Thermodynamic compatibility of proteins in aqueous media. Part. I. Phase diagrams of some water – protein A – protein B systems

The thermodynamic compatibility of proteins belonging to different classes according to Osborne has been investigated in aqueous media. Phase equilibrium for water - ovalbumin - soybean globulin fraction, water - ovalbumin - casein, water - casein - gliadin and water - casein - soybean globulin fraction systems has been investigated. The data obtained were analysed according to the theoretical concepts of Scott, Patterson and Prausnitz concerning the effect of polymer molar masses and the solvent quality on the phase equilibrium in similar systems. The analysis performed indicates that these concepts can be applied to the water - protein A - protein B systems. The phase equilibrium in water - protein A - protein B systems has some distinctive features as compared to that in systems containing two synthetic polymers in the single solvent. Firstly, proteins are usually compatible in a broader concentration range as compared to common polymers. Moreover, the separation of water - protein A - protein B systems into two phases often results in a considerable concentration of one of the protein components. Apparently, the latter fact can be associated with the marked difference in the interaction parameter of proteins belonging to different classes with the solvent, and, hence, with the marked difference in the hydrophilicity of the proteins investigated.     

Wörterbuch „Stärke”︁. Teil 1

Vocabulary „Starch”︁. Part I. After comprehensive preliminary work by the Working Group „Terminology”︁ of the Technical Committee „Starch, Including Derivatives and By-Products”︁ of the International Standardization Organization ISO (WG 10, ISO/TC 193) a vocabulary of important terms of the starch chemistry and starch technology in English and French language was made available. G. Graefe reported in this journal from time to time about the state of this work [Starch/Stärke 16 (1964), 229-232 and 381 -385; 17 (1965), 263–268; 23 (1971), 103–111; 27 (1975), 56–61 and 131–134]. The second, and for the time being last amendment of the vocabulary was edited at 1. 6. 1979 as International Standard ISO 1227-1979 (E/F). In the following the collection of technical terms which exists corresponding to the ISO regulations only in English and French language is made available together with a non obligatory translation into the German language to a bigger community of interest.     

Trägergebundene xylanolytische Enzyme. I. Wirkungsweise xylanolytischer Enzyme

Immobilized Xylanolytic Enzymes. Part I. Mode of Action of Xylanolytic Enzymes. The mode of action of enzymes involved in the total hydrolysis of xylans into monomeric sugars is described. Xylans exclusively consisting of ß-D -xylose residues are degraded into monomeric sugars by the combined action of ß-J, 4-xylanases and ß-1,4-xylosidases. Xylanases split the bonds within the xylan chain at random with the exception of the bonds at the end of the chains. ß-1,4-xylosidases break down the oligosaccharides released by the xylanase into monomeric sugars. On an average hardwood xylans contain one side group of 4-O-methylglucuronic acid per 10 xylose units. The action of ß-1,4-xylanases is disturbed by these side chains. A mixture of xylo-oligosaccharides and 4-O-methylglucuronosylxylooligo-saccharides is produced. The acidic xylooligomers cannot be attacked by ß-1,4-xylosidases until the 4-O-methyl-α-D -glucuronosyl residue is liberated by the action of α-1,2-glucosiduronases.     

Beiträge zur Psychophysik des Süßgeschmacks 7. Mitt. Experimentelle Neubestimmung der Süßintensitätsparameter von Acesulfam,Aspartam, Cyclamat,Saccharin, Glucose und Sorbitol

Contributions to the psychophysics of sweet taste. Part 7. New determination of the sweetness parameters of acesulfame, aspartame, cyclamate, saccharine, dextrose and glucitol By means of a new method (double staircase) concentration pairs of equal intensity for the sweet compounds acesulfame-K, aspartame, cyclamate-Na, saccharine-Na, dextrose and glucitol were determined with sucrose on 6 or 7 equidistant scaled levels, respectively, with 4 repetitions. The parameters maximal intensity R^m, the concentration coefficient b and the mean R^m/b, respectively, are calculated for each substance from the known parameters for sucrose using the exponential function R = R_m(1 - e), which describes the sweetness intensity R in dependence of the concentration S. For exact determination of the maximal intensity the upper concentration level was fixed at very high degree. Additionally, the relative sweetness of each concentration level of each substance is calculated. In all cases the exponential function is valid without limitation. The statistical parameters are homogenous and are laying within the applied staircase method. Systematical deviations could not be found.     

Fungicidal activity and chemical constitution. XIV.—Preparation of 4-substituted 2,6-dinitrophenols

Six 4-(1-phenylalkyl)-, eight 4-(1-cyclohexylalkyl)- and seven 4-(1-cyclopentylalkyl)-2,6-diniirophenois were prepared for testing against powdery mildew of apple (caused by Podosphaera lencotricha (Ell. & Everh.) Salm.) and other fungi.     

Characterisation of the most odour-active compounds in a peel oil extract from Pontianak oranges (<Emphasis Type="Italic">Citrus nobilis</Emphasis> var. Lour. <Emphasis Type="Italic">microcarpa</Emphasis> Hassk.)

Isolation of the volatile fraction from the peel of Pontianak orange (Citrus nobilis var. Lour. microcarpa Hassk.) by a careful solvent extraction/vacuum distillation process followed by application of an aroma extract dilution analysis (AEDA) revealed 32 odour-active compounds in the flavour dilution (FD)-factor range of 4–2048, 26 of which could be identified. On the basis of high FD-factors, (R)/(S)-linalool, myrcene, (R)-limonene, and 1,8-cineole were characterised as the most potent odorants, followed by octanal, (E,E)-2,4-decadienal, nerol, (E)-2-dodecenal, geraniol, and (E,E)-2,4-nonadienal. In addition, one odorant resembling the characteristic sulphurous, resinous aroma of the Pontianak peel oil was detected with a quite high FD-factor of 128. By mass spectrometry followed by synthesis, 1-phenylethanethiol exhibiting an intense sulphurous, resinous smell at the very low odour threshold of 0.005 ng/L in air, was found to be responsible for the odour impression detected in the extract. 1-Phenylethanethiol occurring as a mixture of the (R)-(76%) and the (S)-enantiomer (24%) has previously not been reported as odorant in foods. Application of static headspace aroma dilution analysis (SHA) on Pontianak peel revealed the green, grassy smelling odour-active compounds hexanal and (Z)-3-hexenal as further important odorants in the headspace above the peels.     

Beiträge zur Psychophysik des Süßgeschmacks 5. Mitt. Untersuchungen zum Einsatz sequentieller Staircasemethoden bei der Bestimmung intensitätsgleicher Konzentrationspaare

Contributions to the psychophysics of sweet taste. Part 5. Investigations of the use of a sequential staircase-method for the determination of equal intense pairs of stimuli The suitability of a sequential staircase-method for the determination of equal stimuli of the gustatory sense is experimentally investigated. The aim is the decrease of experimental expenditure when ruling sources of bias. In order to realize them sucrose solutions are used both for the constant stimulus and also for the sequence of stimuli. Possible factors are the gradation of the sequence of stimuli and its displacement towards the constant stimulus. These are factorized in a two-staged trial arrangement and are interpreted in a form of an analysis of variance. The gradation of sequence (grain) is the key factor. It defines both the occasional bias and also the efficiency of systematical sources of bias. Thus the subject-depending judgement errors, which occur in larger gradation, are avoidable with their adjustment on the half of the difference threshold. The errors, which are due to the direction, are counterbalanced through an up and down trial execution with a following meaning average. A remaining influence of the displacement of sequence is normally neglective. The standard deviation for the single determination lies - independently of the concentration level - dimensionally slightly above the half of the setting grain. The method of constant stimuli requires at least the twofold experimental expenditure for a simular result.     

The microstructure of almond (Prunus dulcis (Mill.) D.A.Webb cv. ‘Nonpareil’) cotyledon

Microstructure of almond (Prunus dulcis (Mill.) D.A. Webb cv. ‘Nonpareil’) cotyledon was observed with light, scanning and transmission electron microscopy. The objective of this study was to characterise almond cotyledon surfaces as well as to describe internal and subcellular organisation. The testa has an outer epidermis, which consists of relatively large thin-walled cells, which range from 100 to 300 μm in width. The major portion of the testa consists of approximately 14-20 layers of flattened parenchymal cells with the total thickness of the layers ranging from 80 to 120 μm. The remainder of the testa was comprised of a small amount of vascular tissue. The embryo consisted primarily of parenchymal tissue with relatively thin cell walls (1-3 μm in thickness) and a small amount of provascular tissue. Protein bodies up to 12 μm in width and spaces once occupied by lipid bodies up to 3 μm in width were present in all cells of the embryo.     

工业酿酒酵母重组β-1,3-1,4-葡聚糖酶部分酶学性质的研究

用刚果红法测定β-1,3-1,4-葡聚糖酶的酶活力,研究重组酿酒酵母(S.cerevisiae)菌株SC-βG分泌表达的重组β-1,3-1,4-葡聚糖酶的部分酶学性质,并与出发菌株枯草芽孢杆菌(B.subtilis)表达的原始酶的性质进行比较。结果表明,重组酶保持了与原始酶相同的底物专一性。 重组酶的最适反应温度为35℃,而原始酶为55℃。重组酶的热稳定性也发生了改变,40℃热处理20min只保留63.4%的最初酶活力,但温度再升高时对热处理敏感度降低,70℃的热处理20min仍保留45.9%的最初酶活力;而原始酶50℃时稳定,60℃以上的热处理酶活力损失很大。与原始酶相比,重组酶的最适pH值下降为pH5.0,而原始酶为pH6.5;相比原始酶在pH7.0有最大稳定性,重组酶在pH5.5时有最大稳定性。重组β-1,3-1,4-葡聚糖酶的最适反应条件与原始酶相比更接近啤酒的实际生产条件。     

Absolute und relative Verkleisterungscharakteristik von Stärken. Teil II. Die relative Viskositätsmessung mit dem Schrägflügelkörper und der Einfluß amylolytischer Enzyme auf das Viskogramm

The Absolute and the Relative Gelatinization Characteristics of Starches. Part. 2. Relative Measuring of Viscosity by Special Wing Stirrer and the Influence of Amylolytic Enzymes on the Viscogram. The procedure of relative viscosity measurings of starches in the steeping and gelatinization phase by means of a special wing stirrer are described and the measuring results are discussed regarding the viscograms of potato, maize and wheat starch. Examples are given for the viscosimetric measuring of enzyme action. Especially the influence of α- and β-amylase, of amyloglucosidase and papain on the relative viscograms of potato, maize and wheat starch is examined.     

A Study of Hydroxyethyl Starch. Part II. Degradation-Sites of Hydroxyethyl Starch by Pig Pancreas α-Amylase

The degradation sites of hydroxyethyl starch (HES) by pig pancreas α-amylase were determined by gas liquid chromatography. As a result, it was confirmed that HES could be hydrolyzed by α-amylase only at the glucosidic bond of unsubstituted glucose residues, but not at the bond of 2-0-, 3-0-, and 6-0-hydroxyethylglucose residues. Furthermore, it was suggested that the enzymic degradation rate of HES could be well determined by measuring the reducing power.     

A Novel Type of Corn Starch from a Strain of Maize. Part. 1. Breeding of a Strain of Maize,and Identification of the Starch as New Species Named “Amylo-Waxy”

Amylo-maize was crossfertilized with waxy-maize, and bred F₁- and F₂-seeds were investigated based on phenotype in genetics and on physical and chemical properties of starch. It was elucidated that F₁-seeds became normal-type, but F₂-seeds were assorted into 4 types, that were normal, amylo, waxy and a novel one. Analysis of all kernels of F₂ showed the ratios of the above 4 types to be 9:3:3:1. From the results, the genotypes of endosperm concerned with starch formation were deduced as (Ae - -, Wx - -), (ae ae ae, Wx - -), (Ae - -, wx wx wx), (ae ae ae, wx wx wx) respectively. The novel type was named “amylo-waxy” from its properties that the prepared starch was composed of amylopectin only as waxy, but its iodine stained color reaction was as blue as in amylose.     

Biochemisch-technologische Studienüber die Naßverarbeitung von Mais 4. Mitteilung. Über die qualitative Zusammensetzung des Mais-Hydrolasensystems und Aktivität einzelner Enzyme bzw. Enzymgruppen

Biochemical-technological Studies on Wet-Processing of Maize. Part 4. On the Qualitative Composition of the Maize Hydrolase System and the Activity of Particular Enzymes Respectively Enzyme Groups. Enzyme preparations have been isolated from the maize meal by means of water extraction and following protein precipitation (ethanol, ammonium sulphate, acetone). Cleaning or concentration operations have been left out, in order to preserve the enzyme system of the maize in its totality By paper chromatographical studies on these preparations as well as special activity deter minations a- and β- amylase could be traced in the ungerminated as well as in the germinated maize and the presence of phosphorylase could be confirmed. For enzymatic handling of the non-gelatinized starch a- amylase is above all convenient, but slight degradation by β-amylase cannot be overlooked. By means of paper chromatography and reductometry β-fructofuranosidase, a-glucosidase, β-glucosidase could be clearly traced in the germinated and ungerminated maize. a-Galactosidase could be traced with some reservation. Matters in this group have in common the faculty for hydrolysis and synthesis of glucosidic bondings. Proteinase and lipase have been traced in all preparations, peptidase exclusively in those from germinated maize and their activities have been determined. Of all the maize sorts examined, hard maize shows higher activities with all enzyme species compared to dent maize.     

Studies in fungitoxicity. VII.—Fungicidal activity of certain ethylenes and heterocyclic compounds substituted with the 2,4-dinitrophenylthio- group

Certain ethylenes and heterocyclic compounds substituted with the 2,4-dinitrophenylthio- group were synthesised and tested for activity against Venturia inaequalis, Botrytis cinerea, Fusarium bulbigenum and Cercospora melonis. 1-Alkylthio-1-(2,4-dinitrophenylthio)-2-cyano-2-(ethoxycarbonyl or cyano) ethylenes in which the Ph-S bond is not shielded by the alkyl substituent from attack, perhaps by nucleophilic cell constituents, were found to be active against Venturia. 3,5-Di(methyl- or ethyl-thio)-4-cyanoisothiazoles were also active against Venturia. 2-Substituted-5-(2,4-dinitrophenylthio)-1,3,4-oxadiazoles had no or low fungicidal activity, and of several 2-(2,4-dinitrophenylthio) heterocyclic compounds that were tested 2-(2,4-dinitrophenylthio)-benzothiazole and -benzoxazole had good activity against Venturia. The infra-red and proton magnetic resonance spectra of several compounds were examined.     

Chemical properties of the cultivated Sideritis raeseri Boiss. & Heldr. subsp. raeseri

Phytochemical analyses of the cultivated Sideritis raeseri subsp. raeseri in four different stages of flower development were performed. Traditionally used infusion and decoction were also prepared from aerial parts in full flowering stage, and analyses of active compounds and radical scavenging capacity were performed. The highest yield of the essential oil, obtained by hydrodistillation, was noticed in the full flowering phase (0.11%), with sesquiterpene bicyclogermacrene as the main constituent (42.5%). All examined extracts contained phenolic compounds and their amounts varied from 15.3 to 34.1 mg GAE/g DW. The amounts of total phenolics in infusion and decoction were similar (46.5 and 43.9 mg GAE/100 ml, respectively). LC–ESI-MS analyses of all samples allowed the characterisation of 22 phenolic compounds. Two dominant flavone glycosides, 4′-O-methylhypolaetin-7-O-[6?-O-acetyl-β-d-allopyranosyl (1 → 2)-β-d-glucopyranoside (17) and 4′-O-methylisoscutellarein-7-O-[6?-O-acetyl-β-d-allopyranosyl-(1 → 2)]-β-d-glucopyranoside (19) were quantified using HPLC. Moreover, the mineral content and the percent of transportation were investigated.     

Lactose - ein potentieller Ballaststoff. Zur Regulierung ihrer mikroökologischen Wirksamkeit im Intestinaltrakt 3. Mitt. Ballaststoffwirkung der Lactose als Folge mikrobieller Aktivität

In Caecum und Colon ist die mucosale ß-Galactosidaseaktivität keimfreier wie konventioneller Tiere gering. Die chymale ß- Galactosidaseaktivität findet sich auch unter keimfreien Bedingungen. Sie steigt nach Monoassoziation und ist bei konventionellen Tieren höher als bei keimfreien. Der in das Caecum und Colon eintretende Ballaststoff Lactose wird maßgeblich durch die Intestinalflora hydrolysiert. Die Caecal- und Colonflora der Ratte wird von aeroben Lactobazillen- und Bacteroides-Keimen beherrscht. Lactosefutter erhöht die Gesamtkeimzahl und begünstigt das Anwachsen von Bifidobakterien. Unter speziellem, protein- und phosphatarmem, lactosereichem Futter (Frauenmilch und ähnlich zusammengesetzte Nahrungen) werden Bacteroides und weitere fäulnisaktive Keime zurückgedrängt. Außerdem wirkt sich lactosehaltige Nahrung auf die Stoffwechselaktivität der Makroorganismen aus (mikrobielle ß- Galactosidaseaktivität, Säurebildung and pH-Senkung im Chymus, Wasserstoffproduktion, proteolytische Aktivität). Lactose als Ballaststoff verringert die Harn-Stickstoff- und erhöht die Faeces-Stickstoff-Ausscheidung bei konventionellen Ratten.     

Sensory Perception of Foods. 2nd edition (J.R. Piggott, ed.), Elsevier Science Publishers, London. 1988. 406 pp. £56.

Sensory Perception of Foods. 2nd edition (J.R. Piggott, ed.), Elsevier Science Publishers, London. 1988. 406 pp. 256.
Food Structure - Its Creation and Evaluation. (J.M.V. Blanshard and J.R. Mitchell, eds.) Butterworths, London. 1988. 504 pages. $225.     

Purification of <Emphasis Type="Italic">S</Emphasis>-Alk(en)yl alka/enethiosulfinates of garlic (<Emphasis Type="Italic">Allium sativum</Emphasis> L.) by using recycling preparative HPLC

S-Alk(en)yl alka/enethiosulfinates formed in crushed garlic were purified by using recycling preparative HPLC. Allyl 2-propenethiosulfinate and methyl methanethiosulfinate were effective separated because no other thiosulfinates were coeluted with them. Allyl methanethiosulfinate and methyl 2-propenethiosulfinate, trans-1-propenyl methanethiosulfinate and methyl trans-1-propenethiosulfinate, (cis)- and (trans)-1-propenyl 2-propenethiosulfinate were eluted as 1 peak, respectively, and further separated by using additional kinds of column. Since the quantity of trans-1-propenyl trans-1-propenethiosulfinate (PPTHS) was small in garlic, PPTHS was isolated from a mixture of blanched onion homogenate and garlic alliinase and purified. Purified thiosulfinates can be employed for the study of antimicrobial activity, flavor, and greening of garlic.     

Intrinsic viscosities and apparent specific volumes of amino acids and sugars. ‘Effective size’ and taste of sapid molecules

Intrinsic viscosities ([η]) and apparent specijic volumes (V) are compared for a number of amino acids and simple sugars and their derivatives. While the sugars and their derivatives fit within a narrow range for both parametevs ([η])=2.27–2.61 cm³ g^?1; V=0.60–4.69 cm³ g^?1), the amino acids cover a much wider band ([η]) = 1.29–4.20 cm³ g^?1; V=0.562–0.712 cm³ g^?1). The intrinsic viscosity value of any particular amino acid is always greater than the corresponding apparent specijc volume, and ranges (at 10 mg g^?1) between two and seven times the value of the apparent specific volume. For the sugars and sugar derivatives, on the other hand, the intrinsic viscosities are always three to four times greater than the values of the corresponding apparent specijic volumes. When concentration is increased, all apparent specific volumes increase but they remain relatively constant if they are expressed as parachors (Vγ^1/4). Differences between the sugars and amino acids originate in the greater structural diversification of the latter molecules which in turn accords with their greater range of taste qualities.     

α-(1→4)-D-Glucans. Part XXII. The Iodine Staining Properties of Linear Maltosaccharides

Maltosaccharides of degree of polymerisation (DP) 6-22 have been isolated in a chromatographically pure form, and their iodine staining properties studied under standard conditions. In the range DP 6 to DP 13, there is a logarithmic increase in the intensity of absorption of the iodine complexes; thereafter the relationship is almost linear. A plot of the reciprocals of wavelength of maximum absorption and DP indicates that there are three separate linear sections corresponding to DP 6–11, 12–18 and 18–22. Ammonium sulphate causes an increase in the intensity of absorption and wavelength of maximum absorption in all cases.