摘要:

AbstractThe effects of a 3‐min dip in various concentrations (0–1–100 mg litre−1) of a triacontanol emulsion on sprout growth from single‐eye pieces of seed potato (Solanum tuberosumL) tubers were assessed after 10 days' growth in acid‐washed sand. Treatment effects were compared with those resulting from immersion for 3 min in a mixture of gibberellic acid (6 mg litre−1) and ethrel (4 mg litre−1).Triacontanol dips were more effective than gibberellic acid and ethrel. Treatments increased the fresh weight of sprouts but had little effect on sprout number per tuber fragment. The optimum concentration of triacontanol wa

ISSN:0022-5142    

DOI:10.1002/jsfa.2740500102

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractChanges in quality parameters of crush, tear and curl (CTC) black clonal teas due to variations in altitude within a radius of 10 km were determined. There were significant (P = 0.05) changes in all the quality parameters due to areas of production despite the short sampling radius. The Group I volatile flavour compounds (VFC) increased with decrease in altitude whereas Group II VFC and flavour index (FI), theaflavins (TF), thearubigins (TR) (except in clone TN 14‐3) and caffeine increased with increase in altitude. The tasters' evaluation also increased with increase in altitud

ISSN:0022-5142    

DOI:10.1002/jsfa.2740500103

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe β‐glucan degrading ability of several commercial crude enzyme preparations was determined using three different assay procedures. The assays were based on the ability of the enzymes to reduce the viscosity of a β‐glucan solution, to produce reducing sugars from β‐glucan or to produce a blue‐coloured solution upon hydrolysis of azo‐barley‐glucan.Regression analysis showed that the relationship between the relative improvements in weight gain of chicks fed a barley‐based diet that was supplemented with different concentrations of different enzyme and in‐vitro enzyme activity when the azo‐barley‐glucan and reducing sugar assays were used was quadratic. A linear relationship was observed for the viscosity method. The R2values for both weight gain and feed to gain ratio were highest for the azo‐barley‐glucan method but the other methods yielded similar values under appropriate assay conditions (ie concentration of enzyme). The azo‐barley‐glucan method, nevertheless, is the assay recommended as it is by far the simplest of the three assays and it yields

ISSN:0022-5142    

DOI:10.1002/jsfa.2740500104

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractCell walls from leaves and stems of three tropical grasses (Setaria ancepscv Nandi (Schumach) Moss), pangola grassDigitara decumbensStent and spear grassHeteropogon contortus(L) Beauv ex Roemer&Schultes were extracted with alkali, and ether‐soluble fractions were prepared from the acidified solutions. Cyclobutane dimers derived from p‐coumaric acid (CA: 3‐(4‐hydroxypheny) propenoic acid) and ferulic acid (FA: 3‐(4‐hydroxy‐3‐methoxyphenyl) propenoic acid) were found in all plant residues. Structural information on the dimers was obtained by gas chromatography‐mass spectrometry. Stem cell walls differed from those of leaf in having major dimer components which contained residues tentatively identified as coniferyl alcohol (3‐(4‐hydroxy‐3‐methoxyphenyl)‐2‐propen‐l‐ol). Species differences in leaf cell wall cyclodimers were evident. Pangola and setaria grasses had dimers mainly derived from FA, whereas spear grass had over 70% of dimers derived from CA. Di‐esterification of some dimers in the cell walls was confirmed by the release of dimers containing the reduced forms of CA and FA (coumaryl and coniferyl alcohols respectively) when leaf cell walls were extracted with borohydride. Head to tail dimerisation giving derivatives of truxillic acid (t‐2, c‐4‐diphenyl‐r‐l, t‐3‐cyclobutanedicarboxylic acid) predominated, although evidence was obtained for the presence of head‐to‐head coumaric acid dimers (derivatives of truxinic acid, t‐3, t‐4‐diphenyl‐rl, c‐2‐cyclobutanedicarboxylic acid) in setaria stem and spear grass leaf. The results suggested that cyclodimers in grass cell walls occurred in cross‐linking structures of varying complexity between macromolecules, where they would possibly contribute to fibre strengt

ISSN:0022-5142    

DOI:10.1002/jsfa.2740500105

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractProtocatechuic,p‐hydroxybenzoic, vanillic, caffeic,p‐coumaric and ferulic acids were identified and quantified in bark, stem and leaf of the pigeon pea plant (Cajanus cajan(L) Millsp). Glycerol, erythritol, threitol, arabinitol, xylitol, mannitol, galactitol, glucitol,myo‐inositol, glucose, fructose and sucrose were the alditols, cyclitols and free sugars present in varying amounts in the three parts of the plant. Uronic acid, ash, Klason lignin and polysaccharides in the plant fractions were determined on the extractive‐free dried materials. The stem and bark contained 40·1 and 39·2% of α‐cellulose,

ISSN:0022-5142    

DOI:10.1002/jsfa.2740500106

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe fermentation of apple pomace to ethanol via solid state fermentation has been studied usingSaccharomyces cerevisiae, S. diastaticus, Pichia fermentans, Candida utilisandC tropicalis. The effect of nitrogen, phosphate and trace elements has been compared in selected strains (S cerevisiaeT2 andS diastaticus) on the basis of the fermentation efficiency of apple pomace. An improvement in fermentation efficiency was observed with both the strains on adding various phosphates, nitrogen sources or trace elements. However, the extent of stimulation in most cases was higher when the test strain wasS diastaticus.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740500107

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractAn HPLC method suitable for the determination of canavanine and canaline in jack beans (Canavalia ensiformis (L)DC), chick serum and excreta is described. Canavanine and canaline at ‘on column’ levels of 1–300 pmol were readily detected and quantified fluorimetrically as their orthophthaldehyde (OPA)‐2‐mercaptoethanol adducts. Linearity of response was obtained for both amino acids. Good recoveries of supplemental canavanine and canaline (mean recovery = 97.5%) were also obtained for both amino acids. Analysis time for canavanine was about 6 min using an ODS‐Hypersil column (dp = 3 μm; 5 mm id by 100 mm long). Analysis of both amino acids simultaneously using a Spherisorb ODS2 column (dp = 5 μm; 5 mm id by 160 mm long) took about 8 and 40 min respectively. The Spherisorb column did not prove satisfactory for the analysis of canavanine in serum. Canavanine was present in jack beans and the serum of chicks fed jack beans but canaline was not detected in either. Canavanine and canaline were not detected in excreta from chicks fed a j

ISSN:0022-5142    

DOI:10.1002/jsfa.2740500108

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractSix starches (wheat, kidney bean, rice, corn, amylopectin and amylose) were fermented in vitro with mixed human faecal microbiota for 2, 4, 6, 8, 12 and 24 h to determine differences in rates of fermentation, and production of short chain fatty acid (SCF A) and gas. The starches differed significantly in rates of fermentation with wheat and rice starches being completely fermented by 12 h whereas all other starches had disappeared by 24 h. However, individual and total SCF A production g−1starch fermented did not differ with starch source. Gas production was significantly correlated with SCF A production (P<0.0001). Although all starches were 100% fermentable by 24 h and produced similar types and quantities of SCF A, differences in the profiles, ie rates of gas and SCF A production, were observe

ISSN:0022-5142    

DOI:10.1002/jsfa.2740500109

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractKilishi is a sun‐dried traditional African meat product whose origin is lost in antiquity, but there is a dearth of scientific information regarding its physical, chemical and nutritional attributes and method of processing. This paper reports results of preliminary work carried out to study ingredient formulation, drying characteristics, chemical composition, taste‐panel evaluation and lipid stability at room temperature for 60 weeks. Results of two 4‐kg batches ofkilishiformulated using beef showed that fresh slices (0.17 ± 0.05 cm thick) gave a final product (0.31 ± 0.05 cm thick) consisting of 46.3% beef and 53.4% non‐meat ingredients. Proximate chemical composition in the finished product (g kg−1) was 75 ± 3.2 moisture, 502 ± 19 protein, 178 ± 2.5 fat and 96 ± 1.1 ash. The production process involved two drying stages. In the first, with the product before infusion, the critical moisture content was 1.75 kg H2O kg−1solid, and in the second, after infusion, the moisture content before drying was below the critical moisture content of the fresh meat. The formulated product was organoleptically superior to a commercial sample and was remarkably stable given an initial 2‐thiobarbituric acid test number of 1.53 and of 2.01 after

ISSN:0022-5142    

DOI:10.1002/jsfa.2740500110

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe gross composition and amino acid content of the proteins of barley, corn, rye and wheat grains were determined. Leaf protein concentrates (LPC) were produced from the green matter of clover, lucerne, barley and ryegrass using standard methods and analysed as for the cereal grains. Each cereal was mixed with each concentrate at a protein ratio of 2:1, respectively. The chemical score (CS) and essential amino acid index (EAAI) of the cereals, the protein concentrates and their mixtures were calculated. The biological value (BV) and true digestibility (TD) of all proteins were determined on rats using the Thomas‐Mitchell balance method.LPC proteins contained more lysine (4.6–6.0%) but less cystine than cereal proteins (2.8–3.8 and 2.3–2.7 g per 16 g N, respectively). The CS and BV of LPC proteins were low (30–40 and 44–58, respectively) because of the low cystine content. Mixing cereals with LPC improved the CS, EAAI and BV of their proteins. The BV of the protein mixtures was in almost every case higher than that of either protein alone, but the digestibility of the cereal proteins was reduced as a result of admixture with LPC, especially with

ISSN:0022-5142    

DOI:10.1002/jsfa.2740500111

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY