摘要:

AbstractSorbic acid (SA) at 0·25, 0·5 and 1·0 g kg−1was applied to fresh orange peels before ensiling in special 18 litre fermentation containers in two separate experiments. The higher two concentrations of sorbic acid were effective in reducing dry matter (DM) loss throughout the ensiling period, up to 90 days. Chemical analysis revealed that SA at the higher concentrations slowed down the fermentation rate, with less water‐soluble carbohydrates (WSC) converted into organic acids and ethanol after 5 days of ensiling. However, after 30 and 90 days of ensiling, similar amounts of lactic acid were found in all silages, but less ethanol and more residual WSC were found in the silage treated with the higher SA concentrations. This indicates a more efficient fermentation pattern in the SA‐treated silages. Microbial examination of the fresh and ensiled peels indicated large numbers of yeasts, the activity of which was probably inhibited by the sor

ISSN:0022-5142    

DOI:10.1002/jsfa.2740460302

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractAn investigation into the relative merits of three standard laboratory procedures for lipid determination in fish meal is described. It was found that the amount of lipid extracted by these methods from both stabilised and non‐stabilised anchovy meals decreased on storage of the meals.The decrease in lipid yield as a function of the storage time may be approximated by straight lines, which reveal clear distinctions between the three methods as well as the two types of meal. The cold Bligh and Dyer method gave consistently higher lipid yields than either the hot hexane or a modified EEC method, and the decrease in the Bligh and Dyer lipid content with storage was less than that found in the hot hexane or the EEC lipid content. This difference was more pronounced in the non‐stabilised than in the stabilised meals.No fundamental difference between the hot hexane and the modified EEC lipid extraction method could be established since the hydrolysis step in the EEC procedure does not de polymerise the lipid portion which is unextractable by hot hexane.The effectiveness of the antioxidant ethoxyquin in protecting polyunsaturated fatty acids in anchovy meal from oxidation is demonstra

ISSN:0022-5142    

DOI:10.1002/jsfa.2740460303

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe effect of pH on plant protease activity was investigated using buffered, gamma‐irradiated aqueous extract of ryegrassLolium multiflorum. Rapid protein breakdown occurred in the first few days but was followed by a longer period of reduced activity. The overall pH optimum for ryegrass proteases was between 5·0 and 7·0 but there was still considerable activity at the acid pH levels found, eg in silage. Proteolysis did not proceed to completion even when the pH was not inhibit

ISSN:0022-5142    

DOI:10.1002/jsfa.2740460304

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractFermentation patterns of lucerne silages were studied in laboratory silos. The treatments consisted of: (a) fresh (200 g kg>−lDM) lucerne, ensiled without any treatment (L); (b) lucerne wilted to 525 g kg−1DM prior to ensilage (WL); (c) fresh lucerne + cotton stalks at a ratio of 60:40 on a dry matter (DM) basis (L + CS); and (d) fresh lucerne + ozone‐treated cotton stalks at the same ratio as above (L+O3). Silos were opened after 90 days and the silages analysed. The highest DM loss was found in the L silage (14·7%), whereas in the L+O3silage DM loss was practically nil. Both wilting and the addition of untreated cotton stalks proved to be effective in reducing DM losses during fermentation. The production of lactic acid and volatile organic acids in the L+ O3and WL silages was lower than in the L and L+CS silages. The poorest ability to preserve forage protein was found in the L silage, in which only 28 % of the protein was recovered after 90 days. The greatest ability to preserve protein was found in the L+O3silage, in which 78 % of the protein was maintained. Ammonia production followed generally similar patterns. Amino acids underwent extensive degradation in the L silage. Recovery of amino acids in the WL silage was in the range 69–93 %, and in the L + O3silage it was almost complete. Ozonated CS proved to be a good silage additive with respect to energy and protein preservation. Its future use in the field would allow direct ensilage of fresh leguminous material immediately after harvest, producing a high qualit

ISSN:0022-5142    

DOI:10.1002/jsfa.2740460305

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractA pentosanase component of a crude enzyme product was concentrated and added to chick diets. Four levels of purity were examined: (a) the crude enzyme product, (b) a crude water extract, (c) a pentosanase purified using ion‐exchange chromatography (non‐bound fraction), and (d) residual pentosanase eluted with 0·4 M NaCl salt from the ion‐exchange column (salt‐eluted fraction). All preparations exhibited high viscosity‐reduction capabilities when tested against a soluble pentosan preparation isolated from rye grain. The absence of arabinose release during rapid viscosity reduction of pentosan indicated that the non‐bound pentosanase was an endoxylanase (1,4‐β‐D‐xylan xylanohydrolase, EC 3.2.1.8) without α‐L‐arabino‐furanosidase activity. When added to broiler chick diets containing rye as the only cereal, all enzyme preparations significantly improved growth and feed conversion. At equivalent viscosity‐reduction activity the non‐bound pentosanase was less effective than other preparations, suggesting that multiple enzymes may be necessary to elicit maximum benefit. Alternatively, since the non‐bound enzyme was less pH stable it may have lost activity in the a

ISSN:0022-5142    

DOI:10.1002/jsfa.2740460306

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe cyclodimerisation of trans‐p‐coumaric (tCA; (E)‐3‐(4‐hydroxyphenyl) propenoic acid) and trans‐ferulic (tFA; (E)‐3‐(4‐hydroxy‐3‐methoxyphenyl) propenoic acid) acids to form substituted truxillic and truxinic acids has been investigated since dimers of this type are present in graminaceous cell waits and are likely to be of importance in limiting wall biodegradability. Irradiation of a thin film of a mixture of tCA and tF A, under ‘daylight’ fluorescent tubes and incandescent lamps in a growth cabinet, produced three cyclodimers corresponding to 16 % conversion of monomers. Under the same conditions of irradiation, a thin film of FA alone yielded only 2% of F A‐F A. When tF A crystals were irradiated, no dimerisation occurred, whereas tCA crystals were totally dimerised to CA‐CA. Lower yields of dimers were obtained using UV irradiation. The dimers were shown, by capillary gas‐liquid chromatography and mass spectrometry, to be derivatives of truxillic acid (t‐2, c‐4‐diphenyl‐r‐1, t‐3‐cyclobutanedicarboxylic acid) composed of CA‐CA, CA‐FA and FA‐FA, and to have gas chromatographic retention times identical to those of dimeric compounds found in grass cell walls. The results are considered in relation to dimerisation of phenolic acids

ISSN:0022-5142    

DOI:10.1002/jsfa.2740460307

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractA simple apparatus and method developed for the separation of husk from dehulled (brown) rice contaminated with aflatoxin is described. The performance and efficiency of the apparatus was evaluated by passing a series of dehulled rice and husk mixtures through it. Subsequently the aflatoxin distribution in both rice and husk was determined. The range was 24 to 81% for aflatoxin B1and 11 to 76 % for B2, depending on the rice grain category and variety. The study indicates that the apparatus can be used conveniently to separate husk from aflatoxin‐contaminated rice with a minimum hazard to personnel. It is therefore recommended for use particularly in developing countries, where laboratory test mills may not be availabl

ISSN:0022-5142    

DOI:10.1002/jsfa.2740460308

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractA quantitative study of the glucosinolates in the seed, cortex and medulla (peeled root) from nine cultivars (cvs) of swede, Brassica napus L var napobrassica (L) Peterm using high performance liquid chromatography was undertaken to see whether such characteristics could be used as a biochemical index of cultivar identity. All nine cultivars could be distinguished following an analysis of medulla glucosinolates, but the analysis of seed and cortex glucosinolates yielded no such useful information.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740460309

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe proportions of fatty acids, viz lauric, myristic, palmitic, oleic, linoleic, and linolenic, in tea leaf,Camellia sinensis(L) O Kuntze, were determined at different stages of manufacture as well as in Mack tea. No significant variations were observed in the fatty acid contents of three major cultivars, Assam, China and Cambod. However, some variations were noticeable in leaf cropped in different months. Manufacturing stages have a pronounced effect on the relative proportions of the various fatty acids. Monthly distribution of total lipid was also followed in tea leaf, and the pattern of variation observed was identical for all the three cultivars.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740460310

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe aims of this study were to investigate the detoxification of United Kingdom commercial rapeseed meal by alcoholic extraction of aglucones released after treatment with mustard seed myrosinase. Aglucones released from the commercial rapeseed meal were compared with those resulting from autolysis of laboratory‐defatted rapeseed. 3‐Butenyl isothioc yanate, 5‐vinyl‐oxazolidene‐2‐thione (VOT) and 1‐cyano‐2‐hydroxy‐3‐butene were detected in commercial rapeseed meal after glucosinolate hydrolysis. In comparison, autolysis of rapeseed at 5°C gave VOT, 1‐cyano‐2‐hydroxy‐3‐butene and epithionitriles, but at 60°C epithionitrile release was significantly reduced. In addition, 1‐cyano‐3,4‐epithiobutane was detected in the autolysed samples. Aglucones released at 40°C from commercial rapeseed meal by mustard seed myrosinase were 85% extractable in 60–90% (v/v) aqueous industrial methylated spirits. Extraction was significantly higher than previously reported for the intact glucosinolate. Double extraction of the myrosinase‐treated meal with 80 % (v/v) aqueous industrial methylated spirits gave a meal with no detecta

ISSN:0022-5142    

DOI:10.1002/jsfa.2740460311

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY