1,721,003 research outputs found
Impact of dehulling on the physico-chemical properties and in vitro protein digestion of common beans (Phaseolus vulgaris L.)
No full textThe objective of this study was to study the effect of dehulling on the microstructural, physico-chemical characteristics, and in vitro protein digestion of common bean flours with particular regard to differences between adult and infant human beings. The microstructure of flour samples from undehulled (WB) and manually dehulled (SB) beans, observed through scanning electron microscopy, showed that WB starch granules appeared surrounded by an integral matrix, while the SB starch granule structure was still visible although covered by protein clusters. The starch granules were oval and spherical, with heterogeneous sizes ranging from 19 to 30 μm in diameter. Particle size analysis determined with a laser diffraction particle size analyzer showed similar bimodal particle size distributions of small (1–25 μm) and large (>100 μm) granules, though the particle size of WB was obviously higher than SB. Color and other physico-chemical analyses showed that dehulling had significant (P < 0.05) influence on all investigated characteristics. The in vitro gastric and duodenal digestion experiments carried out under physiological conditions showed that the SB samples are more prone to be digested by infants. From our results, it is possible to conclude that the dehulling process improves bean flour nutritional functionality which could be utilized in various food applications
Extraction and Characterization of Fennel Pectins and Their Use to Prepare Biopolymer Films in the Presence of Phaseolin Protein
No full textPectins from Foeniculum vulgare were extracted under acidic conditions. The obtained pectins were mainly composed of uronic acid but also contained traces of rhamnose, galactose, and arabinose. Extracted pectins were used as a carbohydrate source to prepare biopolymer films in the absence and in the presence of phaseolin protein. The swelling characteristics of the films were examined as a function of ionic strength, pH, and the applied osmotic stress. The swelling behavior was dominated by a Donnan-type effect, which decreases with increasing ionic strength and counterion valency. In all cases the swelling of films containing phaseolin was reduced, suggesting a network formation between protein and pectins. Mechanical property studies have also estimated the validity of the obtained novel biopolymer films in terms of mechanical resistanc
Fresh-cut fruit and vegetable coatings by transglutaminase-crosslinked whey protein/pectin edible films
No full textFresh cut apples, potatoes and carrots were coated by a blended whey protein/pectin film, prepared in the presence of transglutaminase, and several properties of the coated and uncoated fruit and vegetable samples were analyzed during their storage. The linear increase in apple weight loss observed during storage was significantly reduced after 10 days when the samples were coated by whey or soy protein isolate films (about 20 and 40%, respectively) but mostly (about 80%) by whey protein film grafted with pectin and transglutaminase. In addition, the latter film was able to totally prevent the weight loss of potato and carrot samples at least until the 6th day of sample storage. Coating by the crosslinked blended film prevented microbial growth in all samples analyzed, also preserving their phenolic content and carotenoid in carrots. Finally, a marked reduction of both hardness and chewiness, detected after ten days of storage in all the uncoated samples by a texture profile analysis, was shown to be effectively counteracted by coating, whereas no significant differences in the acceptability scores of the coated samples after storage, were recorded by a sensory panel with respect to all samples tested before storage
Biodegradable plastics made of fennel waste and transglutaminase-modified phaseolin are suitable for protecting cultivation.
No full textPolyamines as new cationic plasticizers for pectin-based edible films
No full textZeta potential and particle size were determined on pectin aqueous solutions as a function of pH and the effects of calcium ions, putrescine and spermidine on pectin film forming solutions and derived films were studied. Ca(2+) and polyamines were found to differently influence pectin zeta potential as well as thickness and mechanical and barrier properties of pectin films prepared at pH 7.5 either in the presence or absence of the plasticizer glycerol. In particular, Ca(2+) was found to increase film tensile strength and elongation at break only in the presence of glycerol and did not affect film thickness and permeability to both water vapor and CO2. Conversely, increasing polyamine concentrations progressively reduced film tensile strength and markedly enhanced film thickness, elongation at break and permeability to water vapor and CO2, both in the presence and absence of glycerol. Our findings indicate that polyamines give rise to a structural organization of the heteropolysaccharide different from that determined by calcium ions, previously described as "egg box" model, and suggest their possible application as plasticizers to produce pectin-based "bioplastics" with different features
Proteolytic and clotting activity in Cynara scolymus leaves: new horizons for the cheese manufacture
No full textIncreasing cost and shortage of animal rennet have encouraged new researches for different rennet sources. New aspartic proteinases of vegetable origin are nowadays of growing interest for dairy technology (Durante et al., 2009). Among plant species, extract from flowers of Cynara genus is the most used for cheesemaking. In particular, several studies have been performed on the activity and specificity of proteinases from Cynara cardunculus, whereas, the knowledge on the properties of globe artichoke (Cynara scolymus) proteinases is limited because its flower is usually consumed as a vegetable. In this study we have investigated the presence of proteinases in different parts of Cynara scolymus such as leaves, pappus and roots that represent by-products always disposed off by farmers. By measuring the proteolytic activity on k-casein and milk clotting activity with a sensitive method called caseogram (Foltman et al., 1985) we proved that only leaves possess the proteolytic enzymes showing the optimum activity at pH 5. Hence, the proteinases were partially purified through ammonium sulfate precipitation (from 20% to 80% (w/v)) and ion-exchange chromatography. Interestingly, our results demonstrated the presence of two species with a different electrophoretic mobility. Therefore, based on these findings, the present study could suggest the possibility of use such new proteases having proteolytic and clotting activity in cheesemaking
Performance of edible films obtained from Citrus pectins and transglutaminase-modified phaseolin
No full textThe growing social and economic consequences of pollution derived from plastics are focusing attention on the need to produce novel and environmental friendly systems for enhancing food shelf-life. As a consequence, in recent years the use of edible films for food packaging is generating a huge scientific interest. An edible film is defined as a thin film made of natural substances, which gives the film the characteristic of being ingested. Hydrocolloid films are composed of proteins, cellulose derivatives, pectin and other polysaccharides. In particular in this work edible hydrocolloid films were made by using citrus pectins and the protein phaseolin modified by microbial transglutaminase, an enzyme able to catalyze isopeptide bonds between glutamines and lysines into proteins. Our results have demonstrated that such films show technological features (mechanical properties and barrier properties to gases such as CO2, O2 and H2O) comparable to those performed by the commercial plastics. It is worth noting that such characteristics are maintained even following a storage of the films at 4 °C or -20°C suggesting that our bioplastics can be tailored to protect also those foods that need to be frozen or kept in the fridge. Moreover digestibility studies conducted under physiological conditions have demonstrated that such films are easily digested by the human gut
Use of the enzyme transglutaminase to prepare hydrocolloid-based edible films suitable for the food industry
No full textEdible films can be an alternative to chemically synthesized polymeric films that have been assessed not safe for both human health and the environment. The edible film components are usually hydrocolloids and/or lipids. Typical hydrocolloids for edible film production are proteins and polysaccharides, both highly represented in food processing by-products. Films made of these macromolecules, while possess good gas barrier properties towards oxygen and carbon dioxide, exhibit poor mechanical resistance and, due to their hydrophilic features, are somewhat too water-sensitive for applications in foods with high and intermediate moisture (Krochta and Mulder-Johnston, 1997). A strategy to improve hydrocolloid films containing proteins is to create a net structure introducing covalent cross-links. Despite recurring to chemical cross-linkers, it is advisable to use enzymes able to covalently bind proteins. Transglutaminase (TGase), catalyzing the formation of isopeptide bonds between endoprotein glutamine and lysine residues, is an effective tool in reticulating protein component of hydrocolloid-based films as we have recently reviewed (Mariniello et al., 2008). In this work we have obtained edible films recurring to grapefruit albedo homogenates and phaseolin. Films were obtained by casting in the absence and in the presence of the enzyme and characterized for their mechanical and barrier properties. Results indicate that TGase-containing films exhibit features comparable to those of other TGase-made films previously prepared in our laboratories (Mariniello et al., 2008) and of the already commercialized products Ecoflex and MaterBi. Thus albedo-phaseolin films made in the presence of TGase possess features that suggest a wide and healthy use in food industry
Solubility and permeability properties of edible pectin-soy flour films obtained in the absence or presence of transglutaminase
No full textThe permeability characteristics and water-solubility of edible pectin-soy flour films obtained in the absence or presence of the enzyme transglutaminase were investigated and compared with those possessed by both the commonly used high density polyethylene film and the biodegradable Mater-Bi(R) film. The soy protein transglutaminase-catalyzed crosslinking was found to determine a marked decrease in the solubility of the pectin-soy flour films both at different pH and in different denaturing conditions with respect to the films obtained in the absence of the enzyme, even though their solubility remains higher than that of the commercially available polyethylene and Mater-Bi(R) films. Transglutaminase treatment was also shown to significantly increase pectin-soy flour film barrier properties to oxygen, carbon dioxide and water vapour. In particular, the films obtained in the presence of the enzyme exhibited a permeability to oxygen and carbon dioxide even lower than that possessed by polyethylene films. Our results suggest a possible use of the transglutaminase-polymerized pectin-soy flour films as wrapping of food products requiring a packaging allowing low gas exchange with the environment. Furthermore, the application of these films as coatings to conventional oral dosage forms could provide a viable means of delivering drugs to the colon
Transglutaminase decreases water vapor permeability and solubility of different hydrocolloid edible films
No full textEdible film is a thin layer of edible coating which provides a barrier against mass transfer between food and its environment. As the materials used for edible film production are generally biodegradable, edible film can be used as a packaging alternative to synthetic plastics because of its minimal environment contamination. Components used for the preparation of edible films are classified into three categories: hydrocolloids (such as proteins or polysaccharides), lipids (such as fatty acids, acylglycerols or waxes) and composites (made by combining substances from the two previous categories) (Krochta, J.M. & Johnston, C.D.M. 1997. Food Technol., 51:61-74). It has been generally accepted that the hydrocolloid films provide an effective barrier to oxygen, carbon dioxide and lipids but not to water vapor. Moreover, they exhibit high water solubility depending on the hydrophilic nature of their components (Pol et al. 2002. J. Food Sci., 67, 212-217). It is well known that structure of film matrix is influenced by electrostatic, dipole-dipole, hydrophobic interactions as well as by hydrogen and covalent bonds. Hence, various experimental strategies have been carried out to decrease the water vapor permeability and solubility of hydrocolloids films, i.e. the use of particular crosslinking agents through either chemical or enzymatic reactions. Transglutaminase (TGase, E.C. 2.3.2.13) catalyzes the formation of -(-glutamyl)-lysine cross-links into proteins via an acyl transfer reaction. The -carboxamide group of glutamine acts as acyl donor and the -amino group of lysine serves as acyl acceptor to form intra/intermolecular isopeptide bonds (Zhu et al. 1995. App. Microbiol. Biotch., 44: 227-282). In the present study we report the production, in the absence or presence of TGase, of protein-polysaccharide films. Ovalbumin, soy and whey proteins, high- and low-methoxyl pectin, chitosan or fruit purees from strawberry, apricot and feijoa, were used as protein and polysaccharide sources respectively. Our results showed that films containing TGase cross-linked proteins exhibit improved water vapor barrier properties and are less soluble at different pHs compared to films obtained in the absence of TGase
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