摘要:

AbstractA laboratory method for measuring the dry deposition of sulphur dioxide (SO2) on to soils is described. The effect of soil type on deposition velocity (vg) was examined using samples of soils collected from 16 sites in England and Wales. Although the values ofvgmeasured for soils at field capacity did not differ significantly they were related to soil pH; thus they ranged from 0.422 cm s−1at pH 4.5 to 0.648 cm s−1at pH 7.5. Oven drying reducedvgfrom an average value of 0.535 cm s−1for soils at field capacity to 0.264 cm s−1. A large proportion of deposited SO2was recovered from the soil as sulphate S. At an atmospheric concentration of 36 μg SO2m−3, about the mean for Great Britain, the input of sulphur through this process would be 10 kg ha−1in a 4‐month

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290902

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractAntioxidant potentiality of seed phospholipids for stored ghee was found to be in the order of sunflower (Helianthus annuusL.), groundnut (Arachis hypogea), soybean (Glycine max) and cotton seed (Gossypium sp.), possibly corresponding to their phosphatidyl ethanolamine content. Out of phosphatidyl choline, phosphatidyl ethanolamine and phosphatidic acid, phosphatidyl ethanolamine was found to be the most effective antioxidant. Antioxidant property of phosphatidyl ethanolamine did not vary with the seed source, indicating that the fatty acid portion of the molecule played no role in protecting ghee against oxidation. In stored ghee addition of phosphatidyl ethanolamine and phosphatidyl choline reduced lipolysis, probably by interacting with the lipase system. During storage, phosphatidyl ethanolamine afforded better protection against the oxidation of unsaturated fatty acids.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290903

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe properties of a β‐galactosidase from a thermophilic Bacillus have been studied and compared with the properties of the enzyme contained in whole cells and in cells entrapped in a polyacrylamide gel matrix. The partially purified enzyme appears to be optimally active at a temperature of 60°C and pH 6.0. The enzyme activities from whole cells and immobilised whole cells have slightly different temperature optima (being 75 and 65°C respectively) and pH optima (being 6.2 and 6.6 respectively). The enzyme activity from whole cells is significantly more thermostable than that of the partially purified enzyme; the half‐lives being 125 and 22 min respectively at 70°C. In other properties studied, the enzyme activities of the three sources are similar. The thermostability of the enzyme and the broad pH range over which it is active makes this enzyme suitable for use in the dairy i

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290904

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe adsorption behaviour of three food proteins, a soy protein isolate, a sodium casein‐ate and a whey protein concentrate, at the air‐water interface has been studied by the drop volume method. The kinetics of surface tension decay were evaluated in terms of different rate‐determining steps at different ionic strengths and concentrations. This analysis indicates the following characteristics concerning the surface behaviour of the protein systems studied. The soy proteins diffuse slowly to the interface compared to the other proteins, probably due to the large particle size of the association complex of soy proteins. For the soy proteins, diffusion is slower in distilled water than in 0.2M‐NaCl solution and spreading of molecules at the interface is most easily performed in 0.2M‐NaCl solution. The whey proteins diffuse quickly to the interface, which is in accordance with their aqueous association; mainly small molecular complexes. Diffusion is slower and spreading easier in distilled water than in 0.2M‐NaCl solution. Although the caseinate has a complex quaternary structure, like the soy proteins, it has a very different surface behaviour. The diffusion step is rapid at concentrations above 10−3wt % and contributes to a large extent to the interfacial tension decay, especially when the caseinate is dispersed in 0.2M‐NaCl solution. At a concentration of 10−3wt % and below, the rate of the diffusion step is slowed down drastically, with an accompanying drop in the surface activity of the protein. This type of surface behaviour can be explained if the migration of the caseinates to the interface takes place via the casein monomers

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290905

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractCell walls separated from the leaf blade, leaf sheath and stem of the brown midrib mutant,bm3, ofZea mayswere more degradable by a commercial cellulase than the corresponding part of the isogenic normal inbred cultivar (Tr). The walls of each part of the mutant when compared with the corresponding part of the normal cultivar contained less lignin and bound phenolic components released by treatment with NaOH. The major phenolic components detected weretrans‐p‐coumaric andtrans‐ferulic acids together with small amounts of theircisisomers and diferulic acid. Cell walls of stem of the mutant contained a total of 17.3 mg g−1of these bound acids compared with 9.8 mg g−1for leaf sheath and 3.5 mg g−1for leaf blade: there was more than twice as muchp‐coumaric acid in cell walls of stem as in those of leaf sheath and more than seven times as much as in those of leaf blade. When cell walls of the stem from the mutant or the normal cultivar were treated with NaOH their degradability by cellulase was highly correlated with the amounts of phenolic components released

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290906

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe wood of an African treeFuntumia latifoliahad androgenic properties when mixed with diets fed to chicks. The androgenic principle has been identified tentatively as an hydroxyandrosta‐1,4‐dienedione but it is not identical with 12β‐hydroxyandrosta‐1,4‐diene‐3,17‐dione isolated previously from the leaves of aHalorrhenaspecies in Cameroun or as a microbial metabolite of deoxycholic acid. The androgen is formed by metabolism of the steroidal alkaloids inF. latifoliaby the saprophytic fungusF

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290907

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe acidified vanillin method for determination of plant tannins has been reassessed. Excluding light and controlling the temperature of the reaction mixture increased the colour stability of the vanillin tannin adduct. Selection of optimum concentrations of reactants and solvents enabled the method to be used in the range 5‐500 μg of condensed tannin with a precision and accuracy greater than 1

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290908

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractOptimum conditions for extracting the enzyme degrading the limonin precursor in citrus albedo involved treatment of the macerated albedo with a commercial pectic enzyme. The release of the enzyme from the cells of the albedo was accompanied by a considerable loss of stability, and the instability of the enzyme once dissociated from the albedo cells, together with its low activity in a highly pectinous source, accounts for the failure of previous attempts at its extraction. A method for proximate assay of enzyme actiyity was developed to monitor the extraction process and to compare the concentrations of enzyme activity in various albedo samples.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290909

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe volatile compound produced in greatest yield from the aerobic incubation at 35°C for 35 h of a mixture of butterfat, cupric palmitate and α‐tocopherol was characterised by chromatography and spectroscopy. The same compound was also isolated from a similar reaction mixture containing cod‐liver oil instead of butterfat. The compound was identified astrans‐4,5‐epoxyhept‐trans‐2‐enal and was found to have the same properties as that synthesised by the epoxidation of hepta‐trans‐2,trans‐4‐dienal. Volatile epoxyalkenals of this type have not been previously identified as produc

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290910

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe effect of intraruminal doses (16.8, 33.5 and 50.3 mmol day−1) of D.L‐methionine, methionine hydroxy analogue (2‐hydroxy‐4‐(methylthio)‐butanoic acid calcium salt) andN‐stearoyl‐D, L‐methionine on the flow of methionine (free and protein bound) and its derivatives into the proximal duodenum of the sheep was investigated. Methionine hydroxy analogue was assayed using the reaction of the S‐methyl group with nitroprusside after ion exchange chromatography. On the basal diet the daily flow of methipnine was 20.5 mmol and with the 16.8 mmol treatmentN‐stearoyl methionine, methionine and methionine hydroxy analogue, values of 29.4, 22.1 and 22.5 mmol, total methionine or its equivalent were obtained respectively. With the 33.5 treatment the corresponding flows were 39.6, 22.4 and 22.5 mmol day−1. During the 50.3 mmol treatments complete feed refusal, probably due to methionine toxicity was noted withN‐stearoyl‐D,L‐methionine while with methionine and methionine hydroxy analogue the total flow of methionine equivalents was only 20.5 mmol day−1. Thus,N‐stearoyl‐D,L‐methionine was the only material to increase the flow of methion

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290911

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY