摘要:

AbstractThe structure of mixed‐linked β‐glucans was studied in three hull‐less barley (Hordeum vulgare L) cultivars, Arizona, a waxy‐starch genotype with high mixed‐linked β‐glucan content giving hypocholesterolaemic responses in chickens, and two genotypes with normal mixed‐linked β‐glucan contents. One of these, Washonupana, also a waxy‐starch type, reduces blood cholesterol whereas the other, Franubet has no effect. When a ground sample was suspended in water, Arizona and Washonupana gave highly viscous slurries whereas Franubet gave low viscosity. This viscosity was greatly reduced by addition of endo‐β‐glucanase. Arizona gave the highest yield of water‐soluble mixed‐linked β‐glucans, while the ratio of 1.3 to 1.4 linkages (1:26) was very similar in this fraction for all barleys.13C‐NMR indicated that these water‐soluble fractions from all three barleys had essentially the same repeating sequence patterns and that 1.3 linkages occurred singly. Gel filtration established that the water‐soluble mixed‐linked β‐glucans in Washonupana had the highest average molecular weight and Franubet the lowest. The hypocholesterolaemic responses observed in chickens were attributed to viscous conditions within the gastrointestinal tract, and this was a function of the content and molecular weight of the mixed‐linked β‐glucans and o

ISSN:0022-5142    

DOI:10.1002/jsfa.2740520402

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractRate of moisture removal increased with temperature in tomato (Lycopersicon esculentumMill) pieces dried, using through‐flow and cross‐ flow air patterns, in a pilot‐scale cabinet dryer at 60, 70 and 80°C with an air velocity of 1.75 ms−1. Moisture removal was faster for through‐flow than for cross‐flow drying at each temperature. Lower moisture content and improved appearance were achieved by dipping, for 3 min, tomato slices in NaCl (300 g litre−1) or in a solution containing 9 g litre−1potassium metabisulphite and 100 g litre−1NaCl, or by adding NaCl (33 g kg−1) to tomato slurry prior to sun or oven drying. Nigerian‐type sauces made from pretreated oven‐dried tomatoes were considered acceptable, though inferior to that made

ISSN:0022-5142    

DOI:10.1002/jsfa.2740520403

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractParenchyma of a range of apple varieties was either sectioned in a cryotome and observed under a light microscope, or freeze dried and viewed under a scanning electron microscope. The morphology of the material varied according to the direction from which it was viewed. This phenomenon, known as anisotropy, increased from the outside to the inside of the cortex. The periphery consisted of radially flattened or spherical cells (50 μ dia) with spherical intercellular spaces. Towards the interior the cells increased in size (300 μ dia) and were radially elongated, organised into radial columns. In between these columns were radially elongated spaces up to 3 mm long and 100–200 μ wide. The aspect ratio of the intercellular spaces increased almost linearly from outside to inside (1 to 9, depending on variety). The volume fraction of the cells similarly incre

ISSN:0022-5142    

DOI:10.1002/jsfa.2740520404

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractIn an experiment with three winter wheat (Triticum aestivum L)varieties (Splendeur, Hobbit and Maris Huntsman) cultivated after anthesis in a growth chamber, the upper part of the ear was removed on several dates after anthesis (halving). The remaining grains accumulated more nitrogen, especially between days 5 and 25 after anthesis; the increase depended on variety, the date of halving and the stage of development. The relative composition of the protein was also affected, since the amino acid composition of the grain varied. In the remaining grains the relative amounts of glutamate and, in general after 15 days, those of proline and phenylalanine increased; by contrast those of aspartate, lysine and arginine, among others, decreased. The response of the three varieties was similar. At maturity, the magnitude of the response was related to the variations occurring in the nitrogen (% DW). The stage of development in which the grain accumulated nitrogen supplement did not affect the regressions between the relative amounts of each amino acid and the nitrogen (% D W). However, when the ears were halved on day 25 after anthesis, the relative amounts of glycine, lysine and arginine tended to be slightly higher, especially in the case of Hobbit, than the values that would correspond to these regressions. The departure from regression increased with increasing accumulations of nitrogen in the grain between day 25 and maturity.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740520405

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractFour sheep fitted with cannulas in the rumen and proximal duodenum were used to compare the digestion of two diets in an experiment conducted according to a two‐period reversal design with 28‐day periods. Chopped hay (400 g day−1) was given with either 500 g barley and 120 g soya bean meal day−1or 500 g naked oats and 100 g soyabean meal day−1. Digestion in the stomach, duodenal flow and faecal excretion of chemical constituents were measured using chromium‐mordanted straw as a marker. As a consequence of compositional differences between the cereals, daily intakes of neutral detergent fibre (NDF), acid detergent fibre (ADF) and total fatty acids were 331 and 295, 172 and 161, and 12·1 and 36·9 g for the barley and the naked oats diet respectively.Dietary substitution of naked oats for barley reduced (P<0.05) the extents to which NDF and ADF were digested in the stomach. There was an associated decrease (P<0.05) in the proportion of acetic acid in the rumen volatile fatty acids, and the proportion of propionic acid tended to be increased. Rumen ammonia N concentration was reduced (P<0.05). Duodenal passage of total N and non‐ammonia N was increased (P<0.001), as was that of total fatty acids (P<0.05),when naked oats were given but there were no significant differences between diets in N or total fatty acid digestibilities in the total tract.The results show that dietary substitution of naked oats for barley can alter ruminal digestion through effects that appear to derive from the associated increase

ISSN:0022-5142    

DOI:10.1002/jsfa.2740520406

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe apparent ileal digestibility of the main constituents of a diet based on peas (Pisum sativum L) and of the amino acids of these peas was determined with three pigs which were surgically modified to create an ileo‐rectal anastomosis with complete isolation of the large intestine, and three pigs surgically fitted with a T‐cannula at the terminal ileum. The animals first received a diet containing ground peas as the sole protein source and then a protein‐free diet which permitted the estimation of the excretion of endogenous amino acids at the level of the ileum and the calculation of the true digestibility of pea amino acids. The apparent digestibility of organic matter, crude protein, cell walls, starch and energy was systematically higher in cannulated pigs, but the difference was only significant for cell walls (P<0.05). For the amino acids the difference was only significant for the apparent as well as the true digestibilities of methionine, proline and tryptophan. It seems that the observed difference originates from the collecting method for the cannulated pigs. The nitrogen balance has shown that with pigs an ileo‐rectal anastomosis emitted less urinary N and more faecal N (P<0.05) than cannulated pigs. On the other hand, the estimation of the biological value and of the net protein utilisation of pea proteins was the same for both kinds of pig (

ISSN:0022-5142    

DOI:10.1002/jsfa.2740520407

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractAliphatic nitro compounds (3‐nitropropanoyl esters of glucose)in the roots ofLotus pendunculatusCav were determined by analysis of nitrite released on alkaline hydrolysis. This method was validated for quantitation of both total nitro compounds in ethanolic extracts and for individual components from TLC separations. The profiles of nitro compounds before and after maceration of root tissue were compared. A doubling of unesterified 3‐ nitropropionic acid and an associated increase in the putative monoester and 2, 6‐diester concentrations were detected, indicative of some hydrolysis of higher homologues. However, more than 75% of the 3‐nitropropionic acid remained esterified after the process of crushing root tissue to mimic predation by root‐feedin

ISSN:0022-5142    

DOI:10.1002/jsfa.2740520408

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe non‐volatile, water‐soluble constituents of black tea were studied by using reversed‐phase HPLC with a photodiode‐array detector, using a linear gradient developed for this purpose. The data generated by this detector from one injection of a black tea liquor allowed information on the nature and purity of the constituents to be obtained. The following constituents were identified by the spectral data and the retention times given by reference compounds: caffeine, theobromine, (−)‐epicatechin gallate, (−)‐ epigallocatechin gallate, gallic acid, chlorogenic acid (5‐O‐caffeoylquinic acid), p‐coumaroylquinic acid, quercetin 3‐glucoside, quercetin 3‐rhamnosylglucoside, kaempferol 3‐rhamnosylglucoside, and theaflavin digallate. Other peaks were classified by spectral data, but without reference compounds conclusive assignments could not be made. Finally, a group of peaks could be classified as coloured phenolic pigments, and tentative

ISSN:0022-5142    

DOI:10.1002/jsfa.2740520409

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractDifferent parts of theDieffenbachia maculataSchott plant have been found to possess amylase inhibitor activity. The inhibitor has been found to be non‐dialysable and relatively heat‐stable. Studies with crude extracts ofD maculataplant indicate that the inhibitor is of the non‐competitive type and is active against human salivary amylase, porcine pancreatic α‐amylase, Bacillus subtilis α‐amylase and sweet potat

ISSN:0022-5142    

DOI:10.1002/jsfa.2740520410

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractA number of β‐carbolines whose nitroso derivatives are known mutagens and carcinogens are formed in cooked and processed foods. In this work the formation of N‐nitroso derivatives from 1‐substituted‐1,2,3,4‐tetrahydro‐9H‐pyrido[3,4‐b]indole‐3‐carboxylic acid (1‐R‐THBC‐3‐COOH) and nitrite in aqueous solution was studied. The effect of reaction pH, nitrite concentration and duration of the reaction was evaluated. The yield of N‐nitroso‐1‐R‐THBC‐3‐COOH at 37°C was enhanced at low pH(about pH 2) and reached a maximum within 1 h when the stoichiometric amount was used in the reaction. Formation of the nitroso derivative was detected even when only

ISSN:0022-5142    

DOI:10.1002/jsfa.2740520411

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY