摘要:

AbstractThe volatile constituents of kiwifruit (Actinidia chinensisPlanch.) have been investigated. The volatiles were collected and concentrated using vacuum steam distillation and freeze concentration. The concentrated distillate was analysed by gas chromatography, gas chromatography‐mass spectrometry and reaction gas chromatography. Apart from methyl benzoate, all the components identified were alkyl and alkenyl esters, alcohols, aldehydes and ketones. The most abundant component wastranshex‐2‐enal. Odour evaluation of the components at the exit port of the gas chromato‐graph indicated that ethyl butanoate, hexanal andtranshex‐2‐enal are important contributors to the aroma of kiwifruit. One other component which does not show a peak in the chromatogram and which is not yet completely characterised may have particular s

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340112

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractA UK survey for the occurrence of the Fusarium mycotoxin deoxynivalenol (vomitoxin) in 87 samples of both feeding and malting barleys has shown levels of less than 0.02 mg kg−1in 90% of the samples. The barleys containing deoxynivalenol (0.02–0.36 mg kg−1) were mostly feeding samples and showed no geographical trend within the UK. In contrast, for imported maize and brewers maize, only 25% of the samples showed levels less than 0.02 mg kg−1deoxynivalenol, the remainder ranging from 0.02‐1.4 mg kg−1with ten samples (36% of the total number analysed) having levels greater than 0.1 mg kg−1. All samples were analysed by combined gas chromatography‐mass spectrometry (selected ion monitoring) of the TMS deoxynivalenol derivative. For two of the maize samples full mass spectra were obtained of the deoxynivalenol showing very good agreement with reference spectra and confirming the identity of th

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340113

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractSamples from turkey breast and thigh muscle were taken from freshly slaughtered birds under sterile conditions and stored at 37, 4 or −18°C for up to 24 months. Changes in lipid fractions, fatty acids compositions and oxidised products were determined at intervals. Lipolysis of phospholipids was observed at 37 and at 4°C and to a small extent at −18°C, with little change in triglyceride levels. Free fatty acid levels in general increased as phospholipids decreased. Oxodienes and conjugable oxidation products increased with time of storage, the latter products being negatively correlated with phospholipid concentrations. Changes in the ratio of tetraene to triene conjugated oxidation products formed indicated that some preferential oxidation of fatty acids more unsaturated than linoleic acid was occurring initially and this was followed by an increase in the proportion of dienes being oxidised. Both lipolysis and oxidation were faster in thigh than in breast muscle (P<0.01) in the stored meat and in in‐vitro systems. It is concluded that lipolysis and oxidation interact in the degradation of lipids during storage of tur

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340114

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractEgyptian foods prepared from fababeans contain variable and relatively high concentrations of vicine. Vicine and convicine can be readily extracted from whole or dehulled fababeans. The rate and completeness of extraction depends upon size of beans, the presence or absence of testa, the pH, temperature and volume of the aqueous extracting solution, the duration of the extraction procedure and the frequency with which the extracting solution is changed. In a typical experiment vicine and convicine were almost completely removed from whole or dehulled fababeans when they were extracted at 20 or 40°C with 1% glacial acetic acid (0.17M) or water over a 72 h period with changes in the extracting media every 24 h. This appears to be the most practical procedure for extraction. The low pH of the acid solution prevents bacterial fermentation that occurs when water is used. Water at temperatures greater than 70°C is a highly effective extracting agent. Extraction of fababeans with acetic acid does not markedly affect the concentration of protein (N × 5.7), fat or fibre. Ash content, however, was reduced by a factor of 2 and the total dry matter content of the extracted beans was reduced by 16–17% in whole beans and 20–21% in dehulled

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340115

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractFructose, glucose and sucrose were separated by high performance liquid chromatography (h.p.l.c.) on a 5 μm amine column and detected by absorbance at 190 nm. The procedure quantified these sugars in orange juice and in carambola fruit, but preliminary ion exchange column chromatography was necessary before satisfactory h.p.l.c. results could be obtained. The method is sensitive to 1.2 μg of fructose or 9 μg of glucose or sucro

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340116

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340101

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY