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The enhanced interest in greater convenience foods has recently led to the expansion of minimally processed potato products. This study investigated the effects of isochoric freezing on pre-peeled potato cubes, including quality attributes (microstructure, texture, and color), nutritional value (ascorbic acid (AA) content, total phenolic content, and antioxidant capacity), and polyphenol oxidase activity. Isochoric freezing (-3 °C/30 MPa) was compared with isobaric freezing (-3 °C/0.1 MPa) and individual quick freezing followed by frozen storage at -20 °C for 4 weeks. The isochoric sample had lower drip loss and volume shrinkage as well as better preserved texture and microstructure than the other samples. All freezing methods caused an increase in total phenolic content and antioxidant capacity, but a decrease in AA content. Also, all freezing methods caused browning of the thawed potatoes, but isochoric freezing delayed its onset for more than 1 week. PRACTICAL APPLICATION: Results showed that isochoric freezing of pre-peeled and cut potatoes caused less freeze damage than isobaric and individual quick freezing, which might find application in the commercial preservation of minimally processed food products.

The aim of this work was to evaluate the effects of isochoric freezing on the quality of tilapia fillet. Isochoric freezing was compared to chilling, super-chilling, and freezing. Isochoric freezin...

Efforts are currently directed towards improving the quality of vegetables after freezing and thawing. One of the methods under investigation is isochoric freezing. In this study, we evaluated isochoric freezing for preserving the quality of baby‐leaf spinach. We compared the properties of thawed spinach frozen to −4°C in an isochoric system with those of fresh spinach, thawed spinach frozen to −4°C in an isobaric system and thawed spinach that were commercially frozen. Spinach leaves frozen under isobaric conditions lost mass and thickness, making them softer and translucent. They also lost much of their nutrient content. In comparison, isochoric freezing maintained cell integrity and turgidity. Thawed leaves remained crunchy with characteristics similar to fresh leaves. Isochoric freezing also preserved nutritional content better than isobaric freezing, although significant nutrient losses still occurred.

The cracking of sweet cherries causes significant crop losses. Sweet cherries (cv. Bing) were coated by electro-spraying with an edible nanoemulsion (NE) of alginate and soybean oil with or without a CaCl2 cross-linker to reduce cracking. Coated sweet cherries were stored at 4 °C for 28 d. The barrier and fruit quality properties and nutritional values of the coated cherries were evaluated and compared with those of uncoated sweet cherries. Sweet cherries coated with NE + CaCl2 increased cracking tolerance by 53% and increased firmness. However, coated sweet cherries exhibited a 10% increase in water loss after 28 d due to decreased resistance to water vapor transfer. Coated sweet cherries showed a higher soluble solid content, titratable acidity, antioxidant capacity, and total soluble phenolic content compared with uncoated sweet cherries. Therefore, the use of the NE + CaCl2 coating on sweet cherries can help reduce cracking and maintain their postharvest quality.

Background: The objective of the present work was to investigate the influence of a pre-treatment of microbial-rich digestate (liquid mesophilic anaerobic digestate - AD-supernatant) on the morphology, crystallinity, and thermal stability of cellulose pulp fiber. Results: The six most abundant bacteria in the AD-supernatant were determined by 16S analysis. The bacteria population was comprised mostly of Bacteroides graminisolvens (66%) and Parabacteroides chartae (28%). Enzymatic activity from the bacteria partially removed the amorphous components and increased the crystallinity and crystallite size of the cellulose substrate. The fiber pulp was incubated in AD-supernatant for 5, 10, and 20 days. The X-ray diffraction data provided evidence that the amorphous portion of the cellulose was more readily and quickly hydrolyzed than the crystalline portion. The longest incubation times (20 days) resulted in substantial deconstruction of the cellulose fiber structure and decreased the thermal degradation temperature. Conclusion: The anaerobic digestate is inexpensive and could be used to effectively aid in the pre-treatment of cellulose on large scale transformation processes, e.g. for making biofuels, cellulose micro/nanofiber production or engineered fiber-based materials.

This study investigated the potential of isochoric freezing to preserve tomatoes. Isochoric freezing is an emerging technology that preserves biological matter at subfreezing temperatures without any ice damage. Isochoric freezing was compared with freezing under isobaric conditions and with preservation techniques used in the food industry: cold storage at 10 °C and individual quick freezing (IQF). Physicochemical and nutritional properties were evaluated weekly for four weeks. Preservation under isochoric conditions maintained the mass, color, nutrient content (ascorbic acid, lycopene and phenolics) and antioxidant activity of the fresh tomatoes. Also, isochoric preservation led to minimal texture damage. In comparison, mass loss of tomatoes stored at 10 °C for 3 weeks contributed to changes in overall visual quality and firmness as well as significant losses in nutrient content. The greatest mass, texture, and nutrients losses were obtained for tomatoes subjected to IQF and isobaric freezing. The results show that isochoric freezing has the potential to preserve tomatoes while maintaining physicochemical and nutritional properties similar to those of fresh tomatoes which might find application in the commercial preservation of tomatoes.

Due to the perishable nature of fruits and the importance of reducing food waste, an effective preservation technique is required to prolong the shelf life and maintain the physical and nutritional properties of seasonal fruits. In this study, we evaluated isochoric freezing for preserving the quality of sweet cherries. We examined the physical characteristics and nutritional values of thawed cherries frozen to −4 °C or −7 °C in an isochoric system and compared them with those of fresh cherries, thawed cherries that were individually quick frozen and thawed cherries frozen to −4 °C or −7 °C in an isobaric system. We found that isochoric freezing decreased the drip loss and better preserved the color, texture, structure, ascorbic acid, phenolic and antioxidant content of frozen cherries, thereby proving their potential in frozen fruit applications.

Quantitation of leaf surface wax on a population of switchgrass identified three significant QTL present across six environments that contribute to leaf glaucousness and wax composition and that show complex genetic × environmental (G × E) interactions. The C4 perennial grass Panicum virgatum (switchgrass) is a native species of the North American tallgrass prairie. This adaptable plant can be grown on marginal lands and is useful for soil and water conservation, biomass production, and as a forage. Two major switchgrass ecotypes, lowland and upland, differ in a range of desirable traits, and the responsible underlying loci can be localized efficiently in a pseudotestcross design. An outbred four-way cross (4WCR) mapping population of 750 F2 lines was used to examine the genetic basis of differences in leaf surface wax load between two lowland (AP13 and WBC) and two upland (DAC and VS16) tetraploid cultivars. The objective of our experiments was to identify wax compositional variation among the population founders and to map underlying loci responsible for surface wax variation across environments. GCMS analyses of surface wax extracted from 4WCR F0 founders and F1 hybrids reveal higher levels of wax in lowland genotypes and show quantitative differences of β-diketones, primary alcohols, and other wax constituents. The full mapping population was sampled over two seasons from four field sites with latitudes ranging from 30 to 42 °N, and leaf surface wax was measured. We identified three high-confidence QTL, of which two displayed significant G × E effects. Over 50 candidate genes underlying the QTL regions showed similarity to genes in either Arabidopsis or barley known to function in wax synthesis, modification, regulation, and transport.

Food waste is currently being generated at an increasing rate. One proposed solution would be to convert it to biopolymers for industrial applications. We recovered chitin from mushroom waste and converted it to chitosan to produce edible coatings. We then used layer‐by‐layer (LbL) electrostatic deposition of the polycation chitosan and the polyanion alginate to coat fruit bars enriched with ascorbic acid. The performance of the LbL coatings was compared with those containing single layers of fungal chitosan, animal origin chitosan and alginate. Bars containing alginate‐chitosan LbL coatings showed increased ascorbic acid content, antioxidant capacity, firmness and fungal growth prevention during storage. Also, the origin of the chitosan did not affect the properties of the coatings. Mushroom stalk bases could be an alternative source for isolating chitosan with similar properties to animal‐based chitosan. Also, layer‐by‐layer assembly is a cheap, simple method that can improve the quality and safety of fruit bars.

Due to a large and growing collection of genomic and experimental resources, Brachypodium distachyon has emerged as a powerful experimental model for the grasses. To add to these resources we sequenced 21 165 T-DNA lines, 15 569 of which were produced in this study. This increased the number of unique insertion sites in the T-DNA collection by 21 078, bringing the overall total to 26 112. Thirty-seven per cent (9754) of these insertion sites are within genes (including untranslated regions and introns) and 28% (7217) are within 500 bp of a gene. Approximately 31% of the genes in the v.2.1 annotation have been tagged in this population. To demonstrate the utility of this collection, we phenotypically characterized six T-DNA lines with insertions in genes previously shown in other systems to be involved in cellulose biosynthesis, hemicellulose biosynthesis, secondary cell wall development, DNA damage repair, wax biosynthesis and chloroplast synthesis. In all cases, the phenotypes observed supported previous studies, demonstrating the utility of this collection for plant functional genomics. The Brachypodium T-DNA collection can be accessed at http://jgi.doe.gov/our-science/science-programs/plant-genomics/brachypodium/brachypodium-t-dna-collection/.

This paper provides proof of concept that activated carbon (AC) may be readily produced using limited conversion methods and resources from sawdust of massaranduba (Manilkara huberi) wood, thereby obtaining value-added products. Sawdust was sieved and heat-treated in an oxygen-free muffle furnace at 500 &deg, C to produce charcoal. The charcoal was activated in a tubular electric furnace at 850 &deg, C while being purged with CO2 gas. Microstructural, thermal and physical properties of the three components: sawdust, charcoal and AC were compared by means of field emission scanning electron microscopy (FESEM), X-ray diffractometry (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), density and water adsorption/desorption measurements. The resulting AC had a large surface area as measured by Brunauer-Emmett-Teller (BET) comparable to other such values found in the literature. The large surface area was due to pore development at the microstructural level as shown by FESEM. XRD illustrated that sawdust had a semi-crystalline structure whereas charcoal and AC evidenced mostly amorphous structures. TGA and DSC showed that AC had high reactivity to moisture compared to sawdust and charcoal.

Chitosan nanoparticles with different encapsulation efficiencies were incorporated to obtain gelatin films with controlled-release properties. Nanoparticles tended to aggregate as encapsulation efficiency increased, due to the increase in surface tension of film-forming solutions. The addition of nanoparticles increased the compactness and isotherm hysteresis of films, whereas decreased the moisture diffusion. Tea polyphenol released faster and greater from films in 50% ethanol (4 °C) than in 95% ethanol (25 °C) fatty food stimulant due to the swelling by water. However, controlled-release showed in both simulants, where free tea polyphenol had the largest release followed by 51.3%, 83.3% and 96.9% encapsulation efficiency. The diffusion coefficient in 50% ethanol was 2 orders of magnitude higher than that 95% ethanol (10−13 and 10−11 cm2/s, respectively). Films maintained their structures in 95% ethanol after 240 h but not in 50% ethanol. These results might open up new designs in long-term protection for fatty foods.

The aim of this study was to develop and compare the properties of edible films based on pinhao starch and pinhao flour. Seven formulations were developed by casting methodology: 5% pinhao starch with 0, 1, 1.5, and 2% glycerol, and 5% pinhao flour with 1, 1.5, and 2% glycerol. The films were evaluated and compared to each other for thickness, morphological analysis by Scanning Electronic Microscopy (SEM), glass transition temperature (Tg), apparent porosity (O), water vapor permeability (WVP), tensile properties, color, opacity, and Fourier transform infrared analysis (FTIR). In addition, the raw materials were analyzed for moisture content, water activity (Aw), apparent porosity and pasting profile. Pinhao starch and flour did not show differences in moisture content and pinhao starch presented lower Aw, O, but higher peak viscosity than pinhao flour. Films made with pinhao starch exhibited lower thickness, O, WVP and opacity than pinhao flour films, but higher Young's modulus, tensile strength and elongation at break. In addition, films with higher amounts of glycerol exhibited higher WVP and elongation at break, with lower tensile strength and Young's modulus. The pinhao flour films structure presented irregularities and were rougher than pinhao starch films. Differences in glycerol content did not affect Tg values of these films. Flour films were yellowish and also had a higher opacity value. The FTIR spectra of pinhao starch and pinhao flour films showed similar IR absorbance patterns, with no structural change in the presence or absence of glycerol.

Commercializing dried microfibrillated cellulose (MFC) has always been a challenge mainly due to the tendency of MFC to aggregate. In this study MFC samples were submitted to drying/redispersion cycles at different temperatures. Morphology, crystallinity and mechanical performance of films were analyzed throughout the cycles. Microscopy images, particle size and stability in water showed that aggregation happens more severely with 5 drying/redispersion cycles and at drying temperatures of 75 and 100 °C. Particles once-dried at 20 °C formed the same size and web-like structure as the MFC-control. Crystallinity and crystallite sizes increased with drying/redispersion cycles especially when dried at 75 and 100 °C, however drying/redispersion cycles also led to a reduction in mechanical performance due to aggregation. While oven-drying is not the most suitable method, milder action at room temperature once-drying led to suspension stability in water, morphology and mechanical properties close to never-dried MFC, which makes this treatment a feasible option to maintain cellulose quality.

Edible films and coatings have been applied on fruits to improve their quality during growth and development as well as during postharvest storage. A response surface methodology was used to determine the effects of oil concentration, number of passes and calcium chloride concentration on the physical, mechanical and transport properties of oil-alginate composite films. Alginate-based films were developed using alginate (1.0% w/v), soybean oil (0.5%, 1.0% and 1.5% v/v) and Tween 80® (1% v/v). Coarse emulsions were passed 2, 4 and 6 times through a microfluidizer at 200 MPa. Calcium chloride solutions (0%, 1.5% and 3%) were then applied on the cast films to crosslink them. The oil particle sizes ranged from 360 to 445 nm, regardless of the emulsion composition and number of passes. The lowest water permeability value (1.8857E-10 g/msPa) was obtained for 1.5% oil concentration, 6 passes and no crosslinking. The porosity of the films at low oil concentrations increased with an increase in crosslinking level. In comparison, the porosity of the films at high oil concentrations decreased with an increase in crosslinking level. Emulsified films showed reduced strength and increased elongation with an increase in oil concentration. Films treated with calcium chloride showed lower strength due to greater effects from oil than calcium chloride. In conclusion, oil incorporation in films was the predominant factor in improved film properties, especially for water vapor permeability.

Guayule (Parthenium argentatum) is under development in the southwestern United States as a source of domestic natural rubber; increased rubber yield was found for greenhouse-grown guayule with downregulated allene oxide synthase (AOS). The objective of this study was to evaluate natural rubber production in guayule plants with varying levels of AOS gene expression grown in a field environment. Four plant genotypes: wildtype plants, vector controls, and transgenic plants with overexpressed and downregulated allene oxide synthase (total of 960 plants) were grown at the Bridgestone Guayule Research Farm in Eloy, Arizona between May 2016 to May 2018. Plant phenotypes were evaluated at 6-, 12-, 18-, and 24-months. Downregulated allene oxide synthase (AOSi) genotypes showed remarkable phenotypes including higher photosynthetic activity (net assimilation rate), total number of branches per plant, and plant stembark thickness compared with wildtype, vector control, and overexpressed AOS (AOSoe) lines. Moreover, the rubber particles were smaller and had higher activity (radiolabeled isoprenyl pyrophosphate (IPP) incorporation per g of rubber) in the AOSi genotypes than control and AOSoe lines. The downregulation of AOS also led to significant changes in phytohormone levels, which may have influenced the plants’ morphology and physiology. However, in contrast to laboratory and greenhouse studies, natural rubber concentration and yield were not higher in AOSi plants.

The objective of this work was to prepare bio-based thin films and evaluate the additions of magnetite and glycerol on the physico-chemical (flexibility, wettability and barrier properties) and dielectric properties of cellulose/chitosan-based films. The films were prepared by solution casting and presented a suitable dispersion of the constituents observed by SEM and FTIR. The films were thermally stable up to 150 °C and had a higher flexibility, wettability and lower barrier properties upon addition of glycerol. The calculated dielectric constant (er) for the composite films was based on measurements of capacitance, at 100 and 1000 Hz, with the additions of magnetite and glycerol more than doubling the er increasing the charge storage capacity. The bio-based thin films have potential to be used as insulators in capacitors on the production of green electronics thus, reducing toxic and nonrenewable e-waste generation.

High production costs remain the single greatest factor limiting wider use of cellulose micro/nanofibers by industry. The objective of the present study was to investigate the potential of using a low-cost bacteria-rich digestate (liquid anaerobic digestate—AD-supernatant) on milled eucalyptus fiber followed by high-shear mixing to obtain cellulose micro/nanofibers. The morphology, crystallinity, and thermal stability of micro/nanofibers obtained by this process were studied. The bacteria population in the AD-supernatant was comprised mostly of Bacteroides graminisolvens and Parabacteroides chartae. The digestate treatment partially removed amorphous components of the pulp fiber thereby decreasing micro/nanofiber diameters and enhancing the crystalline content. The treatment also increased the size of the crystalline cellulose. The morphology and crystallinity results demonstrate the effectiveness of digestate treatments coupled with high-shear mixing as a procedure for the production of micro/nanofibers.

This study aims to evaluate the effects of polishing and parboiling on proximate composition, structure, phenolic compounds, antioxidant activity, cooking time and hardness of IAC-600 black rice cultivar and MPB-10 red rice lineage. Proximate analysis and light micrographs revealed higher migration of red rice proteins than black rice proteins to the endosperm as a result of parboiling. Parboiling reduced the ash content of red rice while no difference was determined in black rice. Gelatinized starch granules from both genotypes showed similar appearance. There was a decrease in relative crystallinity on both black and red rice subjected to parboiling, which was an indicative of crystallites disruption. Polishing removed more than 90% of free phenolics for both genotypes, while parboiling allowed the partial preservation of free phenolics content in polished rice. Parboiling induced an increase in the cooking time of red rice, but a decrease in the cooking time of black rice.

Poly(lactic acid) (PLA) nanofibers containing hydroxypropyl methylcellulose (HPMC) and tetracycline hydrochloride (THC) were solution blow spun from two different solvents, chloroform/acetone (CA, 80:20 v/v) and 2,2,2-triflouroethanol (TFE). The diameter distribution, chemical, thermal, thermal stability, water sorption, and antimicrobial properties were examined for the fibers. Fibers spun from CA generally had larger fiber diameters and wider fiber diameter distributions than those spun from TFE. Fourier transform infrared (FTIR) spectroscopy results indicated successful incorporation of HPMC and THC into the fibers. Also, phase separation occurred between PLA and HPMC in the fibers. Fibers containing higher HPMC concentrations showed greater water sorption values, due to HPMC being more hydrophilic than PLA. In addition, fibers containing HPMC had larger inhibitory zones against Escherichia Coli and Listeria monocytogenes than those without HPMC. This was due to THC having better miscibility with HPMC than PLA and HPMC being able to swell and release more THC when in contact with water. Fibers spun from TFE and CA had comparable inhibitory zones, indicating the solvents did not affect antimicrobial properties. All fibers remained effective against bacteria even after six days.

UNLABELLED Thyme essential oil (TEO) and apple skin polyphenols (ASP) are natural compounds considered as generally recognized as safe by FDA, with biological effects against bacteria and fungi. This work aimed to evaluate physical and antimicrobial properties of acai edible films formulated with TEO and ASP at 3% and 6% (w/w) individually or combined at 3% (w/w) each. Physical properties studied include mechanical resistance, water vapor permeability (WVP), color, and thermal resistance. Antimicrobial activity against Listeria monocytogenes was determined using the overlay diffusion test. Addition of ASP resulted in improved mechanical properties. TEO at 6% (w/w) resulted in increased elongation. ASP films had significant higher WVP than control film. ASP films were lighter and had more red color than other films. Incorporation of ASP resulted in improved film thermal stability, whereas TEO caused rapid thermal decomposition. Presence of clusters was observed on the surface of films. Addition of ASP resulted in a smoother surface, whereas addition of TEO led to the formation of crater-like pits on the film surface. Acai edible film incorporated with 6% (w/w) TEO presented the highest antimicrobial activity. However, both antimicrobials are necessary in the acai films in order to obtain edible films with suitable physical-mechanical properties. The results of the present study showed that TEO and ASP can be used to prepare acai edible films with adequate physical-mechanical properties and antimicrobial activity for food applications by direct contact. PRACTICAL APPLICATION Developed acai edible films presented antimicrobial activity against L. monocytogenes and good physical-mechanical properties, showing the potential use of acai edible films in food preservation.

Salinity and wastewater disposal problems associated with the conventional wet-lye method for peeling clingstone peaches result in considerable negative environment impacts. The efficacy of using infrared (IR) heating as an alternative method for peach peel removal was investigated to eliminate the use of water and chemicals. Peaches sorted into three size categories were double-sided heated under IR with three emitter gaps for a range of heating times from 90 s to 180 s. Wet-lye peeling was used as a control. Results showed that 180 s IR heating for medium sized peaches under an emitter gap of 90 mm yielded 84 mm

Poly(glycidyl methacrylate) (PGMA) was grafted onto bacterial cellulose nanowhiskers (BCNW) by means of a redox-initiated free radical copolymerization reaction. The incorporation of PGMA chains decreased the thermal stability and crystallinity of BCNW. The neat and the PGMA-grafted BCNW were subsequently incorporated as fillers into the PLA matrix. PGMA grafting improved both matrix-filler adhesion and the dispersion of cellulose nanocrystals. However, the dispersion of the nanofiller was still not completely optimized and loadings higher than 3 wt.% resulted in increased agglomeration. The incorporation of both neat and PGMA-grafted BCNW significantly reduced the oxygen permeability of PLA for low relative humidity conditions. However, due to the moisture sensitivity of cellulose, smaller improvements were attained when increasing the water activity. The detrimental effect of moisture on the oxygen permeability of nanocomposites was limited by the grafting copolymerization since PGMA-grafted BCNW seemed to present a more hydrophobic behavior. Furthermore, increased elastic modulus and tensile strength were observed for all the nanocomposites, especially when the concentration of nanocrystals was around the percolation threshold, i.e. 3 wt.%, but only nanocomposites containing PGMA-grafted BCNW preserved the ductility of neat PLA.

Cellulose nanocrystals (CNCs) were extracted from Eucalyptus kraft pulp by sulfuric acid hydrolysis, and esterified with maleic anhydride (CNCMA). The incorporation of sulfate ester groups on the cellulose surface resulted in higher stability of the nanoparticles in aqueous suspensions and lower thermal stability. Then, PLA/CNC and PLA/CNCMA nanocomposites were successfully obtained by solution blow spinning (SBS) using dimethyl carbonate (DMC) as solvent. CNC and CNCMA indicated to be acting both as nucleating agents or growth inhibitors of PLA crystal and tends to favor the formation of PLA crystals of higher stability. A fraction of the nanocrystals indicate to be exposed on the surface of the PLA fibers, since the hydrophilicity of the composite films increased significantly. Such composites may have potential application as filtering membranes or adsorbents.

Background Controlled-release formulations of bioactive agents are of increasing interest for effective pest control. Volatile 2-heptanone is a bioactive agent that has shown potential as a pesticide. The aim of this study was to investigate the kinetics of release of 2-heptanone incorporated into lipid films or composite solid lipid particle (SLP) films. Results Effective 2-heptanone diffusivity was estimated to be between 0.1 and 2.5 mm2 day−1 during the first week and between 0.05 and 0.1 mm2 day−1 during the next 5 weeks. The films that showed better retention of 2-heptanone were the paraffin lipid films. Inclusion of SLPs into paraffin films increased the release rate of 2-heptanone, mainly owing to a decrease in the film firmness as the composite SLP film became less crystalline and more brittle. In contrast, SLPs decreased the kinetics of 2-heptanone release in Acetem films owing to an increase in the film firmness. Conclusions The results indicated that the use of SLPs as a method for controlled release can improve the delivery of the natural pesticide 2-heptanone if the SLPs have good compatibility with the matrix, leading to an increase in firmness of the films without increasing their porosity. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

Brown mushroom (Agaricus bisporus) stalk bases from mushroom waste were treated with UV-B light to rapidly increase vitamin D2 content. Chitin was also recovered from this waste and converted into chitosan by N-deacetylation. FTIR spectra showed that the mushroom chitosan were similar to chitosan from animal sources. Chitosan films were prepared using high molecular weight (HW), low molecular weight (LW) and fungal chitosan. UV-B treated mushroom particles were also incorporated into fungal chitosan films. The fungal chitosan films showed similar density, porosity and water vapor barrier properties to the LW and HW chitosan films. However, fungal chitosan films were more hydrophobic and less flexible than the LW and HW chitosan films. Addition of mushroom particles did not significantly affect mechanical or water barrier properties of the fungal chitosan films.

A hybrid catalyst was prepared using cellulose nanofibrils and magnetite to degrade organic compounds. Cellulose nanofibrils were isolated by mechanical defibrillation producing a suspension used as a matrix for magnetite particles. The solution of nanofibrils and magnetite was dried and milled resulting in a catalyst with a 1:1 ratio of cellulose and magnetite that was chemically and physically characterized using light, scanning electron and transmission electron microscopies, specific surface area analysis, vibrating sample magnetometry, thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction, catalytic potential and degradation kinetics. Results showed good dispersion of the active phase, magnetite, in the mat of cellulosic nanofibrils. Leaching and re-use tests showed that catalytic activity was not lost over several cycles. The hybrid material produced was tested for degradation of methylene blue dye in Fenton-like reactions resulting in a potential catalyst for use in degradation of organic compounds.

Zein fibers were successfully fabricated via solution blow spinning (SBS) using acetic acid as solvent. Surface tension, viscosity and modulus of zein solutions were respectively determined by force tensiometer and rheometer. Increases of these properties were observed with an increase of concentration from 20% to 35% (w/w). The fabrication conditions of zein fibers were initially investigated as a function of zein concentration (25% to 35% w/w), feed rate (0.04 to 0.1 mL/min) and air pressure (0.28 to 0.62 MPa). The average fiber diameter (AFD) ranged from 174 to 9595 nm based on scanning electron microscopy (SEM). A Box-Behnken experimental design (BBD) was further performed to identify and quantify the significance of above parameters. The statistical analysis showed that the linear coefficient of concentration, the quadratic term of concentration as well as the interaction between concentration and air pressure were demonstrated statistically significant. Optimal conditions, with an AFD of 138 nm, could be obtained in the SBS of zein fibers by combining a concentration of 23% (w/w), a feed rate of 0.04 mL/min and an air pressure of 0.38 MPa. The moisture sorption capacity of fibers increased slightly as AFD decreased from ∼550 to ∼200 nm, with an increase of BET surface area from 116.5 to 140.0 m2 /g.

Protein concentrates from jatropha (JPC) and soy seeds (SPC) were obtained by solubilization and acid precipitation of proteins. JPC and SPC films were prepared by the casting method, using two different montmorillonite (MMT) clay concentrations and plasticized with glycerol. Film properties were evaluated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy, thermogravimetric analysis, tensile properties, water retention, and water vapor transmission rate (WVRT). Typical tactoid microcomposite structures were found to be heterogeneously dispersed in the films containing MMT. A small XRD peak was found in films with MMT. Slight improvements in thermal stability and tensile strength were observed in the films with MMT. Reductions in water retention and WVRT were obtained when MMT was added into the films. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44459.

Sisal whiskers (SW) were prepared by acid hydrolysis for subsequent evaluation as reinforcing material for biodegradable matrices of thermoplastic starch (TPS) and TPS/polycaprolactone (TPS/PCL) blends. The acid hydrolyzed SW had dimensions of 5 ± 2 nm in diameter and 210 ± 60 nm in length and 78% crystallinity. The nanocomposite blends consisted of whisker contents of 5 and 10 wt% and were coextruded with either TPS or TPS/PCL which formed the matrix material. The influence of SW on the morphology, crystallinity, thermal properties, mechanical behavior, structural, and biodegradation of TPS and TPS/PCL matrices were investigated. The lower SW content of 5 wt% dispersed and interacted well with both matrices. The introduction of PCL in the TPS matrix leads to an increased crystallinity and there was evidence that the carbonyl groups of PCL interacted with the OH groups on the surface of the whiskers. Addition of PCL decreased the whisker/whisker interaction over TPS alone, favoring the dispersion of the whiskers in the matrix and, consequently, the reinforcement effect was more pronounced in TPS/PCL blends than in the pure TPS matrix. The addition of the whiskers as reinforcement increased the biodegradability of TPS and TPS/PCL matrices. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers.

Sisal fibers bleached with sodium-hydroxide followed by hydrogen peroxide treatment were incorporated in a thermoplastic starch/e-polycaprolactone (TPS/PCL) blend via extrusion processing. These samples with smooth and homogenous surfaces were examined for their property, biodegradability and water absorption. Scanning electron microscopy revealed that the fibers were well dispersed in the matrix. In addition, it was found that the fibers and matrices interacted strongly. Blends with 20 % (dry weight-basis) fiber content showed some fiber agglomeration. Whereas blends with 10 % fibers showed increased crystallinity and lower water absorption capacity. The CO2 evolution study showed that the thermoplastic starch samples without any additives had the highest rate and extent of degradation whereas the neat PCL samples had the lowest degradation rate. Addition of fiber to the TPS/PCL blend exhibited the degradation rates and extents that were somewhere in between the pure TPS and neat PCL. This work demonstrates that TPS/PCL composites reinforced with bleached sisal has superior structural characteristics and water resistance and thus, can be used as polymeric engineering composites for different applications.

The incorporation of fibers as reinforcements in polymer composites has increased due to their renewability, low cost and biodegradability. In this study, sisal fibers were added to a polymer matrix of thermoplastic starch and polycaprolactone, both biodegradable polymers. Sisal fibers (5% and 10%) were extruded in a twin-screw extruder with thermoplastic starch/polycaprolactone (80:20 wt). Films were produced with a single extruder and analyzed by field emission gun scanning electron microscopy, mechanical tests, thermogravimetric analysis and differential scanning calorimetry. The morphology of the composites with 10% sisal fiber content presented an interface of fibers at the surface of the matrix, indicating poor adhesion, lower initial temperatures of thermal degradation, and decreased polycaprolactone crystallinity due to the decrease in lamellar thickness and the increase in crystalline disorder. The results were affected mainly by the lack of adhesion at the interface between the matrix and fibers. The interfacial shear strength between sisal and the matrix may be improved by chemical modification of the fiber surface.

Three different types of cellulose nanoparticles: (i) nano-fibrils cellulose (NFC), (ii) nano-fibrils cellulose oxidized using the tempo reaction (NFCt) and (iii) cellulose whiskers, were incorporated into HPMC edible films at different concentrations. The films were examined for mechanical and moisture barrier properties verifying how the addition of cellulose nano-particles affected the water affinities (water adsorption/desorption isotherms) and the diffusion coefficients. In general, addition of NFC or NFCt negatively affected the performance of the HPMC films. However the reinforcing effect of the cellulose particles was observed when whiskers were used as the filling material; an increase of 22% in tensile strength and 55% in Young's modulus were achieved while the elongation at break of the films was preserved. Addition of whiskers also improved the water barrier properties of the composite films. This effect was attributed to the lower water affinity of the composite films, as compared with the HPMC films, since the water diffusivity values were not affected by the addition of whiskers. Furthermore, the whiskers only decreased 3–6% the transparency of the HPMC films showing 86–89% visible light transmission values, allowing application as edible barrier and transparent film.

Catastrophic phase inversion (CPI) was used as a low-energy emulsification method to prepare oil-in-water (O/W) nanoemulsions in a lipid (Acetem)/water/nonionic surfactant (Tween 60) system. CPIs in which water-in-oil emulsions (W/O) are transformed into oil-in-water emulsions (O/W) were induced by changes in the phase ratio. Dynamic phase inversion emulsification was achieved by slowly increasing the water volume fraction (fw) to obtain O/W emulsions from water in oil emulsions. Composition and processing variables were optimized to minimize droplet size and polydispersity index (PdI). It was found that addition of the continuous phase to the dispersed phase following the standard CPI procedure resulted in the formation of oil droplets with diameters of 100-200 nm. Droplet size distribution during CPI and emulsification time depended on stirring speed and surfactant concentration. Droplet sizes in the inverted emulsions were compared to those obtained by direct emulsification: The process time to reach droplet sizes of around 100 nm was reduced by 12 times by using CPI emulsification. The Acetem/water nanoemulsion was also used as a carrier to incorporate oregano and cinnamon essential oils into soy protein edible films. The resulting composite films containing oregano oil showed better moisture barrier and mechanical properties compared to soy protein films.

Coir fibers received three treatments, namely washing with water, alkali treatment (mercerization) and bleaching. Treated fibers were incorporated in starch/ethylene vinyl alcohol copolymers (EVOH) blends. Mechanical and thermal properties of starch/EVOH/coir biocomposites were evaluated. Fiber morphology and the fiber/matrix interface were further characterized by scanning electron microscopy (SEM). All treatments produced surface modifications and improved the thermal stability of the fibers and consequently of the composites. The best results were obtained for mercerized fibers where the tensile strength was increased by about 53% as compared to the composites with untreated fibers, and about 33.3% as compared to the composites without fibers. The mercerization improved fiber-matrix adhesion, allowing an efficient stress transfer from the matrix to the fibers. The increased adhesion between fiber and matrix was also observed by SEM. Treatment with water also improved values of Young's modulus which were increased by about 75% as compared to the blends without the fibers. Thus, starch/EVOH blends reinforced with the treated fibers exhibited superior properties than neat starch/EVOH.

Cellulose nanoreinforcements have been used to improve mechanical and barrier properties of biopolymers, whose performance is usually poor when compared to those of synthetic polymers. Nanocomposite edible films have been developed by adding cellulose nanofibers (CNF) in different concentrations (up to 36 g/100 g) as nanoreinforcement to mango puree based edible films. The effect of CNF was studied in terms of tensile properties, water vapor permeability, and glass transition temperature (T(g)) of the nanocomposite films. CNF were effective in increasing tensile strength, and its effect on Young's modulus was even more noticeable, especially at higher concentrations, suggesting the formation of a fibrillar network within the matrix. The addition of CNF was also effective to improve water vapor barrier of the films. Its influence on T(g) was small but significant. The study demonstrated that the properties of mango puree edible films can be significantly improved through CNF reinforcement.

Xylan is the major component of hemicellulose, and xylan should be fully utilized to improve the efficiencies of a biobased economy. There are a variety of industrial reaction conditions in which an active xylanase enzyme would be desired. As a result, xylanase enzymes with different activity profiles are of great interest. We isolated a xylanase gene (xyn10) from a Flavobacterium sp. whose sequence suggests that it is a glycosyl hydrolase family 10 member. The enzyme has a temperature optimum of 30 degrees C, is active at cold temperatures, and is thermolabile. The enzyme has an apparent Km of 1.8 mg/ml and kcat of 100 sec-1 for beechwood xylan, attacks highly branched native xylan substrates, and does not have activity against glucans.

Screening mutant gene libraries for isolating improved enzyme variants is a powerful technique that benefits from effective and reliable biological expression systems. Pichia pastoris is a very useful organism to express proteins that are inactive in other hosts such as Escherichia coli and Saccharomyces cerevisiae. However, most P. pastoris expression plasmids are designed to integrate into the host chromosome and hence are not as amenable to high-throughput screening projects. We have designed a P. pastoris expression vector, pBGP1, incorporating an autonomous replication sequence that allows the plasmid to exist as an episomal element. This vector contains the alpha-factor signal sequence to direct secretion of the mutant enzymes. Expression of the genes is driven by the constitutive GAP promoter, thus eliminating the need for timed or cell density-specific inductions. The pBGP1 plasmid was used to screen a xylanase gene library to isolate higher activity mutants.

Torrefied almond shells and wood chips were incorporated into polypropylene as fillers to produce torrefied biomass- polymer composites. The composites were prepared by extrusion and injection molding. Response surface methodology was used to examine the effects of filler concentration, filler size, and lignin factor (relative lignin to cellulose concentration) on the material properties of the composites. The heat distortion temperatures, thermal properties, and tensile properties of the composites were characterized by thermomechanical analysis, differential scanning calorimetry, and tensile tests, respectively. The torrefied biomass composites had heat distortion temperatures of 8-24C higher than that of neat polypropylene. This was due to the torrefied biomass restricting mobility of polypropylene chains, leading to higher temperatures for deformation. The incorporation of torrefied biomass generally resulted in an increase in glass transition temperature, but did not affect melting temperature. Also, the composites had lower tensile strength and elongation at break values than those of neat polypropylene, indicating weak adhesion between torrefied biomass and polypropylene. However, scanning electron microscopy results did indicate some adhesion between torrefied biomass and polypropylene. V C 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41582.

Thyme essential oil (TEO) and apple skin polyphenols (ASP) are natural compounds considered as generally recognized as safe by FDA, with biological effects against bacteria and fungi. This work aimed to evaluate physical and antimicrobial properties of açaí edible films formulated with TEO and ASP at 3% and 6% (w/w) individually or combined at 3% (w/w) each. Physical properties studied include mechanical resistance, water vapor permeability (WVP), color, and thermal resistance. Antimicrobial activity against Listeria monocytogenes was determined using the overlay diffusion test. Addition of ASP resulted in improved mechanical properties. TEO at 6% (w/w) resulted in increased elongation. ASP films had significant higher WVP than control film. ASP films were lighter and had more red color than other films. Incorporation of ASP resulted in improved film thermal stability, whereas TEO caused rapid thermal decomposition. Presence of clusters was observed on the surface of films. Addition of ASP resulted in a smoother surface, whereas addition of TEO led to the formation of crater-like pits on the film surface. Açaí edible film incorporated with 6% (w/w) TEO presented the highest antimicrobial activity. However, both antimicrobials are necessary in the açaí films in order to obtain edible films with suitable physical-mechanical properties. The results of the present study showed that TEO and ASP can be used to prepare açaí edible films with adequate physical-mechanical properties and antimicrobial activity for food applications by direct contact.Developed açaí edible films presented antimicrobial activity against L. monocytogenes and good physical-mechanical properties, showing the potential use of açaí edible films in food preservation.

Controlled-release formulations of bioactive agents are of increasing interest for effective pest control. Volatile 2-heptanone is a bioactive agent that has shown potential as a pesticide. The aim of this study was to investigate the kinetics of release of 2-heptanone incorporated into lipid films or composite solid lipid particle (SLP) films.Effective 2-heptanone diffusivity was estimated to be between 0.1 and 2.5 mm(2) day(-1) during the first week and between 0.05 and 0.1 mm(2) day(-1) during the next 5 weeks. The films that showed better retention of 2-heptanone were the paraffin lipid films. Inclusion of SLPs into paraffin films increased the release rate of 2-heptanone, mainly owing to a decrease in the film firmness as the composite SLP film became less crystalline and more brittle. In contrast, SLPs decreased the kinetics of 2-heptanone release in Acetem films owing to an increase in the film firmness.The results indicated that the use of SLPs as a method for controlled release can improve the delivery of the natural pesticide 2-heptanone if the SLPs have good compatibility with the matrix, leading to an increase in firmness of the films without increasing their porosity. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

During rice milling, the bran and germ are successively removed from the caryopsis (kernel). Because bran and germ contain large quantities of lipid, the amount of lipid remaining on the kernel surface may be used as a method for the assessment of milling quality. Bulk samples of rice pureline varieties and an experimental hybrid were milled for 0, 10, 20, 30, and 40 s. Scanning electron microscopy (SEM) revealed that brown rice kernels had large contours of linear protuberances and depressions running lengthwise along the kernel surface. The protuberances were abraded successively during milling, but varying amounts of material remained in the depressions. Light microscopy combined with the lipid-specific probes Nile Blue A or Sudan Black B demonstrated that the material in the depressions observed with SEM was lipid. Sections of whole, milled rice kernels, prepared using a modified sectioning technique and stained with Nile Blue A, showed that portions of the embryo remain after milling and that lipid is located on or near the surface of the kernel. Differences in quantity and distribution of residual lipid as milling duration increased were documented photographically to indicate the extent to which the bran and embryo components were removed during milling. This paper provides proof of concept that residual lipid is a robust measure of the degree of milling.

Scanning electron microscopy is a useful tool for understanding food contamination and directing product development of food and industrial products. The current trend in food research is to produce foods that are fast to prepare and/or ready to eat. At the same time, these processed foods must be safe, high quality and maintain all or most of the nutritional value of the original whole foods. Minimally processed foods, is the phrase used to characterize these "new" foods. New techniques are needed which take advantage of minimal processing or processing which enhances the fresh properties and characteristics of whole foods while spending less time on food preparation. The added benefit coupled to less cooking time in an individual kitchen translates to an overall energy savings and reduces the carbon emissions to the environment. Food processing changes the microstructure, and therefore, the quality, texture and flavor, of the resulting food product. Additionally, there is the need to reduce waste, transportation costs and product loss during transportation and storage. Unlike food processing, structural changes are desirable in co-products as function follows form for food packaging films and boxes as well as for building materials and other industrial products. Thus, the standard materials testing procedures are coupled with SEM to provide direction in the development of products from agricultural residues or what would otherwise be considered waste materials. The use of agricultural residues reduces waste and adds value to a currently underutilized or unutilized product. The product might be biodegradable or compostable, thus reducing landfill requirements. Manufacturing industrial and packaging products from biological materials also reduces the amount of petroleum products currently standard in the industry.

It has been stated that hydroxypropyl methyl cellulose (HPMC) based films have promising applications in the food industry because of their environmental appeal, low cost, flexibility and transparency. Nevertheless, their mechanical and moisture barrier properties should be improved. The aim of this work was to enhance these properties by reinforcing the films with microcrystalline cellulose (MCC) at the nano scale level. Three sizes of MCC nanoparticles were incorporated into HPMC edible films at different concentrations. Identical MCC nanoparticles were lipid coated (LC) prior to casting into HPMC/LC-MCC composite films. The films were examined for mechanical and moisture barrier properties verifying how the addition of cellulose nanoparticles affected the water affinities (water adsorption/desorption isotherms) and the diffusion coefficients. The expected reinforcing effect of the MCC was observed: HPMC/MCC and HPMC/LC-MCC films showed up to 53% and 48% increase, respectively, in tensile strength values in comparison with unfilled HPMC films. Furthermore, addition of unmodified MCC nanoparticles reduced the moisture permeability up to 40% and use of LC-MCC reduced this value up to 50%. Water vapor permeability was mainly influenced by the differences in water solubility of different composite films since, in spite of the increase in water diffusivity values with the incorporation of MCC to HPMC films, better moisture barrier properties were achieved for HPMC/MCC and HPMC/LC-MCC composite films than for HPMC films.

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008