摘要:

AbstractAnthoxanthumspecies are unusual among British grasses in their content of coumarin, a compound whose presence in sweet clover (Melilotus alba) has been alleged to give rise to the production of the anticoagulant dicoumarol in “sweet clover disease”. By chromatographic and spectrophotometric techniques, 7‐hydroxycoumarin 6‐glucoside (aesculin) ando‐hydroxyhydrocinnamic (melilotic) acid,trans‐2‐hydroxycinnamic (o‐coumaric) acid, and 4‐hydroxycinnamic (p‐coumaric) acid were found in annual sweet vernal (A. puelii) and sweet clover. 3‐Methoxy‐4‐hydroxycinnamic (ferulic) acid was also found in annual sweet vernal, and 7‐hydroxycoumarin in sweet clover. Dicoumarol formation was studied in spoilt (i.e., mouldy) hay made from perennial sweet vernal (Anthoxanthum odoratum). The hay contained very small amounts of dicoumarol, and larger amounts were present when the hay was inoculated withPenicillium jenseniand when formaldehyde was added. During spoilage the coumarin content of the hay decreased while the related compounds increased in amount and reached a steady value in about 4 weeks.Although the coumarins and related compounds of annual sweet vernal and sweet clover are virtually the same, much higher levels of dicoumarol were found in the latter after spoilage, possibly because, under the conditions of the experiment, it became more mouldy than the former.Experiments with a mixed oatgrass/cocksfoot hay indicated that addedtrans‐2‐hydroxycinnamic acid and not coumarin gave rise to 4‐hydroxycoumarin which reacted with formaldehyde to produce dicoumarol. This suggests that this acid and not coumarin is the precursor of dicoumarol.The very small amounts of dicoumarol found in spoilt perennial sweet vernal hay, and the results of earlier experiments in which such hay was fed to sheep and rabbits, do not suggest that the increased use ofAnthoxanthumspecies in pastures

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151101

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractMethods which are now widely used to determine the mineral composition of leaves are not necessarily those which are the most suitable for determining the composition of apples. Differences between the chemical composition of fruit and leaf in respect of general composition, and in the ranges and ratio of concentrations of mineral elements, affect the suitability of methods.Methods of sampling and of preparing samples by freezing and grating, and sources of contamination are described.Descriptions of three methods of ashing apple tissue, with nitric acid or nitric and perchloric acids, and by heating in platinum crucibles at 900°G are given. A combustion procedure using an oxygen flask with electrical ignition and magnetic stirring for fume recovery in hydrochloric acid is also described.Comparisons of the methods for samples of frozen, grated apple showed that ashing large sub‐samples with nitric acid gave the most reproducible results. Dry ashing at 900°G gave results comparable with the use of the other methods.Differences due to the shape of crucible and also losses of potassium and sodium with prolonged heating at 900°G are discussed. The effects of filtration and of storage on ash solutions are described.The combustion procedure is quicker than the other methods but is unsuitable for the determination of sodium, and calcium results are slightly less reproduc

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151102

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractTwo methods of determination of potassium in apples using aqueous extraction and a flame photometer are described. Comparisons with results obtained by ashing show that 95–98% of the total potassium can be recovered. Methods of clarifying the extracts are compared.Methods used to determine potassium, sodium, calcium, magnesium and phosphorus in ash solutions are discussed. It is shown that the concentrations of the other ions present in ash solutions do not interfere with the direct determination of potassium and sodium by flame photomete

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151103

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractStudies of the mobilisation of free tocopherols in a number of germinating seeds show that, as a rule, the tocopherols are completely used up in the earliest stages of germination when the fat stores are still largely intact. This is consistent with the view that the tocopherols are intended, at least partially, for some unknown essential function in the growth of the embryo in addition to their possible rǒle asin vivoantioxidants of depot fat

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151104

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractRapid estimates of hypoxanthine concentration in muscle extracts by xanthine oxidase reaction agreed well with those obtained by ion‐exchange chromatography. Assay by precipitation as the silver salt was subject to some inaccuracy. Concentrations of hypoxanthine increased throughout the period of useful storage of a number of species. The increases correlated well with most evaluations of quality by taste pane

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151105

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThe major components in the basic fraction of cigarette smoke studied herein were pyridine, isomeric picolines, 3‐vinylpyridine, nicotine, nornicotine, myosmine and 2,3′‐bipyridyl. Evidence for the presence of several isomeric lutidines, pyrrole, nicotinonitrile, 3‐ethylpyridine, methyl 3‐pyridyl ketone, metanicotine and anabasine was also obtained. The levels of the major bases in smoke from blended or unblended flue‐cured, burley, Maryland and Turkish cigarettes showed some differences which were discussed. The amounts of certain bases in the smoke from flue‐cured cigarettes having different organoleptic properties were determined and possible relationships between smoke flavour and chemical composition w

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151106

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractAn equation that related the shape of irregular soil aggregates to their respiration rates and the oxygen concentration at their surfaces was verified experimentally. For this purpose, models of soil aggregates were prepared by cutting shapes from agar containing yeast and glucose. The respiration rates of these shapes when surrounded by different oxygen partial pressures approximately fitted the equation when the shapes had shape factors [surface area/(volume)2/3] of between 5.5 and 6.8. Since sieved soil aggregates had shape factors independent of size and had values of between 5.3 and 6.1 it was concluded that the equation also applied to soil aggregates.To facilitate the foregoing work, a method was developed for determining the surface area‐to‐volume ratios of soil aggregates from measurements of the mean lengths of random chords through the aggregates. It was found that the equation previously used3for relating these two parameters held only if the chords were thrown at random in a certain way. A different equation was deduced which applied when the chords were thrown in a slightly different random way. Experimental verification of the two equations was obtained for a range of convex and non‐convex b

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151107

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThe eating quality of rib joints and silversides from 10 pairs of bull‐and‐steer twins has been investigated.Steer meat was the more tender. Overall it also had a slight advantage in juiciness and flavour. Significant differences in tenderness were found in thelongissimus dorsi, biceps femorisandsemi‐tendinosus muscles.The differences in quality were most marked in the region of the 7–8th rib. Shear values supported the taste panel assessment of tenderness.The bull meat contained less fat than the steer meat. Several animals, mostly bulls, yielded meat with high pH values but the meat was not dark

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151108

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractProximate composition, energy, calcium, phosphorus and iron contents and vitamin A potency were determined on locally available varieties of 31 different fruits and 49 different vegetables grown in Lebanon. Among certain varieties, considerable variations were observed, especially in mineral content and vitamin A potency. The values obtained agree, in general, with data available from other countries of the Middle East.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151109

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractDeterminations of cell fragility were performed on cod muscle frozen at −29° and then stored at −0.5° to −3.5°, at half degree intervals. The rate of denaturation was found to be maximal at a temperature close to −1.5°. Fresh tissue supercooled to the same temperature was no

ISSN:0022-5142    

DOI:10.1002/jsfa.2740151110

出版商:John Wiley&Sons, Ltd    

年代:1964

数据来源: WILEY