THE DETERMINATION OF PECTIC SUBSTANCES IN CITRUS JUICES AND GRAPES BY TWO SPECTROPHOTOMETRIC METHODS

The pectic substances in two samples of New Zealand grapefruit juice were determined by a spectrophotometric method after fractional extraction of the alcohol-insoluble solids. No significant difference in anhydrogalacturonic acid (AGA) content was found when the chromogen was formed using m-hydroxydiphenyl and carbazole. In the analysis of the pectic substances in red and white grape berries, chromogen formation with carbazole gave AGA contents of the water-soluble fraction of the alcohol-insoluble solids five to seven times greater than when the chromogen was formed using m-hydroxydiphenyl. It is suggested that phenolic material in the grape extracts reacted with the carbazole to give the higher apparent AGA contents.     

A Comparison of Some Properties of Beef and Buffalo (Bubalus bubalis) Meat

Assessments were made of the meat properties of four muscles of differing connective tissue content, from both Achilles tendon-hung and tenderstretched (suspended from the sacrosciatic ligament) sides of buffalo (Bubalus bubalis) and Brahman–cross steers of similar mean age (51 months) and carcass weight (ca 230 kg). Color measurements indicated that muscles from buffalo were darker although ultimate pH values of the groups did not differ. Adhesion, compression, and Warner-Bratzler peak shear force minus initial yield force values were significantly greater in buffalo than in beef muscles; indicating greater connective tissue contribution to toughness of buffalo meat. Taste panel assessment of muscles of relatively low connective tissue content in beef, indicated that generic differences in tenderness were slight although buffalo meat was less juicy than beef. Flavor and overall acceptability of buffalo meat were significantly less than for beef.     

A LIQUID PHOSPHINE OXIDE: SOLVENT EXTRACTION OF PHENOL,ACETIC ACID AND ETHANOL

A liquid phosphine oxide has been developed with a phosphoryl concentration of 2.3M, twice the maximum that can be reached in TOPO solvents at 50^°C. Distribution coefficients are increased by 2^m where m relates to mols phosphoryl in the extracting complex. The value of m is 1.6 for phenol, 1.0 for acetic acid and 0.9 for ethanol. Kinetics are unchanged. Costs of extracting phenol with the new extractant and with isopropyl ether are compared. Extraction coefficient and separation factor for ethanol are compared with other potential extractants.     

The role of iron(iii) and tartrate in the zincate immersion process for plating aluminium

The zincate immersion process is a commercial process used to treat aluminium prior to electroplating. Superior zinc coatings are obtained through modifications to the original process. One such modification involves the addition of ferric chloride, complexed with potassium sodium tartrate, to the plating baths. This paper describes a detailed investigation into the function of these additives. It was found that the addition of tartrate alone did not significantly affect the rate of zinc deposition, the deposit morphology or the position of the aluminium or zinc polarization curves. This suggests that the role of tartrate is solely as a complexing agent to maintain iron (iii) in solution. In contrast to this, the addition of iron(iii)/tartrate had a marked effect on the reaction. It was found that iron(iii) functioned primarily by reducing the size of the zinc crystals as they formed. This produces a thinner and more compact zinc immersion coating.     

Changes in Chlorophyll and Pectin After Storage and Canning of Kiwifruit

Kiwifruit were harvested and stored at 0°C. Over a 92-day period fruit were removed from storage, ripened to 13° Brix by holding at 25°C, and canned as slices in a sugar syrup. Changes in the chlorophylls and pectic substances were measured after storage and canning. The concentration of total chlorophyll remained virtually constant during storage and ripening. During the canning process about 90% of the chlorophylls was degraded, the data fitting a first-order model better than a second-order model. The total pectin content increased by over 100% during storage and ripening but decreased significantly during canning. A significant inverse relationship between the firmness of unpeeled kiwifruit and the water-soluble, high-methoxyl pectin content was derived.     

Testing the self as a control system: Theoretical and methodological issues

This report describes an evolution of research methodology for adducing evidence regarding whether the self functions as a control system. While there has been a great number of studies in the literature on personality and social psychology aimed at demonstrating that behavior of many kinds can be affected by focusing attention upon the subject's self-concept, or by challenging or threatening it, little attention has been given to the question of why this would be so. A proposed explanation would be that the self functions as a control system. Testing this hypothesis has entailed development of a methodological approach in which control action occurs predictably rather than having a statistical probability. This has required defining a model and testing it by predictions rather than attempting to isolate underlying variables with multivariate techniques.     

Relationship between colour and brown pigment concentration in orange juices subjected to storage temperature abuse

The browning index of orange juices which had been subjected to storage temperature abuse (55°C for up to 40.5 hr) was highly correlated with the CIE tristimulus values as measured on a Neotec Du-Color Colour Difference Meter. The correlation coefficients and the multiple regression equation have been calculated. When the tristimulus values were converted to USDA colour scores, the values obtained were not in the same range as the USDA plastic standards for orange juice. The level of correlation between the colour scores and the browning index was too low to be useful for prediction purposes. When the tristimulus values were converted to Hunter's citrus red and citrus yellow parameters, a significant correlation was found between these parameters and the browning index. However, the level of variation explained by the correlation was again too low to be useful for prediction purposes.