Isolation and Identification of Lichen Photobionts Collected from Different Environments in North of Portugal and Evaluation of Bioactivities of Their Extracts.

Lichens are organisms constituted by a symbiotic relationship between a fungus (mycobiont) and a photoautotrophic partner (photobiont). Lichens produce several bioactive compounds; however, the biotechnological exploitation of this organism is hampered by its slow growth. To start studying the possibility of exploiting lichens as alternative sources of bioactive compounds, eighteen lichens were collected in the north of Portugal in order to isolate and study the bioactivity of their photobionts. It was possible to isolate and cultivate only eight photobionts. Three of them, LFR1, LFA2 and LCF3, belong to the Coelastrella genus, the other two (LFA1 and LCF1) belong to the Chlorella genus and for the remaining three photobionts, LFS1, LCA1 and LCR1, it was impossible to isolate their microalgae. These only grow in consortium with bacteria and/or cyanobacteria. All extracts showed antioxidant activity, mainly at a concentration of 10 mg.mL-1. LFS1, a consortium extract, showed the highest antioxidant power, as well as the highest concentration of phenolic compounds (5.16 ± 0.53 mg of gallic acid equivalents (GAE).g-1). The extracts under study did not show significant antibacterial activity against Escherichia coli, Listeria or Salmonella. The Coelastrella sp. and LFA1 extracts showed the highest hyaluronidase inhibition. The LFR1 extract at a concentration of 5 mg.mL-1 showed the highest anti-inflammatory activity (79.77 ± 7.66%). The extracts of Coelastrella sp. and LFA1 also showed greater antidiabetic activity, demonstrating the high inhibitory power of α-amylase and α-glucosidase. LFR1 at a concentration of 5 mg.mL-1, due to its selective cytotoxicity inhibiting the growth of cancer cells (Caco-2 cells), is a promising anticancer agent.

Performance of ß-carotene-loaded nanostructured lipid carriers under dynamic in vitro digestion system: Influence of the emulsifier type.

A better understanding of how emulsifier type could differently influence the behavior of nanostructured lipid carriers (NLC) under the gastrointestinal digestion process, as well as at the cellular level, is of utmost importance for the NLC-based formulations' optimization and risk assessment in the food field. In this study, NLC composed by fully hydrogenated soybean and high-oleic sunflower oils were prepared using soy lecithin (NLC Lß) or Tween 80 (NLC Tß) as an emulsifier. ß-Carotene was entrapped within NLC developed as a promising strategy to overcome ß-carotene's low bioavailability and stability. The effect of emulsifier type on the digestibility of ß-carotene-loaded NLC was evaluated using an in vitro dynamic digestion model mimicking peristalsis motion. The influence of ß-carotene-loaded NLC on cell viability was assessed using Caco-2 cells in vitro. NLC Tß remained stable in the gastric compartment, presenting particle size (PS) similar to the initial NLC (PS: 245.68 and 218.18 nm, respectively), while NLC Lß showed lower stability (PS > 1000 nm) in stomach and duodenum phases. NLC Tß also provided high ß-carotene protection and delivery capacity (i.e., ß-carotene bioaccessibility increased 10-fold). Based on the results of digestion studies, NLC Tß has shown better physical stability during the passage through the in vitro dynamic gastrointestinal system than NLC Lß. Moreover, the developed NLC did not compromise cell viability up to 25 µg/mL of ß-carotene. Thus, the NLC developed proved to be a biocompatible structure and able to incorporate and protect ß-carotene for further food applications. PRACTICAL APPLICATION: The findings of this study hold significant implications for industrial applications in terms of developing nanostructured lipid carriers from natural raw materials widely available and used to produce other lipid-based products in the food industry, as an alternative to synthetic ones. In this respect, the ß-carotene-loaded NLC developed in this study would find a great industrial application in the food industry, which is in constant search to develop functional foods capable of increasing the bioavailability of bioactive compounds.

Valorization of Cork Stoppers, Coffee-Grounds and Walnut Shells in the Development and Characterization of Pectin-Based Composite Films: Physical, Barrier, Antioxidant, Genotoxic, and Biodegradation Properties.

The development of sustainable materials from the valorization of waste is a good alternative to reducing the negative environmental impact of plastic packaging. The objectives of this study were to develop and characterize pectin-based composite films incorporated with cork or cork with either coffee grounds or walnut shells, as well as to test the films' genotoxicity, antioxidant properties, and biodegradation capacity in soil and seawater. The addition of cork, coffee grounds, or walnut shells modified the films' characteristics. The results showed that those films were thicker (0.487 ± 0.014 mm to 0.572 ± 0.014 mm), more opaque (around 100%), darker (L* = 25.30 ± 0.78 to 33.93 ± 0.84), and had a higher total phenolic content (3.17 ± 0.01 mg GA/g to 4.24 ± 0.02 mg GA/g). On the other hand, the films incorporated only with cork showed higher values of elongation at break (32.24 ± 1.88% to 36.30 ± 3.25%) but lower tensile strength (0.91 ± 0.19 MPa to 1.09 ± 0.08 MPa). All the films presented more heterogeneous and rougher microstructures than the pectin film. This study also revealed that the developed films do not contain DNA-reactive substances and that they are biodegradable in soil and seawater. These positive properties could subsequently make the developed films an interesting eco-friendly food packaging solution that contributes to the valorization of organic waste and by-products, thus promoting the circular economy and reducing the environmental impact of plastic materials.

Resveratrol-loaded octenyl succinic anhydride modified starch emulsions and hydroxypropyl methylcellulose (HPMC) microparticles: Cytotoxicity and antioxidant bioactivity assessment after in vitro digestion.

Hydroxypropyl methylcellulose (HPMC)-based microparticles and modified starch emulsions (OSA-MS) were loaded with resveratrol and characterized regarding their physicochemical and thermal properties. Both delivery systems were subject to an in vitro gastrointestinal digestion to assess the bioaccessibility of resveratrol. In addition, cell-based studies were conducted after in vitro digestion and cytotoxicity and oxidative stress were assessed. HPMC-based microparticles displayed higher average sizes (d) and lower polydispersity index (PDI) (d = 948 nm, PDI < 0.2) when compared to OSA-MS-based emulsions (d = 217 nm, PDI < 0.3). Both proved to protect resveratrol under digestive conditions, leading to an increase in bioaccessibility. Resveratrol-loaded HPMC-microparticles showed a higher bioaccessibility (56.7 %) than resveratrol-loaded emulsions (19.7 %). Digested samples were tested in differentiated co-cultures of Caco-2 and HT29-MTX, aiming at assessing cytotoxicity and oxidative stress, and a lack of cytotoxicity was observed for all samples. Results displayed an increasing antioxidant activity, with 1.6-fold and 1.4-fold increases over the antioxidant activity of free resveratrol, for HPMC-microparticles and OSA-MS nanoemulsions, respectively. Our results offer insight into physiological relevancy due to assessment post-digestion and highlight the protection that the use of micro-nano delivery systems can confer to resveratrol and their potential to be used as functional food ingredients capable of providing antioxidant benefits upon consumption.

Chitosan Coating Functionalized with Flaxseed Oil and Green Tea Extract as a Bio-Based Solution for Beef Preservation.

Ecological and safe packaging solutions arise as pivotal points in the development of an integrated system for sustainable meat production. The aim of this study was to assess the effect of a combined chitosan (Ch) + green tea extract (GTE) + essential oil (thyme oil, TO; flaxseed oil, FO; or oregano oil, OO) coating on the safety and quality of vacuum-packaged beef during storage at 4 °C. An optimized bio-based coating formulation was selected (2% Ch + 2% GTE + 0.1% FO) to be applied to three fresh beef cuts (shoulder, Sh; knuckle, Kn; Striploin, St) based on its pH (5.8 ± 0.1), contact angle (22.3 ± 0.4°) and rheological parameters (viscosity = 0.05 Pa.s at shear rate > 20 s-1). Shelf-life analysis showed that the Ch-GTE-FO coating delayed lipid oxidation and reduced total viable counts (TVC) and Enterobacteriaceae growth compared with uncoated beef samples over five days. In addition, Ch-GTE-FO coating decreased total color changes of beef samples (e.g., ∆E* = 9.84 and 3.94, for non-coated and coated Kn samples, respectively) for up to five days. The original textural parameters (hardness, adhesiveness and springiness) of beef cuts were maintained during storage when Ch-GTE-FO coating was applied. Based on the physicochemical and microbial characterization results, the combination of the Ch-GTE-FO coating developed was effective in preserving the quality of fresh beef cuts during refrigerated storage along with vacuum packaging.

Gelation Behavior and Stability of Multicomponent Sterol-Based Oleogels.

Novel fat mimetic materials, such as oleogels, are advancing the personalization of healthier food products and can be developed from low molecular weight compounds such as γ-oryzanol and ß-sitosterol. Following molecular assembly, the formation of a tubular system ensues, which seems to be influenced by elements such as the oleogelators' concentration and ratio, cooling rates, and storage periods. Sterol-based oleogels were formulated under distinct environmental conditions, and a comprehensive study aimed to assess the effects of the mentioned factors on oleogel formation and stability, through visual observation and by using techniques such as small-angle X-ray scattering, X-ray diffraction, confocal Raman spectroscopy, rheology, and polarized microscopy. The long, rod-like conformations, identified by small-angle X-ray scattering, showed that different cooling rates influence oleogels' texture. Raman spectra showed that the stabilization time is associated with the interfibrillar aggregation, which occurred differently for 8 and 10 wt%, with a proven relationship between ferulic acid and the tubular formation. This report gives fundamental insight into the critical point of gelation, referring to the time scale of the molecular stabilization. Our results verify that understanding the structuring mechanisms of oleogelation is decisive for the processing and manufacturing of novel foods which integrate oleogels in their structure.

Curcumin encapsulation in nanostructures for cancer therapy: A 10-year overview.

Curcumin (CUR) is a phenolic compound present in some herbs, including Curcuma longa Linn. (turmeric rhizome), with a high bioactive capacity and characteristic yellow color. It is mainly used as a spice, although it has been found that CUR has interesting pharmaceutical properties, acting as a natural antioxidant, anti-inflammatory, antimicrobial, and antitumoral agent. Nonetheless, CUR is a hydrophobic compound with low water solubility, poor chemical stability, and fast metabolism, limiting its use as a pharmacological compound. Smart drug delivery systems (DDS) have been used to overcome its low bioavailability and improve its stability. The current work overviews the literature from the past 10 years on the encapsulation of CUR in nanostructured systems, such as micelles, liposomes, niosomes, nanoemulsions, hydrogels, and nanocomplexes, emphasizing its use and ability in cancer therapy. The studies highlighted in this review have shown that these nanoformulations achieved higher solubility, improved tumor cytotoxicity, prolonged CUR release, and reduced side effects, among other interesting advantages.

Study of olive pomace antioxidant dietary fibre powder throughout gastrointestinal tract as multisource of phenolics, fatty acids and dietary fibre.

Pulp-enriched powder (POPP) was obtained from olive pomace solid fraction, a derived from the new value chain established for olive by-products. As a multifunctional powder, POPP retains several bioactive compounds (fatty acids, dietary fibre and phenolics) under potential synergic interaction, even more, reactive throughout the digestion. So, in this study, the potential multifunctionality of POPP was evaluated after the gastrointestinal tract. A significant loss of phenolics occurred during oral digestion (62.48%). However, the potential role of dietary fibre as phenolics' carrier and its possible liberation in the stomach allowed recovering a significant amount of phenolics (77.11%) and a bioaccessibility index of at least 50% (mainly for tyrosol and its glucoside). POPP also provides high content of dietary fibre mainly insoluble fibre (69.68 g/100 g dry weight) linked to a substantial amount of bound phenolics (7.63 mg of gallic acid equivalents/g fibre dry weight), with a positive effect on the fatty acids bioaccessibility [decreased the saturated (5-6%) and facilitated the unsaturated fatty acids bioaccessibility (4-11%)]. PCA analysis became evident the negative effect of simulated gastrointestinal digestion upon POPP as mainly linked to phenolics' loss. Despite all negative effects of the simulated digestion on POPP bioactive composition, phenolics and unsaturated fatty acids showed to be bioaccessible in significant amount, and the amount of bound phenolics associated to fibre retained in the colon have the potential to exert gut health benefits.

Modulation and Characterization of Wax-Based Olive Oil Organogels in View of Their Application in the Food Industry.

Olive oil has recognized health benefits but lacks structural resilience to act in a similar fashion as do the typically used triglycerides (TAGs) when applied in food manufacturing. Therefore, olive oil structuring is critical to widening its use as a healthier alternative in spreadable products. Foreseeing the development of an application for the food industry, three types of natural waxes were used as organogelators, generating olive oil organogels with distinct properties. Retail-simulated storage conditions were used to mimic real-life industrial and commercial use. Organogel systems were evaluated according to their oxidation stability and textural and rheological properties. Textural and rheological parameters increased in response to increasing gelator concentration, while oxidation values (below 1.5 meq O2·kg-1) remained within legal limits. Organogels displayed similar textural properties to those of commercially available spreadable products, while displaying a low critical gelation concentration. In short, it was shown that tailoring the physicochemical properties of organogels towards specific applications is possible. The produced organogels showed similar properties to the ones of commercially available spreadable products, revealing favourable oxidative profiles. Therefore, an industrial application can be easily foreseen, building on the natural characteristics of olive oil as a healthier alternative to current spreadable products.

Are olive pomace powders a safe source of bioactives and nutrients?

BACKGROUND: The olive oil industry generates significant amounts of semi-solid wastes, namely olive pomace. Olive pomace is a by-product rich in high-value compounds (e.g. dietary fibre, unsaturated fatty acids, polyphenols) widely explored to obtain new food ingredients. However, conventional extraction methods frequently use organic solvents, while novel eco-friendly techniques have high operational costs. The development of powdered products without any extraction step has been proposed as a more feasible and sustainable approach. RESULTS: The present study fractionated and valorized the liquid and pulp fraction of olive pomace obtaining two stable and safe powdered ingredients, namely a liquid-enriched powder (LOPP) and a pulp-enriched powder (POPP). These powders were characterized chemically, and their bioactivity was assessed. LOPP exhibited a significant amount of mannitol (141 g kg-1 ), potassium (54 g kg-1 ) and hydroxytyrosol derivatives (5 mg g-1 ). POPP exhibited a high amount of dietary fibre (620 g kg-1 ) associated with a significant amount of bound phenolics (7.41 mg GAE g-1 fibre DW) with substantial antioxidant activity. POPP also contained an unsaturated fatty acid composition similar to that of olive oil (76% of total fatty acids) and showed potential as a reasonable source of protein (12%). Their functional properties (solubility, water-holding and oil-holding capacity), antioxidant capacity and antimicrobial activity were also assessed, and their biological safety was verified. CONCLUSIONS: The development of olive pomace powders for application in the food industry could be a suitable strategy to add value to olive pomace and obtain safe multifunctional ingredients with higher health-promoting effects than dietary fibre and polyphenols. © 2020 Society of Chemical Industry.

Green synthesis of lignin nano- and micro-particles: Physicochemical characterization, bioactive properties and cytotoxicity assessment.

Lignin particles (LPs) have gained prominence due to their biodegradability and bioactive properties. LP production at nano and micro scale produced from organosolv lignin and the understanding of size's effect on their properties is unexplored. This work aimed to produce and characterize lignin nanoparticles and microparticles using a green synthesis process, based on ethanol-solubilized lignin and water. Spherical shape LPs, with a mean size of 75 nm and 215 nm and with a low polydispersity were produced, as confirmed by transmission electron microscopy and dynamic light scattering. LPs thermal stability improved over raw lignin, and the chemical structure of lignin was not affected by the production method. The antimicrobial tests proved that LPs presented a bacteriostatic effect on Escherichiacoli and Salmonella enterica. Regarding the antioxidant potential, LPs had a good antioxidant activity that increased with the reaction time and LPs concentration. LPs also presented an antioxidant effect against intracellular ROS, reducing the intracellular ROS levels significantly. Furthermore, the LPs showed a low cytotoxic effect in Caco-2 cell line. These results showed that LPs at different scales (nano and micro) present biological properties and are safe to be used in different high value industrial sectors, such as biomedical, pharmaceutical and food.

Characterization of Enriched Meat-Based Pâté Manufactured with Oleogels as Fat Substitutes.

Nowadays, one of the strongest factors affecting consumers' choice at the moment of purchasing food products is their nutritional features. The population is increasingly aware of the diet-health relationship and they are opting for a healthy lifestyle. Concerns with the increasing number of heart-related diseases, which are associated to the consumption of fats, are placing the functional food market in a relevant growth position. Considering that, our goal was to develop, under semi-industrial processing conditions, a healthy meat-based spreadable product (pâté) with reduced fat content through replacement of pork fat by healthier structured oil. Beeswax was used to develop an edible oleogel based on linseed oil with a high content of linolenic acid. A decrease of the hardness and adhesivity was verified for pâtés with oleogel incorporation. Linseed oil inclusion was the main factor leading to an increase of polyunsaturated fatty acids (PUFA) content in pâté samples. A decrease up to 90% in the n-6/n-3 (omega-6/omega-3) ratio can signify a better nutritional value of the obtained pâté samples, which can result in a possible upsurge in omega-3 bioavailability through digestion of these pâtés. This could be an interesting option for the consumption of n-3 polyunsaturated fatty acids, targeting, for example, the reduction of cardiovascular diseases.

ß-lactoglobulin micro- and nanostructures as bioactive compounds vehicle: In vitro studies.

ß-Lactoglobulin (ß-Lg) is known to be capable to bind hydrophilic and hydrophobic bioactive compounds. This research aimed to assess the in vitro performance of ß-Lg micro- (diameter ranging from 200 to 300 nm) and nano (diameter < 100 nm) structures associated to hydrophilic and hydrophobic model compounds on Caco-2 cells and under simulated gastrointestinal (GI) conditions. Riboflavin and quercetin were studied as hydrophilic and hydrophobic model compounds, respectively. Cytotoxicity experiment was conducted using in vitro cellular model based on human colon carcinoma Caco-2 cells. Moreover, the digestion process was simulated using the harmonized INFOGEST in vitro digestion model, where samples were taken at each phase of digestion process - oral, gastric and intestinal - and characterized in terms of particle size, polydispersity index (PDI), surface charge by dynamic light scattering (DLS); protein hydrolysis degree by 2,4,6-trinitrobenzene sulfonic acid (TNBSA) assay and native polyacrylamide gel electrophoresis; and bioactive compound concentration. Caco-2 cell viability was not affected up to 21 × 10-3 mg mL-1 of riboflavin and 16 × 10-3 mg mL-1 quercetin on ß-Lg micro- and nanostructures. In the oral phase, ß-Lg structures' particle size, PDI and surface charge values were not changed comparing to the initial ß-Lg structures (i.e., before being subjected to in vitro GI digestion). During gastric digestion, ß-Lg structures were resistant to proteolytic enzymes and to acid environment of the stomach - confirmed by TNBSA and native gel electrophoresis. In vitro digestion results indicated that ß-Lg micro- and nanostructures protected both hydrophilic and hydrophobic compounds from gastric conditions and deliver them to target site (i.e., intestinal phase). In addition, ß-Lg structures were capable to enhance riboflavin and quercetin bioaccessibility and bioavailability potential compared to bioactive compounds in their free form. This study indicated that ß-Lg micro- and nanostructures were capable to enhance hydrophilic and hydrophobic compounds bioavailability potential and they can be used as oral delivery systems.

Simulated digestion of an olive pomace water-soluble ingredient: relationship between the bioaccessibility of compounds and their potential health benefits.

Olive pomace is a semisolid by-product with great potential as a source of bioactive compounds. Using its soluble fraction, a liquid-enriched powder (LOPP) was obtained, exhibiting a rich composition in sugars, polyphenols and minerals, with potential antioxidant, antihypertensive and antidiabetic health benefits. To validate the potential of LOPP as a functional ingredient the effect of the gastrointestinal tract on its bioactive composition and bioactivities was examined. Polyphenols and minerals were the most affected compounds; however, a significant bioaccessibility of potassium and hydroxytyrosol was verified (≥57%). As a consequence, the LOPP bioactivities were only moderately affected (losses around 50%). For example, 57.82 ± 1.27% of the recovered antioxidant activity by ORAC was serum-available. From an initial α-glucosidase inhibition activity of 87.11 ± 1.04%, at least 50% of the initial potential was retained (43.82 ± 1.14%). Regarding the initial ACE inhibitory activity (91.98 ± 3.24%), after gastrointestinal tract losses, significant antihypertensive activity was retained in the serum-available fraction (43.4 ± 3.65%). The colon-available fraction also exhibited an abundant composition in phenolics and minerals. LOPP showed to be a potential functional ingredient not only with potential benefits in preventing cardiovascular diseases but also in gut health.

Evaluation of linseed oil oleogels to partially replace pork backfat in fermented sausages.

BACKGROUND: Nowadays, fat replacement in meat products is a matter of concern in the meat industry. The objective of this study was to evaluate the replacement of pork backfat with two oleogels of linseed in dry-cured sausages. RESULTS: Five batches of dry-cured sausages were prepared with two oleogels, a mixture of γ-oryzanol and ß-sitosterol (SO) and beeswax (B), at two levels of replacement (20% and 40%) (SO-20, SO-40, B-20, and B-40, respectively) and a control batch. The fatty acid profile improved in terms of nutrition: the polyunsaturated fatty acid / saturated fatty acid (PUFA/SFA) and n-6/n-3 ratio was about 1.41 and 0.93 for the higher levels of replacement, SO-40 and B-40, respectively. Quality parameters such as pH and color also changed with the inclusion of oleogels, resulting in changes in the sensory quality. CONCLUSION: Oleogels based on linseed enabled the replacement of pork backfat in fermented sausages. Depending on the level of fat substitution, such oleogels could replace fat in dry-cured sausages at the industrial level. © 2019 Society of Chemical Industry.

Influence of AO chain length, droplet size and oil to water ratio on the distribution and on the activity of gallates in fish oil-in-water emulsified systems: Emulsion and nanoemulsion comparison.

The distribution of a homologous series of polyphenol derivatives of increasing lipophilicity has been determined in fish oil-in-water emulsions and nanoemulsions by the pseudophase model. One of the hypotheses on which the pseudophase model is based, is that its application is independent of the size of emulsion droplets. In agreement with our hypothesis, results showed that the smaller droplet size found in nanoemulsions does not affect partition constants of gallic acid (GA) and its esters. The antioxidant efficiency of GA and gallates in the emulsified systems used, correlated positively with the concentration of antioxidant at the interfacial region. The increase in the oil/water ratio increased the overall oxidative stability of emulsions but decreased the antioxidant efficiency of the more lipophilic derivatives. This can be assigned to the fact that, increasing the oil phase volume, the interfacial concentration decreased for the more lipophilic antioxidants.

Strategy towards Replacing Pork Backfat with a Linseed Oleogel in Frankfurter Sausages and its Evaluation on Physicochemical, Nutritional, and Sensory Characteristics.

Different health institutions from western countries ha-ve recommended a diet higher in polyunsaturated fats, especially of the n-3 family. However, this is not a trivial task, especially for meat-processing sectors. The objective of this work was to assess the influence of replacing pork backfat with linseed oleogel on the main quality parameters of frankfurters. The frankfurters were formulated by the pork backfat replacement of 0% (control), 25% (SF-25), and 50% (SF-50), using a linseed oleogel gelled with beeswax. The determination of quality parameters (pH, colour, chemical composition, and texture parameters), the fatty acid profile, and the sensory evaluation was carried out for each batch. The fatty acid profile was substantially improved, and the saturated fatty acid (SFA) content was reduced from 35.15g/100g in control sausages to 33.95 and 32.34g/100 g in SF-25 and SF-50, respectively, and more balanced ratios n-6/n-3 were achieved. In addition, the sausages with linseed oleogel also decreased the cholesterol content from 25.08 mg/100 g in control sausages to 20.12 and 17.23 mg/100 g in SF-25 and SF-50, respectively. It may therefore be concluded that these innovative meat products are a healthier alternative. However, sensory parameters should be improved in order to increase consumer acceptability, and further research is needed.

Hybrid gels: Influence of oleogel/hydrogel ratio on rheological and textural properties.

Hybrid gels can be used for controlled delivery of bioactives and for textural and rheological modification of foods. In this regard the hydrogel:oleogel ratio and gel development methodologies showed to be the aspects that influence most of their properties. The present study shows how different fractions of oleogel can influence the hydrogel matrix of an oleogel-in-hydrogel emulsified system in terms of polymorphic arrangement, microstructure, texture and rheology. The hydrogel was prepared by using an aqueous sodium alginate solution and the oleogel was prepared through the gelation of medium chain triglycerides with beeswax. Hybrid gels were prepared under constant shearing. Crystallinity was clearly changed as hydrogel and oleogel were combined. No polymorphism was observed in the X-Ray diffraction of hybrid gels, as these showed homogeneous results for all component ratios. The behaviour of samples with increasing oleogel-to-hydrogel ratio presented a decrease of both firmness and spreadability, and then, a decrease of gel adhesivity and cohesiveness. This textural response was a consequence of the disaggregated structure, stemming from the disruption of the hydrogel network, due to the inclusion of increasing amounts of oleogel. Rheological results showed that all hybrid gels presented a gel-like behaviour (G´â€¯> G´´). Oleogel's strength influenced the overall textural and rheological performance of hybrid gels. This work demonstrates the possibility of producing hybrid gels aiming to tailor texture on food systems.

Antimicrobial and Antioxidant Performance of Various Essential Oils and Natural Extracts and Their Incorporation into Biowaste Derived Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Layers Made from Electrospun Ultrathin Fibers.

In this research, the antibacterial and antioxidant properties of oregano essential oil (OEO), rosemary extract (RE), and green tea extract (GTE) were evaluated. These active substances were encapsulated into ultrathin fibers of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) derived from fruit waste using solution electrospinning, and the resultant electrospun mats were annealed to produce continuous films. The incorporation of the active substances resulted in PHBV films with a relatively high contact transparency, but it also induced a slightly yellow appearance and increased the films opacity. Whereas OEO significantly reduced the onset of thermal degradation of PHBV, both the RE and GTE-containing PHBV films showed a thermal stability profile that was similar to the neat PHBV film. In any case, all the active PHBV films were stable up to approximately 200 °C. The incorporation of the active substances also resulted in a significant decrease in hydrophobicity. The antimicrobial and antioxidant activity of the films were finally evaluated in both open and closed systems for up to 15 days in order to anticipate the real packaging conditions. The results showed that the electrospun OEO-containing PHBV films presented the highest antimicrobial activity against two strains of food-borne bacteria, as well as the most significant antioxidant performance, ascribed to the films high content in carvacrol and thymol. Therefore, the PHBV films developed in this study presented high antimicrobial and antioxidant properties, and they can be applied as active layers to prolong the shelf life of the foods in biopackaging applications.

Sterol-based oleogels' characterization envisioning food applications.

BACKGROUND: Phytosterols, in particular a mixture of pure γ-oryzanol and ß-sitosterol, develop a tubular system that is able to structure oil. In this study, different concentrations of a combination of γ-oryzanol and a commercial phytosterol mixture, Vitaesterol®, were used for the development of edible oil oleogels. RESULTS: Small-angle X-ray scattering (SAXS) and X-ray diffraction (XRD) were used to characterize at nano and molecular scale the aforementioned oleogels and confirm the formation of sterols-based hollow tubule structures. Increased hardness was observed with the increase of gelator content used in oleogel manufacturing. The produced oleogels showed promising features such as tailored mechanical strength and low opacity, which are important features when considering their incorporation into food products. CONCLUSION: Despite differences in gel strength, oleogels exhibited textural characteristics that make these structures suitable for incorporation in food products. The oil migration profile associated with these oleogels can provide a solution for the controlled release of lipophilic compounds as well as for the retention of oil in cooked food products. © 2018 Society of Chemical Industry.