摘要:

AbstractThe polymorphism of 1,3‐dipalmitin, 1,2‐dipalmitoyl‐sn‐glycerol, 1.2‐dipalmitoyl‐rac‐glycerol has been examined by X‐ray diffraction, IR spectroscopy and Raman spectroscopy and differential scanning calorimetry. The respective spectra and thermographs are presented for these polymorphs. Optically active 1,2‐diglycerides exhibit very different thermal behaviour from the optically inactive 1,2‐diglycerides. A novel HPLC system was devised for the separation

ISSN:0022-5142    

DOI:10.1002/jsfa.2740600402

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe chemical composition and protein quality of the kernels fromLupinus angustifoliusseeds were compared with that for sprouts after 6 days germination. Germination resulted in an apparent increase in protein content from 395 g kg−1to 435 g kg−1DM. Fat and carbohydrate contents decreased. The oligosaccharide content of the sprouted lupin fell to a negligible level, while the phytate and alkaloid concentrations fell from 4.7 g kg−1to 1.6 g kg−1and from 0.72 g kg−1to 0.16 g kg−1, respectively.The quality of lupin kernel protein was poor with a protein efficiency ratio (PER) of 1.45±0.15. Supplementation of kernel with DL‐methionine (2.0 g kg−1) increased the protein quality (PER = 2.87±0.17) to that of casein (PER = 2.86±0.18). Germination reduced protein quality (PER = 0.44±0.16), and did not improve apparent protein digestibility (APD kernel = 80.4%; APD sprout = 77.5%). Supplementation of sprout protein with DL‐methionine (2.0 g kg−1) increased the protein quality (PER = 2.57±0.20). The total sulphur‐containing amino acid concentration of lupin kernel protein, 1.9 g per 16 g N was low, and decreased further to 1.3 g per 16 g N in the sprout, a drop of 32%.The results showed that germination of lupin seeds reduced the concentration of the anti‐nutritive factors; however, it

ISSN:0022-5142    

DOI:10.1002/jsfa.2740600403

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractEight cows were used in a replicated 4 × 4 latin square design experiment with period lengths of 3 weeks to investigate the effects of protein supplementation of a grass silage diet on silage intake and milk production. The four treatments were (i) the basal diet, consisting of grass silagead libitumplus 2 kg day−1of molassed sugar beet pulp; (ii) basal diet plus 1 kg day−1of fish meal (F): (iii) basal diet plus 0.8 kg day−1of feather meal 1 (FE1); and (iv) basal diet plus 0.8 kg day−1of feather meal 2 (FE2). Silage intake was significantly (P<0.01) increased by the F supplement but was not affected by the FE supplements; values were 9.9, 10.6, 9.6 and 9.6 kg DM day−1for basal, F, FE1 and FE2, respectively. Relative to the basal treatment, F increased (P<0.001) the yield of milk and milk protein but, again, these were unaffected by FE; values were, for milk yield, 13.6, 16.3, 13.7 and 13.1 kg day−1; and, for milk protein yield, 420, 545, 429 and 414 g day−1for basal, F, FE1 and FE2, respectively. However, supplementation with FE produced increases in the concentration (P<0.001) and yield (P<0.05) of milk fat; values were 42.8, 39.9, 46.6 and 47.8 g kg−1and 575, 646, 628 and 618 g day−1respectively, for the basal, F, FE1 and FE2 treatments. The profile of amino acids in blood plasma was characterised by markedly lower (at leastP<0.01) concentrations of methionine, lysine, tryptophan and histidine for the diets containing FE compared with F. The results show pronounced effects of the amino acid composition of the undegraded protein component of the supplement on both silage intake and milk production but also draw attention to a possible relationship between amino balance and the sec

ISSN:0022-5142    

DOI:10.1002/jsfa.2740600404

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractDiffuse reflectance Fourier transform infrared (FT‐IR) spectroscopy has been used to characterise the changes in barley straw when subjected to biological and chemical treatments. The untreated and treated straws were also analysed by traditional analytical techniques for neutral sugar residues and lignin. A comparison between the spectroscopic data and the chemical analyses showed that FT‐IR spectroscopy was a quick and non‐destructive analytical technique which could be used to assess the efficacy of treatments applied to annual p

ISSN:0022-5142    

DOI:10.1002/jsfa.2740600405

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractEndogenous ileal amino acid flows were determined in the young growing pig given an enzymically hydrolysed casein (EHC)‐based diet with subsequent treatment of the digesta by ultrafiltration. Comparison was made with endogenous excretions obtained from pigs fed an EHC‐based or a protein‐free diet but without treatment of the digesta. Ten entire male pigs of 15 kg liveweight were fed either an EHC‐based diet or a protein‐free diet, and samples of digesta were collected following euthanasia. The digesta from the EHC‐fed pigs were divided into two equal portions. One portion was untreated, and the second portion was ultrafiltered after centrifugation with the retentate (high‐molecular‐weight fraction) being added to the precipitate. Endogenous ileal amino acid flows were determined for the untreated digesta and for the digesta following the centrifugation plus ultrafiltration treatment. Except for arginine, glycine, leucine and phenylalanine, the endogenous amino acid flows were significantly (P<0.05) higher for the untreated digesta than for the digesta following the centrifugation plus ultrafiltration treatment. Except for arginine, glycine, leucine and phenylalanine, the endogenous amino acid flows were significantly (P<0.05) highter for the untreated digesta than for the digesta following the centrifugation plus ultrafiltration treatment. The pigs fed a protein‐free diet generally had lower amino acid flows than those fed the EHC‐based diet (ultrafiltration treatment). significantly (P<0.05) so for lysine, aspartic acid, threonine, serine, glutamic acid, glycine, valine, isoleucine and leucine. The endogenous flows in different segments of the upper digestive tract of the young growing pig were also determined in the animals fed the protein‐free diet. The endogenous amino acid flow was highest in the second third of the upper digestive tract. There was a significant (P<0.05) difference between the amino acid flows determined in the first and second thirds of the small intestine for mo

ISSN:0022-5142    

DOI:10.1002/jsfa.2740600406

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract‘Kwoka’ (a popular Nigerian non‐fermented maize meal) was produced using steaming for either 30 or 60 min or a combination of potassium sorbate (KS) treatment with steaming for 60 min. Microbiological characteristics and chemical quality were investigated during production and storage, together with organoleptic and objective (firmness only) assessment of quality during ambient storage (30 ± 2°C). The slurry (ie before steaming) and 30 min steamed K woka showed more diverse genera of moulds and bacteria than K woka steamed for 60 min (with or without KS). The organisms isolated from the raw materials and product belonged to the generaBacillus, Staphylococcus, Lactobacillus, Enterobacter, Klebsiella, AspergillusandFusarium.During storageBacillus cereus, Lactobacillus delbrueckii, L leichmanniiandKlebsiella pneumoniaepredominated. Coliforms and fungi were not detected on day 0 in KS‐treated and 60 min steamed K woka. Marked reductions in aerobic plate counts (APC) and in the population of the different bacterial groups were observed in all samples following steaming, These increased sharply within 1 day of storage, the highest (6.50 log cfu g−1) APC occurring on day 3 in 30 min steamed K woka. Of the bacterial groups, theLactobacilluspopulation increased most markedly and this probably reflects the significant increase in acidity observed especially on day 6. Adverse quality changes in appearance, aroma and firmness were more apparent in the control (ie without KS treatment) and the samples were unacceptable after 1 day but the shelf‐life of K woka produced using KS treatment and 60 min steaming was exten

ISSN:0022-5142    

DOI:10.1002/jsfa.2740600407

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractEleven grain samples of Condor, a two‐rowed, hull‐less barley cultivar. were analysed for concentrations of protein, starch, amino acids and fibre. Starch levels were found to be consistently higher than that of a covered barley and approached that of a hard spring wheat. Acid‐detergent fibre was found to be 70% lower in the hull‐less samples than in the covered barley or the wheat. The Condor samples showed a wide range of protein concentrations (12.5‐17.2% on a dry matter basis). The concentrations of arginine, cystine, isoleucine, lysine, methionine and threonine (percent dry matter basis) were consistently higher in the Condor barley samples assayed here than levels stated in the literature for barley. The concentrations (g (100 g protein)−1) of cystine (P<0.01), lysine (P<0.001) and threonine (P<0.01) decreased significantly as protein increased. Isoleucine, methionine and tryptophan showed no such effect. Both glutamic acid and proline concentrations increased significantly (P<0.01) as protein increased which suggested higher amounts of hordeins in high protein Co

ISSN:0022-5142    

DOI:10.1002/jsfa.2740600408

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractDifferent types of inocula for cassava were compared in the Gari type fermentation of cassava. High acidification rates were achieved withLactobacillus plantarum, Lactobacillus cellobiosusand with re‐inoculation from the liquid drained from a previous batch. Slower rates were obtained inoculating from a previously fermented batch and with the natural acidification process. Serial fermentations made re‐inoculating from a previous batch increased the acidification rates and established a population ofLactococcus, LeuconostocandPediococ

ISSN:0022-5142    

DOI:10.1002/jsfa.2740600409

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe aims of this study were to investigate the influence of fertiliser treatments on the chemical flavour composition of kohlrabi (Brassica oleraceavargongylodesL). Increasing nitrogen and potassium supply resulted in variable amounts of isothiocyanates, organic cyanides, sulphides and aldehydes measured by headspace analysis. Therefore it could be suggested that the desirable flavour of kohlrabi is influenced by the level of fertilisation. The effect of applied potassium on flavour quality is less clear cut. The observed inverse relationship between the amounts of flavour compounds and nitrogen supply might be utilised in production practices to obtain an optimal flavour quality.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740600410

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe colour stability of juice and purées made from a mixture of two strawberry varieties, stored at + 20°C or at –20°C under aerobic and anaerobic conditions, was studied. High‐performance liquid chromatography and spectrophotometric analysis were used to monitor the changes in colour during storage. Pelargonidin 3‐glucoside comprised 80% of the total anthocyanin content. Four other pelargonidin‐based peaks were found, being 10.4%, 3.5%, 0.7% and 0.3% of the total and two cyanidin peaks were present, being 3.3% and 0.4% of the total. Clarification before storage caused considerable losses in the initial anthocyanin concentrations. Storage conditions (air versus nitrogen) did not influence the rate of loss of anthocyanins during storage or the formation of polymeric pigments. There were no losses in anthocyanins and no increase in the amount of colour measured at 510 nm due to polymers in samples stored at–20°C. Polymerisation occurred in the samples stored at + 20°C, especially in the cla

ISSN:0022-5142    

DOI:10.1002/jsfa.2740600411

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY