The role of the mitochondrial Na/Ca-exchanger (mNCX) in hearts exposed to ischemia-reperfusion (I/R) and pretreated with cardioplegia (CPG) was studied from a mechano-calorimetric approach. No-flow ischemia (ISCH) and reperfusion (REP) were developed in isolated rat hearts pretreated with 10 micromol/L clonazepam (CLZP), an inhibitor of the mNCX, and (or) a high K+ - low Ca2+ solution (CPG). Left ventricular end diastolic pressure (LVEDP), pressure development during beats (P), and the steady heat release (Ht) were continuously measured and muscle contents of ATP and PCr were analyzed at the end of REP. During REP, Ht increased more than P, reducing muscle economy (P/Ht) and the ATP content. CPG induced an increase in P recovery during REP (to 90% +/- 10% of preISCH) with respect to nonpretreated hearts (control, C, to 64% +/- 10%, p < 0.05). In contrast, CLZP reduced P recovery of CPG-hearts (50% +/- 6.4%, p < 0.05) and increased LVEDP in C hearts. To evaluate effects on sarcoplasmic reticulum (SR) function, ischemic hearts were reperfused with 10 mmol/L caffeine -36 mmol/L Na (C - caff - low Na). It increased LVEDP, which afterwards slowly relaxed, whereas Ht increased (by about 6.5 mW/g). CLZP sped up the relaxation with higher DeltaHt, C - caff - low Na produced higher contracture and lower Ht in perfused than in ischemic hearts. Values of DeltaHt were compared with reported fluxes of Ca2+-transporters, suggesting that mitochondria may be in part responsible for the DeltaHt during C - caff - low Na REP. Results suggest that ISCH-REP reduced the SR store for the recovery of contractility, but induced Ca2+ movement from the mitochondria to the SR stores. Also, mitochondria and SR are able to remove cytosolic Ca2+ during overloads (as under caffeine), through the mNCX and the uniporter. CPG increases Ca2+ cycling from mitochondria to the SR, which contributes to the higher recovery of P. In contrast, CLZP produces a deleterious effect on ISCH-REP associated with higher heat release and reduced resynthesis of high energy phosphates, which suggests the induction of mitochondrial Ca cycling and uncoupling.

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Honeys from different regions of the province of Buenos Aires were stored at ؊20؇C, and factors that affect crystallization were analyzed. Crystals were observed by light microscopy. Firmness, adhesivity and viscosity of the samples were measured. Honey was characterized by determining the water activity, turbidity, moisture, fructose, and glucose contents. Results show that the viscous characteristics of the samples depend on the number, size, and disposition of crystals. Various honey samples exhibited Newtonian, pseudoplastic, and thixotropic behaviors. Crystallization was favored at higher moisture contents, suggesting that the parameters that affect honey crystallization at room temperature have a different effect at freezing temperatures. Honey that presented higher values of firmness had a moisture content lower than 17%, and a linear inverse relationship was observed between the adhesivity and firmness of honey samples.

The effects of honey, lemon juice, and two different whey protein concentrates (WPC) on the structural and functional properties of biscuits, were analysed. Firmness, elasticity, relaxation time, adhesiveness, consistency and cohesiveness of dough and colour, fracture stress and fracture strain of biscuits were also determined. The presence of WPC with a high protein content produced a decrease in the firmness and consistency and an increase in the cohesiveness of dough. Honey increased the adhesiveness of dough, mainly in samples with the WPC of lower protein content and lemon juice, and tended to decrease dough relaxation time. The fracture stress of biscuits decreased with the incorporation of WPC. Also, honey increased the red undertone and yellowness of biscuits and decreased their lightness; however, the addition of lemon juice reduced these effects.

The aim of the present study was to present new evidence supporting the use of saliva as a biological fluid in relative bioavailability studies. Carbamazepine was chosen as a model drug because of its suitability for salivary therapeutic drug monitoring and its well-documented plasma bioavailability. A relative bioavailability study of four different immediate release carbamazepine products was performed. Stimulated saliva samples were collected by chewing on parafilm wax and by the spitting method. In vitro dissolution testing of formulations, using 900 ml of 1% sodium lauryl sulphate in water, was also carried out. The in vitro-in vivo correlations obtained in this salivary study were consistent with previous correlations assessed using plasma. These results support the suitability of saliva as the biological fluid in relative bioavailability studies.

The role of lipid oxidation and humidity absorption on the shelf life of biscuits was analysed. Biscuits with low lipid and sugar content were prepared employing different oils, and texture changes that biscuits experience during storage were studied. Water activity, peroxide value, malonaldehyde content and colour were also determined at different storage times. The maximum peroxide level was between 1 and 1.5 mmol kg À1 of oil, at 166 days of storage. Values of malonaldehyde were between 5.2 and 15.8 nmol g À1 of dry sample. Water activity and peroxide value influence the biscuit texture (P ≤ 0.05). To study the effects of both factors simultaneously, a mathematical model was adjusted to the data. Results indicate that an increase in the peroxide level, even at low level of lipid oxidation, increases Young's modulus and leads to a harder biscuit, while the humidity absorption lowers the fracture stress and Young's modulus.

Araucaria angustifolia and Araucaria araucana are conifers that cover different areas of South America. Their seeds have been consumed from prehistoric times until today in Brazil, Argentina and Chile. In this work, the starch of Araucaria angustifolia and Araucaria araucana seeds were analysed by light and environmental scanning electron microscopy, X‐ray diffraction, and differential scanning calorimetry. The starch granules of A. angustifolia and A. araucana were round or slightly oval, with a central hilum. Both starches gave X‐ray diffraction patterns compatible with the A‐type, with strong peaks at 15°, 17°, and 23°. The gelatinisation temperature of A. angustifolia starch (68.5°C) was higher than that of A. araucana (66.6°C), probably due to the higher amylose content of the former (22.4 % and 17.3 %, respectively). The thermograms of A. araucana starch presented a minor peak at about 71°C, which was attributed to the fact that the starch granules population of A. araucana was heterogeneous, with large and small granules, whereas A. angustifolia starch contained mainly large granules.