摘要:

The rate of fermentation of wheat mashes byAerobacillus polymyxawas markedly increased by providing a high surface-area–volume ratio. Exposure to air or oxygenper sewas not a controlling factor since an atmosphere of nitrogen gave the same effect. Inhibition of fermentation of shallow layers of mash by exposure to carbon dioxide suggested that escape of fermentation gases (mainly carbon dioxide) might be the major factor affecting the fermentation rate. Support has been given to this hypothesis by the marked increase in rate obtained when wheat mashes were fermented under reduced pressures.Fermentation of 15% wheat mashes, normally requiring 72 to 96 hr., were complete in 48 hr. under 5 in. pressure (absolute). The fermentation rate was accelerated by decreasing pressures but was retarded slightly by increasing depths of mash. The butanediol–ethanol ratio became progressively lower with decreasing pressures, showing that such conditions favour ethanol formation.Fermentation of sugar media byAerobacter aerogeneswas only mildly stimulated by reduced pressures. This treatment compares unfavourably with aeration as a means of increasing the fermentation rate of this organism.

ISSN:1923-4287    

DOI:10.1139/cjr46f-012

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Packaging materials were dusted with mould spores and stored in a cabinet at 95° F. and 95 to 100% relative humidity for periods of one to eight weeks.M.S.T. and M.S.A.T. "Cellophane" were attacked only slightly by mould, but deterioration of the heat-sealing, moisture-proof lacquer occurred during storage under conditions suitable for optimum mould growth. Moulds grew abundantly on M.S.Y.T. Cellophane. Wax-coated materials supported abundant mould growth, and their water-vapour transmission values increased when wax peeled from the surface of the sheet. The transmission rate of laminated materials having metal foil as one layer was not greatly affected by mould growth or delamination of the other layers. Abundant mould growth developed on most samples of kraft, and on glassine. Very little mould developed on cellulose acetate, Pliofilm, or vinyl-film.

ISSN:1923-4287    

DOI:10.1139/cjr46f-013

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Exposure of milk powders to sunlight resulted in a much greater destruction of riboflavin than did exposure to ultra-violet light in the range 3200 to 4200 Å. The rate of photolysis was greater for skim-milk powders than for whole milk powders. Increased intensities of visible light accelerated riboflavin destruction. In the spectral region of 4200 to 5600 Å the wave band causing the greatest destruction in liquid skim-milk had a principal wave-length of 4450 Å, which corresponded to a maximum in the absorption spectrum of riboflavin. The rate of photolysis of riboflavin was a function of both wave-length and intensity of the impinging energy.

ISSN:1923-4287    

DOI:10.1139/cjr46f-014

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

The direct measurement of fluorescence on clarified sera collected as exudate from defrosting egg distinguished between samples of frozen egg of varying quality. The method may be useful in egg drying establishments where large quantities of frozen egg are available for test purposes.A similar serum was extracted from liquid and frozen egg by the following procedure. Approximately 50 ml. of fresh or thawed egg liquid was added to approximately 100 ml. of chloroform, mixed by gentle swirling, allowed to stand two minutes, shaken vigorously for 30 sec, and immediately centrifuged for 15 min. at 2000 r.p.m. The top layer, consisting of 15 to 20 ml. of red serum, was poured off and clarified by centrifuging for one minute, and the fluorescence of the clear serum determined. The latter measure consistently distinguished between samples of liquid and frozen egg of varying quality. The serum produced was less highly fluorescent than that obtained as exudate, and consequently the range between quality types was narrowed.The sera extracted with chloroform from freshly broken eggs of good quality had a higher fluorescence than that extracted from the material after standing at temperatures of 30° to 90° F. for short periods. However, the fluorescence rose when deterioration became evident. Freezing of liquid egg resulted in a decrease in fluorescent materials.

ISSN:1923-4287    

DOI:10.1139/cjr46f-015

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

A rapid process for separating starch and gluten from hard wheat patent flour (consisting of dispersal of a soft dough in water followed by screening) has been applied to pastry flour, whole wheat flour, and patent flours from the following wheats: No. 1 Northern, Hard Red Spring of high protein content; No. 2 Northern, Hard Red Spring of low protein content; No. 4 Northern, Hard Red Spring, severely damaged by frost; No. 2 C. W. Garnet; No.: C. W. Amber Durum; and No. 1 Alberta Red Winter. The original separation procedure required only minor modifications in spite of varying quantities and characteristics of the glutens of these flours. Whole wheat flour required a substantially greater amount of mixing water for the preparation of a satisfactory dough. Approximately 90% of the starch present in each flour was recovered. Starches from the patent flours had protein contents ranging from 0.49 to 0.64% while that from whole wheat flour contained 1.06% of protein. Recoveries of gluten from all flours were practically complete. Crude dry gluten prepared from patent flours contained 20 to 30% of starch while the bran–gluten fraction from whole wheat flour contained 9.9%.

ISSN:1923-4287    

DOI:10.1139/cjr46f-016

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Meats purchased in Winnipeg retail stores contained less thiamin than is reported in the literature for the same meats from other places. The values for pork compare with the ones reported in the literature, but those for other meats are distinctly lower. Arranged in descending order of thiamin content, the meats studied were: pork, variety meats, fowl, lamb, veal, and beef. Losses in cooking are quite high for fowl and some variety meats. Stewing and parboiling cause greater losses than roasting or frying.

ISSN:1923-4287    

DOI:10.1139/cjr46f-017

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Yields of 2 to 3% of a resin–rubber gum from milkweed pod hulls were obtained by a process that included alkaline digestion and pebble milling. The effects of various digestive treatments and milling procedures in laboratory and pilot plant are reported. The pod hulls contained 10% of resin–rubber, but 40% of this was lost during digestion. However, the resin–rubber content of the digested material was 17%. The pebble mill comminuted the plant tissue and agglomerated the resin–rubber, the milling conditions having a marked effect on the efficiency of this operation.

ISSN:1923-4287    

DOI:10.1139/cjr46f-018

出版商:NRC Research Press    

年代:1946

数据来源: NRC