ISSN:0022-5142    

DOI:10.1002/jsfa.2740021202

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe effect of humidity on mould growth on constructional materials is discussed. It has been found that at a relative humidity of 70% or less mould growth is inhibited on bricks, wood, painted wood and distempered surfaces. The physical properties of the substrate determines to a large extent the rate of mould growth at particular R.H. values. An apparent optimum humidity for growth has been observed on certain of the materials examined.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740021203

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe chemical tissue test for phosphate using the Morgan reagent was examined.The time of extraction was very critical, the phosphate extracted being in linear relationship to time up to four hours. The first extraction (15 minutes) removed phosphate varying from 3 to 21% of the total in the plant, and the total amounts of extractable phosphate in II extractions varied from 20 to 76%. Of the total phosphate extracted, over 60% was inorganic. When the time of extraction was 30 minutes or less, the quantities of inorganic phosphate extracted by the Morgan reagent and by water were materially the same.In applying the test to flax on the fertilized plots on two sampling dates, it was evident that the test did not indicate any response to the inorganic fertilizer treatments, but showed significantly higher values for dung‐treated plots. The error of the chemical tissue test was exceptionally hig

ISSN:0022-5142    

DOI:10.1002/jsfa.2740021204

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe receipt at different times during the past seven years of a large number of specimens of candlenuts, rubber seeds, linseed and hemp seeds has resulted in an accumulation of data which serve to illustrate the possible range of variation in the composition of each of these seed oils. Candlenut oils seem prone to exhibit variations, usually of a minor but occasionally of a major order, in their content of linolenic acid; and it is shown that definite but minor variations occur in the oils from different fruits of the same tree. Rubber seed oils, so far as at present studied, have shown relatively little difference in composition. Linseed oils from seed grown in England or in South Africa have proved satisfactory as regards a high content of linolenic acid. The few specimens of hemp seed oil studied in detail show considerable similarity in composition.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740021205

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe component acids and glycerides of several specimens of tung oils have been investigated. Oils of both Aleurites Fordii and A. montana species were included and one oil from authentic A. montana nuts contained as high (78%) a proportion of elaeostearic acid as that usually associated with A. Fordii oils, although a Nyasaland oil of the A. montana type contained only 72% of elaeostearic acid in its total acids. The proportion of elaeostearic acid in the mixed acids of the oils examined varied between 72% and 82%, but it is considered that these differences are more likely to be due to environmental than to genetic influences.The oil of lowest (72%) elaeostearic acid content contained 23% of trielaeostearin, 67% of dielaeostearic and 10% of monoelaeostearic glycerides, whereas that of the highest (82%) elaeostearic acid content contained 56% of trielaeostearin, 40% of dielaeostearic and 4% of monoelaeostearic glycerides: the difference in constituent glycerides is especially pronounced at this particular range of elaeostearic acid content, owing to the normal effect of the ‘rule of even distribution’.The validity of heat‐gelation tests for adulteration of tung oils is critically disc

ISSN:0022-5142    

DOI:10.1002/jsfa.2740021206

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe action of trimethylamine oxide on unsaturated fatty esters has been investigated. At 100° c. the oxide was reduced quite rapidly by autoxidizing esters, or by pre‐oxidized esters in the absence of oxygen: unoxidized esters were unable to reduce the oxide in the absence of oxygen.At 37° c. reduction of the oxide by autoxidizing esters had become very slow and neither haemoglobin nor a pork‐muscle homogenate catalysed the reaction. No obviously fishy odours were observed in the esters recovered after any of the treatments emp

ISSN:0022-5142    

DOI:10.1002/jsfa.2740021207

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractIn the electrometric method for estimating chloride, more accurate results are obtained with a small wire‐type of silver electrode, coated with a film of silver chloride by electrolysis, than with a relatively large spade‐type of electrode coated with silver chloride by precipitation during titrat

ISSN:0022-5142    

DOI:10.1002/jsfa.2740021208

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe effect of various factors on rate of drying of wheat (below the critical moisture content) has been studied at temperatures in the range 12°‐45° c., and under absolute pressures in the range 0.5–8 cm. of mercury. The results imply that the rate of diffusion of moisture within individual grains remains the factor governing rate of drying in vacuo in the manner known for air‐drying in the falling‐rate period, and that the rate of change of the diffusion coefficient with temperature (over the range 12° 46° c.) is the same as that of the vapour pressure of water. Within the range 13–30% moisture content (dry‐weight basis), the rate of drying in vacuo is directly proportional to the free water content, but the term ‘free’ means the difference, not between total and equilibrium moisture contents as in air‐drying, but between total and firmly held or bound water, the level of which must depend upon temperature: at 30°‐40° c. it is about 9–10% (dry‐weight basis). However, with wheats of similar total moisture content, the rate of drying is greater if the concentration of moisture in the outer layers is higher than that in the interior of individual grains, as in freshly wetted wheat. Variation in pressure affects directly only the rate of removal of vapour which has already left the solid, but this in turn affects the rate of drying. The effect depends on impedance to vapour movement caused by form of apparatus and disposition of the material, and can be substantially counteracted by admission of a small sweeping current of air, the optimum proportion of which is equimolecular with re

ISSN:0022-5142    

DOI:10.1002/jsfa.2740021209

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe possibility of producing chitin from the large quantity of rock‐lobster waste which is available in South Africa has been investigated. A study of the distribution of chitin in the rock lobster has shown that over 80% of the total chitin present is concentrated in the tail shell, dorsal body shell and legs. Tail shell has been found to be the most suitable starting‐material for chitin production, and the details of a satisfactory procedure, involving successive extractions with sodium hydroxide solution and hydrochloric acid, have been worked out. Alkali and acid liquors are recycled for further use. A high‐quality chitin product containing 92–96% chitin on a dry basis and less than 2% ash has been obtained by this

ISSN:0022-5142    

DOI:10.1002/jsfa.2740021210

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740021201

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY