摘要:

AbstractSheep fitted with cannulas in the rumen and proximal duodenum were used to study the digestion of two diets of rolled barley and dried grass (39:61 on a dry matter basis) which were given in 24 meals (at 1‐h intervals) each day. The two diets contained the barley either in untreated form or treated with an acidic formaldehyde reagent which was designed to cross‐link the barley protein and starch and thereby reduce its rate of degradation in the rumen.There were no significant (P<0.05) differences between the diets in rumen pH, protozoal numbers and concentrations of ammonia N and total and individual volatile fatty acids. However, the diet containing the treated barley increased (P<0.05) duodenal passage of total N from 17.4 g day−1to 20.5 g day−1and duodenal passage of starch from 8g day−1to 16 g day−1, the latter representing a change from 0.038 to 0.074 of the dietary starch intake. For both constituents there were associated increases in the amounts absorbed in the intestines. There were no significant differences between treatments in the digestion of acid dete

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420102

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractRumen degradation of cell wall polysaccharide constituents using the in sacco technique was studied for untreated cereal brans (oats, wheat and barley) and nine technically alkali‐treated batches of barley straw. The alkali treatment included four ammonia treatments, two dry sodium hydroxide treatments and three wet sodium hydroxide treatments. On degradation of the cell wall polysaccharides, their main constituents, xylose and glucose, were released at about the same rate for the ammonia treatments and the dry sodium hydroxide treatments. For the wet sodium hydroxide treatments the degradation of the xylose residues was faster than the liberation of the glucose residues. For all treatments the liberation of the arabinose residues was faster than that of the xylose and glucose residues. The reason for the increased digestibility of the cell wall polysaccharides is suggested to be the breaking of ester and hydrogen bonds and the breaking of alkali‐labile linkages in lignin, as well as changes in the surface layer of the straw. For the wet sodium hydroxide treatments the larger amount of water present during the alkali treatment processes is suggested to increase the diffusion of the alkali into the straw and to translocate a part of the hemicellulose. On the degradation of wheat and barley bran the liberation of xylose residues was fast whereas xylose and arabinose residues in oat bran were slowly libera

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420103

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractWhen sugarcane bagasse was pretreated at room temperature with various chemicals singly or in combination, (0.25 m NaOH; 0.5 m H2SO4; 2.6 M NH3;0.14 M Ca(OH)2+0.12 M Na2CO3;4.2 m EDA; and 0.5 M H2SO4or 0.25 M NaOH followed by 4.2 M EDA), increases in in‐vitro digestibility range from 28.9 to 48.6% depending on the particular chemicals. With most pretreatments, the hemicellulose content decreased and the cellulose content increased slightly, while lignin levels decreased only with NaOH + EDA pretreatments. Further fermentation of the chemically pretreated bagasse withPhanerochaete chrysosporiumgave increased digestibilities, the highest final digestibility (59%) being achieved by pre‐treatment with 0.25 M NaOH. Pretreatment with NaOH or Ca(OH)2+Na2CO3and fermentation gave greatly increased levels of hemi‐cellulose and cellulose and substantial decreases in lignin levels. Chemical pretreatments of bagasse together with autoclaving considerably enhanced in‐vitro digestibility (up to 75%) and lignin degradation (1.4%). Pretreatment with NaOH, Ca(OH)2+Na2CO3, and EDA plus autoclaving gave large increases in total hemicelluloses and cellulose and marked decreases in lignin. Further fermentation withP. chrysosporiumgave only slight increases in digest

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420104

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe changes in the composition of free and total amino acids in wheat grain during development are described: the experiment was performed in a growth chamber with three varieties of winter wheat (Triticum aestivumL.): Splendeur, Hobbit and Maris Huntsman. The changes in the total composition of amino acids of the grain as development progressed were consistent with an increase in the proportion of storage proteins. At 15 days after anthesis, the relative amount of glycine increased, suggesting that at this moment the proportion of gliadins was relatively low. The relative amount of arginine increased in mature grain, showing that at times close to maturity the relative proportion of synthesis of a protein fraction rich in this amino acid increased. Free glutamate, proline and arginine decreased at 15 days to a greater extent than the other amino acids and was present in low relative amounts during the period of maximum protein synthesis in the grain; these three amino acids could be the most limiting for protein synthesis in grain. In the free fraction the following showed a similar pattern of change during grain development: aspartate, arginine and histidine on the one hand, and on the other alanine, valine, leucine, isoleucine, threonine, phenylalanine and tyrosine; moreover both groups were inversely correlated. Glycine and lysine were directly related to each other and inversely to glutamate.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420105

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThirty‐four French red wines originating from six different grape varieties and three different production areas were analysed in duplicate for 15 anthocyanins, ten flavonoids and three colour parameters, F‐statistics, principal component analysis and stepwise discriminant analysis were used to identify and to explain differences among samples.Clear difference between wines made from different varieties were mainly related to anthocyanin 3‐acylglucosides. Malvidin and peonidin 3‐acetylglucosides were found in increasing concentrations in wines made respectively from Grenache, Carignan, Cinsault, Merlot, Carbernet Sauvignon and Cabernet Franc grapes; the concentrations of peonidin and malvidin 3‐p‐coumarylglucosides were higher in the Cinsault wines studied.Cabernet Sauvignon and Merlot wines made near Bordeaux had a less intense colour and a higher malvidin 3‐glucoside content than wines from the same varieties produced near Narbonne. Wines made from Merlot, Cabernet Sauvignon and Cabernet Franc grapes contained more catechin, epicatechin and myricetin when produced in the south than in the north (Narbonne, Bordeaux, Angers).Of the samples analysed, 96%, and all of the nine extra wines, were correctly classified according to the variety of the grapes using four anthocyanins and catechin selected by step wise discrimi

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420106

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractCloud stability in citrus fruit aqueous peel extract (PEX) and the derived serum (SPEX) was studied with respect to endogenous coagulants and the possible involvement of soluble pectin as stabilising agent. Heat treatment of the pectin‐degraded SPEX induced the appearance of turbidity as a result of protein coagulation, particularly in the pH range of 3.5–4.5, whereas only slight coagulation occurred without heat treatment. The pectin in non‐degraded SPEX therefore inhibited heat coagulation of most of the protein present. Incubation of PEX itself with exogenous depolymerising pectinase (DP) slightly increased its transmittance, and subsequent heat treatment clarified the suspension within a short time, especially at pH 2.5–4.5. Under the electron microscope, heat‐coagulated proteins from DP‐incubated SPEX appeared as dispersed amorphous bodies showing two main types of pattern; the coagulate from a PEX preparation of high oil content appeared as ultramicro‐droplets of oil encapsulated within coagulated proteins.The evidence indicates that soluble pectin in PEX preparations affects cloud stability by preventing the coagulation of heat‐denatured proteinaceous components; once the pectin is degraded by endogenous and exogenous DP, protein coagulation occurs rapidly on heat treatment, resulting in co‐precipitation of the other encapsulated

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420107

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe quality of fried chips made from cassava flour depended on total soluble sugar (TSS) concentration and on some paste viscosity parameters of the flour. Chip colour darkened as TSS content increased. Taste was not affected by total HCN content but became bitter as TSS levels increased. Chip HCN concentration was minimal if flour with low HCN was used. Greater surface expansion of the dried chips during frying produced crisper chips. Expansion during frying correlated positively with maximum and setback viscosities of the flour paste.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420108

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractDried sugar beet pulp was ground and washed with 95% ethanol in order to obtain a colourless and odourless product which could be used as dietary fibre after drying and sieving. Sugar beet fibre had the same chemical composition as the initial pulp: 26–32% of hemicelluloses, 22–24% cellulose, 21.5–23% uronic acids, ∼1–2% lignin, ∼7–8% protein, 7.5–12% ash and ∼0.5% residual sucrose. The main physicochemical properties such as density, cation exchange capacity (∼0.6 meq g−1) and water holding capacity (24–32 g g−1) were determined. The water holding capacity of sugar beet fibre was only slightly affected by pH and ionic strength (adjusted by NaCl or CaCl2) but it held less water in the H+form than in

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420109

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420110

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420101

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY