1,721,032 research outputs found
Polymers and Food Packaging: A Short Overview
No full textA discussion on the state-of-the-art performance of biopolymers and functional biopolymers, focusing on food packaging applications, is presented in this chapter. An overview is given of the most important materials used for producing biobased films, their limitations, recycling pattern, and solutions thereof. Furthermore, transport phenomena and regulation concerns are extensively treated
Functional Polymers for Food Processing
No full textPolymeric materials can be used as functional elements for reaching an efficient food production and processing, with considerable advantages for the whole food industry. Among others, the applicability of polymers involves their use in agriculture, animal feed, modification of food rheology, and the development of functional food and nutraceutics
Functional Polymers in Food Science: From Technology to Biology
No full textPolymers are an important part in everyday life; products made from polymers range from sophisticated articles, such as biomaterials, to aerospace materials. One of the reasons for the great popularity exhibited by polymers is their ease of processing. Polymer properties can be tailored to meet specific needs by varying the "atomic composition" of the repeat structure, by varying molecular weight and by the incorporation (via covalent and non-covalent interactions) of an enormous range of compounds to impart specific activities. In food science, the use of polymeric materials is widely explored, from both an engineering and a nutraceutical point of view. Regarding the engineering application, researchers have discovered the most suitable materials for intelligent packaging which preserves the food quality and prolongs the shelf-life of the products. Furthermore, in agriculture, specific functionalized polymers are used to increase the efficiency of treatments and reduce the environmental pollution. In the nutraceutical field, because consumers are increasingly conscious of the relationship between diet and health, the consumption of high quality foods has been growing continuously. Different compounds (e.g. high quality proteins, lipids and polysaccharides) are well known to contribute to the enhancement of human health by different mechanisms, reducing the risk of cardiovascular disease, coronary disease, and hypertension. This first volume, of this two volume book, concerns the application of polymers in food packaging
Determination of biogenic amine profiles in conventional and organic cocoa-based products
No full textCocoa contains a lot of compounds knowing to influence consumers health, as biogenic amines (BAs). Spermine, spermidine, putrescine, histamine, tyramine, -phenylethylamine, cadaverine and serotonine have been determined in several cocoa-based products by LC-UV after derivatization with dansyl-chloride. Once optimized in terms of linearity, recovery percentages, LOD, LOQ and repeatability, the method has been applied to real samples. Total BAs concentration ranged from 5.7 μg g-1 to 79.0 μg g-1 with wide variations depending on the sample. BAs present in all samples were, in decreasing order, HIS (1.9-38.1 μg g-1) and TYR (1.7-31.7 μg g-1), while PUT (0.9-32.7 μg g-1), SPD (1.0-9.7 μg g-1) and SPM (0.6-9.3 μg g-1) were present in most of the samples. CAD, SER and PHE are in few samples at much lower concentrations. Organic samples always contained much lower BAs levels than their conventional counterparts and, generally speaking, the highest BAs amounts has been found in the most processed products
Molecularly Imprinted Polymers Based On Amidic Functional Monomers For Selective Recognition Of Cholesterol In Aqueous Media
No full textThe aim of this work was to investigate the possibility of employing
amidic functional monomers for the preparation of Molecularly
Imprinted Polymers (MIPs) able to bind selectively cholesterol in aqueous
media. For this purpose, Acrylamide and N,N-Dimethylacrylamide were
employed in order to maximize the hydrogen bound forming both in
pre-polymerization complex and in rebinding experiments which were
performed in polar solvents; in particular, an acetonitrile:water (7:3 v/
v) mixture was employed. The so obtained matrices showed a good
binding capacity towards the template molecule, they bound, indeed,
much more cholesterol than the corresponding non-imprinted ones.
Finally, the polymers affinity for cholesterol and its selectivity using two
steroids quite similar to cholesterol such as progesterone and
hydrocortisone. The synthesized materials, showed a good selectivity,
because they recognised less effectively the two analogues
Flavonoid-based pH-responsive hydrogels as carrier of unstable drugs in oxidative conditions
No full textIn this study, pH-responsive hydrogels, synthesized by the coupling reaction of polyacrylic acid and catechin, are proposed as carriers of oxidable drugs toward the GI tract. The presence of polyphenolic moieties in the network gives the polymers properties suitable for the release of unstable drugs in oxidative conditions. The characterization of the hydrogels is obtained by means of morphological and physico-chemical analyses, antioxidant assays and evaluation of the swelling behavior in media simulating the gastric (pH 1.0) and the intestinal (pH 7.4) tracts. The hydrogels are tested as pH-responsive carriers in in vitro release studies of folic acid and thiamine, two model drugs easily degraded by oxidative conditions simulated by UV irradiation and t-butyl hydroperoxide treatment, respectively. Results show that catechin-based carriers are able to control the release of drugs at different pH values, giving a remarkable improvement in the stability of the therapeutics
Extraction Efficiency of Different Solvents and LC-UV Determination of Biogenic Amines in Tea Leaves and Infusions
No full textBiogenic amines (BAs), that is, spermine, spermidine, putrescine, histamine, tyramine, β-phenylethylamine, cadaverine, and serotonin, have been determined in several samples of tea leaves, tea infusions, and tea drinks by LC-UV method after derivatization with dansyl chloride. Different extraction solvents have been tested and TCA 5% showed better analytical performances in terms of linearity, recovery percentages, LOD, LOQ, and repeatability than HCl 0.1 M and HClO4 0.1 M and was finally exploited for the quantitative determination of BAs in all samples. In tea leaves total BAs concentration ranged from 2.23 μg g−1 to 11.24 μg g−1 and PUT (1.05–2.25 μg g−1) and SPD (1.01–1.95 μg g−1) were always present, while SER (nd–1.56 μg g−1), HIS (nd–2.44 μg g−1), and SPM (nd–1.64 μg g−1) were detected more rarely. CAD and PHE were determined in few samples at much lower concentrations while none of the samples contained TYR. Tea infusions showed the same trend with total BAs concentrations never exceeding 80.7 μg L−1. Black teas showed higher amounts of BAs than green teas and organic and decaffeinated samples always contained much lower BAs levels than their conventional counterparts
Food Analysis: A Brief Overview
No full textFood products are complex mixtures consisting of naturally occurring compounds with nutritional value and contaminating substances, generally originating from technological processes, agrochemical treatments, or packaging materials. Since the exact content of a food product must be assessed before it can be put on the market, routine and/or specialized analysis protocols have been pointed out for the characterization of all compounds present in food and beverages. ThThe main approaches involve separation methods (e.g., chromatography), spectroscopic and biologically derived protocols. By developing effiffi cient methodology with high reproducibility and low detection limits, high quality and safety standards can be achieved to fit the developed government regulations
BIOMACROMOLECULES IN RADICAL PROCESSES: INNOVATIVE STRATEGIES FOR THE SYNTHESIS OF BIOMATERIALS
No full textNatural polymers, such as polysaccharides and proteins, are materials extensively investigated due to their biocompatibility, biodegradability and non-toxic and non-immunogenic characteristics. Enclosing the biomacromolecules, in a complex structure, these features can be transferred to a biomaterial in order to extend the performance of the device. Basically, the synthesis of bioconjugates, by insertion of natural polymers in a macromolecular network by radical polymerization processes, can be achieved employing two different synthetic approaches. The first method involves the chemical modification of the biomacromolecules to introduce functionality able to undergo radical polymerization reactions. In addition, polysaccharides and proteins, without any functional changes, can take part in graft radical polymerization reactions that involve the heteroatoms of the substrates. Both synthetic approaches allows to prepare biocompatible bioconjugates showing improved physico-chemical and mechanical properties respect to the starting natural species. Furthermore, radical polymerization of biomacromolecules with monomeric species bearing specific functionality, carry out to the synthesis of polymeric network that undergo a phase transition process in response to external stimuli changes (temperature, pH, magnetic and electric field). These findings showed that the radical polymerization techniques, improving the performance of natural polymer, represent an innovative tools for the preparation of macromolecular devices potentially useful in pharmaceutical and biomedical field
Synthesis of protein-based hydrogel for pharmaceutical and biomedical applications
No full textNatural polymers, such as proteins, are materials extensively investigated due to their biocompatibility, biodegradability and non-toxic and non-immunogenic characteristics. Enclosing these biomacromolecules in a complex structure, these features can be transferred to a biomaterial in order to extend the performance of the device. Thus, the covalent conjugation of a biodegradable macromolecule, as a protein, represents a versatile strategy to produce intelligent biodegradable hydrogels, suitable for pharmaceutical and biomedical applications. The cross-linking of biomacromolecules is somewhat important in these fields because it increase the mechanical properties of the hydrogels without to affect, in severe degree, the biodegradability. Basically, albumin and gelatin represents the protein mainly used in the biomedical field and their insertion in a polymeric network was performed employing different synthetic strategy involving the functional groups in the side chain of the polypeptides. Hydrogel containing proteic moieties in the polymeric network can be achieved by thermal denaturation of the protein either by direct reaction between functional groups (usually carboxyl and amino goups) in the polypeptide side chains and also by use chemical cross-linking agents as bifunctional carbonyl reagents. Finally, involving the protein in a radical process innovative synthetic procedures were proposed in order to modify polymeric network composition and to design hydrogels with appropriate and mouldable physicochemical properties
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