In-mouth amylase activity can reduce perception of saltiness in starch-thickened foods

Sensory scores for saltiness and thickness obtained for savory liquids thickened with starches or the nonstarch hydrocolloid hydroxypropylmethyl cellulose (HPMC) were correlated with the panelists' amylase activity. Although higher enzyme activities were linked to lower thickness scores for systems thickened by starch, they were also associated with a decreased taste perception, particularly for starches retaining a granular structure after gelatinization (wheat and modified waxy maize). Microscopic evidence showed that the enzyme can disrupt such structures, and this is associated with a decreased mixing efficiency with water and consequently a reduced transport of tastant (sodium) to the saliva (aqueous) phase and to the taste buds. This explains the lower saltiness scores for subjects with higher amylase activity, even if they are associated with a lower perceived thickness.     

Fourier transform raman spectroscopy study of heat-induced gelation of plasma proteins as influenced by pH

Fourier transform (FT) Raman spectroscopy was used to elucidate heat-induced structural changes of albumin, globulins, serum, and plasma protein solutions (15% w/w) as affected by pH (4.5, 6.0, and 7.5). Reduction of alpha-helix and formation of beta-sheet, disulfide bond reactions, and exposure and buriedness of hydrophobic groups and amino acid residues were observed. All of these features contributed to the formation of strong, irreversible heat-induced gels. The application of a dimensionality reducing technique such as principal component analysis proved to be useful to determine the most influential qualities of protein samples, as well as the pH-dependent behavior of some of the attributes of both unheated and heated solutions. Analysis of Raman spectra in terms of differences demonstrated the interactions of albumin and globulins in co-occurrence and the significant role of fibrinogen on the gel's attributes.     

Intake of specific flavonoids and risk of acute myocardial infarction in Italy

OBJECTIVE: As intake of flavonoids has been associated with reduced risk of coronary heart disease but data on the relation with specific classes of flavonoids are scarce, we assessed the relation between dietary intake of specific classes of flavonoids and the risk of acute myocardial infarction (AMI) in an Italian population.DESIGN: Case-control study. Dietary information was collected by interviewers on a questionnaire tested for validity and reproducibility. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were obtained by multiple logistic regression models including terms for energy and alcohol intake, as well as sociodemographic factors, tobacco and other major recognised risk factors for AMI.SETTING: Milan, Italy, between 1995 and 2003.SUBJECTS: Cases were 760 patients, below age 79 years, with a first episode of non-fatal AMI, and controls were 682 patients admitted to hospital for acute conditions unrelated to diet.RESULTS: A reduced risk of AMI was found for increasing intake of anthocyanidins (OR=0.45, 95% CI 0.26-0.78 for the highest vs. the lowest quintile, Ptrend=0.003) and flavonols (OR=0.65, 95% CI 0.41-1.02, Ptrend=0.02). A tendency towards reduced risks, although not significant, was observed for flavan-3-ols (OR=0.73, 95% CI 0.48-1.10) and total flavonoids (OR=0.74, 95% CI 0.49-1.14). No meaningful heterogeneity was found between the sexes. No association emerged for other flavonoids, including isoflavones, flavanones and flavones.CONCLUSIONS: High intake of anthocyanidins reduced the risk of AMI even after allowance for alcohol, fruit and vegetables, supporting a real inverse association between this class of flavonoids and AMI risk.     

Effects of natural phenolic compounds on the antioxidant activity of lactoferrin in liposomes and oil-in-water emulsions

The effect of natural phenolic compounds on the antioxidant and prooxidant activity of lactoferrin was studied in liposomes and oil-in-water emulsions containing iron. The antioxidants tested with lactoferrin were alpha-tocopherol, ferulic acid, coumaric acid, tyrosol, and natural phenolic extracts obtained from three different extra-virgin olive oils and olive mill wastewater. The natural extracts of olive oils and mill wastewaters were composed mainly of polyphenols and simple phenolics, respectively. Lipid oxidation at 30 degrees C was determined by the formation of hydroperoxides and fluorescent compounds resulting from oxidized lipid interactions. All phenolic compounds showed synergistic properties in reinforcing the antioxidant activity of lactoferrin in lipid systems containing iron. The highest synergistic effects were observed for the phenolic extracts rich in polyphenols of extra-virgin olive oils and lactoferrin. This synergistic effect was higher in liposomes than in emulsions.     

Crop contamination by selected trace elements

Goal and Background  The regulatory limit for the allowable concentration of heavy metals (HM) in agricultural soils should be based both on HM status and on soil parameters that influence HM mobility. In this paper, a soil categorization scheme is proposed which is based on the main factors that influence HM mobility in soils. The scheme also makes use of the existing regulatory limits for total concentrations of trace elements in Slovak soils but additionally takes into account the potential ability of the soils to mobilize trace elements. A map of the Slovak Republic showing the soil categorization using this scheme is presented. Methods  Besides total soil content of Cd, Pb, Cr, Hg, As, Cu, Zn, Ni, soil parameters with dominant influence on HM mobility are included in the scheme pH, organic matter content, quality of humus represented by spectral parameter Q⁴ ₆ and content of fraction f < 0.01 mm. Point rating approach was used for categorization. Database of localized soil data from 3556 locations was used for creation of map in GIS environment. Results  Based on the point scoring method described herein, soils are ranked from a (the least risk of crop contamination) to d (medium risk). Categories e and f are reserved for soils where the risk exceeds the allowable regulatory limits. For each of the six categories, the most suitable usage of agricultural land is recommended. The Slovak map presented shows that the main factor that affect the spatial distribution of each soil category is soil parent material which governs the existing total HM content and the predisposition for certain soil types to have high HM mobility. Agricultural usage of land in Slovakia is in most cases limited by exceedences of Cr and Ni, originating from widespread flysch rock parent material. Conclusions  Application to regional geochemical data shows that, for more than half of Slovak agricultural land, risk of crop contamination is low. For the rest of the area, planting should consider sensitivity of crops to HM uptake. Recommendation and Outlook  Evaluation of suitable agricultural usage based on HM contamination risk, should include not only the total HM content but also the potential for HM mobility, which can increase the risk of plant contamination. Where HM mobility data are not available, soil parameter data that influence HM mobility can be used to predict the potential HM soil contamination hazard.     

Influence of cultivar and concentration of selected phenolic constituents on the in vitro chemiopreventive potential of olive oil extracts

One of the main olive oil phenolic compounds, hydroxytyrosol (3,4-DHPEA), exerts in vitro chemopreventive activities (antiproliferative and pro-apoptotic) on tumor cells through the accumulation of H(2)O(2) in the culture medium. However, the phenol composition of virgin olive oil is complex, and 3,4-DHPEA is present at low concentrations when compared to other secoiridoids. In this study, the in vitro chemopreventive activities of complex virgin olive oil phenolic extracts (VOO-PE, derived from the four Italian cultivars Nocellara del Belice, Coratina, Ogliarola, and Taggiasca) were compared to each other and related to the amount of the single phenolic constituents. A great chemopreventive potential among the different VOO-PE was found following this order: Ogliarola > Coratina > Nocellara > Taggiasca. The antiproliferative and pro-apoptotic activities of VOO-PE were positively correlated to the secoiridoid content and negatively correlated to the concentration of both phenyl alcohols and lignans. All extracts induced H(2)O(2) accumulation in the culture medium, but this phenomenon was not responsible for their pro-apoptotic activity. When tested in a complex mixture, the olive oil phenols exerted a more potent chemopreventive effect compared to the isolated compounds, and this effect could be due either to a synergistic action of components or to any other unidentified extract constituent.     

Bound fatty acids modulate the sensitivity of bovine β-lactoglobulin to chemical and physical denaturation

Fatty acids are the natural ligands associated with the bovine milk lipocalin, β-lactoglobulin (BLG), and were identified by means of mass spectrometry. The naturally bound ligands were found to contribute to the stability of the proteins toward denaturation by both temperature and chaotropes. To assess the nature of the structural regions involved in this stabilization, the thermodynamic and kinetic aspects of the stability of various structural regions of the proteins were studied in the presence of bound palmitate, which is the most abundant natural ligand. Binding of a single palmitate molecule was found to affect not only the stability of the calyx region, where palmitate is bound, but also that of the region at the hydrophobic interface between the barrel itself and the long helix in the protein structure, where the thiol group of Cys121 is buried. This region is known to be essential for the stability of the BLG dimer and is relevant to the generation of "reactive monomers" that are involved in covalent and noncovalent polymerization of BLG and in the formation of covalent adducts with other milk proteins.     

The larch wood pasture: structure and dynamics of a cultural landscape

As a consequence of land abandonment and marginalization, open areas and traditionally managed wood pastures are disappearing from many alpine valleys. Landscape and stand scale dynamics were analyzed in two neighboring inner valleys of central Italian Alps (Valmalenco, SO) dominated by larch (Larix decidua Mill.) forests and experiencing different historical land use intensities. Land cover mapping obtained from object-oriented analysis of aerial photographs was used to quantify land cover changes between 1961 and 2003. Spatial statistics were used to quantify landscape patterns, and intensive sampling in permanent plots was employed to perform point pattern analysis at the stand scale. Expansion of forested area at the expense of wood pastures was the main land cover transition observed. Differences in land use intensities were responsible for different patterns at the landscape scale: (1) heavier grazing and human pressure created a more diverse and fragmented mosaic of meadows, open woodlands, forests and wood pastures, (2) lower human impact favored a more homogeneous and stable system. A decline in grazing pressure in the late 1970s favored the establishment of larch and spruce in a clustered pattern, typical of the subalpine belt. Subalpine wood pastures, likewise many other semi-natural environments, are in danger of disappearing and lose their productive and cultural characteristics, because they are developing into more closed and dense stands.