Analysis of tannins in seeds and skins of Shiraz grapes throughout berry development

The flavan-3-ol and proanthocyanidin composition of both seeds and skin of Vitis vinifera L. cv. Shiraz grapes was determined by reversed-phase HPLC after acetone extraction and acid-catalysis in the presence of excess phloroglucinol. Samples were taken at weekly intervals from fruit-set until commercial harvest. The main period of proanthocyanidin accumulation in grape seeds occurred immediately after fruit-set with maximum levels observed around veraison. Over two seasons there was variation in both the timing and content of proanthocyanidins in seeds. In skin, proanthocyanidin accumulation occurred from fruit set until 1–2 weeks after veraison. Proanthocyanidin subunit composition was different in seeds and skin and changed during berry development but the mean degree of polymerisation of the tannin polymers in skins was higher than in the seeds at all stages of berry development. Proanthocyanidin levels in both seeds and skin decreased between veraison and harvest. Additional proanthocyanidin subunits were released when the residues remaining after acetone extraction were subjected to direct acid-catalysis in the presence of phloroglucinol. In the seeds, these accounted for much of the post-veraison decrease, but not in grape skin. At harvest, 75% of extractable berry proanthocyanidin was in the seeds. Accumulation of proanthocyanidins in the seeds appears to be independent of that in the skins, but in both tissues synthesis occurs early in berry development and maximum levels are reached around veraison.     

POLARIZATION OF RECTANGULAR ARRAYS OF SPHERES IN A POTENTIAL FLOW

General theorems are derived, relating the impulse, polarization (internal dipole moment) and average velocity field for a dispersion of spheres in a potential flow. A constitutive equation is developed and a structure-dependent coefficient, λ, defined. A first approximation to λ, valid for low concentrations of spheres, is obtained and evaluated for rectangular arrays, using image methods.     

Fire detection using data from the NOAA-N satellites

Abstract

Due to increased concern over the climatic and economic impact of fires associated with deforestation and seasonal burning, most of which occurs in remote parts of the worid, it is necessary to find ways to effectively monitor such activity. The 3.8μm channel on board the National Oceanic and Atmospheric Administration's polar-orbiting satellites is very sensitive to high temperature sources such as fires. Case studies in Mexico, Brazil, Mozambique and the Soviet Union have been selected to demonstrate the utility of this channel for fire detection. With the fire detection capability of the 3.8 μm channel and the daily global coverage, it is possible to monitor world-wide fire activity.     

Comparison between satellite and ship measurements of sea surface temperature in the north-east Atlantic Ocean

Abstract

A comparison is made between in situ measurements of sea surface temperature (SST) in the north-east Atlantic Ocean, obtained during Cruise 145 of RRS Discovery, and SSTs derived from several overpasses of the Advanced Very High Resolution Radiometer on the NOAA-7 satellite during the same period in March 1984. The objective of the analysis was to test the ability of the satellite to map the detailed features of SST structure and to examine the performance of atmospheric correction and temperature calibration procedures in this context. Gross comparison between all the cloud-free ship and satellite data confirms agreement normally within 1 degC. More detailed comparison of SST structure along the cruise tracks shows that the satellite data are able to identify features with a resolution of 0.3°C.     

The occurrence of isoperoxidases in conference pears

Soluble and ionically-bound peroxidases have been obtained from the pulp and peel of Conference pears. The peel soluble fraction contained the highest level of peroxidase activity. The peel peroxidases, both soluble and ionically bound, were particularly heat stable. Following heat inactivation, regeneration of enzymic activity was observed for the peel peroxidases and soluble pulp enzymes. Plots of the percentage of heat inactivation for the pear peroxidases against heating time were non-linear.     

Microbiology of brines used to mature feta cheese

The microfloras of brines from two commercial factories manufacturing traditional feta cheese were examined over a period of 60 days, which is the normal maturation time for Greek feta. Non-starter lactic acid bacteria were the dominant group, and Lactobacillus paracasei ssp. paracasei and Lactobacillus plantarum were the principal species identified. A number of strains of Debaryomyces hansenii were isolated from the brines, and both the yeasts and the lactobacilli possessed enzymes capable of degrading fat or protein. It is suggested that these microfloras play an important role in the maturation of feta cheese. No recognized pathogens were isolated from the brines of' either factory.     

Energy,Power and Group Velocity†

Conservation of energy is shown to imply that, in any system which supports unattenuated harmonic waves, the energy travels with the group velocity of the waves.