摘要:

AbstractSpinach, kale, cauliflower and potatoes were grown in pots at differing levels of nitrogen fertilisation. Increased nitrogen in the soil led to increased total‐N and nitrate contents but decreased amino acid concentrations (g/16 g total‐N) in spinach and kale. Similar treatments on cauliflower and potatoes also increased the total‐N but the nitrate concentrations were negligible; amino acid concentrations in the crude protein decreased except for aspartic and glutamic acids in potatoes. The essential amino acid indices and chemical scores decreased with increasing N‐content in all crops. When compared with egg protein, methionine and cystine were generally the most limiting amino acids. At low N‐levels, methionine and cystine were generally above the FAO amino acid reference limits. In rat feeding experiments, increased total‐N concentrations were associated with higher true digestibilities of the crude protein in all four crops, and the biological values tended to increase. Addition of synthetic methionine to potatoes increased their biological values by 35 and 12% at low and high N‐levels. Increasing total‐N contents increased the net crude protein utilisation in the four crops. Increased N‐applications decreased the nutritive value of the crude protein when judged on the basis of amino acid determinations, but the opposite conclusion was reached from the results of the fe

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290402

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractVolatile compounds were obtained by steam distillation‐continuous extraction of coastal bermudagrass and their origin and possible association with fresh grass palatability determined. The compounds were separated by gas chromatography and individually trapped with an effluent‐splitter for infrared analysis. Furfural, furfuryl alcohol and phenylacetaldehyde were identified by infrared spectral analysis, GC‐mass spectroscopy, and by comparison of GC retention times with authentic compounds. Acetic acid was identified by infrared spectral analysis and GC retention times. Phytol (3,7,11,15‐tetramethyl‐2‐hexadecen‐1‐ol) and β‐ionone [4‐(2,6,6‐trimethyl‐1‐cyclohexen‐1‐yl)‐3‐buten‐2‐one] were identified by GC‐mass spectroscopy. Phenylacetaldehyde was the only volatile compound identified that may be a natural component of bermudagrass. This compound could be an important flavour component and palatability factor in fresh grass because of its fragrant aromatic properties. Furfuryl alcohol, furfural, acetic acid, β‐ionone and phytol were formed as a result of lengthy steam distillation and do not occur naturally in coastal bermudagrass. Furfuryl alcohol was the principal volatile compound obtained under these conditions and results showed it could be formed directly from 2‐deoxyribose. The low level of these volatiles obtained from bermudagrass suggested that limit

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290403

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractWhen 7, 14, or 21% kapok seed meal was incorporated into diets of broiler chicks as a replacement for maize and soya bean meal, liveweight at 9 weeks old was impaired and feed intake reduced. The addition of methionine or lysine did not improve performance when added individually, but restored growth to that of the control when added together. Nitrogen retention was reduced by increased amounts of kapok seed meal but was equal to that of the control when supplemented with methionine and lysine.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290404

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractA specific method of analysis for each of the pyrimidine glucosides, vicine and convicine, is described. This involves extraction by ethanol, evaporation, separation on t.l.c. and quantitative ultraviolet spectrophotometry. Using this method mature dehulled fababeans were shown to contain on average 0.73% vicine and 0.30% convicine on a dry matter basis. No significant variation was found between varieties. The glycosides seem to be associated to the protein bodies in the raw bean, and are absent from the hull. The total content of vicine + convicine in isolated fababean proteins ranged from 0.07 to 2.0%. The highest content was found in a protein fraction produced by air‐classification of dry milled fababeans. The lowest content was found in proteins isolated from a watery extract either by precipitation with acetic acid or by diafiltration. Protein isolates produced by direct ultrafiltration have contents of about 0.60%. The ratio vicine:convicine was found to be relatively constant in the raw beans (average 2.5), but varied from 1.4 to 3.0 in the protein isolates, thus indicating a different reaction of vicine and convicine to conditions during the processing of the fababean. It is the opinion of the authors that the etiology of favism is still controversial as far as vicine and convicine are concerne

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290405

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe chemical composition and nutritive value of sunflower, cv. Armavirec, was examined at 12 stages of growth. Maximum yield of dry matter (18.2 t ha−1) occurred at the dough seed stage. Ether extract showed a five‐fold increase with the development of the seed. This increase was reflected in the gross energy value which was maximal at 19.1 MJ kg−1dry matter at the dough seed stage. In‐vitro organic matter digestibility was highest at the onset of flowering when the estimated metabolisable energy value was 10.5 MJ kg−1dry matter. Throughout the sampling period the calcium to phosphorus ratios varied from 3.9‐5.9:1, an imbalance which would have to be redressed on diets based largely on sunflowers. Fresh and wilted sunflowers were successfully ensiled at the flowering stage, without the use of additives. pH values of the resulting silages were 3.86 and 4.01. The silages were each fed to six cross‐bred wethers and voluntary dry matter intakes were 23.9 and 26.5 g kgW−1for the fresh and wilted silages respectively. For the fresh silage, intakes of digestible organic matter and digestible nitrogen were 612 and 13.6 g day−1compared with 684 and 16.7 g day−1for the wilted silage. Nitrogen retention increased with increase in silage dry matter. The optimum time of cutting for yield of nutrients is at the milky ripe stage. The composition of the crop at this stage should facilitate a satisfactory preservation by ensiling. The crop provides a high yield of dry matter over about 10 weeks in late summer and could provide a valuable standby forage crop for

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290406

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractFor each of the cereals oats, barley and wheat, metabolisable energy concentrations were estimated in 16 samples of known origin and chemical composition. Each sample was fed at three levels of substitution with a fishmeal/vitamin supplement. There was not a significant difference in metabolisable energy concentration among individual samples within the barley and wheat groups. Significant differences found among values for the oat samples did not seem to correlate in any meaningful way with chemically determined components. The overall mean values with standard deviations found for oats, barley and wheat respectively were 11.9±0.29, 12.6±0.23 and 13.6 ± 0.29 MJ kg−1dry matter. These results are discussed and compared with values published recently for laying hens and roosters and with average figures from tables of feedingstuffs composition in current

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290407

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractAn enzymatic assay for the cyanide contents of cassava parenchymal tissue (peeled root), cassava peel or cassava leaves is described. The material is homogenised in orthophosphoric acid; filtered through glass‐fibre paper and aliquots of the filtrate are neutralised and incubated with exogenous linamarase for 15 min. The cyanogenic glucosides present are hydrolysed to free cyanide which is estimated spectrophotometrically. The acid extraction solution inactivates endogenous linamarase, and assay of aliquots without enzyme treatment gives the free (non‐glycosidic) cyanide contents of the extracts. The acid extracts are stable for at least 4 days at 4°C, and the steam‐distillation/aspiration of earlier methods is unnecessary. The detection limit is<0.01 mg (0.1 parts 10−6) cyanide per 100 g fresh weight and peeled root, and 40‐50 samples per day can be handled easily. Analyses of eight cultivars indicated longitudinal and radial cyanide gradients in the roots, and the problem of sampling bulky roots is

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290408

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractProteinase inhibitory activities of a number of finger millet and five representative varieties of other millets were determined. Inhibitory activities in the buffer extracts of the millets varied widely. Trypsin inhibitory activity (TIA) was more pronounced than the chymotrypsin inhibitory activity (CIA) in all the finger millet varieties tested. On germination, TIA and CIA were markedly reduced in the endosperm, but in the axis considerable TIA remained while CIA disappeared. Proteinase inhibitors of finger millet were found to be heat‐labile under neutral conditions and comparatively heat‐stable under acidic conditions. These studies suggest the presence of multiple forms of protein proteinase inhibitors in finger mil

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290409

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThirty‐two varieties of rice, belonging to various classes and characteristics, were studied for their textural and physicochemical properties. The varieties could be divided into five groups depending on their total and hot water‐insoluble amylose contents. It was found that the textural properties of the samples (stickiness and consistency of cooked rice and viscogram characteristics) could not be explained on the basis of the total amylose content alone, but they correlated well with the insoluble amylose content. As the insoluble amylose increased, the consistency and the setback increased, and the stickiness and breakdown decreased. The alkali degradation type of rice, and the equilibrium moisture content attained by it after soaking in water, also seemed to have an important relationship with its quality. Neither the protein content nor the gelatinisation temperature, or its various manifestations, seemed to have any relationship to the other quality characteristics stud

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290410

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractUntreated flour and flour treated with chlorine (2.2 g Cl2kg‐1) were stored in air at 25°C for 4 months. Starch samples prepared from the original flours were stored in air at 25°C for 4 months. Starch samples were also prepared from the fresh flours (control starches) and from the stored flours. Some of the starches from the stored flours were subsequently held at 70°C for 1 month. Starch lipids were not affected by flour chlorine treatment, or by storage at 25°C. There was slight hydrolysis of starch lysophospholipids at 70°C, but negligible autoxidation of unsaturated fatty acids in the total starch lipids. There was appreciable hydrolysis of non‐starch lipids in the untreated stored flour, but no detectable autoxidation of unsaturated fatty acids. Chlorine treatment of flour caused an immediate loss of approximately half of the oleic, linoleic and linolenic acids in all the non‐starch lipids which were examined. There was no further change in the fatty acid composition of the non‐starch lipids when the treated flour was stored, but lipid hydrolysis was substantially reduced compared with the untreated

ISSN:0022-5142    

DOI:10.1002/jsfa.2740290411

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY