

Mean values for measured properties of 33 samples of lard obtained from 26 packing plants across Canada were: iodine number, 58.7; saponification number, 193.9; melting point, 43.5 °C.; smoke point, 382° F.; colour, 8.8Y, 1.6R; unsaponifiable matter, 0.43%; fatty acid composition: saturated, 45.6%, oleic, 44.7%, linoleic, 8.7%, linolenic, 0.6%, arachidonic, 0.4%; storage life at 26.7 °C., 9.2 weeks; Swift stability, 3.5 hr.; iodimetric peroxide, 1.6 ml. of 0.002 N thiosulphate per gm.; ferrometric peroxide, 9.7 m.e. per kgm.; Kreis test, 9.9; Stamm test, 2.3; alpha-dicarbonyl test, 3.4; free fatty acid, 0.4%; fluorescence, 79.2. The distribution of values is shown by histograms.Simple correlation coefficients computed between measured properties showed the following to be associated: melting point with iodine number; free fatty acid content with melting point, smoke point, and red colour; storage life at 26.7 °C. with log of Swift stability and initial ferrometric peroxide, Kreis, and alpha-dicarbonyl values.