The Loganberry and the Acid Content of Its Juice
Journal of Industrial & Engineering Chemistry
Horne's). One hundred cubic centimeters of the milk were taken and 3 g. of the acetate accurately weighed and added, thoroughly shaken and filtered t o 50 cc. Readings were then made on the clear sera. The determinations made on laboratory samples I t o 16 show a fair degree of uniformity. It will be observed from a comparison of the conductivity and t h e chemical analysis, that the differences in fat and total solids content bear no relation t o the differences in conductivity. The sera from
... uthentic samples 18 t o 23 show a far greater variation than has been observed in any of the foregoing determinations and 'the results are entirely unreliable. I n the authentic samples adulterated in the laboratory (24 to 29) the water was first added t o the samples and IOO cc. of the adulterated milk were then taken and coagulated as described above. These results show great differences, even a t the same adulteration and these differences are greater than those between the authentic and adulterated samples. This is probably due t o an irregular adsorption of the lead salt by the coagulum, which would account for the lack of uniformity in the results, as was the case in experiments mentioned under Method I at the beginning of this paper. Having tried out the method and investigated all of the modifications at hand in a most exhaustive manner and being unable t o obtain any uniformity in results it was decided t o abandon the method as impractical. It is to be regretted t h a t this method proved ineffective, as a rapid and accurate method of this sort would be of great value t o t h e food analyst. One of the authors, Durand, proposes at an early date to continue this research, making use of the OSmotic pressure of milk, in a cell specially constructed t o measure the differential osmotic pressure between milks and a standard saline solution. Attention has been called t o the composition of loganberry pulp and juice and t o the drying properties of loganberry oil.1 This paper gives the composition of the fresh, ripe, whole berry and some data o n the juice, with special reference t o its acid content.