Air, water and food from a sanitary standpoint / by Ellen H. Richards and Alpheus G. Woodman.
- Ellen Swallow Richards
- Date:
- [1904], [©1904]
Licence: Public Domain Mark
Credit: Air, water and food from a sanitary standpoint / by Ellen H. Richards and Alpheus G. Woodman. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
228/302 page 210
![perature at which starch becomes pasty. If, however, the material contains little starch in the presence of much fibrous material, nothing is gained by adding malt before heating to boiling, since most of the diastase is destroyed by the high temperature before it has had time to act on the starch. If the malt itself is not readily procurable, certain forms of prepared diastase are on the market and may be found more convenient either for analytical use or for purposes of illustration. When possible, however, it is preferable to use the freshly prepared malt extract, as the prepared diastase, made at different times and from separate portions of malt, may show great differences in hydrolytic power. Pentosans.—These are determined usually directly upon the original material. The methods in general use depend upon the conversion of the pentose substance into furfurol by distillation with strong acid and the subsequent precipi- tation and estimation of the furfurol. The latter may be done by treatment with phenylhydrazine acetate and for- mation of the furfurol hydrazone, or by the formation of an insoluble condensation product with phloroglucin accord- ing to the method of Councler. For the details of these methods reference may be made to Wiley, Principles and Practice of Agricultural Analysis, Vol. Ill, p. 178 et sea., also an article by Sherman.* The phloroglucin method is given as a provisional method in Bull. 46 [Rev. Ed.] of the Bureau of Chemistry. It should be noted, however, that the method of filtering and drying the phloroglucid should be modified in accordance with the directions of Krober.f See also Bull. 73 of the Bureau of Chemistry, p. 173. * J. Am. Chern. Soc, ig (7897), 291. I Ztschr. angew. Chem. (igo2), 477.](https://iiif.wellcomecollection.org/image/b21209637_0228.jp2/full/800%2C/0/default.jpg)
