8 research outputs found
Effect of Mesoporous Silica Nanoparticles on The Physicochemical Properties of Pectin Packaging Material for Strawberry Wrapping
Citrus peel pectin was used to prepare films (cast with or without glycerol) containing mesoporous silica nanoparticles. Nanoparticles reduced significantly the particle size, and had no effect on the Zeta potential of pectin solutions. Mechanical characterization demonstrates that pectin+nanoparticles containing films slightly increased tensile strength and significantly decreased the Young’s modulus in comparison to films made only of pectin. However, elongation at the break increased in the pectin+nanoparticles films cast in the presence of glycerol, while both Young’s modulus and tensile strength were reduced. Moreover, nanoparticles were able to reduce the barrier properties of pectin films prepared with or without glycerol, whereas positively affected the thermal stability of pectin films and the seal strength. The 0.6% pectin films reinforced or not with 3% nanoparticles in the presence of 30% glycerol were used to wrap strawberries in order to extend the fruit’s shelf-life, over a period of eighty days, by improving their physicochemical properties
Advanced Biomaterials for Food Edible Coatings
The aim of this Special Issue is to highlight recent investigations on different biopolymers obtained from renewable sources for use as edible coatings [...
The Effect of Transglutaminase to Improve the Quality of Either Traditional or Pectin-Coated Falafel (Fried Middle Eastern Food)
In this study, the effect of transglutaminase (TGase) (5 or 20 U/g of chickpea proteins) on falafel dough was investigated. The resulting falafel balls were either treated or not by dipping them into a pectin (PEC 1%) coating solution. Acrylamide (ACR), oil, and water content were then evaluated. Texture profile analyses and in vitro gastric digestion experiments were also carried out. The ACR content was reduced by 10.8% and by 34.4% in the samples prepared with 5 and 20 U TGase/g, respectively. In PEC-coated samples, the reduction of ACR was equal to 59.3%, 65.3%, and 84.5%, in falafel balls prepared either without TGase or containing 5 U or 20 U of the enzyme, respectively. However, TGase treatment did not affect oil content, while the PEC coating reduced oil uptake by 23.5%. No difference was observed in the texture properties between the control sample and the one dipped in PEC, while these properties changed in samples prepared with the enzyme. Finally, digestion studies, carried out under physiological conditions, demonstrated that the falafels prepared in the presence of TGase were efficiently digested in the gastric environment
Glycerol-Plasticized Films Obtained from Whey Proteins Denatured at Alkaline pH
Whey represents the major by-product of cheese industry. One possibility to recycle the whey wastes is the use of their globular proteins as a polymer source for the production of biodegradable plastic materials. Whey protein (WP)-based films are usually obtained by protein heat treatment in the presence of glycerol (GLY) as plasticizer at pH 7, a method which would require commercially high costing process. In this work we explored the possibility of producing manageable whey-derived materials without any heat-treatment but under alkaline conditions. The reported results demonstrated that the casting at pH 12 of the unheated WP film forming solutions (FFSs), containing either 40% or 50% GLY, led to produce more resistant and flexible materials than the ones obtained at pH 7. Film opacity was observed significantly increased, being higher in the samples obtained at alkaline pH without WP heating and with higher GLY concentrations. Finally, moisture content decreased with the reduction of GLY content, both in heated and unheated WP-based films, whereas water uptake of the different films prepared at pH 12 did not significantly change
Physicochemical and Antimicrobial Properties of Whey Protein-Based Films Functionalized with Palestinian Satureja capitata Essential Oil
The present study aimed to produce bio-active packaging materials made of whey proteins (WPs) and essential oil (EO) extracted from Thymbra (Satureja capitata, L.), one of the most popular Palestinian wild plants. In this study, two different Thymbra leaves from Nablus and Qabatiya in Palestine were collected and analyzed for EOs by gas chromatography and mass spectrometry. Based on the analysis, two EOs, namely, TEO1 and TEO2, were extracted, and it was found that both samples primarily contain γ-terpinene and carvacrol, whereas p-cymene was detected only in TEO1. The antimicrobial activity of TEO1 and TEO2 was evaluated by microbroth microdilution assays against pathogenic bacteria and yeast. Based on the results, TEO1 exhibited potent antimicrobial activity against the test strains. Besides, TEO1 was chosen to functionalize WP-based films at different concentrations (0.1%, 0.4%, and 0.8% v/v of Film Forming Solutions). Film mechanical property investigation showed a marked reduction in the tensile strength and Young’s modulus at 0.8% TEO1. In contrast, its elongation at break value was significantly (p < 0.05) increased due to the plasticizing effect of the EO. Moreover, the film transparency was found to be significantly (p < 0.05) reduced by increasing TEO1 concentrations. Finally, microbiological investigations indicated that film antimicrobial activity against both gram-positive and gram-negative bacteria increased dose-dependently. The overall results open interesting perspectives for employing these films as preservative materials in food packaging
A biorefinery approach for the conversion of Cynara cardunculus biomass to active films
Cardoon (Cynara cardunculus), an herbaceous perennial plant able to grow with high productivity in dry and hot
regions, as well as in unproductive soils, was used as a biomass source for the production of both bioactive
compounds derived from leaves and proteins extracted from seeds. Naviglio\uae technology was found as an
efficient method to obtain a cardoon leaf extract (CLE) characterized by high phenol content and oxygen
scavenging activity. On the other hand, cardoon proteins (CPs) were demonstrated to give rise to handleable
greenish films endowed with promising mechanical and barrier properties in the presence of glycerol used as
plasticizer. Hence, the CLE was used to functionalize the films that were further characterized. Film microstructure
observed by SEM revealed a good compatibility among CPs and CLE, showing a uniform distribution of
the leaf extract components throughout the film network that reflected, in turn, an improvement in the mechanical
and barrier properties of the obtained material. In addition, the CLE containing films exhibited higher
hydrophobicity, as indicated by the contact angle measurement and by the evaluation of water solubility and
swelling degree experiments. Finally, CLE-containing films showed a marked antioxidant activity, highlighting
the potential of Cynara cardunculus to be exploited as a biorefinery where different low-value renewable biomass
materials are turned in several higher value bio-based products
Enhanced Streptomyces roseochromogenes melanin production by using the marine renewable source Posidonia oceanica egagropili
Since the possibility to biotechnologically produce melanin by Streptomycetes using plant biomass has been so far poorly investigated, Posidonia oceanica egagropili, a marine waste accumulating along the Mediterranean Sea coasts, was explored as a renewable source to enhance extracellular melanin production by Streptomyces roseochromogenes ATCC 13400. Therefore, different amounts of egagropili powder were added to a culture medium containing glucose, malt extract, and yeast extract, and their effect on the melanin biosynthesis was evaluated. A 2.5 g·L−1 supplementation in 120-h shake flask growths at 26 °C, at pH 6.0 and 250 rpm, was found to enhance the melanin production up to 3.94 ± 0.12 g·L−1, a value 7.4-fold higher than the control. Moreover, 2-L batches allowed to reach a concentration of 9.20 ± 0.12 g·L−1 in 96 h with a productivity of 0.098 g·L−1·h−1. Further studies also demonstrated that the melanin production enhancement was due to the synergistic effect of both the lignin carbohydrate complex and the holocellulose components of the egagropili. Finally, the pigment was purified from the broth supernatant by acidic precipitation and reversed-phase chromatography, characterized by UV absorbance and one- and two-dimensional NMR, and also tested for its chemical, antioxidant, and photo-protective properties