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Using green techniques to convert native starches into nanoparticles is an interesting approach to producing stabilizers for Pickering emulsions, aiming at highly stable emulsions in clean label products. Nanoprecipitation was used to prepare the Pickering starch nanoparticles, while ultrasound technique has been used to modulate the size of these nanoparticles at the same time as the emulsion was developed. Thus, the main objective of this study was to evaluate the stabilizing effect of cassava starch nanoparticles (SNP) produced by the nanoprecipitation technique combined with ultrasound treatment carried out in the presence of water and oil (more hydrophobic physicochemical environment), different from previous studies that carry out the mechanical treatment only in the presence of water. The results showed that the increased ultrasound energy input could reduce particle size (117.58 to 55.75 nm) and polydispersity (0.958 to 0.547) in aqueous dispersions. Subsequently, Pickering emulsions stabilized by SNPs showed that increasing emulsification (ultrasonication) time led to smaller droplet sizes and monomodal size distribution. Despite flocculation, long-term ultrasonication (6 and 9 min) caused little variation in the droplet size after 7 days of storage. The cavitation effects favored the interaction between oil droplets through weak attraction forces and particle sharing, favoring the Pickering stabilization against droplet coalescence. Our results show the potential to use only physical modifications to obtain nanoparticles that can produce coalescence-stable emulsions that are environmentally friendly.

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Essential oils show several biological properties, such as antimicrobial activity, but have limitations regarding their availability and stability. To maximize their antimicrobial effect and protection against environmental conditions, Pickering-type emulsions were used to vehiculate oregano essential oil (OEO) using cellulose nanofibers (CNF) as emulsion stabilizer. Enzymatic hydrolysis was used to produce CNF from a food industry waste (cassava peel), obtaining an environmentally sustainable emulsion stabilizer. It was evaluated how the different properties of the nanofibers affected the stability of the emulsions. Furthermore, the composition of the dispersed phase was varied (different ratios of OEO and sunflower oil-SO) in view of the target application in biodegradable active coatings. Even at very low concentration (0.01 % w/w), CNF was able to form kinetically stable emulsions with small droplet sizes using oil mixtures (OEO + SO). The stabilization mechanism was not purely Pickering, as there was a reduction in interfacial tension. Excellent antimicrobial activity was observed against bacteria and the fungus Alternaria alternata, demonstrating the ability to apply these emulsions in active systems such as coatings and films. An improvement in the stability of emulsions was observed when using a mixture of oils, which is extremely advantageous considering costs and stability to heat treatments, since the desired antimicrobial activity is maintained for the final application.

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Cellulose nanofibers (CNF) have been widely studied for their biodegradability and for their unique advantages as a stabilizer in Pickering-type emulsions. However, it is challenging to produce cellulose nanofibers from agroindustry waste with good techno-functional properties, without the use of harsh process conditions. Green alternatives (eco-friendly) have been studied to obtain nanofibers, such as enzymatic hydrolysis and/or application of mechanical processes. In this work, we used acid hydrolysis (as a control and example of an efficient method), enzymatic hydrolysis and a mechanical process (ultrasound) to obtain cellulose nanofibers. We also evaluated the effect of the presence of ethyl groups in the cellulosic matrix (ethylcellulose) on the stabilizing mechanism of emulsions. All cellulose nanofibers were able to produce Pickering emulsions at concentrations of 0.01-0.05% (w/w), although showing differences in emulsion stability and digestibility. Morphology of the different cellulose nanofibers affected the viscosity of the aqueous suspensions used as continuous phase. Emulsions with nanofibers obtained from cassava peel (without the presence of ethyl groups) were stabilized only by the Pickering-type mechanism, while ethylcellulose nanofibers also showed surface activity that contributed to the stability of the emulsion. Furthermore, these latter emulsions showed greater release of free fatty acids in in vitro digestion compared to emulsions stabilized by cellulose nanofibers. Despite these differences, in vitro digestion showed the potential of applying cellulose-stabilized emulsions to control the rate of lipid digestion, due to the low amount of free fatty acids released (<20%).

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This study aimed to investigate the digestibility and bioaccessibility of spray-dried microparticles co-encapsulating paprika and cinnamon oleoresins using simulated gastrointestinal conditions. It focused on exploring the potential of these co-encapsulated active compounds, which possess diverse technological and functional properties, particularly within a food matrix, in order to enhance their bioavailability. Mayonnaise was selected as the food matrix for its ability to promote the diffusion of carotenoids, as most hydrophobic compounds are better absorbed in the intestine when accompanied by digestible lipids. Model spice mayonnaise, containing 0.5 wt% paprika and cinnamon microparticles content, was formulated in compliance with Brazilian regulations for spices, seasonings, and sauce formulations. Droplet size distribution, optical microscopy and fluorescence microscopy analyses were conducted on the microparticles, model spice mayonnaise, and standard mayonnaise both before and after in vitro gastric and intestinal digestion. Following digestion, all samples demonstrated droplet aggregation and coalescence. Remarkably, dispersed particles (37.40 ± 2.58%) and model spice mayonnaise (17.76 ± 0.07%) showed the highest release rate of free fatty acids (FFAs), indicating efficient lipid digestion. The study found that using mayonnaise as a delivery system significantly increased bioaccessibility (22.7%). This suggests that particles in an aqueous medium have low solubility, while the high lipid composition of mayonnaise facilitates the delivery of active compounds from carotenoids present in paprika and cinnamon oleoresin after digestion.

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Hybrid meat products are an excellent strategy to incorporate plant proteins into traditional meat formulations considering recent market trends focusing on the partial reduction in red meat content. In this work, we evaluated the effects of different concentrated plant proteins (soy, pea, fava bean, rice, and sunflower) in partially replacing meat in meat emulsion model systems. Soy, pea, and sunflower proteins showed great compatibility with the meat matrix, giving excellent emulsion stability and a cohesive protein network with good fat distribution. Otherwise, adding rice and fava bean proteins resulted in poor emulsion stability. Color parameters were affected by the intrinsic color of plant proteins and due to the reduction in myoglobin content. Both viscoelastic moduli, G' and G″ decreased with the incorporation of plant proteins, especially for rice and fava bean. The temperature sweep showed that myosin denaturation was the dominant effect on the G' increase. The water mobility was affected by plant proteins and the proportion between immobilized and intermyofibrillar water was quite different among treatments, especially those with fava bean and rice proteins. In vitro protein digestibility was lower for hybrid meat emulsion elaborated with rice protein. It is concluded that soy, pea, and mainly sunflower proteins have suitable compatibility with the meat matrix in emulsified products.

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Ingestion of trans-resveratrol promotes health benefits, but the low solubility and chemical stability of this compound may hamper its bioaccessibility. To overcome these drawbacks, O/W emulsions loaded with resveratrol (liquid or gelled) and stabilized by soy protein isolate (SPI) were used to protect and vehiculate the bioactive compound to the target absorption site. Two distinct strategies were used to allow protein denaturation: heating the A) aqueous phase of the emulsion before homogenization; or B) emulsion after homogenization. Delivery efficacy of resveratrol was evaluated by static or semi-static in vitro digestion assays. For the semi-static approach, a dynamic gastric model was developed that was able to simulate the intensity of contraction forces and the gradual decrease of pH in the gastric step in vivo. The structure of the liquid emulsions remained similar in the static and semi-static digestion approaches, showing little influence of peristalsis on droplet size. The gelled emulsions showed breakdown of the gel network in the presence of the mechanical forces of the semi-static tests, although its structure was not completely degraded at the end of the in vitro digestibility tests. Anyway, the results of bioaccessibility of the carriers were similar (around 70-75%) and high, being these emulsions effective carriers of resveratrol. However, the bioaccessible fraction of liquid emulsions was much higher after digestion under static conditions, showing the relevance of developing dynamic systems for a more realistic simulation of in vitro digestion processes.

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This study evaluated the phenolic compound extraction from olive pomace with deep eutectic solvents (DES) prepared with choline chloride ([Ch]Cl) and four (poly-)carboxylic acids. Temperature, water addition in the solvent, and solid-liquid ratio were evaluate in total phenolic content and antioxidant activity of extracts obtained with DES and ethanol, as control. Moreover, the antimicrobial activities of solvents and extracts were evaluated. Oil-in-water emulsion with DES extract was prepared, characterized and its oxidative stability analyzed. The extract with the highest total phenolic content was obtained with [Ch]Cl:malonic acid. Under optimal conditions, DES extracted 9 % more total phenolic content than ethanol. DES extract showed superior antibacterial activity to the ethanolic extract, and its presence in oil-in-water emulsion increased the induction time in 10-fold when compared to the one prepared with water. These results reinforce that DES are a potential solvent for phenolic compound extraction from olive pomace with antibacterial and technological benefits.

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In the last decade, food structuring has received considerable attention due to the concern of replacing trans and saturated fats with healthier alternatives without compromising neither technological nor sensorial aspects of food products. Moreover, sustainability topics, consumers' preference for natural ingredients and the molecular architecture displaying a myriad of techno-functionalities embolden the use of proteins. Therefore, a promising approach is to explore this biopolymer as a texture promoter in lipid-based systems, conveying an extra edge in nutritional, sustainable and technological values. A more in-depth comprehension should be cemented to fully harness the potential of proteins in developing soft matter intended for use as fat mimetic. High Internal Phase Emulsion (HIPE), High Internal Phase Pickering Emulsion (HIPPEs), emulgels, oleogels or even bigels can be used in such strategies. Essentially, the formation of such systems relies on the amphiphilic character of proteins. In this sense, the question that arises is how to optimize their solubility in oils to form oil-structured systems? Thus, for oleogel formation the challenge is to overcome the limited dispersibility of proteins in a hydrophobic environment. Therefore, face the growing interest and untapped potential in applying proteins in lipid media, a more wide-ranging picture of their colloidal form (e.g. native, microgels and protein-polysaccharide complexes or conjugates) affecting the structure-function relationship of proteins must be investigated. This review covers different strategies using proteins as building blocks to manufacture different structured systems. Finally, an outlook over the use of protein-based soft matter on an industrial basis is discussed, considering the challenges and perspectives.

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Biopolymer beads can be used as carrier and encapsulation system for a wide variety of materials in food, medical, pharmaceutical, cosmetics, agricultural, and environmental applications. Beads of low acyl gellan gum (0.4-1.2% w/w) were produced using extrusion technique (dripping) followed by an ionotropic gelation step with calcium or potassium chloride. In this methodology, gel formation is accomplished by cations diffusion at room temperature and, as a consequence, different structure and gel properties could be obtained. Gellan beads were subjected to uniaxial compression measurements. The force-displacement curves showed that the occurrence of structural failure under tested conditions depended on beads formulation and was only observed at polysaccharide concentration above 0.8% (w/w). Maximum force or force at failure was mainly dependent on the type (monovalent or divalent cation) and salt concentration. Moreover, at fixed salt amounts, higher values of maximum force were reached using a concentration of 1% (w/w) gellan. Young modulus, determined using Hertz approach, showed values between 445 and 840 kPa depending on polysaccharide concentration and salt type added. Mechanical properties are critical features of gel beads and can define their suitability for a specific application. Therefore, the results obtained, mainly intrinsic properties such as Young modulus, could be a tool for comparing and choosing polysaccharides for specific uses.

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Electrostatic complexes produced by interactions between polysaccharides have promising applications in the medical, pharmaceutical and food fields. In this light, for the development of such particles, microfluidics emerges as a promising technique in which processes occur at a strict laminar flow regime, allowing diffusion-dominated transport and particle formation in highly-controlled conditions. As a proof of concept, we compared bulk versus microfluidic (different devices simulating a range of residence times) processes for the production of electrostatic complexes of gellan with either chitosan (molecular weight âˆ¼ 28 kDa) or hydrolyzed chitosan (molecular weight âˆ¼ 3 kDa). Regardless of the process, polysaccharide solutions (pH 4.5) were mixed in pre-defined concentrations (polysaccharide ratios) to form electrostatic complexes that were used to encapsulate caffeine. These complexes were characterized by zeta potential measurements and particle size distribution. Overall, microfluidics produced complexes with improved characteristics such as lower polydispersity index (PDI âˆ¼ 0.1) and mean size (∼200 nm) when compared to the conventional bulk process (PDI âˆ¼ 0.3 and mean size âˆ¼ 400 nm). Moreover, hydrolyzed chitosan (HC) contributed to an even smaller size and PDI value of the complexes. Such outcome is associated with the lower molecular weight and higher solubility of HC when comparing to conventional chitosan, which in turn improves electrostatic complexation. Caffeine could also be encapsulated in all complexes, but the highest encapsulation efficiency was achieved using microfluidics (70%) and with the geometry that provided a longer residence time. Therefore, we were able to demonstrate that microfluidics is clearly an effective strategy for generating electrostatic complexes with improved properties. Ultimately, this technique demonstrated a high potential for the production of vehicles of bioactive compounds.

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