bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibition of animal and pathogenic fungal proteases by phloem exudate from pumpkin fruits (cucurbitaceae)
Authors: MacGibbon D. Bryan , Mann Jay D.
Published: October 2006

Healthy pumpkin fruits exude a gel‐forming liquid when the skin is cut. This exudate inhibits trypsin activity (EC 3.4.21.4). The inhibitor differs from p‐protein in not being precipitated by aeration nor by heating. One inhibitory zone at approximately pH 5 was detected by isoelectric focusing. Using polyacrylamide gel electrophoresis (PAGE), one major and four minor bands of inhibitor were detected. With sodium dodecyl sulphate‐polyacrylamide gel electrophoresis (SDS‐PAGE), the inhibitor moved with the tracker dye, indicating a molecular weight of less than 6000 daltons. Inhibition of trypsin activity was noncompetitive. Pumpkins of longer keeping cultivars generally had higher levels of inhibitor. The concentration of inhibitor activity in pumpkin flesh was approximately one thousandth that of phloem exudate, but exudate from the stems of pumpkin seedlings contained inhibitor at similar concentrations to fruit exudate. Protease obtained from the fungal rot regions of pumpkins was, like trypsin itself, inhibited by the exudate material. Since high levels of antitrypsin factors have been associated with disease resistance in other plant/pathogen combinations, it is suggested that this inhibition provides a protective mechanism aganst fungi causing rot of pumpkins.
The effect of guar gum in solution on diffusion of cholesterol mixed micelles
Authors: Phillips David R.
Published: October 2006

A technique was developed to measure the diffusion of cholesterol mixed micelles through solutions of guar gum. By incorporating β‐carotene in the micelles it was possible to make the suspension visible using the yellow colour for spectrophotometric quantification and to gauge the extent of diffusion. The results showed a rapid reduction in rate of diffusion with increase in guar gum concentration until above 0.2% the rate became constant and extremely slow.
The effect of salivary amylase on the viscosity behaviour of gelatinised starch suspensions and the mechanical properties of gelatinised starch granules
Authors: Evans Ian D. , Haisman Derek R. , Elson Elliot L. , Pasternak Carmela , McConnaughey William B.
Published: October 2006

The digestion of gelatinised starch suspensions by salivary amylase was studied using a viscometric assay and also by measuring the mechanical properties of individual granules. Viscosity decay as a function of time was approximately exponential. A comparison with a reducing group assay showed that a 50% fall in viscosity corresponded to the scission of about 0.05% of the glycosidic bonds. The half‐time for the reduction of viscosity by the enzyme was found to be proportional to enzyme concentration but independent of starch concentration over a wide concentration range. This result suggests that the starch concentrations used were well below the saturating point for the enzyme, which was thus largely in the free state, and that the enzyme attacked the gelatinised granules throughout their structure rather than just at the surface. Measurements of the forces required to deform individual granules supported this hypothesis by showing that the gelatinised granules lost nearly all their mechanical strength during initial contact with salivary amylase, without any apparent change in diameter.
Incidence of bitter pit in relation to the calcium content of apples: Problems and paradoxes, a review
Authors: Perring Michael A.
Published: October 2006

The problems of relating low fruit calcium concentrations in stored apples to the development of bitter pit lesions are reviewed. They include nomenclature, anomalous fruit analyses, variability in the susceptibility of apples to pitting and in the time and rate of pit development, effect of harvest date, accumulation of calcium in pitted tissue and the apparant translocation of calcium during storage from the core into zones of tissue most at risk. Recent evidence suggests that bitter pit lesions are induced by the removal of calcium from these outer zones to meet intermittent demands by the core tissue.
The determination of oil and moisture contents in commercial rapeseed samples, the former by solvent extraction
Authors: Kershaw Stephen J.
Published: October 2006

Some protocols based on standard methods for the determination of oil in rapeseed by solvent extraction are compared. Test portions of whole seed give unacceptably poor repeatability in results and ground samples should be used for analysis. Moisture content of rapeseed can equally well be determined on ground as on whole seed. The standard methods require modification to take account of these findings.
The uptake of na and its redistribution between leaves during the development and alleviation of K deficiency
Authors: Burns Ian G. , Hutsby Wendy
Published: October 2006

Changes in the concentration of Na in the shoot dry matter and in the petiole sap of individual leaves of lettuce were measured in order to determine the extent to which Na was able to replace K within the plants during K deficiency. The results were used to estimate changes in the distribution of the total ionic concentration between leaves and to make deductions about likely variations in osmotic potential within the shoots and their effect on plant growth. Measurements of Na concentration revealed both a pronounced delay in the uptake of additional amounts of Na and in its translocation within the K‐deficient plants. Sodium concentrations increased most rapidly in the young expanding leaves during the onset of K deficiency but the changes in its concentration were ultimately larger in the middle to older ones. Elevated Na concentrations in the younger leaves of K‐deficient plants also declined more rapidly than those in any of the other leaves following reintroduction of the K supply. Although the pattern of these changes broadly mirrored the corresponding changes in K concentration within the shoots there were significant reductions in the combined K+Na concentrations during the onset and development of K deficiency. The deficit in K+Na was initially greatest in the young leaves but subsequently disappeared more quickly when either the uptake of Na was increased or the K supply was resumed. Since the combined concentrations of K+Na were directly related to the changes in total ionic concentrations within the shoots, the results suggest that during K deficiency, plants adopt a strategy which reduces the effects of a decline in ionic strength at the most actively growing sites in order to minimise the damage to normal growth processes from changes in the internal osmotic pressure.
Praseodymium and copper cation‐exchange capacities of neutral‐detergent fibres relative to composition and fermentation kinetics
Authors: McBurney Michael I. , Allen Michael S. , Van Soest Peter J.
Published: October 2006

The cation‐exchange capacity (CEC) of 12 neutral‐detergent fibres (NDF) was measured using the elements praseodymium (Pr III) and copper (Cu II) at pH 3.5. CEC was positively correlated with lignin and nitrogen content as well as the lignin: acid‐detergent fibre ratio of the NDF. CEC was also measured using Pr at pH 7.0. Increasing the pH of exchange from 3.5 to 7.0 significantly increased the CEC. Lignin had a higher correlation with CEC at pH 7.0. The relationship between CEC and the fermentation rates of NDF was non‐significant. However, lag, i.e. the period of time before the initiation of fermentation, tended to decrease with increasing CEC. NDF influences the rumen ecosystem by buffering rumen pH, exchanging cations to influence osmotic pressure, and providing substrate and microenvironments for anaerobic microorganisms. Consequently, CEC needs to be measured at conditions which simulate the rumen. It is recommended that the Pr method should be used to measure CEC as it is a simple, yet robust technique that can be buffered to simulate conditions of the entire gastrointestinal tract ranging in pH from 2.0 to 7.0.
Volatile oil composition of greek mountain tea (Sideritis spp.)
Authors: Koedam Arthur
Published: October 2006

The composition of the essential oils of two species of the genus Sideritis (Labiatae) was investigated by gas chromatography‐mass spectroscopy (g.c.‐m.s.). Ca50 components were identified. The smell of the diluted oils closely resembled that of a beverage prepared from it in the Balkans, the so‐called ‘mountain tea'’.
The effects of α‐amylase inhibitors on insect storage pests: Inhibition of α‐amylase in vitro and effects on development in vivo
Authors: Gatehouse Angharad M. R. , Fenton Katherine A. , Jepson Ian , Pavey Deborah J.
Published: October 2006

Protein α‐amylase inhibitors were prepared from wheat and their effects tested against insect storage pests both in vitro against the insect α‐amylases and in vivo in insect feeding trials. Inhibitor fraction A was found to inhibit porcine pancreatic α‐amylase but not insect α‐amylases, whereas fractions B, C and D (0.28) did not inhibit porcine pancreatic α‐amylase but were strong inhibitors of digestive α‐amylases from larvae of Tribolium confusum, a storage pest of wheat products, and Callosobruchus maculatus, a storage pest of legume seeds. Fraction D, which was a single polypeptide of Mr 13 000 was the most effective inhibitor in vitro. It would appear that the degree of inhibition by the wheat α‐amylase inhibitor preparations can be correlated with the presence of the Mr 13 000 (0.28) polypeptide since the purer this polypeptide the stronger was the inhibition; fraction A which contained two polypeptides of Mr 60 000 and 58 000 caused no inhibition. The effects of fractions B and C on larval development were determined in insect feeding trials. With C. maculatus both fractions were toxic, their relative effectiveness being directly paralleled by their effectiveness observed in vitro. Only fraction C was tested against T. confusum in feeding trials. Despite this fraction being equally effective against both pests in vitro it had very little effect upon larval development of T. confusum in vivo, thus suggesting that this organism is able to detoxify the wheat α‐amylase inhibitors. As far as the authors are aware, this is the first time that the effects of identified inhibitor fractions have been monitored both in vitro and in vivo. The results, in contrast to previous proposals, suggest that selecting wheat varieties for high α‐amylase inhibitory activity may not be a very reliable criterion in selecting for insect resistance.
Effect of processing on the antinutrient content of rapeseed
Authors: Fenwick G. Roger , Spinks E. Ann , Wilkinson Andrew P. , Heaney Robert K. , Legoy Maurice A.
Published: October 2006

The effects of dry extrusion of mixtures of rapeseed and soya bean on total and individual glucosinolates, selected glucosinolate hydrolysis products, myrosinase, sinapine and tannins have been compared with those of more conventional processing, e.g. lime treatment, micronisation and ammoniation. Extrusion at 150°C effectively inactivated myrosinase but had relatively little effect on glucosinolate content unless chemicals were added before extrusion; the most effective combination, 5% alkali+1% ferrous sulphate, reduced the total glucosinolate content by 80%. Under the latter conditions very high (>30 μmol g−1 defatted meal) levels of nitriles were produced, leading to the suggestion that nitriles in addition to oxazolidine‐2‐thione and isothiocyanates be used to monitor the effectiveness of processing techniques. None of the extrusion conditions showed any significant effect on reducing sinapine or tannin contents. In view of the chemical data presented, and the probable adverse effects which the processing conditions selected have on the nutritional value of the processed meal it seems unlikely that extrusion will play a significant role in rapeseed detoxification.
The effect of dietary linoleic acid on the firmness of backfat in pigs of 85 kg live weight
Authors: Whittington Frances M. , Prescott Nicola J. , Wood Jeffrey D. , Enser Michael
Published: October 2006

Three groups of 15 female pigs were fed diets containing 0.8%, 1.1%, or 1.8% linoleic acid from 20 to 35 kg followed by 1.0%, 1.2% or 1.4% linoleic acid respectively from 35 kg to slaughter at 85 kg live‐weight. Pigs grew at similar rates on all three diets and had similar proportions of carcass fat. The mean proportions of linoleic acid in the backfat lipids were 8.6%, 11.0%, and 13.9% respectively as the amount of the diet increased. There was a significant correlation between the concentration of linoleic acid in the inner backfat lipid and P2 backfat thickness for those animals on the high and medium linoleic acid diets but not for those on the low diet. Backfat from pigs fed the high linoleic acid diet was softer than that from the other two groups of pigs which could not be distinguished using the subjective finger probe method. Using a mechanical probe backfat consistency was distinguished between all three groups and was inversely correlated (r=−0.775, P<0.001) with the concentration of linoleic acid in the lipid. However, none of the pigs had fat which was too soft for bacon production based on either consistency data or linoleic acid content. If 15% linoleic acid is taken to be the maximum acceptable in bacon, then extrapolation of the regression of linoleic acid concentration on backfat thickness suggested that only the 1.4% linoleic acid diet is likely to result in unacceptably soft fat as pigs become leaner. However, this high concentration, although frequently present in current feeds, is not necessary since it is twice that recommended for normal growth and development of pigs.
A modified indirect ELISA procedure for raw meat speciation using crude anti‐species antisera and stabilised immunoreagents
Authors: Jones Sheila J. , Patterson Ronald L. S.
Published: October 2006

Indirect enzyme‐linked immunosorbent assay (ELISA) for species identification of unheated meat materials has been modified to facilitate the use of non‐specific (unpurified) anti‐species antisera by integral assay inhibition of heterologous cross‐reactivity. Effective ELISA treatments of three antisera (identifying beef, horse and pig) and four commercial products (identifying beef, horse, pig and sheep/goat) were determined using chequer‐board microtitration assays against pure species antigens. Subsequent tests with aqueous meat extracts gave consistent absorbance differences between the homologous (high colour) and heterologous (low colour) responses and provided reliable, accurate species identification without the extensive prior purification of antisera (i.e. by affinity chromatography) previously required. This modified ELISA enabled efficient use of stabilised anti‐species sera discs, prepared initially for application in a simplified agar‐gel immunodiffusion (AGID) test; i.e. one disc (20 μl freeze‐dried antiserum) for testing two meat samples by the prescribed AGID made sufficient treated solution to test 50 meat samples on microtitre plates. Authentic species meat extracts are also stabilised on discs for convenience (reference responses and routine controls). ELISA in this form is a practical alternative to AGID screening tests or can be used in parallel back‐up tests providing sensitive results in less than 3 h on a large or small scale.
A simplified procedure for quantification of potato glycoalkaloids in tuber extracts by H.p.l.c.; comparison with ELISA and a colorimetric method
Authors: Hellenäs Karl‐Erik
Published: October 2006

An improved high‐performance liquid chromatography (h.p.l.c.) procedure for determination of glycoalkaloid levels in potato tubers has been developed in which Sep‐Pak cartridges replace the commonly used alkaline precipitation for clean‐up of tuber extracts. Glycoalkaloids are extracted from fresh tuber tissue into an aqueous medium, the extract is submitted to clean‐up and α‐solanine and α‐chaconine are quantitatively separated on a reversed phase column with ethanolamine modifier added to the mobile phase. Potato tubers were comparatively analysed for their glycoalkaloid content by this and two other methods: a recently developed immunoassay (ELISA) and a colorimetric procedure representing the traditional chemical approach. Agreement between the h.p.l.c. and the other methods was good.
Nutritional value of acid stabilised silage and liquefied fish protein
Authors: Stone Frederick E. , Hardy Ronald W.
Published: October 2006

Fish silage made by a conventional method (pH 4.0) contained a variety of active enzyme systems which not only hydrolysed fish proteins to short peptides and free amino acids, but also caused the degradation of free amino acids to ammonia and other metabolic products. Acid‐stabilised fish silage (pH 2.0) contained only those polypeptides released by endogenous pepsins with only slight accumulation of free amino acids and degradation products. Liquefied fish which was autolysed for less than 1 h at 60°C at physiological pH (6.2–6.6) and then pasteurised and acidified to pH 4.0 contained polypeptides of intermediate length which remained stable. These processes provide a means for adjusting the peptide and free amino acid content of autolysed fish protein to suit the nutritional requirements of a variety of aquatic and terrestrial species.
Production of antisera against sterigmatocystin hemiacetal and its potential for use in an enzyme‐linked immunosorbent assay for sterigmatocystin in barley
Authors: Morgan Michael R. A. , Kang Angray S. , Chan Henry W.‐S.
Published: October 2006

Highly specific antisera of high titre to sterigmatocystin hemiacetal has been produced in rabbits and used to set up a microtitration plate enzyme‐linked immunosorbent assay. Novel conjugation procedures were used in synthesis of both immunogen and the material used to make the assay solid phase. The assay has been validated for the determination of sterigmatocystin in barley—extraction conditions are such that the toxin is converted quantitatively to the more soluble hemiacetal form.
The subunit structure and stability of conglutin δ, a sulphurrich protein from the seeds of Lupinus angustifolius L.
Authors: Lilley Glenn G.
Published: October 2006

The oligomeric structure and stability of conglutin δ, the 2S sulphur‐rich lupin seed protein, has been studied. Molecular weights were determined by sedimentation equilibrium methods in the analytical ultracentrifuge. Conglutin δ2 (Mr 14 000, 2S), the most abundant form, was composed of one large (˜9600) and one small polypeptide chain linked by disulphide bonds. The minor oligomeric form, conglutin δ1 (Mr 28 000, 2.8S), was a disulphide‐linked dimer of conglutin δ2. Each form was capable of reversible association and at low ionic strength (neutral pH), the conglutin δ1 momomer associated to a homogeneous dimer (Mr 56 000, 4.1S). Calculated frictional ratios (f/f0 ˜ 1.28–1.49) suggested that the three different forms were asymmetric. Spectral studies (ORD/CD) showed that conglutins δ1 and δ2 were rich in alpha‐helix (˜38%) unlike the major 7S and 11S legume seed storage proteins. The helical structure was unusually stable both to heat and chemical denaturants; below 60°C (at neutral pH) the helix remained unaffected and only partial denaturation occurred at higher temperatures. Nevertheless, complete denaturation was achieved (at 20°C) in high concentrations of guanidine hydrochloride (greater than 6.5 M). The stability was due to the presence of disulphide cross‐links; with the addition of reducing agent, as little as 1 M guanidine hydrochloride (GuHCl) was sufficient for denaturation of the helical structure. Titration experiments showed a single buried tyrosine (pK 11.4) which could be exposed (pK 10.2) in 6 M GuHCl.
Degradation in muscle fibre‐connective tissue junctions in the spotted trevalla (seriolella punctata) examined by scanning electron microscopy
Authors: Bremner H. Allan , Hallett Ian C.
Published: October 2006

The junctions between the muscle fibres and the connective tissues of the myocommata in the spotted trevalla (Seriolella punctata Forster) were investigated by scanning electron microscopy. In prerigor muscle, the fine collagen fibrils which arise from the myocommata to form the muscle cell envelope were evident. After the fish were stored several days in ice, progressive deterioration was observed in these fibrils. The structure and the degradation was similar in nature to that reported previously in blue grenadier.
Hastening of leaf senescence in the processing of green tea leaf to black tea
Authors: Ullah Mohammed R. , Bordoloi Ashok K. , Gogoi Nogen
Published: October 2006

The current system of processing green tea leaf (Camellia sinensis) to produce black tea involves a long period, especially because of the withering process practised in acquiring leaf senescence which is essential to impart fullness to the resulting tea liquors. Hastening leaf senescence by artificial withering at temperatures favourable to enzymic transformations accelerated the process and considerably shortened the manufacture of black teas.
Comparison of methods to describe the kinetics of digestion and passage of fibre in sheep
Authors: Aitchison Elisabeth , Gill Margaret , France James , Dhanoa Mewa S.
Published: October 2006

A mathematical model is described which was developed with the objective of analysing and interpreting data from rumen‐emptying studies to estimate rates of digestion (kd) and passage (kp) in sheep offered hay once daily. It assumed that first‐order kinetics applied to digestion in and passage from the rumen within a 24 h feeding cycle. The model predictions of kd and kp were compared with rates of digestion estimated by incubation of the hays in dacron bags and rates of passage determined using chromium‐mordanted hay, in the same experiments. The predictions for rates of passage determined over the period 5–15 h postfeeding were lower than those determined from the chromium‐mordant data and the simulations indicated that the fractional rate of passage during feeding was higher than that recorded in the postfeeding period. This suggests either that more than one fractional rate constant applies within a 24 h period, or that first‐order kinetics do not apply. The estimates for kd were considerably higher than those determined in dacron bags. Evaluation of the ability of the combined dacron bag and mordant techniques to estimate extent of digestion by comparison with in‐vivo digestibility values indicated that the extent of digestion was underestimated. The predictions obtained from the rumen‐emptying data were much closer to the in‐vivo values.
Effects of eight tillage treatments on a tropical alfisol: Maize growth and yield
Authors: Lal Rattan
Published: October 2006

The effects of eight methods of preplanning tillage systems were investigated on maize growth and yield for eight consecutive crops grown from 1980 to 1983 on an Alfisol in south‐west Nigeria. The tillage systems were: (A) no‐till with residue mulch, (B) no‐till with chiselling in the row zone to 50 cm depth, (C) mouldboard ploughing followed by (fb) harrowing, (D) disc ploughing fb rotovation, (E) no‐till without residue mulch, (F) mouldboard ploughing at the end of rains, (G) mouldboard ploughing fb two harrowings with residue mulch (H) mouldboard ploughing fb two harrowings and ridging. In seasons with infrequent rains and long dry spells, seedling emergence was significantly suppressed on ridged plots (treatment H). The 1500 h soil temperature on the ridged seedbed (H) at 5 cm depth exceeded 40°C, and was about 10°C more than in no‐till with mulch (A). The oxygen diffusion rate (ODR) at 10 cm depth was the most in the no‐till mulch and the least in the furrow bottoms. The soil moisture reserve was larger in the no‐till plots than in the ploughed treatments. Plant height and vigour were adversely affected on ridges in seasons with frequent dry spells. In these seasons, maize grain yield declined with the increasing intensity of mechanical tillage. For the eight seasons, the cumulative benefits in grain yield of all the no‐till treatments were 1.76 and 0.32 tonnes ha−1 in comparison with ridges (H) and ploughed (C, D, F, G) treatments, respectively. The mean seasonal yield was 3.37 and 1.00 t ha−1 for the first and second seasons respectively. The seasonal fluctuations in grain yield were related to rainfall amount and the length of growing season.
Body composition and feed intake of young pigs postweaning
Authors: Tullis J. Bronwyn , Whittemore Colin T.
Published: October 2006

Thirty‐five female Large White pigs were weaned at 14 days of age, penned individually, given a single diet and slaughtered serially at 25, 40, 55 and 70 days of age. A control group was fed to appetite throughout while three groups were subjected to feed restriction at various ages postweaning. For the periods 25 to 40, 40 to 55, 55 to 70 days of age pigs fed to appetite gained 321 (±19.9), 532 (±35.4) and 601 (±35.5) g liveweight day−1. Pigs restricted between 25 and 55 days, followed by refeeding from 55 to 70 days, gained 192 (±14.0), 169 (±44.8) and 508 (±81.0) g liveweight day−1; pigs restricted between 40 and 55 days, followed by refeeding from 55 to 70 days, gained 425 (±42.8), 409 (±49.6) and 480 (±70.1) g liveweight day−1. A group given 200 g feed day−1 gained 42 (±4.2) g liveweight daily between 25 and 70 days. Refed groups did not differ significantly from controls in their feed intakes for the period 55 to 70 days, either in absolute intakes or in feed intake kg−1 mean liveweight. Refed pigs grew no faster, and made no greater protein gains than controls of equivalent weight; however, lipid gains were elevated.
The saponin content and sapogenol composition of the seed of 13 varieties of legume
Authors: Price Keith R. , Curl Caralyn L. , Fenwick G. Roger
Published: October 2006

The total saponin content of various legume seeds together with their sapogenol composition have been determined. Extraction of the defatted flours was effected with methanol and subsequent acid hydrolysis yielded the soyasapogenols which were analysed using gas and thin‐layer chromatography. The saponin levels ranged from 0–0.65% for defatted seed while the major sapogenol present in these saponins was soyasapogenol B. The figures obtained are compared with those previously reported and reasons are suggested for the discrepancies.
Nutritive value of rapeseed meal: Effects of individual glucosinolates
Authors: Vermorel Michel , Heaney Robert K. , Fenwick G. Roger
Published: October 2006

In the first of a series of studies on the nutritional value of rapeseed meal, rats were fed diets containing six individual glucosinolates over a period of 29 days. The diets included progoitrin and gluconapin both of which are major components of high glucosinolate rapeseed cultivars. No reduction of feed intake or growth rate was noted and thyroid weights were significantly affected only by the progoitrin diet, which also produced small increases in the weights of the livers and kidneys. There was no depression of plasma thyroid hormone levels.
The use of soya bean, sunflower and lupin seeds in the preparation of protein bases for nutritious beverages
Authors: Taha Fakhriya S. , Mohamed Samira S. , El‐Nockrashy Ahmed S.
Published: October 2006

Seed meal of soya bean, sunflower and lupin, and mixtures were examined for the preparation of protein bases suitable for nutritious beverages. Single step and successive extractions with aqueous calcium hydroxide solutions and water effect complete extraction of meal nitrogen. The calcium hydroxide extracted proteins of meal samples had an isoelectric pH of 5.0 at which 63–81% of the soluble protein was precipitated. Two successive extractions with calcium hydroxide and water had an isoelectric pH range of 4.4–4.6 and give maximum precipitation of 67% of the extracted protein. A detailed procedure is given for the preparation of creamy or light greyish coloured protein, readily soluble in water, with improved amino acid pattern.
The in‐vitro metabolism of D, L‐lactic acid by rumen microorganisms
Authors: Newbold Charles J. , Williams Alan G. , Chamberlain David G.
Published: October 2006

Bacterial and protozoal fractions, isolated by centrifugation and filtration from the rumen of sheep given various diets, were used to examine the in‐vitro metabolism of both the D(‐) and L(+) isomers of lactic acid. The rate of disappearance of both the D‐ and L‐lactic acid isomers in protozoal incubations was up to 15 × higher than the rate of disappearance in bacterial incubations, which was relatively constant at between 0.04 and 0.073 lactate per g protein per h for cells recovered from animals receiving various diets. However, the rate of lactate disappearance in the protozoal fraction varied from 0.133 g per g protein per h with a barley/hay diet to 1.12 g per g protein per h with a silage diet. L‐Lactate disappeared more rapidly than the D‐lactate in all protozoal incubations. It was confirmed that the disappearance of lactate associated with the protozoal fraction did not originate from adherent or associated bacteria.

Further fractionation of the protozoal population by differential filtration showed that lactate only disappeared when incubated with entodiniomorphid protozoa and not with holotrich protozoa.

Endogenous propionate and butyrate production by the entodiniomorphid ciliates was stimulated by 100% in the presence of lactate. It was calculated that on certain diets up to 30% of the volatile fatty acids formed from lactate could be protozoal in origin.
Variation in the natural enrichment of 15N in apple trees and soils
Authors: Atkinson David , Johnson Martin G. , Crisp Carol M. , Maude Gillian , Mercer E. Reuben
Published: October 2006

Leaf, wood and soil materials taken from an established apple orchard contained 15N in excess of atmospheric levels. Enrichments were highest (0.380 atom%) in surface soil and lowest in leaves (0.376 atom%). Enrichments varied over the course of a single season, being generally higher in late summer (August) and autumn (November) than in June and July. The patterns of variation in enrichment suggested that assessments of tree to tree variation for leaves should be made; but time variation for surface soil would be more important.
Physico‐chemical changes in guava (Psidium guajava L.) during development and maturation
Authors: Yusof Salmah , Mohamed Suhaila
Published: October 2006

Guava of the Vietnamese variety is commercially grown in Malaysia. To obtain a better understanding of the fruit, the physical and chemical changes occurring during development and maturation were studied.

The weight increase, reduction in hardness, total pectin content, and changes in glucose and ascorbic acid levels showed a sigmoid curve. The maximum weight and glucose increases occurred between weeks 10 and 12. Reduction in hardness, and changes in pectin and ascorbic acid content occurred most between weeks 12 and 14. Reduction in chlorophyll content, and increase in fruit diameter, fructose content and water soluble pectin fraction showed a more linear change. Fructose level was highest among the three sugars (fructose, glucose and sucrose) monitored during maturity. The density of the fruit increased rapidly at the beginning, remained constant between weeks 4 and 12 and then decreased again.

The moisture content increased rapidly at first, followed by a more gradual increase and remained constant after week 14. The pH and percentage titratable acidity of the Vietnamese guava fluctuated, being fairly acidic at week 4 (pH 4.5), least acidic at week 10 (pH 5.4) and acidic again on maturity (pH 4.05). The tannin level was high in immature guava but dropped drastically after week 8, and remained at a constant low level after week 10. Soluble pectin increased during development and maturity. Insoluble pectin (NaOH soluble) increased during development but was converted to soluble pectin during maturity (after week 14).
Nutritional evaluation of high protein genotypes of pearl millet (Pennisetum americanum (L.) leeke)
Authors: Singh Pheru , Singh Umaid , Eggum Bjorn O. , Kumar Kambham A. , Andrews David J.
Published: October 2006

Three high protein (HP) inbred lines (700112, WC‐190 and B‐816) of pearl millet were studied for their nutritional quality and the results compared with those of normal protein varieties. The protein content of HP lines showed an average increase of 60% but the starch and soluble sugars together and the fat content decreased by 40 and 20%, respectively. Total dietary fibre of the HP lines was about 10% higher. A decrease (about 20%) in the albumin fraction was associated with an increase in prolamin in HP lines. The amino acid composition of the HP lines remained normal except for an approximately 16% decrease in lysine. However, the total amount of lysine in the sample increased by an average of 37%, as a result of a substantial increase in protein content. True protein digestibility was very high for each line but, expectedly, the biological value was markedly lower. The values for utilisable protein were highest for high protein genotypes. Digestible energy was high in all the genotypes, although slightly lower values were obtained for the HP lines; this was attributed to the fibre fractions.
Characteristics and composition of the pulp oil and cake of the African pear, Dacryodes edulis (G. don)
Authors: Lam H. J. , Omoti Umoru , Okiy Dere A.
Published: October 2006

The pulp of the African pear, Dacryodes edulis, was investigated for its nutritional quality and oil characteristics. The crude protein, fat, fibre and carbohydrate contents were 25.9, 31.9, 17.9 and 13.5%, respectively. The pulp was found to contain significant levels of Ca, Mg, K and P. The fatty acid profiles showed a saturated fatty acid content of 50.85% and an unsaturated fatty acid content of 49.14%. The predominant fatty acids were palmitic and oleic acids. The saponification value and iodine value were 201.4 and 59.6. The amino acid profiles showed high contents of the essential amino acids lysine, leucine and threonine.
Iron availability from bread—traditional versus Chorleywood
Authors: Fairweather‐Tait Susan J. , Symss Lisa L.
Published: October 2006

The effect of two different baking procedures, traditional long fermentation and the Chorleywood process, on iron availability from white bread was measured in rats using 59Fe as an extrinsic label and whole‐body counting. There was no significant difference in Fe absorption between the two breads; the availability of added Fe (reduced Fe powder) was similar to that of FeSO4.
Protease inhibitors in germinating echinocloa (Echinocloa fruneutacea) seeds: Changes in protease inhibitory activities during germination
Authors: Udupa Saraswati L. , Pattabiraman Thillaisthanam N.
Published: October 2006

Antitryptic activity in echinocloa seedlings disappeared completely by the seventh day during germination, whereas antichymotryptic activity remained at a level comparable with that of the dormant seeds. Purified trypsin/chymotrypsin inhibitor from dormant echinocloa seeds was used as a substrate to study the nature of proteases arising during germination. A carboxyl protease localized in the root portion of the seedlings was responsible for the inactivation of the seed inhibitor with reference to the loss of antitryptic activity, and a thiol protease diminished its antichymotryptic activity in vitro. The shoot portion of the seedlings contained both antichymotryptic activity and antitryptic activity. The root extract preferentially destroyed the antitryptic activity of the shoot extract. The data suggest that the trypsin/chymotrypsin inhibitor of echinocloa seed is inactivated and mobilized during plant growth and that a new inhibitor appears in the shoot portion of the plant during growth.
Effects of plant population on soil structure, soil moisture depletion and on yield of cassava (Manihot esculentd) on an Ultisol in Southeast Nigeria
Authors: Opara‐Nadi Oliver , Lal Rattan
Published: October 2006

The effects of four cassava populations (8, 10, 13 and 20 × 103 plants per ha−1) on soil physical properties, moisture retention characteristics, moisture potential profiles and moisture depletion patterns were compared with uncropped plots receiving no cultivation of an Ultisol in the humid region in eastern Nigeria. The growing of cassava decreased the bulk density of 0–10 cm depth by 17% in comparison with the uncultivated soil (1.53 Mg m−3). The bulk density of the 10–20 cm depth was higher for the cropped than the uncropped control plots. The moisture retention below a suction of pF 2.4 for 0–10 cm depth was less for the uncultivated control than for soil growing cassava. The reverse was found in moisture retention characteristics of the 20–40 cm depth especially for low suction ranges of pF below 0.8. The 0–10 cm soil layer of uncropped control dried more rapidly than the cropped soil. Below 10 cm, however, cassava depleted moisture reserves more rapidly than in uncropped control. The effect of plant population on soil moisture depletion was more conspicuous within than between rows. Significant differences in water flux and in water uptake from different horizons were observed among various population densities. The total water loss was the highest for the least plant population for the between‐row zone, and for the highest population for the within‐row zone. Plant population had no effect on tuber and stalk yield.
Seasonal variations of chemical composition in prickly pear (Opuntia ficus‐indica (L.) miller)
Authors: Retamal Norma , Durán José M. , Fernández Jesús
Published: October 2006

The moisture, ash, free reducing sugar, starch, ether extractive, crude protein, amino acid and the heat energy contents of young and mature cladodes of Opuntia ficus‐indica, with or without fruits, are described. The measurements were made in each of the following stages of development: vegetative growth (March), full vegetative development, and at the beginning of fructification (October). Independently of developmental stage (different cladode types) the highest values were reached always in young cladodes in the following months: moisture content in March and October; ash and free reducing sugars in March; starch and ether extractive in September and October; crude protein in March and July. Crude fibre was maximal in September and global heat energy in October. The nutritive and caloric value of cladodes are compared to other products used for livestock nutrition.
Aerobic stability of wheat silages in a subtropical climate
Authors: Lisker Norberto , Taari Eli , Ashbell Gilad , Henis Yigal
Published: October 2006

Batches of wheat silage stored under farm conditions in bunker silos at two locations in Israel were exposed to air for up to 3 days in order to study their aerobic stability. Each batch was examined five times at approximately two month intervals during 1983/84 for changes in dry matter, pH, watersoluble carbohydrates, in vitro digestibility, ash, crude protein, ammonianitrogen, glucose, crude fibre, volatile fatty acids, lactic acid, moulds, yeasts and aerobic bacteria. Consistent changes in silage composition after 3 days of aerobic exposure were noticed with an increase in dry matter and in mould counts, and a decrease in acetic acid and in most cases also in lactic acid. Yeasts and bacteria had a tendency to increase during the 3 days of air exposure.

Experiments carried out under laboratory conditions with silages kept at 26°C in an atmosphere of 99% RH showed that after 3 days there was only a slight increase in dry matter, a decrease in acetic and lactic acids, watersoluble carbohydrates and ammonia‐nitrogen, and an increase in the total number of micro‐organisms. Only after 7 days did the deterioration process start.
Protein quality of chapathies preserved with sorbic acid and stored for six months
Authors: Prasad N. Narayan , Santhanam K. , Rao M. V. Rama
Published: October 2006

The protein quality of chapathies preserved with sorbic acid and stored for six months was evaluated by the standard method of Protein Efficiency Ratio (PER) and compared with that of fresh chapathies. The food consumed and weight gained by the animals fed preserved chapathies were significantly lower than the corresponding values of the fresh chapathy group. However, the PER and Feed Efficiency Ratio (FER) values did not show any differences, hence it is concluded that the preservation treatment has no effect on the protein quality of chapathies.
Purification and characterisation of cathepsin D from the digestive gland of the pelagic squid Todarodes sagittatus
Authors: Gildberg Asbjørn
Published: October 2006

A proteinase from the digestive gland of squid (Todarodes sagittatus) was purified from a neutral extract by ammonium sulphate fractionation, S‐Sepharose chromatography and gel filtration on Sephadex G‐75. Inhibition by pepstatin showed that the enzyme is an aspartic proteinase. The enzyme is fairly stable in the pH range 2.5‐7, and optimum pH for haemoglobin digestion is 3.7. Combined results from gel filtration and sodium dodecyl sulphate electrophoresis indicate a molecular weight of 38 kDa, and that the enzyme consists of two different subunits with molecular weights approximately 10 and 28 kDa. Analytical electrofocus‐ing showed an enzyme pi of 8.5. As judged from the physical properties and the amino acid composition, it is concluded that the enzyme is a cathepsin D. This enzyme probably counts for the major part of proteinase activity in the digestive gland.
Biomass composition of a Candida pseudotropicalis new strain grown on crude sweet whey
Authors: Michel Agnès , Poncet Simone , Jacob Francois , Perrier Joseph
Published: October 2006

A yeast strain isolated from whey and named Candida LY 496 was grown continuously on crude sweet whey. The obtained biomass had a crude protein content of 47%. The amino acid composition was determined by high performance liquid chromatography (h.p.l.c). All essential amino acids were present and among them lysine was predominant (11.8%). The total nucleic acids of the biomass was 6.4%. Lipids represented 5% and the fatty acids 2% of the dry matter; 75% of the fatty acids were unsaturated, and linoleic acid constituted only 1% of the total fatty acids. Niacin and vitamin B2 were the most abundant vitamins of the B group. Therefore Candida LY 496 biomass could be incorporated in animal food intakes.
The trisaturated glycerides of bovine milk fat
Authors: Banks William , Christie William W. , Clapperton John L. , Girdler Anne K.
Published: October 2006

Dietary manipulation has been used to produce a range of milk fats differing substantially in fatty acid composition. These fats have then been fractionated by preparing the mercuric acetate adducts to produce the trisaturated glyceride components. The method produced fractions having a very low unsaturated fatty acid content. Calculations suggest that the trisaturated fractions contained appreciably less 4:0 than would be predicted; with a compensating increase in the relative proportion of long‐chain fatty acids. The triglyceride distributions of the parent fats were shown to be markedly bimodal in nature, whereas those of the trisaturated glycerides were unimodal or exhibited fairly small second peaks. Calculations based on the proportion of unsaturated fatty acids present in the milk fat suggest that the strategy of triglyceride synthesis within the bovine mammary gland is not to reduce the production of trisaturated glycerides to a minimum unless only small amounts of unsaturated fatty acid are available. The melting spectra, determined by differential scanning calorimetry, of the parent milk fats were quite different from those of the trisaturated components, with the latter fraction having little material melting below 0°C, but complete melting occurred at slightly higher temperatures. The positions of the major endotherms in the melting spectra of the parent fats on the one hand and the trisaturated fractions on the other indicate that extensive solid solution occurred between the unsaturated and trisaturated components of the parent fat. The heat of melting of the trisaturated glycerides was much greater than that of the parent fats.
Seed ergot alkaloid contents of Ipomoea hederifolia, I. quamoclit, I. coccinea and I. wrightii
Authors: Wilkinson Robert E. , Hardcastle Willis S. , McCormick Cynthia S.
Published: October 2006

Ergot alkaloides were extracted from seed of native, wild‐type morning glories (i.e. Texas red morning glory (Ipomoea hederifoliaL.), cypress vine morning glory (I. quamoclit L.), red morning glory (I. coccinea L.) and palmleaf morning glory (I. wrightii Gray) and quantified by spectrophotometry as ergonovine maleate equivalents. A horticultural variety (I. tricolor Cav. cv. Heavenly Blue) was utilized for comparison and contained 0.052% total alkaloids in the seed. Total ergot alkaloids in these four native, wild‐type morning glories ranged from 0.003 to 0.005% (i.e. 5.97 to 9.77% of the alkaloids found in Heavenly Blue seed) and were not present in sufficient quantity to induce any psychotomimetic hazard. Major alkaloids found in these wild‐type morning glory species were separated and identified by two‐dimensional thin‐layer chromatography and co‐chromatography with authenticated standards. Alkaloids identified included chanoclavine, elymoclavine, penniclavine, ergonovinine, agroclavine, ergonovine, ergosine and ergosinine. Alkaloids varied between morning glory species.
The effect of extrusion cooking on iron absorption from maize and potato
Authors: Fairweather‐Tait Susan J. , Symss Lisa L. , Smith Andrew C. , Johnson Ian T.
Published: October 2006

Maize and potato samples were extruded at high temperature (120–140°C) and pressure (500–900 p.s.i.) and the effect on Fe absorption was measured by whole body counting in rats using 59Fe as an extrinsic label. The equipment used in the extrusion process considerably increased the Fe content of the products but the processing itself had no effect on % Fe absorption: maize, non‐extruded 59.6 (SEM 1.5), extruded 59.9 (SEM 1.7); potato, non‐extruded 41.5 (SEM 1.5), extruded 35.5 (SEM 2.8). A similar percentage of Fe was absorbed from a commercially available extruded maize snack: 63.0 (SEM 1.2). The Fe in maize was 85.90% and in potato 70.82%, as well absorbed as Fe from FeSO4. These studies indicate that extrusion cooking has no effect on the amount of Fe absorbed and that any Fe picked up in the extrusion process is as available for absorption as the endogenous Fe in the food.
Investigation of flavour defects in Asian cocoa liquors
Authors: Baigrie Brian D. , Rumbelow Stephen J.
Published: October 2006

The role of individual organic acids in relation to the excessive acidity exhibited by Asian cocoa liquors has been investigated.

Volatile fatty acids (other than acetic) did not affect significantly either acidity scores or liquor pH. Variations in levels of specific water soluble, acids, viz. lactic, citric and acetic, were found to be particularly important in accounting for differences in both acidity scores and pH values between Asian liquors and a West African liquor. However, only when adjustments were made for differences in levels of total water‐soluble acids between the liquors did sensory scores for acidity and pH values achieve parity.

Volatile flavour analysis using headspace sampling techniques indicated that 2‐phenylethyl acetate and, to a lesser extent, linalool were important contributors to the fruity flavour attribute exhibited by Asian cocoa liquors.