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Assays of consumer attitudes, qualitatively via a focus group and quantitatively through questionnaires, determined that freshness of produce, fish and poultry is important to consumers, but because of the availability of fresh foods and ready access to refrigeration, there is no real demand to extend the shelf-life of foods. Consumers initially respond negatively to the idea of irradiated food, but information about the process and long-term experimental feeding results, as well as straightforward labelling terminology (no euphemisms) will influence some consumers to purchase and try irradiated foods. 相似文献
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MARTA ABREU CARLA ALEGRIA ELSA M. GONALVES JOAQUINA PINHEIRO MARGARIDA MOLDO‐MARTINS JOS EMPIS 《Journal of food quality》2011,34(5):315-326
ABSTRACT
Response surface methodology based on a five‐level, three‐variable central composite rotatable design was used for modeling the effects of preheat treatments on fresh‐cut “Rocha” pear quality. Studied variables were time (t: 0–150 min), temperature (T: 20–50C) and posttreatment storage time (St: 0–20 days, 5C). The quality‐affecting parameters including color, firmness, pH, soluble solid content, and total ascorbic acid content were the monitored dependent variables. Results provide reasonable estimation of the impact of preheat treatments on the quality of fresh‐cut “Rocha” pear and its shelf life. The time–temperature range of 33–41C during less than 20 min was selected as the conditions that best provided surface browning control, without impairing other studied quality parameters, with an estimated 8‐day shelf life period. The achieved kinetic changes of polyphenoloxidase, partial reduction in enzyme activity (ca. 23%) and depletion of phenolic content (ca. 11%) could be responsible for the browning control.PRACTICAL APPLICATIONS
Minimal processing, namely cutting operations, triggers physiological reactions which limit fresh‐cut Rocha pear shelf life. Superficial browning is one of the major concerns to this industry, and new “clean” methodologies aiming at the inhibition of such reaction and maximization of the product shelf life will benefit not only from product marketability but also will respond to the consumers' demand of “chemical free” products. Heat treatments have been used to improve fresh‐cut commodities' browning resistance. The present work evaluated the use of preheat treatments against this physiological disorder during storage. Results will provide an optimized preheat treatment that grants high‐quality fresh‐cut Rocha pear with suitable shelf life.3.
RAFAEL SCAF DE MOLON MARTA MARIA ALVES PEREIRA ERICA DORIGATTI DE AVILA 《Biocell》2022,46(5):1151-1156
It has been recognized that physical and chemical properties of biomaterial surfaces mediate the quality of extracellular matrix (ECM) that may affect cell behaviors. In nature, ECM is a heterogeneous three-dimensional superstructure formed by three major components, glycosaminoglycan, glycoconjugate, and protein, that anchors cellular compartments in tissues and regulates the function and the behavior of cells. Changes in the biointerface alter the quality of ECM and morphology through cell surface receptors, which, in turn, enable it to trigger specific cell signaling and different cellular responses. In fact, a number of strategies have been used to improve the functionality of surfaces and direct cell behavior through precisely designed environments. Herein, we aimed to discuss, through a science-based viewpoint, the biomaterial surface features on cell behavior and analyze the impact of cell physical modification on dental implant development. 相似文献
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GIOVANNA CERVATO MARTA CARABELLI SILVIA GERVASIO REA CITTERA ROBERTA CAZZOLA BENVENUTO CESTARO 《Journal of Food Biochemistry》2000,24(6):453-465
We tested the antioxidant properties of both aqueous and methanolic extracts of oregano (origanum vulgare) They proved to be effective in the inhibition of all phases of the peroxidative process: first neutralizing free radicals (superoxide anion, hydroxyl radical and 1,1‐diphenyl‐2‐picrylhydrazyl radical), then blocking peroxidation catalysis by iron (through iron‐chelating and iron‐oxidizing properties), and finally through interruption of lipid‐radical chain reactions (chain‐breaking activity). Their anti‐glycosylation activity was also effective. The glycosylation oflipoproteins is directly related to their peroxidation. The amount of extract used in our experiments was obtained from 0.1–1 mg of dried leaves, amounts far less than those normally used in the Mediterranean diet. 相似文献
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ENRIQUE ROTSTEIN PATRICIO A. LAURA MARTA E. de CEMBORAIN 《Journal of food science》1974,39(3):627-631
A study is made to develop a tool to predict drying performance of nonconventional shapes. Many food drying processes are diffusion-controlled. An approximated analytical solution to Fick's diffusion equation is given for bodies which have a cardioidal, corrugated, circular, epitrochoidal, square, or hexagonal cross section. A conformal mapping approach is used to obtain the concentration distribution and the result is integrated over the volume to yield analytical weight loss equations for each shape. The result is applied to compare drying performance of apples on an equal weight-equal cross sectional area or an equal weight-equal thickness basis. 相似文献
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ROLE OF WATER IN THE KINETIC MODELING OF METHANOL TRANSFORMATION INTO HYDROCARBONS ON HZSM-5 ZEOLITE
ANA G. GAYUBO ANDRES T. AGUAYO MARTA CASTILLA ANGEL L. MORAN JAVIER BILBAO 《Chemical Engineering Communications》2013,200(7):944-967
The attenuating effect of reaction-medium water (feed and/or reaction product) on the kinetics of the steps of methanol transformation into hydrocarbons on a HZSM-5 zeolite catalyst was studied by means of a kinetic model. In this model, the effect of water was quantified in all the steps of the kinetic scheme by means of a kinetic parameter, which is constant with temperature under the conditions of the MTG process. At low temperature, under conditions in which only methanol dehydration occurs, the kinetics of this reaction is attenuated by the presence of water, and the coefficient that quantifies the attenuation decreases as temperature is increased. In addition to considering the effect of water content in the reaction medium, another innovation of the kinetic model proposed, compared to those proposed in the literature consisting of lumps, is the fact that the higher reactivity of dimethyl ether over methanol is taken into account. A step of cracking of gasoline lump hydrocarbons to produce light olefins (ethene and propene) was also taken into account. The kinetic model proposed was verified by using the results obtained in an integral isothermal fixed bed reactor, in the 573–723 K range, for an ample range of space time values. The results revealed that the effect of water is due to its adsorption on the active sites by competition with the intermediate compounds of the kinetic scheme. 相似文献
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Polar lipids extracted from heated, nitrite-treated meats by a dry column procedure contain pigmented contaminants that interfere with subsequent analyses. Three modifications to the standard extraction procedure were studied: (a) changes in the composition of the trap, (b) insertion of additional material between column proper and trap, and (c) changes in the solvent system. Most satisfactory results were obtained by the addition of magnesium oxide to the trap (I). This resulted in the retention of impurities on the column and provided convenient, trouble-free operation. Polar lipids isolated in this manner were free of peroxides. Uncontaminated lipids were extracted from commercially processed meats by use of the modified procedure. 相似文献
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ROBERT DUBIN 《国际通用系统杂志》2013,42(1):107-113
In the study of social systems a causal orientation leads to the familiar two-variable analysis of components of the systems, rather than the analysis of the characteristics of the system as a whole. The result is that predictions made about social systems are usually either wrong or trivially correct. A general systems approach docs not lean on causal analysis and, therefore, provides the analytical framework for comprehending system characteristics, and predicting their state. 相似文献