摘要:

AbstractDiurnal variation in faecal excretion of dietary chromium (Cr) was studied in this experiment in mature swine. Five gestating sows weighing between 225 and 250 kg were fed a corn/soya bean meal diet containing 14% crude protein, NRC recommended amounts of vitamins and minerals with a Ca: P ratio of 1.3:1. Chromic oxide was added (0.1% w/w) to the test diet, and ferric oxide was added (0.5% w/w) to the pre‐test and post‐test diets as dietary markers. Sows received 0.9 kg of the diet twice daily for 8 days. Total faeces from the test diet were collected and a sample of approximately 150 g of morning samples for days 6 to 9 of the experiment was separated. Faecal recovery of dietary Cr was calculated from the total collection and the samples of the 4‐day period. It was found that faecal concentration of the Cr varied between days (P<0.05) and between times of the day (P<0.05); true equilibrium of Cr excretion was never reached. Diurnal variation in faecal excretion of dietary Cr was shown to exist; Cr concentration was higher in the late morning samples than in the morning samples (P<0.05). Total faecal recovery of dietary Cr was 93.27%, whereas a greater (P<0.05) value was obtained by morning sampling (118.76%). A portion of the dietary Cr (6.73%) was retained in the gastrointestinal tract even after 2 days of Cr withdrawal from the

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560402

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractMore than 500 carbohydrate samples have been characterised by hydrogen, carbon and oxygen isotopic parameters measured on ethanol and water resulting from controlled fermentation. Different chemical states of the carbohydrate pool have been considered: polysaccharides from cereals, tubers and leguminosae (maize, sorghum, rice, wheat, barley, potato, bean), glucose, fructose and sucrose from fruits (pineapple, citrus, apple, soft fruits), sucrose from sugar plants (beet, cane). The overall carbon‐13 content of ethanol and the deuterium and oxygen‐18 contents of water before fermentation were determined by mass spectrometry of isotope ratios whereas the investigation of site‐specific natural isotope fractionation by deuterium NMR has provided access to the deuterium contents in the methyl (I) and methylene (II) sites of ethanol. The results have been analysed in the multidimensional space of these isotopic variables. Hierarchical clustering, principal component and discriminant analyses have been performed. Among fruits, for example, the pineapple group exhibits a 100% discrimination with respect to the apple and citrus groups which are themselves well distinguished. A still higher discrimination is reached between the three groups, citrus, cane and beet, and the addition of 10% exogenous cane or beet sucrose to citrus juice is unambiguously det

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560403

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractAzocaseolytic (endopeptidase) and carboxypeptidase activities in cotyledons of germinating seeds of Citrus limon (L) Burm f (cv Verna) showed a peak on the fourth day after the onset of imbibition and then decreased. A second peak of activity in both enzymes appeared 16 days after imbibition. The activities of leucine‐aminopeptidase and alanine‐aminopeptidase increased until 12 days after imbibition and then declined.When cotyledons were detached from seedlings 8 days after imbibition and then incubated in water, protein breakdown was accelerated and α‐amino N accumulation increased. In detached and incubated cotyledons, the azocaseolytic activity decreased whereas the carboxypeptidase activity continued to increase more markedly than when the axis remained attached. The effect of the axis on azocaseolytic activity was replaceable by kinetin. On the other hand, kinetin, GA3and IAA showed no significant effect on the carboxypeptidase and aminopeptidase activities in detached coty

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560404

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe sterols and fatty acids contents of 22 extravirgin olive oil samples produced in the Etna area and in other areas of Sicily were determined. Principal component analysis (PCA) of these data provided a ‘scores’ plot where samples produced in the Etna area were clearly grouped and unknown samples could be classified according to their geographical origin. This classification was confirmed by the residual standard deviation values of all samples fitted into a disjoint principal components model derived from Etna oils only. The above results suggest that the DOC (denominazlone di origine controllata) origin mark for Etna extravirgin olive oils can be attributed on the basis of their sterols and fatty acids contents by means of

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560405

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe influence of the composting process on the agronomic value of urban waste (UW) from Murcia (south‐eastern Spain) was studied. UW compost had a higher percentage of P, K and nitrate N than fresh UW, as well as a higher cation exchange capacity and a more stable organic matter. By contrast, total N content and values of extractable P/ total P × 100 ratio were lower.The addition of fresh UW to a calciorthid soil had an initially depressive effect on rxegrass (Lolium perenne) yield, which disappeared with time as this waste matured in the soil. No depressive effect was observed when composted UW was applied. When soil was amended with high doses of UW compost, yields were always significantly greater than the control.The uncomposted waste induced a large concentration of macroelements (except N) in the plants of the first harvest. Plants grown in amended soil had a higher concentration of Fe, Mn and Zn than the contr

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560406

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractA synthetic model system containing p‐coumaric and ferulic acids esterified to hemicellulose was used to study polysaccharide degradability. Oatspelts xylan was fractionated into Alinear, Blinearand Branchedfractions prior to synthetic esterification with phenolic acids at treatment concentrations of 0, 25, 50, 75 and 100 g phenolic acid per kg hemicellulose. Concentrations of phenolic acids esterified to the hemicellulose fractions were determined by alkaline hydrolysis. In‐vitro dry matter disappearance (IVDMD) and degradability of hemicellulose neutral sugars were measured after 48 h ruminal fermentations. Esterification efficiency of the phenolic acids to the hemicellulose fractions was low (0.3 to 13.9%) and greater for p‐coumaric than ferulic acid (4.7 vs 3.1%, respectively). Concentration of esterified phenolic acids was negatively correlated with IVDMD for the Alinearand Bbranchedfractions. Ferulic acid appeared to be more inhibitory to IVDMD than p‐coumaric acid. Generally the degradability of the side chain sugars of the hemicellulose fractions was negatively correlated with esterified phenolic acid concentrations. Xylose degradation was only correlated with esterified ferulic acid level in the Alinearfraction. The in‐vitro ruminal fermentations resulted in the degradation of the majority of the phenolic acid esters. Analysis of the synthetic phenolic acid‐hemicellulose esters by13C NMR and FTIR was unable to prove the presence of monomeric phenolic acid esters. The presence of phenolic acid polyesters was unlikely because of the solubility of the synthetic phenolic acid‐hemicellulose esters. The neutral sugar degradation data suggest that esterification of the phenolic acids was limited to sugars with primary hydroxyl groups. While this model system was useful for studying cell wall degradation, future studies must employ model systems in which the chemical constituents being tested accurately model those fo

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560407

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractSamples consisting of the whole above‐ground part of the oilseed rape plant (Brassica napus L), were taken every 2 weeks from before stem extension to maturity. The plants were separated into vegetative tissue, floral tissue, pods and seeds (when these components appeared), and the individual glucosinolates present were quantified by high performance liquid chromatography. A high glucosinolate variety (Rafal) and a low glucosinolate variety (Cobra) were compared. The effect of sulphur (32 kg ha−1elemental sulphur applied at the beginning of stem extension) on the various parts of the plant was investigated. Total glucosinolate concentration in all plant parts was higher in Rafal than in Cobra. Glucosinolate concentration in the vegetation declined over time, most noticeably when the flowers and seeds were produced, and glucosinolate concentration of the pods also fell as that of the seeds rose. It is suggested that there may have been some redistribution of glucosinolates or glucosinolate precursors within the plant as maturity approached. Changes occurred in the proportions that individual glucosinolates contributed to the total glucosinolate content, and this may be relevant to plant/pathogen relationships. Sulphur application increased the glucosinolate concentration of the vegetative tissue by mid April and also increased the glucosinolate concentration of the flowers. It is suggested that this could affect the plant's resistance to dise

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560408

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe green fraction of leaf protein from lucerne (Medicago sativa L) was prepared by heating freshly extracted juice to 55°C. From the same part of the juice unfractionated leaf protein concentrate (LPC) was obtained by heating it to 80°C. The green fraction was divided into four parts and treated as follows: dried at 55°C (I), washed with water (II), washed with buffer (III) and extracted with ether (IV).The LPCs obtained were analysed for gross composition and amino acid content as well as for phenolics and carotene. The true digestibility (TD) and biological value (BV) of LPC proteins were determined on growing rats using the Thomas‐Mitchell balance method. In addition the effects of DL‐methionine or L‐lysine supplementation of native green LPC were studied.The native green protein fraction contained more fat, phenolics and carotene but less protein than unfractionated LPC. The ether extraction lowered fat and carotene content of concentrate, and washing with buffer eliminated most phenolics.There were only small differences in the amino acid composition of proteins. The buffer‐washed concentrate contained more amino acids than any other treatment.Both the true digestibility and biological value of unfractionated LPC were higher than those of each green concentrate. Ether extraction mainly improved TD (from 73 to 79) and washing with buffer improved BV (from 41 to 50) of green protein. The best result was obtained when the green fraction was supplemented with methionine (BV increased from

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560409

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractLantern fish of the species Lampanyctodes hectoris were shown to contain phospholipids (10 g kg−1) and non‐phosphorylated lipids (140 g kg−1). The phospholipid fraction consisted of phosphatidyl choline (47% of total phospholipids), phosphatidyl ethanolamine (42%), phosphatidyl serine (3%), phosphatidyl inositol (1%), sphingomyelin (4%), lyso‐phosphatidyl choline (1%) and cardiolipins (2%).Lantern fish (L hectoris) meals normally contain unacceptably high lipid contents (150 g kg−1and over); this characteristic was found not to be due to a high phospholipid level in the lantern fish.The major fatty acid of the phospholipids was C22:6n‐3 (25% total fatty acids) followed by C16:0 (18%), C18:ln‐9 (16%) and C20:5n‐3 (8%). This distribution was different from that of the non‐phosphorylated lipids where the major fatty acid was C16:0 (21%) followed by C18:ln‐9 (19%), C20:5n‐3 (11%), C20:l (7%) and C22:6n‐3 (7%). The lantern fish press oil and residual meal lipids had fatty acid distributions similar to those of the no

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560410

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe effects of different rabbit grazing regimes on the concentration and relative amounts of individual glucosinolates were studied overwinter in the green tissue of two oilseed rape cultivars (Bienvenu, a single‐low type, and Ariana, a double‐low type) and two forage rape cultivars (Hobson and Bonar). Grazing significantly increased total glucosinolate content. Within this general increase, the proportion of aliphiatic glucosinolates was reduced whereas the proportion of both indole and phenylethyl glucosinolates increased. Possible reasons for such changes are discus

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560411

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY