Properties and application of antioxidant and antibacterial composite films based on methylcellulose and spine grape pomace fabricated by thermos-compression molding.

Methylcellulose (MC)/grape pomace (GP) films, plasticized with either glycerol (GLY) or cinnamon essential oil (CEO), were prepared by thermo-compression molding and characterized. Compared to the GLY-plasticized MC50/GP50 films, a considerable increase in TS and YM values of CEO-plasticized films was observed, rising from 9.66 to 30.05 MPa, 762 to 1631 MPa, respectively. Moreover, the water vapor barrier, surface hydrophobic properties, and antioxidant/antibacterial activities of CEO-plasticized films remarkedly improved with increasing CEO content from 5 to 15% w/w. From scanning electron microscopy, phase separation between GP and the MC/GLY mixture were evident for GLY-plasticized MC/GP films. On the other hand, the CEO-plasticized films showed compact morphologies, attributable to the formation of hydrogen bonding and π-π stacking interaction. Preliminary shelf-life study on showed that fresh chicken wrapped with the CEO-plasticized MC/GP films exhibited lower TVB-N, TBARS, and TVC values than the unwrapped control samples, during 7 d storage at 4 °C.

Bioinspired pullulan-starch nanoplatelets nanocomposite films with enhanced mechanical properties.

Inspired by the leaf-vein network structure, the pullulan-starch nanoplatelets (SNPs) bioinspired films with enhanced strength and toughness were successfully fabricated through a water evaporation-induced self-assembly technique. SNPs (SNP200 and SNP600) of two sizes were separated by differential centrifugation. Interactions between SNPs and pullulan during drying resulted in the vein-like network structure in both nanocomposite films when the appropriate amounts of SNP200 or SNP600 were added to pullulan, respectively. The TS and toughness values of pullulan with 1 % w/w SNP200 films reached up to 51.05 MPa and 69.65 MJ·m-3, which were 86 % and 223 % higher than those of the neat pullulan films, respectively. Moreover, the TS and toughness values of pullulan-SNP200 were significantly higher than those of pullulan-SNP600 films, when SNP content exceeded the 1 % w/w level. By applying a graph theory, the network structures were found to correlate with the mechanical properties of the pullulan-SNPs bioinspired films. The new strategy for designing starch nanoplatelets-based edible films that combine mechanical strength and toughness holds promises for the development of novel biobased composite materials for food packaging application.

Upcycling of post-industrial starch-based thermoplastics and their talc-filled sustainable biocomposites for single-use plastic alternative.

This study utilized post-industrial wheat starch (biological macromolecule) for the development of poly(butylene adipate-co-terephthalate) (PBAT) based thermoplastic starch blend (TPS) and biocomposite films. PBAT (70 wt%) was blended with plasticized post-industrial wheat starch (PPWS) (30 wt%) and reinforced with talc master batch (MB) (25 wt%) using a two-step process, consisting of compounding the blend for pellet preparation, followed by the cast film extrusion at 160 °C. The effect of the chain extender was analyzed at compounding temperatures of 160 and 180 °C for talc-based composites. The incorporation of talc MB has increased the thermal stability of the biocomposites due to the nucleating effect of talc. Moreover, tensile strength and Young's modulus increased by about 5 and 517 %, respectively as compared with the TPS blend film without talc MB. Thermal, rheological, and morphological analyses confirmed that the use of talc in the presence of chain extender at a processing temperature of 160 °C has resulted in an enhanced dispersion of talc and chain entanglement with PBAT and PPWS than PBAT/PPWS blend and PBAT/PPWS/Talc composite films. On the other hand, at 180 °C, the talc-containing biocomposite with chain extender tended to form PPWS agglomerates, thereby weakening its material properties.

Enhanced hydrophobic paper-sheet derived from Miscanthus × giganteus cellulose fibers coated with esterified lignin and cellulose acetate blend.

Biobased packaging materials derived from carbon-neutral feedstocks are sustainable alternatives to conventional fossil-based polymers. In this study, a method was developed to prepare paper-sheets derived from Miscanthus × giganteus cellulose fibers for potential food contact applications. The papers were hydrophobized with modified lignin from Miscanthus × giganteus biomass and commercial Kraft alkali lignin through hydroxyethylation with ethylene carbonate, followed by esterification with propionic acid. The esterified lignin (10 % w/w) and cellulose acetate (5 % w/w, based on lignin content) were dissolved in acetone and applied as a coating on the miscanthus paper sheets. The esterified lignins were characterized using FTIR, NMR, DSC, TGA, and elemental analyses. The uncoated and coated paper-sheets had contact angle values 52.4° and >130°, respectively, indicating an increased surface hydrophobicity of the coated paper samples. The water vapor transmission rate decreased significantly from 213.7 (uncoated paper-sheet) to 63.3 g/m2.d (coated paper-sheet). The tensile strength of the coated paper (64.6 MPa) was higher than the uncoated counterpart (57.1 MPa). Results from this study suggest that the esterified lignin coated miscanthus paper is a promising hydrophobic food packaging material alternative to conventional fossil-based thermoplastics.

Environmentally friendly microbeads to model the dispersal of particulates in aquatic systems.

The transport of particulate matter including the gametes, larvae and propagules of reproducing organisms and other organic matter involved in nutrient/contaminant transport are important processes, yet there are few environmentally friendly methods available to examine dispersal empirically. Herein we report on the development and application of a biodegradable and non-toxic physical model, based on alginate microbeads with modifiable size, density (ρ), and colour for use in dispersal studies. Specifically, the microbeads were designed to model the size and ρ of parasitic juvenile freshwater mussels (Unionidae; ρ = 1200 kg m-3), which undergo dispersal upon excystment from fish hosts. We released the juvenile-mussel and neutrally buoyant microbeads (ρ = 1000 kg m-3) in a local river and captured them in drift nets downstream. The concentration of microbeads declined with downstream distance, but neutrally buoyant microbeads were transported farther. Analysis of microbead capture rates could be described using the patterns of several mathematical models (negative exponential, power, and turbulent transport), which were consistent with the reported dispersal of mussel larvae and other benthic macroinvertebrates. These results support the use of alginate microbeads in dispersal studies, because their environmentally friendly and customizable properties offer improvements over non-biodegradable alternatives.

Triggered and controlled release of bioactives in food applications.

Bioactive compounds (e.g., nutraceuticals, micronutrients, antimicrobial, antioxidant) are added to food products and formulations to enhance sensorial/nutritional attributes and/or shelf-life. Many of these bioactives are susceptible to degradation when exposed to environmental and processing factors. Others involve in undesirable interactions with food constituents. Encapsulation is a useful tool for addressing these issues through various stabilization mechanisms. Besides protection, another important requirement of encapsulation is to design a carrier that predictably releases the encapsulated bioactive at the target site to elicit its intended functionality. To this end, controlled release carrier systems derived from interactive materials have been developed and commercially exploited to meet the requirements of various applications. This chapter provides an overview on basic controlled and triggered release concepts relevant to food and active packaging applications. Different approaches to encapsulate bioactive compounds and their mode of release are presented, from simple blending with a compatible matrix to complex multiphase carrier systems. To further elucidate the mass transport processes, selected diffusion and empirical release kinetic models are presented, along with their brief historical significance. Finally, interactive carriers that are responsive to moisture, pH, thermal and chemical stimuli are presented to illustrate how these triggered release mechanisms can be useful for food applications.

A review on colorimetric indicators for monitoring product freshness in intelligent food packaging: Indicator dyes, preparation methods, and applications.

Intelligent food packaging system exhibits enhanced communication function by providing dynamic product information to various stakeholders (e.g., consumers, retailers, distributors) in the supply chain. One example of intelligent packaging involves the use of colorimetric indicators, which when subjected to external stimuli (e.g., moisture, gas/vapor, electromagnetic radiation, temperature), display discernable color changes that can be correlated with real-time changes in product quality. This type of interactive packaging system allows continuous monitoring of product freshness during transportation, distribution, storage, and marketing phases. This review summarizes the colorimetric indicator technologies for intelligent packaging systems, emphasizing on the types of indicator dyes, preparation methods, applications in different food products, and future considerations. Both food and nonfood indicator materials integrated into various carriers (e.g., paper-based substrates, polymer films, electrospun fibers, and nanoparticles) with material properties optimized for specific applications are discussed, targeting perishable products, such as fresh meat and fishery products. Colorimetric indicators can supplement the traditional "Best Before" date label by providing real-time product quality information to the consumers and retailers, thereby not only ensuring product safety, but also promising in reducing food waste. Successful scale-up of these intelligent packaging technologies to the industrial level must consider issues related to regulatory approval, consumer acceptance, cost-effectiveness, and product compatibility.

Investigation of the factors affecting foamability and foam stability of cold brew coffee.

BACKGROUND: In this study, the foamability and foam stability of nitrogen-infused cold brew coffee, as affected by coffee variety (Arabica and Robusta), degree of roast (light, medium, dark), brewing temperature (4, 20, 35 °C), brew ratio (1:5-1:15 w/w; coffee/water), ground particle size (712, 647 and 437 µm volume mean diameter) and beverage temperature (4, 20 and 35 °C), were investigated. RESULTS: Dynamic surface tension of cold brew, as determined from bubble tensiometry, decreased from 65-70 mN m-1 to about 60 mN m-1 as the bubble lifetime increased from 0.1 s to 1 s. Infusing the cold brew coffee (70 mL) with nitrogen gas for 30 s at 50 mL min-1 generated 30-40 mL of foam head. At the same degree of roast, brews prepared from Arabica beans had more stable foam than those from Robusta. Foam stability increased with increasing degree of roast, increasing brewing temperature, decreasing particle size, and decreasing the beverage temperature. By contrast, brew ratio had relatively less effect on foaming properties. Nitrogen-containing constituents present in the 80% (v/v) ethanol-soluble fraction (55.9% of total dissolved solids) of the brew samples were important contributors to foaming, while the 80% (v/v) ethanol-insoluble fraction (42.3% of total dissolved solids) that contained polysaccharides was important in stabilizing the foam. CONCLUSION: The foamability and foam stability of cold brew coffee are significantly affected by coffee variety, degree of roast, brewing temperature, ground particle size, and beverage temperatures. The foam properties are dictated by the low-molecular-weight nitrogen-containing compounds and high-molecular-weight polysaccharides present in the cold brew coffee. © 2022 Society of Chemical Industry.

Formation and structure evolution of starch nanoplatelets by deep eutectic solvent of choline chloride/oxalic acid dihydrate treatment.

In this study, we report a top-down approach to fabricate starch nanoplatelets (SNPs) based on a deep eutectic solvent (DES) comprised of choline chloride and oxalic acid dihydrate. When subjecting waxy maize starch (WMS) to 2 h of DES treatment, the SNPs of oxalate half-ester were successfully fabricated. The formation mechanism of SNPs was studied by monitoring the changes in nanoplatelet morphology, amylopectin chain distribution, long-range crystallinity, and semi-crystalline lamellar structure of the DES-treated WMS at various treatment times. During the DES treatment, relative crystallinity values of WMS gradually decreased from 28.7 to 25.2%. With increasing DES treatment time from 0 to 1.5 h, the thickness of crystalline lamellae decreased from 6.38 to 5.57 nm, whereas the opposite trend was observed for the thickness of amorphous lamellae. The method developed in this work offers a green and efficient route to prepare non-toxic starch nanomaterials.

Cationic inulin as a new surface decoration hydrocolloid for improving the stability of liposomal nanocarriers.

The aim of the present study was to investigate the cationization of inulin with Williamson's etherification method, and compare cationic inulin with unmodified inulin coatings for stabilizing nanoliposomes (NLPs). The synthetized cationic inulin was characterized by Fourier transforms infrared (FT-IR) spectroscopy, carbon hydrogen nitrogen (CHN) elemental analysis, and energy-dispersive X-ray spectroscopy. Three concentrations of inulin and cationic inulin (1, 2, and 4 mg/mL) were used for the coating of NLPs. The concentration of 4 mg/mL was found to be optimal for inulin and cationic inulin as surface coating, on the basis of particle size, zeta potential, and microstructural morphology. The lowest values of particle size (93.41 nm), polydispersity index (0.25), and negative zeta potential (-24.41 mV) were related to the coated NLPs with cationic inulin at a concentration of 4 mg/mL. The transmission electron microscopy image of the coated NLPs with cationic inulin exhibited a spherical and core-shell structure. The coated NLPs with cationic inulin showed the highest thermal stability, physical stability, and oxidative stability. In conclusion, cationic inulin coating conferred a stronger protection than the unmodified inulin coating of NLPs. The technique developed here can be applied for surface decoration of NLPs to improve their stability.

Low temperature extrusion blown ε-polylysine hydrochloride-loaded starch/gelatin edible antimicrobial films.

Edible antimicrobial films made from starch/gelatin (S/G) incorporated with different ε-polylysine hydrochloride (ε-PL) contents were developed by low-temperature extrusion blowing process. ε-PL addition reduced the complex viscosity and storage modulus of blends, while promoted the formation of hydrogen bonding among film components. The control film had an A-type crystalline structure, while increasing the ε-PL content promoted its transformation to B-shaped structure. Without ε-PL and under the processing temperature used, the starch granules were not sufficiently gelatinized. However, ε-PL addition significantly enhanced the gelatinization degree. Increasing ε-PL content in S/G films increased film flexibility, water contact angle value, swelling degree, antimicrobial effect, and storage period of fresh bread, but decreased water vapor permeability and tensile strength. S/G film with 4 wt% ε-PL had the highest water contact angle (94°) and elongation at break (149%). This research demonstrates the plasticizing effects of ε-PL and potential of S/G films containing ε-PL for food preservation/packaging.

Coating of betanin and carvone Co-loaded nanoliposomes with synthesized cationic inulin: A strategy for enhancing the stability and bioavailability.

Betanin (BET) and carvone (CAR) as antioxidant and antibacterial compounds were co-loaded in the coated nanoliposomes (NLPs) with cationic inulin to improve their stability and bioavailability. A cationic inulin was successfully synthesized and used for surface coating of the NLPs. The zeta potential, particle size, and PDI values of the coated NLPs were 21.70 ± 7.00 mV, 143.5 ± 15.2 nm, and 0.35 ± 0.03 respectively. The encapsulation efficiency values of the coated NLPs for BE and CAR were 86.1 ± 3.9 and 77.2 ± 5.2 %, respectively. Electron microscopy results showed that the coated NLPs had spherical and core-shell structures. The slowest sustained release profile in the simulated gastrointestinal condition was obtained for the coated NLPs. The physical and oxidative stability of NLPs, as well as the physical stability of loaded compounds were improved by surface coating. In conclusion, the developed nanocarrier is a suitable platform to use all benefits of BET and CAR in the food industry.

Triggered and controlled release of active gaseous/volatile compounds for active packaging applications of agri-food products: A review.

Gaseous and volatile active compounds are versatile to enhance safety and preserve quality of agri-food products during storage and distribution. However, the use of these compounds is limited by their high vapor pressure and/or chemical instability, especially in active packaging (AP) applications. Various approaches for stabilizing and controlling the release of active gaseous/volatile compounds have been developed, including encapsulation (e.g., into supramolecular matrices, polymer-based films, electrospun nonwovens) and triggered release systems involving precursor technology, thereby allowing their safe and effective use in AP applications. In this review, encapsulation technologies of gases (e.g., CO2 , ClO2 , SO2 , ethylene, 1-methylcyclopropene) and volatiles (e.g., ethanol, ethyl formate, essential oils and their constituents) into different solid matrices, polymeric films, and electrospun nonwovens are reviewed, especially with regard to encapsulation mechanisms and controlled release properties. Recent developments on utilizing precursor compounds of bioactive gases/volatiles to enhance their storage stability and better control their release profiles are discussed. The potential applications of these controlled release systems in AP of agri-food products are presented as well.

High-Throughput Fabrication of Antibacterial Starch/PBAT/AgNPs@SiO2 Films for Food Packaging.

In this current work, antimicrobial films based on starch, poly(butylene adipate-co-terephthalate) (PBAT), and a commercially available AgNPs@SiO2 antibacterial composite particle product were produced by using a melt blending and blowing technique. The effects of AgNPs@SiO2 at various loadings (0, 1, 2, 3, and 4 wt%) on the physicochemical properties and antibacterial activities of starch/PBAT composite films were investigated. AgNPs@SiO2 particles were more compatible with starch than PBAT, resulting in preferential distribution of AgNPs@SiO2 in the starch phase. Infusion of starch/PBAT composite films with AgNPs@SiO2 marginally improved mechanical and water vapor barrier properties, while surface hydrophobicity increased as compared with films without AgNPs@SiO2. The composite films displayed superior antibacterial activities against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The sample loaded with 1 wt% AgNPs@SiO2 (SPA-1) showed nearly 90% inhibition efficiency on the tested microorganisms. Furthermore, a preliminary study on peach and nectarine at 53% RH and 24 °C revealed that SPA-1 film inhibited microbial spoilage and extended the product shelf life as compared with SPA-0 and commercial LDPE packaging materials. The high-throughput production method and strong antibacterial activities of the starch/PBAT/AgNPs@SiO2 composite films make them promising as antimicrobial packaging materials for commercial application.

Toxicity of Five Plant Volatiles to Adult and Egg Stages of Drosophila suzukii Matsumura (Diptera: Drosophilidae), the Spotted-Wing Drosophila.

The environmental impact of methyl bromide (MB) has resulted in its phase out as an insecticidal fumigant except for critical use exempted categories. Consequently, there is an urgent need to develop an environmentally sustainable MB alternative fumigant. trans-Cinnamaldehyde (TC), benzaldehyde, allyl isothiocyanate (AITC), hexanal, and ethyl formate (EF) are naturally occurring plant volatiles with insecticidal properties. This study assessed the toxicity of these plant volatiles to adult and egg stages of the spotted-wing drosophila (SWD) (Drosophila suzukii Matsumura). The plant volatile treatments had a significant effect on adult SWD mortality. The descending order of toxicity to adult SWD was benzaldehyde > AITC > TC > hexanal > EF at a headspace concentration of 0.50 µL/L air for 24 h. All the volatiles, at a concentration of 4.00 µL/L air, significantly inhibited larval emergence from SWD eggs in artificial diet compared to the control. At a 0.50 µL/L air level, among the volatiles tested, only AITC exhibited 100% inhibition against larval emergence from SWD eggs in blueberry fruits after 24 h exposure. In summary, this study shows that all volatiles tested elicited varying degrees of toxicity toward SWD adults and eggs. However, AITC was the most efficacious volatile and the one with the greatest promise as a post-harvest fumigant for both adult and egg stages of SWD.

The Effect of Electrospun Polycaprolactone Nonwovens Containing Chitosan and Propolis Extracts on Fresh Pork Packaged in Linear Low-Density Polyethylene Films.

Fresh meat products are highly perishable and require optimal packaging conditions to maintain and potentially extend shelf-life. Recently, researchers have developed functional, active packaging systems that are capable of interacting with food products, package headspace, and/or the environment to enhance product shelf-life. Among these systems, antimicrobial/antioxidant active packaging has gained considerable interest for delaying/preventing microbial growth and deteriorative oxidation reactions. This study evaluated the effectiveness of active linear low-density polyethylene (LLDPE) films coated with a polycaprolactone/chitosan nonwoven (Film 1) or LLDPE films coated with a polycaprolactone/chitosan nonwoven fortified with Colombian propolis extract (Film 2). The active LLDPE films were evaluated for the preservation of fresh pork loin (longissimus dorsi) chops during refrigerated storage at 4 °C for up to 20 d. The meat samples were analyzed for pH, instrumental color, purge loss, thiobarbituric acid reactive substances (TBARS), and microbial stability (aerobic mesophilic and psychrophilic bacteria). The incorporation of the propolis-containing nonwoven layer provided antioxidant and antimicrobial properties to LLDPE film, as evidenced by improved color stability, no differences in lipid oxidation, and a delay of 4 d for the onset of bacteria growth of pork chops during the refrigerated storage period.

Trypan blue removal from water with zein sorbents and laccase.

ABSTRACT: Zein-based materials were used to remove Trypan blue from water under flow conditions and in batch tests. In flow tests, zein dissolved at pH = 13 was injected in sand columns and subsequently coagulated with CaCl2, to create an adsorbent filter which removed over 99% of Trypan blue. Batch tests were conducted using zein powder, zein dissolved at pH = 13 and coagulated with CaCl2, Fe2Cl3 or citric acid, and zein dissolved in ethanol and then coagulated with water. The highest Trypan blue removal was achieved with zein powder (4000 mg Trypan blue/kg sorbent, as determined through spectrophotometry), followed by zein coagulated with Fe2Cl3 (500 mg Trypan blue/kg sorbent) and with other salts (140 mg Trypan blue/kg sorbent). Differences in the sorption efficiency are attributed to differences in the surface area. The sorption isotherm of Trypan blue onto zein-based sorbents was a Type II isotherm, suggesting physisorption. Desorption of Trypan blue was limited when zein-based coagulated sorbents were immersed in pure water. Trypan blue could be degraded by free laccase in water, as determined through spectrophotometry and electrospray ionization mass spectroscopy (ESI-MS). Trypan blue could also be degraded by laccase when zein-based laccase-containing sorbents were prepared at pH = 10, using Fe2Cl3 as coagulant. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s42452-020-04107-w.

Degree of crosslinking in ß-cyclodextrin-based nanosponges and their effect on piperine encapsulation.

Piperine (PIP) is an alkaloid which is potent as a therapeutic agent. However, its applications are restricted by its poor water solubility. Nanosponges (NS) derived from polymers are versatile carriers for poor water-soluble substances. The aim of this work was to synthesize ß-cyclodextrin NS, by microwave-assisted fusion, for the encapsulation of PIP. Different formulations of NS were synthesized by varying the molar ratio of ß-cyclodextrin:diphenyl carbonate (ß-CD:DPC; 1:2, 1:6 and 1:10). NS specimens derived from 1:2, 1:6 and 1:10 ß-CD:DPC molar ratios exhibited degree of substitution values of 0.345, 0.629 and 0.878, respectively. The crystallinity of NS was enhanced by increasing diphenyl carbonate concentration. A high degree of crosslinking in the NS increased the loading efficiency due to increased surface area available for bioactive inclusion. This study demonstrated the feasibility of synthesizing NS derived from ß-cyclodextrin of high crystallinity for the encapsulation of PIP at high loading capacity.

Review of Analytical Methods to Detect Adulteration in Coffee.

As one of the most consumed beverages in the world, coffee plays many major socioeconomical roles in various regions. Because of the wide coffee varieties available in the marketplaces, and the substantial price gaps between them (e.g., Arabica versus Robusta; speciality versus commodity coffees), coffees are susceptible to intentional or accidental adulteration. Therefore, there is a sustaining interest from the producers and regulatory agents to develop protocols to detect fraudulent practices. In general, strategies to authenticate coffee are based on targeted chemical profile analyses to determine specific markers of adulterants, or nontargeted analyses based on the "fingerprinting" concept. This paper reviews the literature related to chemometric approaches to discriminate coffees based on nuclear magnetic resonance spectroscopy, chromatography, infrared/Raman spectroscopy, and array sensors/indicators. In terms of chemical profiling, the paper focuses on the detection of diterpenes, homostachydrine, phenolic acids, carbohydrates, fatty acids, triacylglycerols, and deoxyribonucleic acid. Finally, the prospects of coffee authentication are discussed.

Ultrasound-assisted alkali-urea pre-treatment of Miscanthus × giganteus for enhanced extraction of cellulose fiber.

Ultrasound-assisted-alkali-urea (UAAU) pre-treatment of miscanthus biomass was investigated for enhanced delignification and extraction of cellulose fiber. The effects of pre-treatment conditions investigated were: sonication time (10.0, 15.0 and 20.0 min), alkali (NaOH) concentration (2.0, 3.5 and 5.0 %, w/v) and urea-concentration (1.0, 1.75 and 2.5 %, w/v) on the delignification and cellulose content. The process parameters were studied and optimized using a response surface methodology (RSM) based on the Box Behnken Design (BBD). From the RSM-BBD analysis, he optimized pre-treatment conditions were 2.1 % NaOH, 1.7 % urea and 15.5-min sonication time with maximal cellulose and lignin contents of 47.8 % (w/w) and 27.5 % (w/w) respectively. The pre-treated samples were further characterized by FTIR, colorimeter, SEM, XRD, and TGA analyses. The UAAU pre-treated samples have higher delignification and cellulose contents than the AU pre-treatment without sonication. Furthermore, the ultrasound process allowed selective removal of lignin without substantially degrading the functionalities of cellulose fiber. The UAAU pre-treated samples exhibited higher thermal stability, fibrillation, crystallinity index and smaller crystallite size.