摘要:

AbstractPractically all the calcium could be extracted from apple tissue, provided that particle size was reduced initially by a blending procedure, by heating with 6 N‐hydrochloric acid for 10 min. Tests with commercial samples indicated that including the time required to remove the seeds, a determination of calcium could be completed within 45 min of receiving a sample of 20 apples.Potassium, phosphorus and hydrochloric acid were the main factors interfering with the determination of 0.25 to 1.25 parts/million of calcium in solutions similar to those of apple ash or extracts by emission in a flame spectrophotometer. Average proportions of these and the other main constituents of the ash were added to standard calcium solutions to overcome interferences in routine analyses after dry ashing or extraction with hydrochloric acid.Recoveries of potassium and magnesium were low when the extraction procedure was use

ISSN:0022-5142    

DOI:10.1002/jsfa.2740250302

出版商:John Wiley&Sons, Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractBulked samples of pairs of opposite quarters of apples with seeds included and their remainders without seeds were analysed for K, P, Ca, Mg and N in 1971 and 1972. Differences in results due mainly to high concentrations in the seeds were large for P, Ca, Mg and N. The large variations in errors from sample to sample and in mean percentage errors in different years would make predictions of incidences of storage disorders based on calcium concentrations in fruit with seeds extremely inaccurate. Errors for potassium were small in the range of concentrations normally found in Cox's Orange Pippin apples.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740250303

出版商:John Wiley&Sons, Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractWe used quantitative methods to show that there are changes in the concentrations of catechins and hydroxycinnamic acids during the development of apples and pears.First, the concentrations of the phenolic compounds rise sharply until an age of about 2 to 3 months and then the catechin content is reduced (mg/whole fruit).Second, large quantities of catechins and hydroxycinnamic acid derivatives are formed in the early fruit (mg/1000 g). After a few weeks these concentrations decline very sharply, especially during the progressive growth of the fruits, to reach a more steady level at maturity.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740250304

出版商:John Wiley&Sons, Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractGamma radiation (8000 rad) of fresh onion bulbs, used in the dehydration industry in Egypt, was investigated. Irradiation reduced sprouting of the fresh bulbs but did not affect the rotting of the bulbs, No effects on sugar content or colour (optical density at 330 nm) of the fresh bulbs and dried onion flakes were observed. The irradiated onion had a noticeably lower ascorbic acid content, pungency (measured as volatile reducing substances) and free amino nitrogen content in comparison with non‐irradiated bulbs. Darkening of onion flakes during storage for 8 weeks at 40ºC did not differ when the bulbs were treated with gamma rays before dehydrati

ISSN:0022-5142    

DOI:10.1002/jsfa.2740250305

出版商:John Wiley&Sons, Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractAromatic carboxylic acids strongly inhibited 4‐methylcatechol oxidation by ano‐diphenol oxidase extracted from sweet cherry fruits (Prunus avium). Esterification of the acids decreased their inhibitory strength. Inhibitors containing the benzene nucleus showed a greater effectiveness than the corresponding aliphatic and heterocyclic compounds (except 2‐naphthalenecarboxylic acid). Similar inhibitory effects were observed by replacing the benzene ring with a highly unsaturated open chain. The inhibitory properties of benzoic acid, cinnamic acid,p‐coumaric acid and 3,4‐dihydroxybenzoic acid were investigated. It is proposed that the catalytic and inhibitory sites are close together in the enzyme

ISSN:0022-5142    

DOI:10.1002/jsfa.2740250306

出版商:John Wiley&Sons, Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractTwo pot experiments, one with 23factorial (1969) the other with 33factorial (1970) N × K × Na design, showed that yields of Italian ryegrass (Lolium multiflorum) were increased by both potassium and sodium, when sufficient nitrogen was given but responses to potassium were larger than to sodium. Yields were only increased by potassium fertiliser when the grass contained less than 2.0 % K in the dry matter, irrespective of the Na content.The main effect of potassium and sodium on the soluble carbohydrates was to increase the production of fructosan; again potassium was more effective than sodium.Total N concentrations in the grass decreased with the increased production of dry matter from potassium and sodium fertilisers. Ammonium N, nitrate N and soluble organic N (expressed as the percentage of total N) were also decreased by potassium and sodium. In 1969, both potassium and sodium increased the percentages of most amino acids and decreased the percentages of asparagine and glutamine within the free amino acid pool; potassium was more effective than sodium. In 1970, sodium alone had little effect on the percentage distribution of free amino acids.Under conditions of severe potassium deficiency sodium can substitute to some extent for potassium in its effects on yields, soluble carbohydrates and various N fraction

ISSN:0022-5142    

DOI:10.1002/jsfa.2740250307

出版商:John Wiley&Sons, Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe main site of decomposition of methyl bromide in cocoa beans was shown to be in the alcohol‐insoluble proteins of the shells. The methyl group of the fumigant becomes covalently bonded to the α‐amino group of the various amino acids, the imidazole ring of histidine and the ε‐amino group of lysine. An amino acid analysis of cocoa beans shows that methionine is the limiting essential amino acid and that cysteine is concentrated in the alcohol‐insoluble proteins o

ISSN:0022-5142    

DOI:10.1002/jsfa.2740250308

出版商:John Wiley&Sons, Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractA wide range of antioxidants (amine, phenolic and one sulphur‐containing) were all found to inhibit the autoxidation of α‐farnesenein vitro. Some were somewhat more effective than others but no class showed any marked superiority.When added to apples as a dip or by injection, only amine type antioxidants inhibited the autoxidation of α‐farnesenein vitro. Phenolic antioxidants were ineffective and some acted as pro‐oxidants, notably α‐tocopherol. In all instances the severity of superficial scald was proportional to the extent of α‐farn

ISSN:0022-5142    

DOI:10.1002/jsfa.2740250309

出版商:John Wiley&Sons, Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractSixteen varieties of apples were examined for their cuticular content of antioxidants. Eleven antioxidants were detected by t.l.c., α, γ and δ‐tocopherol being the only ones identified. α‐Tocopherol and four of the unidentified antioxidants were of general occurrence in fresh apples, whilst the presence of the others depended not only on variety but also on maturity and origin of the sample. Superficial scald did not occur during storage if the antioxidant content remained adequate to prevent or sufficiently limit the extent of α‐farnesene autoxidation. The amount required depends largely on the quantity of α‐farnesene produced by the apple d

ISSN:0022-5142    

DOI:10.1002/jsfa.2740250310

出版商:John Wiley&Sons, Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractA procedure is described for quantitation of results from the phenol test, an established qualitative procedure for checking purity and identity of grain samples. After grains have reacted with phenol, the extent of browning is determined by boiling the grains for 20 minutes in alkaline buffer and by estimating the brown coloration of the extract photometrically. Results are expressed as the phenol ratio which is calculated by dividing the absorbance of this extract by the absorbance of a similarly prepared extract of grains untreated with phenol. The phenol ratio is virtually independent of grain size and is useful in characterising the genotype of a grain sample.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740250311

出版商:John Wiley&Sons, Ltd    

年代:1974

数据来源: WILEY