Sensory characteristics of 'Douradão' peaches submitted to modified atmosphere packaging

The sensory, physical and chemical characteristics of 'Douradão' peaches cold stored in different modified atmosphere packaging (LDPE bags of 30, 50, 60, 75µm thickness) were studied. After 14, 21 and 28 days of cold storage (1 ± 1 ºC and 90 ± 5% RH), samples were withdrawn from MAP and kept during 4 days in ambient air for ripening. Descriptive terminology and sensory profile of the peaches were developed by methodology based on the Quantitative Descriptive Analysis (QDA). The assessors consensually defined the sensory descriptors, their respective reference materials and the descriptive evaluation ballot. Fourteen individuals were selected as judges based on their discrimination capacity and reproducibility. Seven descriptors were generated showing similarities and differences among the samples. The data were analysed by ANOVA, Tukey test and Principal Component Analysis (PCA). The atmospheres that developed inside the different packaging materials during cold storage differed significantly. The PCA showed that MA50 and MA60 treatments were more characterized by the fresh peach flavour, fresh appearance, juiciness and flesh firmness, and were effective for keeping good quality of 'Douradão' peaches during 28 d of cold storage. The Control and MA30 treatments were characterized by the mealiness, the MA75 treatment showed lower intensity for all attributes evaluated and they were ineffective to maintain good quality of the fruits during cold storage. Higher correlation coefficients (positive) were found between fresh appearance and flesh firmness (0.95), fresh appearance and juiciness (0.97), ratio and intensity of fresh peach smell (0.81), as well as higher correlation coefficients (negative) between Hue angle and intensity of yellow colour (-0.91), fresh appearance and mealiness (-0.92), juiciness and mealiness (-0.95), firmness and mealiness (-0.94).

Chemical, physico-chemical and sensory characterization of mixed açai (Euterpe oleracea) and cocoa´s honey (Theobroma cacao) jellies

Four formulations of mixed açaí (Euterpe oleracea) (A) and cocoa´s honey (Theobroma cacao) (CH) jellies were prepared according to the following proportions: T1 (40% A:60% CH), T2 (50% A:50% CH), T3 (60% A: 40% CH) and T4 (100% A - control). All formulations were prepared using a rate 60:40 (w/w) of sucrose and pulp, plus 0.5% pectin and the products reached to average of 65% soluble solids content. The jellies were analyzed by chemical and physicochemical (titratable acidity, pH, soluble solid content, dry matter, total protein, lipids, vitamin C and calories) and sensory characteristics; also were evaluated levels of P, K, Ca, Mg, Fe, Zn, Cu and Mn. It was used a hedonic scale of 7 points to evaluate the attributes: overall impression, spreadability, brightness, flavor, texture and color, and also was verified the purchase intention score. The titratable acidity and pH ranged from 0.46 to 0.64% and 3.35 to 3.64, respectively, that are within the range found at most fruit jellies. The soluble solids content ranged between 65.2 and 65.5 ºBrix. The sensory acceptance results showed that all treatments (T1, T2, T3 and T4) presented means of sensory attributes above 4, demonstrating good acceptance of the product, but the treatment T1 presented the higher scores for the evaluated attributes. Cocoa´s honey added a positive influence on the attributes of color, texture and spreadability.

Sensory profiles of chocolates produced from cocoa cultivars resistant to Moniliophtora Perniciosa

The present study evaluated the sensory quality of chocolates obtained from two cocoa cultivars (PH16 and SR162) resistant to Moniliophtora perniciosa mould comparing to a conventional cocoa that is not resistant to the disease. The acceptability of the chocolates was assessed and the promising cultivars with relevant sensory and commercial attributes could be indicated to cocoa producers and chocolate manufacturers. The descriptive terminology and the sensory profile of chocolates were developed by Quantitative Descriptive Analysis (QDA). Ten panelists, selected on the basis of their discriminatory capacity and reproducibility, defined eleven sensory descriptors, their respective reference materials and the descriptive evaluation ballot. The data were analyzed using ANOVA, Principal Component Analysis (PCA) and Tukey's test to compare the means. The results revealed significant differences among the sensory profiles of the chocolates. Chocolates from the PH16 cultivar were characterized by a darker brown color, more intense flavor and odor of chocolate, bitterness and a firmer texture, which are important sensory and commercial attributes. Chocolates from the SR162 cultivar were characterized by a greater sweetness and melting quality and chocolates from the conventional treatment presented intermediate sensory characteristics between those of the other two chocolates. All samples indicated high acceptance, but chocolates from the PH16 and conventional cultivars obtained higher purchase intention scores.

Anatomy and physiology of Cattail as related to different population densities

The objective of this work was to evaluate the effects of the population density of Typha angustifolia plants in the anatomical and physiological characteristics. Plants were collected from populations of high density (over 50% of colonization capacity) and low density (less than 50% of colonization capacity) and cultivated under controlled greenhouse conditions. Plants from both populations were grown in plastic trays containing 4 L of nutritive solution for 60 days. At the end of this period, the relative growth rate, leaf area ratio, net assimilatory rate, root/shoot ratio, leaf anatomy, root anatomy, and catalase and ascorbate peroxidase activities were evaluated. Plants from high density populations showed increased growth rate and root/shoot ratio. Low density populations showed higher values of stomatal index and density in leaves, as well as increased palisade parenchyma thickness. Root epidermis and exodermis thickness as well as the aerenchyma proportion of high density populations were reduced, these plants also showed increased vascular cylinder proportion. Only catalase activity was modified between the high and low density populations, showing increased values in low density populations. Therefore, different Typha angustifolia plants show differences in its anatomy and physiology related to its origins on high and low density conditions. High density population plants shows increased growth capacity related to lower apoplastic barriers in root and this may be related to increased nutrient uptake capacity.

Leukocyte adhesion - a fundamental process in leukocyte physiology

Leukocyte adhesion is of pivotal functional importance. The adhesion involves several different adhesion molecules, the most important of which are the leukocyte ß2-integrins (CD11/CD18), the intercellular adhesion molecules, and the selectins. We and others have extensively studied the specificity and binding sites in the integrins and the intercellular adhesion molecules for their receptors and ligands. The integrins have to become activated to exert their functions but the possible mechanisms of activation remain poorly understood. Importantly, a few novel intercellular adhesion molecules have been recently described, which seem to function only in specific tissues. Furthermore, it is becoming increasingly apparent that changes in integrins and intercellular adhesion molecules are associated with a number of acute and chronic diseases.

An update on the physiology of two- and three-toed sloths

Physiological and pharmacological research undertaken on sloths during the past 30 years is comprehensively reviewed. This includes the numerous studies carried out upon the respiratory and cardiovascular systems, anesthesia, blood chemistry, neuromuscular responses, the brain and spinal cord, vision, sleeping and waking, water balance and kidney function and reproduction. Similarities and differences between the physiology of sloths and that of other mammals are discussed in detail.

Apoptosis of sensory neurons and satellite cells after sciatic nerve transection in C57BL/6J mice

The rate of axonal regeneration, after sciatic nerve lesion in adult C57BL/6J mice, is reduced when compared to other isogenic strains. It was observed that such low regeneration was not due just to a delay, since neuronal death was observed. Two general mechanisms of cell death, apoptosis and necrosis, may be involved. By using the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) technique, we demonstrated that a large number of sensory neurons, as well as satellite cells found in the dorsal root ganglia, were intensely labeled, thus indicating that apoptotic mechanisms were involved in the death process. Although almost no labeled neurons or satellite cells were observed one week after transection, a more than ten-fold increase in TUNEL labeling was detected after two weeks. The results obtained with the C57BL/6J strain were compared with those of the A/J strain, which has a much higher peripheral nerve regeneration potential. In A/J mice, almost no labeling of sensory neurons or satellite cells was observed after one or two weeks, indicating the absence of neuronal loss. Our data confirm previous observations that approximately 40% of C57BL/6J sensory neurons die after sciatic nerve transection, and indicate that apoptotic events are involved. Also, our observations reinforce the hypothesis that the low rate of axonal regeneration occurring in C57BL/6J mice may be the result of a mismatch in the timing of the neurons need for neurotrophic substances, and production of the latter by non-neuronal cells in the distal stump.

The brain decade in debate: VI. Sensory and motor maps: dynamics and plasticity

This article is an edited transcription of a virtual symposium promoted by the Brazilian Society of Neuroscience and Behavior (SBNeC). Although the dynamics of sensory and motor representations have been one of the most studied features of the central nervous system, the actual mechanisms of brain plasticity that underlie the dynamic nature of sensory and motor maps are not entirely unraveled. Our discussion began with the notion that the processing of sensory information depends on many different cortical areas. Some of them are arranged topographically and others have non-topographic (analytical) properties. Besides a sensory component, every cortical area has an efferent output that can be mapped and can influence motor behavior. Although new behaviors might be related to modifications of the sensory or motor representations in a given cortical area, they can also be the result of the acquired ability to make new associations between specific sensory cues and certain movements, a type of learning known as conditioning motor learning. Many types of learning are directly related to the emotional or cognitive context in which a new behavior is acquired. This has been demonstrated by paradigms in which the receptive field properties of cortical neurons are modified when an animal is engaged in a given discrimination task or when a triggering feature is paired with an aversive stimulus. The role of the cholinergic input from the nucleus basalis to the neocortex was also highlighted as one important component of the circuits responsible for the context-dependent changes that can be induced in cortical maps.

Role of sensory nervous system vasoactive peptides in hypertension

The goal of the present research was to elucidate the roles and mechanisms by which the sensory nervous system, through the actions of potent vasodilator neuropeptides, regulates cardiovascular function in both the normal state and in the pathophysiology of hypertension. The animal models of acquired hypertension studied were deoxycorticosterone-salt (DOC-salt), subtotal nephrectomy-salt (SN-salt), and Nomega-nitro-L-arginine methyl ester (L-NAME)-induced hypertension during pregnancy in rats. The genetic model was the spontaneously hypertensive rat (SHR). Calcitonin gene-related peptide (CGRP) and substance P (SP) are potent vasodilating neuropeptides. In the acquired models of hypertension, CGRP and SP play compensatory roles to buffer the blood pressure (BP) increase. Their synthesis and release are increased in the DOC-salt model but not in the SN-salt model. This suggests that the mechanism by which both models lower BP in SN-salt rats is by increased vascular sensitivity. CGRP functions in a similar manner in the L-NAME model. In the SHR, synthesis of CGRP and SP is decreased. This could contribute to the BP elevation in this model. The CGRP gene knockout mouse has increased baseline mean arterial pressure. The long-term synthesis and release of CGRP is increased by nerve growth factor, bradykinin, and prostaglandins and is decreased by alpha2-adrenoreceptor agonists and glucocorticoids. In several animal models, sensory nervous system vasoactive peptides play a role in chronic BP elevation. In the acquired models, they play a compensatory role. In the genetic model, their decreased levels may contribute to the elevated BP. The roles of CGRP and SP in human hypertension are yet to be clarified.

The conservative physiology of the immune system

Current immunological opinion disdains the necessity to define global interconnections between lymphocytes and regards natural autoantibodies and autoreactive T cells as intrinsically pathogenic. Immunological theories address the recognition of foreignness by independent clones of lymphocytes, not the relations among lymphocytes or between lymphocytes and the organism. However, although extremely variable in cellular/molecular composition, the immune system preserves as invariant a set of essential relations among its components and constantly enacts contacts with the organism of which it is a component. These invariant relations are reflected, for example, in the life-long stability of profiles of reactivity of immunoglobulins formed by normal organisms (natural antibodies). Oral contacts with dietary proteins and the intestinal microbiota also result in steady states that lack the progressive quality of secondary-type reactivity. Autoreactivity (natural autoantibody and autoreactive T cell formation) is also stable and lacks the progressive quality of clonal expansion. Specific immune responses, currently regarded as the fundament of the operation of the immune system, may actually result from transient interruptions in this stable connectivity among lymphocytes. More permanent deficits in interconnectivity result in oligoclonal expansions of T lymphocytes, as seen in Omenn's syndrome and in the experimental transplantation of a suboptimal diversity of syngeneic T cells to immunodeficient hosts, which also have pathogenic consequences. Contrary to theories that forbid autoreactivity as potentially pathogenic, the physiology of the immune system is conservative and autoreactive. Pathology derives from failures of these conservative mechanisms.

Building bone tissue: matrices and scaffolds in physiology and biotechnology

Deposition of bone in physiology involves timed secretion, deposition and removal of a complex array of extracellular matrix proteins which appear in a defined temporal and spatial sequence. Mineralization itself plays a role in dictating and spatially orienting the deposition of matrix. Many aspects of the physiological process are recapitulated in systems of autologous or xenogeneic transplantation of osteogenic precursor cells developed for tissue engineering or modeling. For example, deposition of bone sialoprotein, a member of the small integrin-binding ligand, N-linked glycoprotein family, represents the first step of bone formation in ectopic transplantation systems in vivo. The use of mineralized scaffolds for guiding bone tissue engineering has revealed unexpected manners in which the scaffold and cells interact with each other, so that a complex interplay of integration and disintegration of the scaffold ultimately results in efficient and desirable, although unpredictable, effects. Likewise, the manner in which biomaterial scaffolds are "resorbed" by osteoclasts in vitro and in vivo highlights more complex scenarios than predicted from knowledge of physiological bone resorption per se. Investigation of novel biomaterials for bone engineering represents an essential area for the design of tissue engineering strategies.

Ca2+ signaling in pancreatic acinar cells: physiology and pathophysiology

The pancreatic acinar cell is a classical model for studies of secretion and signal transduction mechanisms. Because of the extensive endoplasmic reticulum and the large granular compartment, it has been possible - by direct measurements - to obtain considerable insights into intracellular Ca2+ handling under both normal and pathological conditions. Recent studies have also revealed important characteristics of stimulus-secretion coupling mechanisms in isolated human pancreatic acinar cells. The acinar cells are potentially dangerous because of the high intra-granular concentration of proteases, which become inappropriately activated in the human disease acute pancreatitis. This disease is due to toxic Ca2+ signals generated by excessive liberation of Ca2+ from both the endoplasmic reticulum and the secretory granules.

Learning about brain physiology and complexity from the study of the epilepsies

The brain is a complex system, which produces emergent properties such as those associated with activity-dependent plasticity in processes of learning and memory. Therefore, understanding the integrated structures and functions of the brain is well beyond the scope of either superficial or extremely reductionistic approaches. Although a combination of zoom-in and zoom-out strategies is desirable when the brain is studied, constructing the appropriate interfaces to connect all levels of analysis is one of the most difficult challenges of contemporary neuroscience. Is it possible to build appropriate models of brain function and dysfunctions with computational tools? Among the best-known brain dysfunctions, epilepsies are neurological syndromes that reach a variety of networks, from widespread anatomical brain circuits to local molecular environments. One logical question would be: are those complex brain networks always producing maladaptive emergent properties compatible with epileptogenic substrates? The present review will deal with this question and will try to answer it by illustrating several points from the literature and from our laboratory data, with examples at the behavioral, electrophysiological, cellular and molecular levels. We conclude that, because the brain is a complex system compatible with the production of emergent properties, including plasticity, its functions should be approached using an integrated view. Concepts such as brain networks, graphics theory, neuroinformatics, and e-neuroscience are discussed as new transdisciplinary approaches dealing with the continuous growth of information about brain physiology and its dysfunctions. The epilepsies are discussed as neurobiological models of complex systems displaying maladaptive plasticity.

TMEM16 proteins: the long awaited calcium-activated chloride channels?

Currents mediated by calcium-activated chloride channels (CaCCs), observed for the first time in Xenopus oocytes, have been recorded in many cells and tissues ranging from different types of neurons to epithelial and muscle cells. CaCCs play a role in the regulation of excitability in neurons including sensory receptors. In addition, they are crucial mediators of chloride movements in epithelial cells where their activity regulates electrolyte and fluid transport. The roles of CaCCs, particularly in epithelia, are briefly reviewed with emphasis on their function in secretory epithelia. The recent identification by three independent groups, using different strategies, of TMEM16A as the molecular counterpart of the CaCC is discussed. TMEM16A is part of a family that has 10 other members in mice. The discovery of the potential TMEM16 anion channel activity opens the way for the molecular investigation of the role of these anion channels in specific cells and in organ physiology and pathophysiology. The identification of TMEM16A protein as a CaCC chloride channel molecule represents a great triumph of scientific perseverance and ingenuity. The varied approaches used by the three independent research groups also augur well for the solidity of the discovery.

New concepts in white adipose tissue physiology

Numerous studies address the physiology of adipose tissue (AT). The interest surrounding the physiology of AT is primarily the result of the epidemic outburst of obesity in various contemporary societies. Briefly, the two primary metabolic activities of white AT include lipogenesis and lipolysis. Throughout the last two decades, a new model of AT physiology has emerged. Although AT was considered to be primarily an abundant energy source, it is currently considered to be a prolific producer of biologically active substances, and, consequently, is now recognized as an endocrine organ. In addition to leptin, other biologically active substances secreted by AT, generally classified as cytokines, include adiponectin, interleukin-6, tumor necrosis factor-alpha, resistin, vaspin, visfatin, and many others now collectively referred to as adipokines. The secretion of such biologically active substances by AT indicates its importance as a metabolic regulator. Cell turnover of AT has also recently been investigated in terms of its biological role in adipogenesis. Consequently, the objective of this review is to provide a comprehensive critical review of the current literature concerning the metabolic (lipolysis, lipogenesis) and endocrine actions of AT.