1!)1<>] AGRlCUl.TUEAJ. CHEMISTRY AGROTECHNY. 807 



given of the three types of these juices cori-espomliug to the types of grapes 

 grown in the principal grape-growing districts of tlie United States, and of the 

 two general methods employed in preparing the juice. 



The types of juices are (1) the northeastern type, prepared especially from 

 the northeastern fox grape, Titis lahrnsca, which is characterized by its rela- 

 tively high content of acid in proportion to sugar; (2) the western type, pre- 

 pared from the European grapes, V. vinifera, of the Pacific coast grape sec- 

 tions, which have a high sugar content; and (3) the southeastern type, pi'e- 

 pared from Muscadine grapes (F. rotundifoUa and Y. munsoniana) of the 

 Southeastern States, which are somewhat lower in sugar content and higher 

 in acidity than the western grapes but resemble them in the transparency and 

 brilliancy of their juices. 



The cold-press method of extracting juice is considered preferable for use 

 with the western and southeastern types and the hot-press method for the 

 eastern type. The main steps of the process in both methods, from the selection 

 of the grapes to tlie storage of the final product, are outlined and discussed, 

 and diagrams witli accompanying descriptions are given of homemade grape 

 crushers and presses of different types. 



Culture of cabbage for sauerkraut, L. I^ebbun {Culture du Chou a Chou- 

 croute. Paris: Libr. Ayr. Maison Ru^stique, 1918, pp. 32, figs. 2). — This pam- 

 phlet contaiiis directions for the culture of cabbage to be used for sauerkraut, 

 for the manufacture of sauerkraut on a small and a commercial scale, and for 

 its preparation for the table. 



Low temperature-vacuum food dehydration, K. G. Falk, E. M. Fkankel, 

 and R. H. McKee (Jam: Jndvs. and Engin, Chem.. 11 (1919), No. 11, pp. 103G- 

 1049, fig. 1). — In this article a description is given of the low temperature- 

 vacuum dehydration process originally developed for the dehydration of meat, 

 but later employed successfully for the dehydration of vegetables and fruits as 

 well as meat and fish. The process consists briefly in heating the meat (or 

 other food products), cut in pieces of suitable size, to a temperature below that 

 at which cooking or appreciable changes take place, continuously maintaining a 

 degree of vacuum such that the vapor pressure of water at the temperature 

 employed is greater than the pressui-e within the vacuum drier, thus causing 

 boiling and evaporation of the water from all parts of the meat, and intro- 

 ducing a sufficient quantity of heat to evaporate the large amount of water 

 liberated. 



In the commercial vacuum shelf drier used, hot water or low-pressure steam 

 circulates through the shelves upon which are placed galvanized iron wire-gauze 

 trays containing the substance to be dried. In the dehydration of meat the 

 vacuum maintained cori'esponds to a pressure of 2 in. of mercury, and the tem- 

 perature of the circulating fluid is kept at about 70° C. The time of dehydra- 

 tion varies with the size of the individual pieces of meat used. With steaks 

 0.25 in. thick dehydration requires from 2 to 3 hours. The final product weighs 

 about 28 per cent of its original weight, contains approximately 10 per cent of 

 water, and occupies about one-half the original volume. If kept under ordinary 

 atmospheric conditions, no perceptible chemical change has been found to occur 

 at the end of a year. 



Fish, shell fish, fruits, and vegetables have been dried by this process without 

 difficulty and with very satisfactory results. In general, the process has been 

 found to cause less destruction of enzyms and less loss of volatile products than 

 with air-blast dehydration. 



The work of the Harrimaa Besearch Laboratory, Roosevelt Hospital, New 

 York City, in affiliation with the Division of Food and Nutrition, Medical 

 158071°— No. 9—20 2 



