Accumulation of potassium and calcium by ripening berries on field vines of Vitis vinifera (L) cv. Shiraz

Ripening berries of Vitis vinifera (L) cv. Shiraz can show pre-harvest weight loss at sub-optimal sugar content (shrinkage). This later-age decline in berry weight implies that water loss from mature berries has begun to exceed water inflow from the parent grapevine. Such decrease in net inflow has been attributed to a cessation of xylem flow subsequent to veraison, followed by a cessation of phloem flow into berries during later stages of ripening. We address this issue in this present paper, and show a continuing increase in berry content of both potassium and calcium throughout ripening. We measured changes in berry fresh weight and berry content of potassium (phloem mobile) and calcium (phloem immobile) in fruit on field vines sampled from set to harvest. Berry fresh weight reached a plateau between 81 and 95 days after flowering, then declined to 75% of maximum fresh weight by 115 days. Dry weight maximum occurred 14 days after the onset of the fresh weight plateau. Potassium accumulation was slow preveraison, increased 3.5-fold post-veraison, and continued during berry shrinkage. Calcium content per berry also showed a linear increase throughout fruit enlargement and ripening phases. Assuming both potassium and calcium were entering berries via vascular conduits, our results imply a continuing connection between parent grapevine and ripening berries. Moreover, an abrupt change (increase) in the ratio of potassium/calcium content per berry subsequent to veraison implies that phloem inflow has increased relative to xylem inflow during post-veraison enlargement

A standard calculation methodology for human doubly labeled water studies

The doubly labeled water (DLW) method measures total energy expenditure (TEE) in free-living subjects. Several equations are used to convert isotopic data into TEE. Using the International Atomic Energy Agency (IAEA) DLW database (5,756 measurements of adults and children), we show considerable variability is introduced by different equations. The estimated rCO(2) is sensitive to the dilution space ratio (DSR) of the two isotopes. Based on performance in validation studies, we propose a new equation based on a new estimate of the mean DSR. The DSR is lower at low body masses (<10 kg). Using data for 1,021 babies and infants, we show that the DSR varies non-linearly with body mass between 0 and 10 kg. Using this relationship to predict DSR from weight provides an equation for rCO(2) over this size range that agrees well with indirect calorimetry (average difference 0.64%; SD = 12.2%). We propose adoption of these equations in future studies

Better wine for better health: fact or fiction?

In the first decade of the twenty-first century, the potential therapeutic effects of regular moderate wine consumption are being increasingly acknowledged. They include a reduction in the risk of, and death from, cardiovascular disease, which accounted for 40% of all Australian deaths in 2000. The reduction in risk for wine consumers is similar to that of consumers of fruits, grains and vegetables, which, together with wine, are the core components of a 'Mediterranean-style diet'. The chemical components of wine considered primarily responsible for this therapeutic effect are ethanol, and the phenolic compounds and their polyphenolic forms. Indeed, moderate wine consumption has been observed to supplement the cardioprotective effects of an already high phenolic diet, and more importantly, to counter the harmful effects of a high fat diet on blood clotting, endothelial function and lipid oxidation, which contribute to the development of cardiovascular disease. This paper explores both the viticultural and vinification factors that influence phenolic concentration in grapes and wine. The synthesis and accumulation of phenolic compounds in grapes is primarily dependent upon varietal factors, the expression of which is influenced by a combination of climatic and viticultural factors such as sunlight and temperature during ripening, as well as ripeness at harvest. While the maximum possible concentration of phenolic compounds in a wine will be determined by the content in the constituent grapes, factors which influence the extraction of the phenolic compounds from the skins and seeds primarily influence their concentration in the juice, must and wine. Once harvested, the concentration of phenolic compounds in grapes is invariate, but extraction efficiency can vary during vinification. Accordingly, this paper also explores innovative techniques and technologies that can increase the phenolic content of the resultant wine. At best, winemaking can only extract at 50% of the total phenolic compounds accumulated in the grapes. Therefore, the phenolic content of the resultant wine can only be increased by supplementation of the must during fermentation with additional sources of phenolic compounds. Alternatively, a grape seed extract could be added to wine post fermentation to supplement its phenolic content, although this same grape seed extract may also be added to other foods such as yoghurt, from which the phenolic compounds are readily absorbed. Regular and moderate consumption of wine by consumers should, however, be placed in context with the other constituents and characteristics of a healthy diet and lifestyle. Indeed, wine consumers generally have fewer risk factors for cardiovascular disease compared with beer and spirits consumers, which is reflected in an approximately 25% to 35% lower risk of cardiovascular disease for wine consumers compared to consumers of beer and spirits, respectively