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The study was conducted in order to study breakfast skipping (BKS) frequency, factors associated with, health consequence and undergraduate students academic performance during Covid-19 pandemic as earliest studies focusing on this area. A cross-sectional study was carried out among 2225 of undergraduate students. The study was carried between the period of 15/1/2020 to 3/4/2020 using an online self-report Breakfast Eating Habit Survey (BEHS). The BEHS survey was divided into two sections. The first sections included sociodemographic information (gender, BMI, age, smoking, residency, parental education, family income, studying system and stage (public or private), and studying institution (university or institute) academic performance. The second part included questions regarding breakfast eating habits including frequency of skipping meals, factors related to BKS health consequences and types of snacks. Logistic regression is a common technique used for modeling outcomes that fall into the range of 1 and 0. For this purpose, a logistic regression was performed to find adjusted odds ratio and crude odds ratio. The results showed that the majority of participants were female (1238, 55.7%). Out of 2,224 students, 2059 are aged between 18 to 24 years. Most of the participants were from first level (26.5%), second level (32.8%), third level (17.6%) or the fourth level (21.3%). Over 92% of participants were single and about 68% came from families of medium income families. The statistical analysis showed that the odds of BKS is reduced among students who live in accommodation by 54% (odds ratio = 54%, CI (41-71%), p value = 0.000). It seems that students with low income and normal or higher BMI are more likely to skip breakfast more regularly. The odds of skipping breakfast among students with BMI of 18-24.9 is reduced by 41% (odds ratio = 59%, CI (27%-93%), p value = 0.027) and the odds of BKS is reduced among students with BMI of 25-29.9 by 45% (odds ratio = 55%, CI (31-95%). Additionally, students with medium or high incomes are more likely to skip breakfast as much as twofold in comparison with students with low income (medium income (odds ratio = 1.85, CI (1.08-3.17), p-value = 0.024), high income (odds ratio = 1.98, CI (1.12-3.51), p-value = 0.019). The most common reasons for skipping breakfast included include time constraint, not hungry, breakfast is not ready, afraid to be overweight and lack of appetite. The consequences of skipping breakfast were feeling hungry throughout the day, feeling tired, and not paying attention in class and low academic performance. To concluded, BKS during Covid-19 is more common among students with higher BMI, higher income and living in accommodation. The main reason is time constraint and the most common health problems are being tired and luck of attention.
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Rendimiento Académico , Desayuno , COVID-19 , Ayuno Intermitente , Estudiantes , Adolescente , Adulto , Femenino , Humanos , Masculino , Adulto Joven , Rendimiento Académico/estadística & datos numéricos , Desayuno/psicología , COVID-19/epidemiología , COVID-19/psicología , Estudios Transversales , Ayuno Intermitente/psicología , Modelos Estadísticos , Prevalencia , Estudiantes/estadística & datos numéricos , UniversidadesRESUMEN
Cellulose nanofibers (CNFs) were used to improve the electrospinnability of the gelatin protein in a water/ethanol/acetic acid (3:2:3, v/v) solution. The effects of different concentrations of CNFs (0.5-4%) on the important physical properties of the gelatin solution (15%), including rheology, conductivity, and surface tension, were investigated. The apparent viscosity and shear-thinning behavior were increased by increasing the CNF concentration from 0 to 4% at a low shear rate (<10 s-1). CNFs also increased the electrical conductivity and surface tension of the gelatin solution. Scanning electron microscopy (SEM) images revealed uniformly ordered structures with good continuity without fracture or bead formation in all hybrid nanofibers. They also showed that the average diameters of fibers decreased from 216 nm in the pure gelatin nanofibers to 175.39 nm in the hybrid gelatin/CNF (4%) ones. Differential scanning calorimetry (DSC) results showed that CNFs increased Tg, and X-ray diffraction (XRD) analysis showed that the electrospinning process caused the formation of more amorphous structures in the gelatin/CNF hybrid nanofibers. The tensile test indicated that by adding 2% CNFs, the ultimate tensile strength (UTS) and strain at break (SB) of nanofiber mats increased from 4.26 to 10.5 MPa and 3.3% to 6.25%, respectively. The current study indicated that incorporating CNFs at the optimal concentration into a gelatin solution can improve the resulting hybrid nanofibers' morphology, average diameter, and mechanical properties.
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Phenolic extract of Vitis vinifera grape pulp was prepared using ultrasonication at frequencies of 28, 40, and 28-40 kHz with a 1:10, 1:15, and 1:20 ratio of solid (grape pulp) to water. The 1:10 ratio and 40 kHz frequency were considered optimal conditions for the preparation of red grape pulp extract (RGPE). Then, RGPE was encapsulated within maltodextrin using a spray drying technique, and the produced powder was used in the gummy candy production. The results revealed that the phenolic content of the powder was almost constant during the storage time. The solubility of the powder decreased, whereas its moisture content increased during the 45-day storage period. The results of scanning electron microscopy showed that the produced microparticles had spherical shapes with a micron size. Fourier-transform infrared spectroscopy and X-ray diffraction showed that RGPE was encapsulated in the structure of maltodextrin through the formation of hydrogen bonds, considering the amorphous structure of the powder. The antioxidant properties of the microencapsulated RGPE containing gummy candy were preserved. Sensory evaluation and colorimetric values of the enriched gummy candy had acceptable results compared to the control sample. In general, microencapsulation of RGPE within maltodextrin as a carrier using the spray drying technique and its application in gummy candy enrichment could be useful.
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Lentil protein hydrolysates (LPH) and lentil protein hydrolysates cross-linked (LPHC) were grafted with gum Arabic (GA) through a wet Maillard reaction at 100°C for 2 h and called MLPH and MLPHC. The samples were assessed for absorption, degree of grafting (DG), surface hydrophobicity, antioxidant activity, molecular weight (MW) profile, chemical alteration, volatile compounds, functional and sensory properties. Results showed that Maillard grafting led to increase in absorption and DG (maximum value: MLPHC), and led to the reduction of the surface hydrophobicity and antioxidant activity (minimum value: MLPHC). MW profiles indicated that MLPH and MLPHC formed new bands at MW >250 kDa. Regarding the Fourier transform infrared spectroscopy (FTIR), Maillard conjugation led to the occurrence of peaks at 1759 and 1765 cm-1, while the intensities of amide I bands at 1637 and 1659 cm-1 and amide II bands at 1498 and 1495 cm-1 were decreased. Hydrolysis, cross-linking, and especially Maillard grafting provided well-balanced content of volatile components. Indeed, the proportions of alcohols, ketones, aldehydes, and acids were changed, thereby, the inherent grassy and planty tastes were diminished while new umami taste was developed. Maillard grafting led to significant improvement of functional properties, while MLPH and MLPHC indicated the highest emulsifying activity at pH 10.0 (73.76 and 70.12 m2/g, respectively) and stability (369.64 and 288.22 min), foaming capacity (88.57% and 142.86%) and stability (60.57% and 72%). Sensory analysis has demonstrated that umami taste was highly developed in MLPH and MLPHC, which can be well considered as meat proteins and flavor enhancers such as monosodium glutamate (MSG).
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The current study aims to synthesize the gelatin-coated nanostructured lipid carrier (NLC) to encapsulate sage extract and use this nanoparticle to increase the quality parameters of beef burger samples. NLCs were prepared by formulation of gelatin (as surfactant and coating biopolymer), tallow oil (as solid lipid), rosemary essential oil (as liquid lipid), sage extract (as active material or encapsulant), polyglycerol ester and Tween 80 (as low-molecular emulsifier) through the high-shear homogenization-sonication method. The effects of gelatin concentrations and the solid/liquid ratio on the particle size, polydispersity index (PDI), and encapsulation efficiency (EE%) of sage extract-loaded NLCs were quantitatively investigated and optimized using a combined D-optimal design. Design expert software suggested the optimum formulation with a gelatin concentration of 0.1 g/g suspension and solid/liquid lipid ratio of 60/40 with a particle size of 100.4 nm, PDI of 0.36, and EE% 80%. The morphology, interactions, thermal properties, and crystallinity of obtained NLC formulations were investigated by TEM, FTIR, DSC, and XRD techniques. The optimum sage extract-loaded/gelatin-coated NLC showed significantly higher antioxidant activity than free extract after 30 days of storage. It also indicated a higher inhibitory effect against E. coli and P. aeruginosa than free form in MIC and MBC tests. The optimum sage extract-loaded/gelatin-coated NLC, more than free extract, increased the oxidation stability of the treated beef burger samples during 90 days of storage at 4 and -18 °C (verified by thiobarbituric acid and peroxide values tests). Incorporation of the optimum NLC to beef burgers also effectively decreased total counts of mesophilic bacteria, psychotropic bacteria, S. aureus, coliform, E. coli, molds, and yeasts of treated beef burger samples during 0, 3, and 7 days of storage in comparison to the control sample. These results suggested that the obtained sage extract-loaded NLC can be an effective preservative to extend the shelf life of beef burgers.
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Lutein is a prominent biologically active carotenoid pigment with a polyene skeleton that has great benefits for human health. The study examined the synergistic effects of potentially functional components, including lutein carotenoid (LC), Mentha × Piperita extract (MPE), and Citrus × aurantifolia essential oil (CAEO), all three as bioactive components and antioxidants (AOs), on the physicochemical characteristics of a new low-sugar and carotenoid-enriched high-antioxidant beverage. Sucralose was utilized as a non-nutritive sweetener. Polynomial equations obtained by combined design methodology (CDM) were fitted to the experimental data of total phenolic and flavonoid contents (TPC and TFC, respectively) and antioxidant potential of the beverages using multiple regression analysis with R2 (determination coefficient) values of 0.87, 0.89, and 0.97, respectively. Estimated response values for the TPC, TFC, and antioxidant potential (determined as 2, 2-diphenyl-1-picrylhydrazyl radical (DPPHâ¢) scavenging activity) of the optimum beverage formulation were 41.90 mg gallic acid equivalent (GAE) per L-1, 27.51 mg quercetin equivalent (QE) per L-1, and 34.06%, respectively, with a desirability value of 0.74. The potentially functional components had a synergistic effect on the antioxidant potential. This healthy beverage can have the potential to enhance health benefits and may have therapeutic potential for diabetic patients.
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In this research, garlic extract (GE)-loaded water-in-oil nanoemulsion was used as a novel preservative and antioxidant in mayonnaise. GE (5%, 10%, 15%, and 25%) as a dispersed phase, olive oil as a continuous phase, and polyglycerol polyricinoleate (PGPR) as a low HLB surfactant, with a constant surfactant/garlic extract ratio (1:1), were used in the formulations of water-in-oil nanoemulsions. The properties of the active nanoemulsion, including droplet size, free radical scavenging capacity, antimicrobial activity against gram-positive (Staphylococcus aureus [25923 ATCC]), and gram-negative (Escherichia coli H7 O157 [700728 ATCC]) were evaluated. The results showed that the mean droplet size of nanoemulsion increased from 62 to 302 nm and antioxidant capacity was also improved from 95.43% to 98.25% by increasing GE level from 5% to 25%. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) showed that antimicrobial activity against S. aureus could be observed only in high levels of GE (25%) in the formulation of nanoemulsion. The results of the total count analysis showed that the GE-loaded nanoemulsion (NEGE) was effective against the microorganisms, particularly after 4 months of storage. The incorporation of GE and NEGE did not affect significantly the acidity of different mayonnaise samples; however, they affected the concentration of the primary product of lipid oxidation. Adding GE and NGE did not significantly affect the rheological properties of mayonnaise and all samples showed shear-thinning behavior. Sensory evaluation showed that the samples with NEGE had higher scores in texture, spreadability, and mouthfeel, while the control samples had better scores in appearance, color, taste, and total acceptance. In general, the samples containing free GE (not encapsulated) had the lowest scores in all organoleptic characteristics.
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In this study, a new polysaccharide was isolated from Ocimum album L. seed (OA), and its physicochemical and rheological properties were investigated. Ocimum album polysaccharide (OAP) was an acidic heteropolysaccharide with a molecular weight of 1935 kDa, and it was composed of five types of sugars: mannose (32.95 %), glucose (27.57 %), galactose (19.29 %), rhamnose, (15.96 %) and galacturonic acid (4.23 %). According to the results obtained from Huggins and Kraemer equations, the intrinsic viscosity was 6.9 dL/g in distilled water. The OAP solutions at a concentration between 0.1 and 1.5 %, showed shear-thinning behavior, and the Herschel-Bulkley and Cross models exhibited a high ability to describe the flow behavior of OAP solutions. The apparent viscosity of 1 % OAP solution was decreased in the presence of different concentrations of NaCl (0.1, 0.3, and 0.5 M), at different pHs (3-11), and in temperatures between 5 and 100 °C. Also, the pseudoplastic behavior was observed in all samples. In OAP solutions (0.1-1.5 %), the up and down curves in the shear stress-shear rate diagram did not coincide, which indicated time-dependent (thixotropic) behavior. Although, the thixotropic properties of 1 % OAP solution were weakened with adding NaCl (0.1-0.5 M) and at different pH (3-11). The results obtained from the dynamic oscillatory test showed that the OAP solutions at concentrations higher than 0.1 % had a gel-like behavior, and the viscoelastic moduli (G' and Gâ³) were weakened in the presence of salt and with a change in pH. Also, in the temperature sweep test, the 1 % solution showed the behavior of thermally irreversible gels.
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Ocimum , Cloruro de Sodio , Polisacáridos/química , Viscosidad , Semillas/química , Geles , ReologíaRESUMEN
Lentil peptides have shown promising bioactive properties regarding the antioxidant activity and also inhibitory activity of angiotensin-I-converting enzyme (ACE). Sequential hydrolysis of proteins has shown a higher degree of hydrolysis with enhanced antioxidant and ACE-inhibitory activities. The lentil protein concentrate (LPC) was sequentially hydrolyzed using Alcalase and Flavourzyme at 2% w/w. The hydrolysate (LPH) was cross-linked (LPHC) or sonicated (LPHUS) and sequentially cross-linked (LPHUSC). Amino acid profile, molecular weight (MW) distribution, DPPH and ABTS radical scavenging activities (RSA; 7 mg/mL), ACE (0.1-2 mg/mL), α-glucosidase, and α-amylase inhibitory activities (10-500 µg/mL), and umami taste were determined. The highest DPPH RSA was obtained for LPH (68.75%), followed by LPHUSC (67.60%), and LPHUS (67.49%) while the highest ABTS RSA values were obtained for LPHC (97.28%) and LPHUSC (97.20%). Cross-linking and sonication led to the improvement of the ACE-inhibitory activity so that LPHUSC and LPHC had IC50 values of 0.23 and 0.27 mg/mL, respectively. LPHC and LPHUSC also indicated higher α-glucosidase inhibitory activity (IC50 of 1.2 and 1.23 mg/mL) compared to LPH (IC50 of 1.74 mg/mL) and LPHUS (IC50 of 1.75 mg/mL) while the IC50 value of acarbose indicated 0.51 mg/mL. Moreover, LPHC and LPHUSC exhibited higher α-amylase inhibitory activities (IC50 of 1.35 and 1.16 mg/mL) than LPHUS (IC50 of 1.95 mg/mL), and LPH (IC50 of 2.51 mg/mL) while acarbose had an IC50 value of 0.43 mg/mL. Umami taste analysis revealed that LPH and LPHC due to MW of 1.7 and 2.3 kDa and also high umami amino acids could be well considered as representative of meaty and umami analog flavors while indicating stronger antioxidant, antihypertension, and antidiabetic attributes.
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The mechanical and physical properties of the bionanocomposite films based on κ-carrageenan (KC)-gelatin (Ge) containing zinc oxide nanoparticles (ZnONPs) and gallic acid (GA) were optimized using the response surface method, and the optimum amounts of 11.19 wt% GA and 1.20 wt% ZnONPs were obtained. The results of XRD, SEM, and FT-IR tests showed the uniform distribution of the ZnONPs and GA in the film microstructure, and suitable interactions between biopolymers and these additives, which led to increasing the structural cohesion of the biopolymer matrix and improving the physical and mechanical properties of the KC-Ge-based bionanocomposite. In the films containing gallic acid and ZnONPs, an antimicrobial effect was not observed against E. coli; however, the GA-loaded and optimum films show an antimicrobial effect against S. aureus. The optimum film showed a higher inhibition effect against S. aureus compared to the ampicillin- and gentamicin-loaded discs.
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The applications of protein hydrolysates as food preservatives and nutraceutical ingredients have attracted much attention because of their beneficial effects. The interest in these ingredients has shifted toward their biological activities with benefits to human health. Bioactive peptides are known as antioxidant agents that could promote health-promoting effects and prolong food shelf-life beyond their basic nutritional value. Thus, the aim of this study was to investigate antioxidant, antimicrobial, and in vitro cytotoxic properties of corn pollen protein (CPP) hydrolysates obtained by different enzymes. Proteolytic activity in terms of degree of hydrolysis (DH) and SDS-PAGE analysis was measured in pancreatin (H-Pan), pepsin (H-Pep), and trypsin (H-Tri) hydrolysates. Amino acid composition, antioxidant and antimicrobial activities, and cytotoxicity of hydrolysates were evaluated. DH and SDS-PAGE revealed higher proteolytic activity of pepsin compared to other enzymes. Amino acid analysis showed that the functional amino acids such as antioxidant types were most predominant in H-Pep compared to two other samples. Antioxidant activity of hydrolysates was found to be affected by the type of enzyme and the concentration of hydrolysates. There was a significant difference (p < 0.05) between antioxidant activity of different hydrolysates. The highest antioxidant activity in terms of Trolox equivalent antioxidant capacity (0.23-2.75 mM), DPPH (33.3%-64.8%), and hydroxyl (33.7%-63.2%) radical scavenging activities, chelation of iron (33.2%-62.5%) and copper (30.2%-50.5%) metals, and total antioxidant activity (0.65-0.85) was obtained for H-Pep followed by H-Pan and H-Tri samples. Antibacterial tests showed that pepsin-hydrolyzed protein was not significantly (P > 0.05) effective against E. coli at any concentrations, however, it showed significant (P < 0.05) concentration-dependent effect against S. aureus (with inhibition zones of 15-25 mm). Cytotoxicity results revealed that CPP, as a nonhydrolyzed protein, did not generally show antiproliferative activity, however, a significant (P < 0.05) ability of H-Pep hydrolysate in decreasing HT-29 colon cancer cell line viability was seen in a concentration-dependent manner (the lowest cell viability of 32% at 5 mg/mL). Overall, investigating the application of protein-based hydrolysates is one of the possible strategies that govern their applied intentions as preservatives and nutraceuticals in the food and pharmaceutical industries.
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A novel lime-juice based low-calorie functional beverage was developed by using D-optimal combined design optimization. For the preparation of the beverage, the following functional ingredients were used: lime juice, lime peel essential oil (LEO) as a flavoring agent and bioactive component, sucralose as a low-calorie sweetener, an inulin/polydextrose (I/P) mixture as prebiotic fibers, pectin as a thickening agent and soluble dietary fiber, lutein as a carotenoid colorant and antioxidant, and peppermint extract (ME) as a flavoring agent and bioactive component. A combined design consisting of one mixture factor (LEO/ME ratio), one numeric factor (lutein concentration), and one categoric factor (presence or absence of prebiotics) was used for optimizing the functional beverage based on the sensory quality. Regression models were adequately fitted to the data of sensory acceptance with a determination coefficient >90%. The sample containing a mixture of prebiotics, 2:3 (v/v) ratio of LEO: ME, and 3 mg/100 mL lutein was selected as the best formulation among the six optimal beverages which was suggested by Design-Expert software. This final optimum sample showed the highest total phenolic (44.22 mg gallic acid equivalents/L) and flavonoid (25.49 mg quercetin equivalents/L) contents, and its antioxidant activity (as 2,2-diphenyl-1-picrylhydrazyl radical (DPPHâ¢) scavenging) was 38.30%. The newly designed beverage has the potential to promote health benefits and in therapeutic applications.
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The formulation of a novel functional juice, enriched with wheat germ powder and spirulina algae and based on cantaloupe and pear juice, was optimized by D-optimal combined design. Firstly, sensory evaluation was performed by hedonic test to evaluate the organoleptic properties, and organoleptically desirable samples were screened for further experiments. Various chemical experiments including PH, acidity, formalin index, total phenol, flavonoids, antioxidant capacity, mineral contents (Fe, Zn, Ca, P, K, Mg, and Cu), and fatty acids profile were evaluated. The steady shear flow rheological test also was performed on the screened samples. The results of sensory evaluation showed that the samples containing 1% spirulina and wheat germ had the highest organoleptic score. The results of physicochemical tests on the selected samples showed that the addition of spirulina and wheat germ powder had little effect on pH, acidity, and formalin index but they affected brix, dry matter, and protein content. Also, the addition of spirulina and wheat germ powder, changed the amounts of antioxidant capacity (from 90 to 98%), total phenol (from 4 to 22 mg GAE/g), and flavonoid content (from 5 to 15 mg/L) in the functional beverages. Furthermore, the results of rheological tests showed that the addition of wheat germ powder in the functional fruit juices increased apparent viscosity however; spirulina did not affect important change in rheological properties. The GC-Mass analysis presented fatty acid profiles of the functional beverages and confirmed the presence of polyunsaturated fatty acids (for example decanoic acid and heptadecanoic acid) in the samples.
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An "intelligent" or smart packaging is able to continuously monitor physicochemical and/or biological variations of packaged food materials, providing real-time information concerning their quality, maturity, and safety. Electrospun nanofiber (ENF) structures, nowadays, reckon as versatile biomaterial platforms in designing intelligent packaging (IP) systems. Natural biopolymer-based ENF traits, for example, surface chemistry, rate of degradation, fiber diameter, and degree of alignment, facilitate the development of unique, tunable IP, enhancing food quality, and safety. In this review, after a brief overview of the electrospinning process, we review food IP systems, which can be utilized to detect variations in food features, for example, those based on alterations in temperature, O2 level, time, humidity, pH, or microbial contamination. Different intelligent approaches that are applicable in engineering IP materials are then highlighted, that is, indicators, data carriers, and sensors. The latest research on the application of ENFs made with natural biopolymers in food IP and their performance on different packaged food types (i.e. meat, fruits and vegetables, dairy products, etc.) are underlined. Finally, the challenges and outlook of these systems in the food industry are discussed.
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In this research work, the effects of myrtle essential oil (MEO) and Caucasian whortleberry extract (CWE) as natural additives were investigated on mechanical, physico-mechanical and antimicrobial properties of gellan/polyvinyl alcohol (G/PVA) film. Then, optimal blend active films were used for the wrapping of turkey breast meat stored at low temperature (4 ± 1 °C) for 15 days and chemical and sensory properties of wrapped meats were evaluated. The addition of MEO and CWE decreased tensile strength and increased the strain at the break of the films (p ≤ 0.05). Additionally, with increasing the amount of MEO and CWE, the permeability to water vapor (WVP) and the moisture content (MC) of the films decreased (p ≤ 0.05). MIC test showed that MEO and CWE were effective against S. aureus, E. coli, S. typhimurium, and P. fluorescens. at the concentrations of 5-6 and 15-17 mg/mL, respectively. Different microbiological, chemical, and sensory tests indicated that active films significantly enhanced the shelf life of turkey breast meat (p ≤ 0.05). Therefore, based on our finding in this study, the use of these active and biodegradable packagings can be effective and useful for protecting the microbial and sensory quality of turkey breast meat.
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Three red color fruit juice (pomegranate (PJ), barberry (BJ), and grape juice (GJ)) and three plant extracts (cardamom essential oil (CE), ginger extract (GE), and hibiscus solution (HS)) were used for the development of different functional beverages. Organoleptic analysis was done to detect the most acceptable fruit juice blend. The physicochemical properties of the samples including total phenols, 1,1-diphenyl-2-picrylhydrazyl (DPPH) inhibition percent, anthocyanin, flavonoid, and vitamin C content of optimum fruit juice blend (60% PJ/20% BJ/20% GJ) were 121.57 µg gallic acid equivalent (GAE)/ml, 80.28%, 4.03 mg/L, 64.87 mg/100 ml, and 51.10 mg/100 ml, respectively. To determine the optimum level of extracts and essential oil (GE, CE, and HS) in fruit juice blends, the mixture design method was used and 14 runs (formulations) were obtained. In all formulations, samples containing HS had the highest content of antioxidant and active components and the statistical analysis indicated that the sample containing 0.5 CE/0.5 GE/1 HS (ml/100 ml) had the optimum content of antioxidant components. Thus, the results of this study introduce a functional drink possessing high polyphenols, antioxidants, anthocyanin, and vitamin C content.
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An O/W nanoemulsion of garlic essential oil (GEO) at different oil-to-emulsion (O/E) ratios (5%, 10%, 15%, and 25%) was formulated to protect the volatile components of GEO. The effects of O/E ratios on the encapsulation efficiency (EE%) of volatile compounds and droplet size of nanoemulsions were studied. The results showed that with increasing in E/O ratio, droplet size increased while EE% decreased so that the droplet size was below 100 nm for all samples and the EE% was almost above 80% for most samples. The effects of various factors such as temperature (5°C-45°C), pH values (3-7), ionic strength (0-500 mM), and O/E ratios (5%-25%) on kinetic of nanoemulsions stability were studied. Reducing pH values and raising the temperature, ionic strength, and O/E ratios intensified the instability process and constant rate of instability in all nanoemulsions. The effects of temperature and O/E ratios on the release kinetics of volatile components were evaluated over time, and kinetic parameters such as release rate constant (k), Q10, and activation energy (Ea) were calculated in which results showed a zero-degree model to describe the release kinetic behavior of most nanoemulsions. Both temperature and O/E ratios factors as well as their interaction (which had a synergistic effect) had a significant effect on increasing the release rate of volatiles so that the degree of reaction rate was changed from zero to the first order at simultaneous high levels of both factors. FT-IR spectroscopy was carried out to study interactions among nanoemulsion ingredients. The presence of sulfur-containing functional groups of garlic oil (thiosulphate, diallyl trisulfide, etc.) in nanoemulsions was confirmed by FT-IR.
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This study was aimed to encapsulate lemongrass (Cymbopogon commutatus) essential oil (LGEO) into chitosan nanoparticles (CSNPs) and to investigate their physicochemical, morphological, structural, thermal, antimicrobial and in-vitro release properties. CSNPs exhibited spherical morphology with an average hydrodynamic size of 175-235 nm. Increasing EO loading increased the average size of CSNPs from 174 to 293 nm (at CS:EO ratio from 1:0 to 1:1.25). SEM and AFM confirmed the results obtained by hydrodynamic size indicating that EO loading led to formation of large aggregated NPs. The successful physical entrapment of EO within NPs was shown by fourier-transform infrared spectroscopy. X-ray diffractogram of loaded-CSNPs compared to non-loaded CSNPs exhibited a broad high intensity peak at 2θ = 19-25° implying the entrapment of LGEO within CSNPs. Thermogravimetric analysis (TGA) showed that encapsulated EO was decomposed at a temperature of 252 °C compared to a degradation temperature of 126 °C for pure LGEO, indicating a two-fold enhancement in thermal stability of encapsulated CSNPs. Differential scanning calorimetry also proved the physical entrapment of EO into polymeric matrix of chitosan. In-vitro release study showed a time- and pH-dependent release of EO into release media demonstrating a three-stage release behavior with a rapid initial release of EO, followed by a steady state migration of EO from its surrounding envelope at the later stages. Antimicrobial assay showed strong antimicrobial properties of free form of LGEO against the bacteria (both gram positive and gram negative) and fungi species tested. Moreover, loaded-CSNPs exhibited stronger antibacterial and anti-fungal activities than non-loaded CSNPs.
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Antiinfecciosos/química , Antiinfecciosos/farmacología , Quitosano/química , Cymbopogon/química , Nanopartículas/química , Aceites Volátiles/química , Fenómenos Químicos , Portadores de Fármacos/química , Composición de Medicamentos , Liberación de Fármacos , Cromatografía de Gases y Espectrometría de Masas , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Nanopartículas/ultraestructura , Tamaño de la Partícula , TermogravimetríaRESUMEN
A water-soluble acidic polysaccharide (AOP-2) from Althaea officinalis L. root was isolated by water extraction and purified by ion exchange chromatography (Cellulose DEAE-52) and gel filtration (Sephadex G-200). The structure characteristics of AOP-2 was determined by gel permeation chromatography (GPC), high performance liquid chromatography (HPLC), fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR) spectrum and gas chromatography-mass spectrometry (GC_MS). The results indicated that the AOP-2 was an acidic hetropolysaccharide with the molecular weight of 639.27 kDa. The AOP-2 composed of 51% galacturonic acid, 32.56% rhamnose, 12.73% glucose and 3.71% galactose. It could be found that the main backbone chain of AOP-2 consisted of â3)-α-D-GalpA-(1â, â3)-α-D-Rhap-(1â andâ3,4)-ß-D-Galp-(1â with branches of â4)-α-D-Rhap-(1â, â4)-α-D-Glcp-(1â and α-D-Rhap-(1 â . Thermal analysis revealed that the AOP-2 had high thermal stability and according to the results obtained from XRD analysis, it had a semi-crystalline structure. The results of Steady-shear flow and dynamical viscoelasticity showed that AOP-2 solutions exhibited shear-thinning behavior with high viscosity and a weak gel-like behavior at concentrations above 1% in linear viscoelastic region. In addition, it showed relatively high antioxidant property.
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Althaea/química , Antioxidantes/farmacología , Raíces de Plantas/química , Polisacáridos/farmacología , Antioxidantes/química , Antioxidantes/aislamiento & purificación , Compuestos de Bifenilo/antagonistas & inhibidores , Conformación de Carbohidratos , Picratos/antagonistas & inhibidores , Polisacáridos/química , Polisacáridos/aislamiento & purificación , ReologíaRESUMEN
Synergistic effect of zinc oxide nanoparticles (ZnO-NPs) as photocatalyst and organonanoclay (ONC) as biodegradable promoter on the degradation of polystyrene (PS) film was investigated. The films were exposed to ultraviolet irradiation under ambient air at room temperature for photo-catalytic degradation and then submitted to biodegradation test in soil using respirometric procedure. Fourier-transform infrared and ultraviolet-visible spectroscopy, thermogravimetric analysis, colorimeter technique, contact angle measurement, and the carbon dioxide evolution results showed higher photo- and biodegradation efficiency of PS-ONC-ZnO nanocomposite compared to the neat PS, PS-ONC and PS-ZnO nanocomposites. Thermal stability, optical band gap, and water contact angle of photo-degraded PS-ONC-ZnO nanocomposite decreased by 11.37, 18.33 and 63.99%, respectively, while that of PS film was only 6.20, 6.44 and 5.84%, respectively. The photo-degraded PS-ONC-ZnO and PS-ZnO film indicated a biodegradation percentage value of 3.3 and 2.1%, respectively, over 16 weeks of incubation in soil. The possible degradation mechanism of nanocomposites was briefly discussed.