摘要:

AbstractThe incorporation of (a) sorbic acid (0.18 and 0.90 g kg−1, fresh weight basis) and potassium sorbate (0.90 g kg−1) with chopped lucerne, and (b) sorbic acid (0.90 g kg−1) and potassium sorbate (0.90 g kg−1) with chopped maize (whole‐plant) at the time of ensiling, led to a reduction in the surface spoilage associated with the ensilage of these two forages. Use of sorbic acid (0.90 g kg−1) and potassium sorbate (0.90 g kg−1) led to (a) a reduction of volatile nitrogen (VN), higher levels of residual water‐soluble carbohydrates (WSC) in lucerne silage and more aerobically stable lucerne silage and (b) a reduction in weight loss, population of yeasts and moulds, and VN, higher levels of WSC in maize silage and more aerobically stable maize silage when compared to the untreated forages or forages treated with sorbic acid and potssium sorbate at 0.045 and 0.18 g kg−1(fresh weight bas

ISSN:0022-5142    

DOI:10.1002/jsfa.2740360202

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractA new method is described for reducing nitrate prior to Kjeldahl digestion of soil and crop samples. Zinc is used to reduce CrIII to CrII, which in turn reduces NO3—N. Zinc powder is mixed with the sample, a solution of CrK(SO4)2in H2SO4added and the mixture allowed to stand at room temperature for 2h. The usual Kjeldahl reagents (K2SO4, CuSO4and H2SO4) are then added and the digestion completed in a digestion block at 360°C. Nitrate is quantitatively converted to NH4—N, whether on its own, in plant material or in

ISSN:0022-5142    

DOI:10.1002/jsfa.2740360203

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe benzoic and cinnamic acids found in forages were tested for their inhibitory effects on digestion of cellulose and hemicellulose by mixed cultures of rumen microorganismsin vitro.Rate and extent of cellulose digestion with the addition of cinnamic acids were determined. The benzoic acids and aldehydes were also compared for their inhibitory potential. Of the benzoic acid derivatives, only the parent compound (benzoic acid) inhibited in vitro dry matter disappearance (IVDMD) of cellulose after 48 h, whereas most of the cinnamic acids were inhibitory. None of these compounds depressed IVDMD of hemicellulose. Extent of cellulose digestion was unaffected by cinnamic acids, but rate of digestion was significantly reduced. The ranking of compounds for inhibitory potential was essentially reversed between 48 and 168 h of fermentation as compared with the ranking for 0 to 48 h of fermentation. There were also shifts in the molar proportions of volatile fatty acids produced between these times. The rapid reduction in concentration of cinnamic acids by microbial fermentation may explain these shifts. Benzoic aldehydes were more inhibitory of structural carbohydrate fermentation than were acids. No clear relationship existed between addition of hydroxyl or methoxyl groups to benzoic or cinnamic acids and their depressing effects on IVDMD. Cinnamic acids, which are more abundant in forages, were more inhibitory than the benzoic acids; but for all compounds, it appeared that hemicellulolytic bacteria were generally more tolerant of these compounds than the cellulolytic bacteria.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740360204

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe size of the manganese labile pools of three sandy soils from south east Scotland with a history of Mn deficiency was investigated by four methods: extraction with CaCl2; extraction with DTPA;E‐value determination by exchange with54Mn; andL‐value determination using barley as the test crop. There was little agreement between the methods. TheL‐values varied with the period of plant growth and with soil bulk density but greatly exceeded theE‐values, which in turn were about twice the quantities obtained by prolonged extraction with CaCl2and an order of magnitude greater than the quantities extracted after 1 h with CaCl2‐DTPA extraction gave values three to six times those obtained with CaCl2. Extractable Mn increased dramatically after prolonged air drying, indicating the need for standardisation of both pre‐extraction conditions and extraction times when comparing the Mn availability of diff

ISSN:0022-5142    

DOI:10.1002/jsfa.2740360205

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740360206

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractEighty commercial hybrid pigs (55 kg) consisting of equal numbers of boars and castrates were slaughtered after a 24 h fast, having been transported 48 km to the abattoir and laired for 1 h. During transport and lairage, pigs from different rearing pens were mixed and some fought. Photographs of each carcass were scored for the degree of fighting damage. The greater the damage the higher were the concentrations of cortisol (P<0.001), glucose (P<0.01) and lactate (P<0.001) in blood collected from the pigs at slaughter. The amount of ascorbic acid was lower (P<0.05) in the adrenal glands from pigs which showed most evidence of fighting. The pH45in the m.longissimus dorsi, its colour and the loss of drip during storage were not significantly related to the amount of fighting but the pHuin both the m.semimembranosus and m.adductor was higher (P<0.05) in the carcasses showing greatest damage. There was a tendency for boars to show more carcass damage but there were no significant differences between the sexes in the measures of meat quality.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740360207

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractApproximately 80 samples of Sri Lankan nutmeg oil (both industrially produced and laboratory distilled) were examined for relative density, optical rotation and refractive index and also analysed by gas chromatography. Results showed that although the oil resembled the West Indies type nutmeg oil rather than the East Indies type it had distinguishing features. Results of studies on industrially produced samples were as follows: relative density (30°/30°C). 0.8690±0.0085; optical rotation (30°C), 31.7±2.7°; refractive index (30°C). 1.4726±0.0024; sabinene content, 38.9±12.7%; myristicin content, 2.3% (mean); and elemicin content, 1.2% (mean). On the basis of these studies there appears to be a strong case for revising the Sri Lanka Standard for nutmeg oil, Sri Lanka, which at the present time lays down specifications similar to that of the East In

ISSN:0022-5142    

DOI:10.1002/jsfa.2740360208

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractIt has already been suggested that when glutenin chains are synthesised, two cysteine residues on each chain preferentially form interchain disulphide bonds (SS) resulting in linear arrays of polypeptide chains. Presumably steric factors stop the growth of a molecule eventually, leaving each terminal chain with a free SH group. It is now postulated that the free SH groups later react with low molecular weight (mol. wt) thiols and SS compounds, which also break some interchain bonds by SS interchange so reducing the average mol. wt of the glutenin. Terminal SH groups and the halves of each broken SS become blocked by low mol. wt compounds. Therefore, if the quantity of glutenin‐bound low mol. wt thiols (end‐blockers) bound to glutenin could be measured it would enable the number of glutenin molecules to be calculated and hence a number‐average mol. wt. When six wheats spanning the normal range of baking quality were tested, glutenin‐bound half‐cystine and glutathione residues were eventually found, but no SH groups could be detected. The number‐average number of chains per glutenin molecule (proportional to mol. wt) was correlated with intrinsic viscosity of glutenin and with loaf volume per gram of loaf protein, thus supporting the hypothesis. It is suggested that the main aim of reducing the native thiol content of flour with improvers is to limit degradation of glutenin molecules. If the hypothesis should be confirmed it may be advantageous to breed wheats with low contents of thiols and active disulphides in the grain, since their quantities may largely account for glutenin mol. wt and, in turn, prot

ISSN:0022-5142    

DOI:10.1002/jsfa.2740360209

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe values for dietary fibre in the current UK food tables were obtained using a fractionation method which involved digestion of starch with a takadiastase preparation. For the revision of the food tables new values for the dietary fibre in cereal and cereal‐containing meat products were obtained by an improved fractionation method which used a mixture of amyloglucosidase and α‐amylase to digest starch. The full details of this analytical method are given, along with the fibre components which were found in 138 cereal‐containing foods. This method produced higher values than the previous method in most processed cereal products. Also the levels of pentoses in the non‐cellulosic polysaccharide fraction and of lignin residues are greater. The study considerably extends the range of cereal‐containing foods for which the amount of dietary fibre and its components has been

ISSN:0022-5142    

DOI:10.1002/jsfa.2740360210

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe following are summaries of papers presented at a symposium on ‘The Shelf Life of Red Meat, Fish and Poultry’ organised jointly by the Meat and Sensory Panels of the SCI Food Group. It was held at the Society of Chemical Industry, 14 Belgrave Square, London SWIX 8PS on 23 February 1983. The papers published here are entirely the responsibility of the authors and do not reflect the views of the Editorial Board of the Journal of the Science of Food and Agricult

ISSN:0022-5142    

DOI:10.1002/jsfa.2740360211

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY