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.     

Deterioration of β-carotene in certain hydrogenated fats. II.—Products of β-carotene deterioration and nature of the green pigment

The non-saponifiable fraction from a sample of β-carotene-hardened palm kernel oil which had developed a green discoloration has been examined. A number of β-carotene oxidation products were found and these included a number of β-carotene epoxide derivatives. A compound thought to be β-apo-3-carotenal was also found, but the apo-2- and apo-4-carotenals were not present in more than trace amounts. A major component was similar to, but not identical with, mutatochrome (β-carotene 5,8-epoxide). It is suggested that the green discoloration of the carotenised fat was due to oxidation of β-carotene to epoxide derivatives by traces of peroxyacids and the conversion of these epoxides into green-blue ionised forms by the action of an acidic material present in the fat.     

Insecticidal activity of pyrethrins and related compounds: II.—Relative toxicity of esters from optical and geometrical isomers of chrysanthemic,pyrethric and related acids and optical isomers of cinerolone and allethrolone

Department of Insecticides and Fungicides, Rothamsted Experimental Station, Harpenden, Herts. The relative toxicities of esters related to the natural pyrethrins and to allethrin were evaluated against Phaedon cochleariae (mustard beetle), Tenebrio molitor (yellow mealworm beetle), Dysdercus fasciatus (cotton stainer) and Plutella maculipennis (diamond-back moth) and the results were compared with those of workers who used Musca domestica (housefly). With the insect species used here there were no outstanding reversals of the toxicity ratings established in the studies with M. domestica. However, the toxicities of the esters depended more on the nature of the alcohol when two acids were compared and on the acid component with different alcohols. (+)-Allethrolone and (+)-cinerolone gave more toxic esters than their optical isomers but there was less difference than had been found with other insect species between esters from trans-and cis-chrysanthemic acids.     

Kaffircorn malting and brewing studies XIV.—Mashing with kaficorn malt: Factors affecting sugar production

The effects of temperature, time, pH, diastatic power, malt/grain ratio and nature of the substrate on the production of sugar by sorghum malts have been investigated. The optimum temperature for sugar production is 60°. Although sugar production decreases with increasing acidity of the mash, yields are still appreciable. sorghum malt being more active than barley malt under such conditions. With malts of diastatic powers up to 25 K.D.U./g the substrate is in excess; with diastatic powers of 45 K.D.U./g or greater, the amylases are in excess. The use of grain adjuncts permits the control of the enzyme/substrate ratio. The optimum malt/grain ratio lies between 1:3 and 1:2 at pH 6·3 and is a reflection of the ratio of ungelatinised to gelatinised starch and the affinity of the amylases for these two forms of the substrate.     

Extraction and Isolation of β‐Glucan from Grain Sources—A Review

A collective report on the extraction and isolation of β‐glucan from grain sources, namely, oat, barley, and wheat is presented. An analysis on the effect of medium, pH, and temperature on the purity and yield of the β‐glucan derived under acidic/alkaline/aqueous/enzymatic conditions is also made. Water extraction and alkali extraction processes are preferred as the yield and recovery of extracted β‐glucan were good. Cost‐effective development of the process for deriving high molecular weight β‐glucan is the current requirement for its wide applications in food and pharmaceutical industries.     

Deterioration of β-carotene in certain hydrogenated fats. I.—Incidence of green discoloration during storage

An investigation of the stability of β-carotene in 111 samples of hydrogenated edible fats revealed that during storage at temperatures in the range of +20° to —20°, green discoloration of the yellow fats occurred in 38 samples during the first year of storage. The green discoloration was found mostly in hydrogenated palm kernel oil and coconut oil; samples of hydrogenated marine and soyabean oils were much less susceptible to colour change. The rate of development of the colour change was generally a maximum in the temperature range +6° to —6° and decreased rapidly as the temperature was raised.     

Species identification of Wickerhamomyces anomalus and related taxa using β‐tubulin (β‐tub) DNA barcode marker

Wickerhamomyces anomalus is used in food and feed processing, although the species has been reported as an opportunistic human pathogen, predominantly in neonates. Neither phenotypic nor the most frequently applied genotypic marker (D1/D2 LSU ribosomal DNA) provide sufficient resolution for accurate identification of this yeast. In this study, the β‐tubulin gene was used for species identification by direct DNA sequencing and as marker in a species‐specific PCR assay. The results showed that all examined W. anomalus strains were clearly distinguished from the closely related species by comparative sequence analysis of the β‐tubulin gene. In addition, the species‐specific primers were also developed based on the β‐tubulin gene, which was employed for polymerase chain reaction with the template DNA of Wickerhamomyces strains. A single 218 bp species‐specific band was found only in W. anomalus. Our data indicate that the phylogenetic relationships between these strains are easily resolved by sequencing of the β‐tubulin gene and combined with species‐specific PCR assay. Copyright © 2012 John Wiley & Sons, Ltd.     

Deterioration of β-carotene in certain hydrogenated fats. III.—Factors affecting the rate at which green discoloration occurs

The influence of a variety of additives and thermal treatments upon the rate at which green discoloration develops in β-carotene-hydrogenated fat systems is reported. The observed effects are discussed in relation to the hypothesis that the colour change is associated with the production of β-carotene epoxides from the oxidation of β-carotene by peroxy acids which are formed by the interaction of aldehydoglycerides with dissolved oxygen. Possible methods which might be employed in avoiding the incidence of the discoloration include suitable choice of oil, the use of certain additives, notably commercial lecithin (for food uses), adequate ‘tempering’ of the finished fat, and care in the use of cool (and cold) storage.     

Natural skin coating of the apple and its influence on scald in storage III.—α-farnesene

In a study of apple fruits grown under English conditions it was found that at the time of the respiratory climacteric the concentration of α-farnesene in the waxy skin coating began to increase rapidly from a low level and at 12° reached a peak after about 30 days. in the relative amounts of farnesene produced there was little to distinguish the scald-resistant from the scald-sensitive apple variety. Under the various conditions of low-temperature storage in use, it was found that the farnesene content of the skin was most influenced by the nature of the atmosphere, whether air or 8% CO₂, white the farnesene content of the waxy skin coating was more responsive to delay at room temperature before storage, diphenylamine treatment or wrapping in oiled wraps. The results are discussed in relation to the theory that farnesene is a chemical factor in the induction of superficial scald.     

Studies on the north sea cod. V.—Effects of starvation. 3. Electrophoresis of the muscle myogens

Measurements of the contents of water, protein nitrogen and non-salt-extractable nitrogen of a group of cod starved in an aquarium showed that at various times profound changes were occurring in the muscle. However, the electrophoretic patterns of water extracts of the muscle did not change, apart from a partial fading of some bands 8 weeks after the beginning of starvation. No bands disappeared or changed their speed of migration, neither did new bands appear during starvation. One significant conclusion is that the identification of species or local races by electrophoresis is unlikely to be invalidated by the nutritional state of the fish.     

Influence of whey peptides on the surface activity of κ‐casein and β‐lactoglobulin A

Whey protein hydrolysate (WPH) was fractionated by reverse‐phase chromatography to obtain fractions of varying surface‐hydrophobicities. A model oil–water interface (MI) was pre‐coated with the WPH or fractions thereof. Contact angle (θ) of sessile drops of κ‐casein (κ‐CN) or β‐lactoglobulin A (β‐LGA) were measured on the MI. Pre‐coating of MI with un‐fractionated WPH decreased θ, that is, increased surface activity, of both κ‐CN (35–8.3°) and β‐LGA (38–21.3°). Conversely, pre‐coating of MI with the fractions significantly increased θ of both proteins as a function of hydrophobicity. Data provide insight into variability of whey protein functionality in food applications.