摘要:

AbstractSmall‐scale trials were carried out to optimise the conditions for micromalting triticale grain, using three varieties grown in the UK. Compared with barley, triticale grains required short steeping periods with a short air rest. They malted rapidly, and produced malts with high hot water extracts after 4 or 5 days' germination. Applications of gibberellic acid and potassium bromate during malting significantly altered the qualities of malts. Gibberellic acid increased hot water extracts, soluble nitrogen levels and malting losses. When the additives were used in combination, high hot water extracts were obtained and malting losses were reduced relative to controls, but unexpectedly the level of total soluble nitrogen was elevated and did not significantly differ from that obtained using gibberellic acid alone. Both additives usefully reduced wort viscosities, which were unacceptably high by barley malt brewing standards. Wort separation from small‐scale mashes was s

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560202

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractSmall‐scale trials were carried out to compare the malting characteristics of 12 triticale varieties harvested in the UK in 1985. Grain samples from two locations, each having grain total nitrogen contents of between 1.78 and 2.57%, were micromalted. The results established varietal differences in malting quality with respect to grain water uptake, optimum germination period and malt hot water extract. Hot water extracts after a 5‐day germination period ranged between 302 and 324 litre° kg−1with malt yields in the range 87–90%. Compared with barley malts, triticale malts possessed extremely high 70° mash wort viscosities of between 10.4 and 26.9 cSt. The appendix shows the advantages of adjusting × 0.2‐scale hot water extract mashes to a final weight of 100 g rath

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560203

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractWorts from triticale malts, in particular well modified malts, separated poorly from mashes. Worts prepared at 70° C had high viscosities (10–27 cSt) indicating that problems would occur during filtration in brewing. The viscosities of triticale worts were higher than those of worts from barley malts. In addition, worts from well modified malts were generally turbid. Proteinaceous material (partly degraded prolamins) was the primary cause of this turbidity. Although the degree of malt modification did influence the rate of wort separation, it had little effect on wort viscosity. High viscosity was caused by pentosans dissolved from the triticale malt during mashing. Oxidative gelation was not observed with these pentosans. Grains and malts were fractionated, and the high molecular weight fractions were analysed for their sugar and acyl components. All were rich in arabinose and xylose. There was a rough inverse correlation between the solubility of the poly saccharide fractions and the levels of substitution with acetyl and feruloyl residues. The poor wort separation from triticale malt grists appeared to be related to the particle size distributions, which were narrow. The sedimentation values of the grist ‘fines’ wer

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560204

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractStraw samples from five cultivars of spring barley (Hordeum vulgare L; Golden Promise, Golf, Klaxon, Heriot and Doublet), selected to show a range of rumen degradabilities, were examined to measure the effect of gaseous ammonia on aspects of their cell wall composition and degradability after treatment. Cellulose degradability of the untreated straws, as measured by the nylon‐bag method, ranged from 41.0% for Golden Promise to 57.1% for Doublet. The extent of improvement in degradability following ammonia treatment was 12.5% units for Golden Promise and only 2.5% units for Doublet, showing that the effect of ammonia was more pronounced for materials of lower inherent degradability (r= −0.774). Straw from three of the five cultivars was dissected into its botanical parts, and the dry matter content and digestibility of the fractions were determined. Leaf material formed a higher fraction of dry matter in Doublet (0.48), the most degradable cultivar, than in Golden Promise (0.30), the least degradable straw. Half of the observed difference in degradability between Doublet and Golden Promise could be attributed to differences in dry matter distribution between botanical fractions. For untreated straw, degradability was weakly, negatively correlated with the proportion of arabinose residues substituted with alkali‐labile linkages at position 0–5 (r = −0.690), and positively correlated with the moisture retention (water‐holding capacity) of straws (r = 0.838), water‐soluble dry matter content (r = 0.922) and water‐soluble phenolic content (r = 0.791). The proportion of pentose residues carrying alkali‐labile linkages was only slightly decreased followign ammonia treatment. In the case of the 0–5 position of arabinose residues the original values were reduced by 2.4–15.9%. Ammonia treatment had little effect on the capacity of the straw to retain moisture, and did not significantly increase the proportion of water‐soluble dry matter or phenolics. Cellulose degradability, or the improvement in degradability, of ammonia‐treated straw was not correlated with any of the physical and chemical characteristicds

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560205

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe acceptability of diets containing fried sardines (Sardinia pilchardus Walb) was studied for 4 weeks in growing Wistar rats. Group 1 was fed with a diet containing casein and olive oil as protein and fat sources respectively, and groups 2 and 3 received diets containing sardines fried in olive oil which had been used a known number of times. Group 2 was fed with a mixture of fried sardines from the first and second oil‐use occasions as the only source of protein and fat, while group 3 got a mixture of fried sardines from the eighth to tenth oil‐use fryings. All diets contained cholesterol plus bovine bile as a blood cholesterol‐raising agent. Food intake, body weight increase and dietary efficiency ratio (DER) were all similar in groups 1 and 2, showing that the olive oil fried sardine diet was well accepted. However, group 3 ate significantly less (P<0.01) and showed smaller (P<0.01) body weight increase and DER than groups 1 and 2. The hepatosomatic index of group 3 was higher (P<0.05). The hyper‐cholesterolaemic effect of group 1 diet was markedly reduced (5‐ and 15‐fold after 2 weeks and 4 weeks respectively) in gro

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560206

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractExperimental strategies have been developed which make amino acid probes accessible to the NMR study of site‐specific natural isotope fractionation. A multi‐isotope approach, based on combined mass spectrometry determination of hydrogen‐, carbon‐ and nitrogen‐overall isotope contents and on2H‐NMR determination of site‐specific hydrogen isotope ratios, shows that relatively wide ranges of variation are exhibited by the isotopic parameters of glutamic acid, aspartic acid, alanine, proline and lysine samples from different origins. Moreover, relatively large deviations with respect to a random distribution of deuterium among the molecular sites are quantified and compared. A noticeable enantiomeric imbalance at the methylenic site adjacent to the chiral centre is also detected in natural samples of L ‐glutamic and L ‐aspartic acids in particular. The results are analysed in terms of filiation criteria and technological effects. It is shown in particular that the C3or C4metabolic origin of the raw materials utilised in fermentation processes can be recognised. Principal component analyses involving the two mean isotopic variables δ13C and δ15N and the three site‐specific variables (D/H)x(D/H)βand (D/H)γassociated with positions α, β and γ of glutamic acids, for example, are helpful for interpreting the main discriminating factors. This approach provides the basis for new applications to origin recognition of fundamental constituents and metabolites

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560207

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractA fluorescent probe method using 8‐anilino‐l‐naphthalene sulfonic acid (ANS) and all‐trans‐retinol (RET) has been used to study the effects of heat treatments on the hydrophobicity of meat proteins. The number of ANS binding sites per unit protein increased from 0.75 for unheated samples to 2.12 for meat proteins heated at 100° C for 30 min. The number of RET binding sites increased from 0.13 to 0.46 with the same heat treatment. This is discussed in terms of % increase in aromatic (182.7%) and aliphatic (253.5%) hydrophobicity for meat proteins heated at 100° C for 30 min. On the other hand, the assay was able to discriminate between samples of meat proteins receiving heat treatments with 100° C intervals (between 40

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560208

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe potential for using corn (Zea mays L) husk residues (carbohydrates 827 g kg−1, lignin 66 g kg−1DM) as a carbohydrate source for the production of soluble sugars by combined chemical pretreatment and enzymic hydrolysis was assessed. Comparative investigations of acidic and alkaline pretreatments on corn husk have shown that pentose‐containing carbohydrates comprised 86–93% of the solubilised fraction. While pretreatments with 1.25 M NaOH at 25.85° C resulted in preferential extraction of hemicellulose having DP;>12, acid pretreatments 0.51 M H2SO4, 0.51 M H3PO4at (85° C) resulted in extensive depolymerisation of this polysaccharide. Xylose and low molecular weight carbohydrates were identified as the major products. Subsequent hydrolysis of the solubilised fraction with crude hemicellulase preparations yielded 40.90% fermentable sugars. When NaOH (0.02–1.25 M), H2SO4and H3PO4(0.02–0.51 M) were used as pretreatment solvents (25–85° C, 2 h), NaOH was the most effective in increasing the susceptibility of the residual husk towards enzymes, yielding 83–96% reducing sugars. This solvent solubilised up to 60.6% of the lignin and appeared to disintegrate the fibrillar structure of husk.The crystallinity of husk residues increased following the chemical pretreatments and was positively correlated with cellulose content. Enzymic hydrolysis with commercial cellulase preparations proceeded in two stages: a rapid breakdown of amorphous cellulose after which the hydrolysis rate levelled off. Similar biphasic patterns were observed for the pyrolysis temperature of cellulose. Under the most optimal conditions for husk saccharification (pretreatment with 1.25 M NaOH, 25° C, 2 h, followed by enzymic hydrolysis using a mixture of cellulase and cellobiase), 96% of the cellulose‐enriched residues was hydrolysed to reducing sugars. A cellulase preparation from Trichoderma reesei exhibited substantial hemicellulolytic activity and could, therefore, be used as the sole saccharifying enzyme preparation for

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560209

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560210

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740560211

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY