摘要:

Aeration by mechanical agitation of 15% wheat mash fermented byAerobacillus polymyxainhibited the formation of 2,3-butanediol and particularly of ethanol. Aeration of similar mashes by passage of finely dispersed air or oxygen at the rate of 333 ml. per minute per litre of mash increased the rate of formation and yield of 2,3-butanediol but inhibited ethanol formation. However, the over-all time required for the completion of fermentation was not shortened from the usual 72 to 96 hr. required for unaerated mashes. There was no evidence of a shift from fermentative to oxidative dissimilation. Under aerobic conditions, the final butanediol–ethanol ratio was approximately 3:1. Anaerobic conditions, as produced by the passage of nitrogen or hydrogen through the mash, increased the rate of formation of both butanediol and ethanol and shortened the fermentation time to about 48 hr. Under these conditions, the butanediol–ethanol ratio was reduced to about 1.3:1.0. Carbon dioxide gave a butanediol–ethanol ratio resembling that of anaerobic fermentation but did not reduce fermentation time.

ISSN:1923-4287    

DOI:10.1139/cjr46f-001

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Comparative studies have shown that the pH of 15% wheat mashes fermented byAerobacillus polymyxacan be as satisfactorily controlled by ammonium hydroxide as by calcium carbonate. The formation of 2,3-butanediol and ethanol was unaffected by all pH levels tested (5.8, 6.0, 6.5, 7.0) with the possible exception of pH 7.0, where a slight diminution of diol formation appeared at 96 hr. Over the pH range 5.8 to 6.0, the amount of ammonium hydroxide required, the escape of ammonia from the mash, and the production of acid were all minimized. The consumption of ammonia was greatest in the first 36 hr. of the fermentation owing to rapid acid production. Fermentation at the different pH levels did not affect the butanediol–ethanol ratio, which was approximately 1.5.Replacement of calcium carbonate by ammonium hydroxide reduced the ash content of the unfermented residue from approximately 20 to 4%. Protein contents (N × 5.7) of insoluble residues from carbonate and ammonia treated washes were 25 and 32%, respectively. In both mashes approximately 50% of the unfermented solids were soluble.Calculation of carbon balances on fermentables showed that increased acid production was accompanied by a decrease in carbon dioxide formation.Riboflavin and nicotinic acid contents per 100 gm. of fermented mash averaged 19.2 and 1270 μgm., respectively and were unaffected by pH of fermenting mash and heat treatment at 100 °C. for 10 hr. The riboflavin showed an 80% increase over that present in the original wheat; nicotinic acid showed a 40% decrease.

ISSN:1923-4287    

DOI:10.1139/cjr46f-002

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Wheat starch is a poor medium for fermentation byAerobacillus polymyxa. The solubles recovered from the separation of starch and gluten in patent flour enhance the fermentation but not as effectively as the similar fraction from whole wheat flour. Addition of supplements is necessary for a satisfactory yield of products in a reasonable length of time. Wheat gluten has no stimulatory effect but bran and shorts are both effective, the latter being slightly superior. An 8% starch medium fortified with the solubles from whole wheat required a 2.5% supplement of shorts to bring fermentation byA.polymyxato 90% completeness in 72 hr.Of the various supplements tested, a 1% addition of malt sprouts proved to be the most effective, fermentation being 90% complete in 72 hr. Shorts, bran, Cerogras (dehydrated young oats), alfalfa, soya beans, yeast extract, and corn-steep liquor follow in order of decreasing effectiveness.The solubles from whole wheat when ashed have no beneficial effects on the fermentation of starch byA.polymyxa.

ISSN:1923-4287    

DOI:10.1139/cjr46f-003

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Acidification of liquid egg prior to drying did not improve subsequent storage life, although pH measurements showed that powder from untreated egg became acid more rapidly during storage. Reduction in the moisture content (total volatiles) from 4.7 to 3.0% doubled, and reduction from 4.7 to 1.7% tripled, the storage life of dried whole egg powder as assessed by fluorescence tests. The maximum storage life predicted for the low moisture powder by this test was only 36 wk. at 27 °C. and 5 wk. at 38 °C. Palatability tests suggested that the product was somewhat less perishable, as a powder of 1.7% moisture was considered fit for use as an egg dish after 64 wk. at 27 °C. Gas-packing low moisture powders in an atmosphere of carbon dioxide appeared to be slightly more effective as a means of retaining palatability than packing in an atmosphere of air or nitrogen, but was particularly effective in preventing loss of solubility (assessed by potassium chloride values) during storage.

ISSN:1923-4287    

DOI:10.1139/cjr46f-004

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Storage trials have been conducted on a large number of roller and spray-process whole milk powders. Accelerated tests at 65 °C. were found to give an accurate indication of the relative keeping qualities of the samples. Wheat germ oil antioxidants were found effective in inhibiting deterioration due to copper. Reducing substances that develop in milk powders during storage in a moist atmosphere or at elevated temperatures are strong antioxidants and may offset the effect of added antioxidants. The riboflavin content of several powders with a high concentration of reducing groups decreased appreciably during storage.

ISSN:1923-4287    

DOI:10.1139/cjr46f-005

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Milk powders with fat contents of 1, 26, 28, and 30% from two plants were tempered to moisture contents of 2, 3, and 5% and stored for periods up to 16 weeks at temperatures of from 40° to 140° F. Appreciable deterioration, assessed by palatability, occurred in the whole milk powders stored at temperatures of 60° F. and higher, and there was considerable difference in the stability of powders from the two plants. For both plants, the keeping quality of powders of 26 and 28% of butter fat was equal. At 80° F. and lower, the powder containing 30% of butter fat was more stable than the 26 and 28% powders from the same plant, but at higher temperatures the 30% powder deteriorated more rapidly. At 80° F. the average decrease in palatability of whole milk powders with 2% moisture was two palatability units. The palatability of the skim-milk powder increased greatly at all temperatures during the early part of the storage period, but later decreased at temperatures of from 100° to 140° F. Skim-milk powder of 2% moisture stored at 80° F. had a palatability score 2.5 units higher than the initial score. In general, a moisture content of 3% was preferable to moisture contents of 2 and 5% for both whole and skim-milk powders. The differences in stability of powders from different plants were enhanced by increased moisture contents and higher storage temperatures.

ISSN:1923-4287    

DOI:10.1139/cjr46f-006

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

The storage life of a dehydrated mixture of egg and milk, when assessed by both palatability and fluorescence measurements, was shorter than the life of milk powder of similar protein, fat, and carbohydrate content. Increased quantities of egg in the mixture decreased the quality of the mixture, both initially and during 16 weeks' storage. These effects were noticeable at all temperatures studied between 40° and 140° F. but were most marked above 80° F. After 16 weeks at 80° F., material packed under carbon dioxide usually had better palatability than the air-packed products. The effect of added sugar was most noticeable at 120° and 140° F. Lactose had a slightly beneficial effect; sucrose was more effective.

ISSN:1923-4287    

DOI:10.1139/cjr46f-007

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Using selective media, an examination of 2400 hens' eggs was made to determine the incidence ofSalmonellatypes in the egg or on the shell. The contents of 1000 eggs laids by a flock of presumably normal hens did not yield any representatives of theSalmonellagroup. Of a similar number of eggs produced by a flock of 55 known pullorum reactors, 61 were found to containS.pullorum; no otherSalmonellaorganisms were isolated. The exteriors of an additional 400 eggs obtained from the latter source failed to produce anySalmonellatypes.

ISSN:1923-4287    

DOI:10.1139/cjr46f-008

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

A tunnel smokehouse with an output of 3000 lb. of smoked fillets per nine hour day has been in operation about one year. The temperature, relative humidity, and smoke velocity are controlled at optimum values independent of climatic conditions. Hence the colour and shrinkage of the product may be standardized and losses from cooking and dropping of the fish avoided. The relatively short time of smoking of two to three hours reduces spoilage of the fish to a minimum with resulting improvement in quality. Power and steam consumption have been kept as low as feasible.

ISSN:1923-4287    

DOI:10.1139/cjr46f-009

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

This paper describes a carbon compression rheostat having, in addition to all the advantages set out in the handbooks of electricity and engineering, compactness and great steadiness of operation. The method of operation is detailed and a graph of a performance test is included.

ISSN:1923-4287    

DOI:10.1139/cjr46f-010

出版商:NRC Research Press    

年代:1946

数据来源: NRC