Delivery of green tea catechins through Oil-in-Water (O/W) nanoemulsion and assessment of storage stability

O/W nanoemulsions encapsulated octacosanol: Preparation, characterization and anti-fatigue activity

Octacosanol has various biological effects such as antioxidant, hypolipidemic and anti-fatigue. However, poor solubility has limited the application of octacosanol in food. The aim of this study was to prepare octacosanol nanoemulsions with better solubility, stability and safety and to investigate in vivo anti-fatigue effect. The food-grade formulation of the octacosanol nanoemulsions consisted of octacosanol, olive oil, Tween 80, glycerol and water with 0.1 %, 1.67 %, 23.75 %, 7.92 % and 66.65 % (w/w), respectively. The nanoemulsions had an average particle size of 12.26 ± 0.76 nm and polydispersity index of 0.164 ± 0.12, and showed good stability under different pH, cold, heat, ionic stress and long-term storage conditions. The results of animal experiments showed that the octacosanol nanoemulsions significantly prolonged the fatigue tolerance time, alleviated the fatigue-related biochemical indicators, and weakened the oxidative stress. Meanwhile, octacosanol nanoemulsions upregulated hepatic glycogen levels. Taken together, these findings suggested that octacosanol nanoemulsions have promising applications as anti-fatigue functional foods.

Improving fried burger quality and modulating acrylamide formation by active coating containing Rosa canina L. extract nanoemulsions

During the frying of foods, undesirable reactions such as protein denaturation, acrylamide formation, and so on occur in the product, which has confirmed carcinogenic effects. The use of antioxidants has been proposed as an effective solution to reduce the formation of these compounds during the process. The current study aimed to assess the impact of an edible coating holding within chia seed gum (CSG) and Rosa canina L. extract (RCE) nanoemulsions on the physicochemical properties, oil uptake, acrylamide formation, 5-hydroxymethyl-2-furfural (HMF) content, and sensory characteristics of beef-turkey burgers. The RCE-loaded nanoemulsions were prepared using the ultrasonic homogenization method, and different concentrations (i.e., 10%, 20%, and 40% w/w) were added to the CSG solutions; these active coatings were used to cover the burgers. CSG-based coatings, especially coatings containing the highest concentration of nanoemulsions (40%), caused a significant decrease in the oil uptake and moisture retention, acrylamide content, and HMF content of fried burgers. The texture of coated burgers was softer than that of uncoated samples; they also had a higher color brightness and a lower browning index. Field emission scanning electron microscopy analysis showed that RCE concentration less than 40% should be used in CSG coatings because it will cause minor cracks, which is an obvious possibility of failure of coating performance. Coating significantly (4-10 times) increased the antioxidant activity of burgers compared to the control. In conclusion, it is suggested to use the active coating produced in this study to improve fried burger quality and modulate acrylamide formation.

Health benefits, mechanisms of interaction with food components, and delivery of tea polyphenols: a review

Tea polyphenols (TPs) are the most important active component of tea and have become a research focus among natural products, thanks to their antioxidant, lipid-lowering, liver-protecting, anti-tumor, and other biological activities. Polyphenols can interact with other food components, such as protein, polysaccharides, lipids, and metal ions to further improve the texture, flavor, and sensory quality of food, and are widely used in food fields, such as food preservatives, antibacterial agents and food packaging. However, the instability of TPs under conditions such as light or heat and their low bioavailability in the gastrointestinal environment also hinder their application in food. In this review, we summarized the health benefits of TPs. In order to better use TPs in food, we analyzed the form and mechanism of interaction between TPs and main food components, such as polysaccharides and proteins. Moreover, we reviewed research into optimizing the applications of TPs in food by bio-based delivery systems, such as liposomes, nanoemulsions, and nanoparticles, so as to improve the stability and bioactivity of TPs in food application. As an effective active ingredient, TPs have great potential to be applied in functional food to produce benefits for human health.

A Cocktail-Based Formula for the Design of Nanosized Cosmeceuticals as Skincare and Anti-Age Products

Nasco and Bovale grape pomace extracts, alone or in association, were loaded in nanoemulsions tailored for cosmetic application, using Kolliphor®RH40 (kolliphor) as the synthetic surfactant, Olivem®1000 (olivem) as the natural one, and lecithin as the cosurfactant. Pink transparent or milky dispersions, as a function of the used extract and surfactant, were obtained to be used as cosmeceutical serum or milk. The sizes of the nanoemulsion droplets were small (≈77 nm with kolliphor and ≈141 nm with olivem), homogenously dispersed (~0.24 with kolliphor and ~0.16 with olivem), highly negatively charged (≈-43 mV irrespective of the used surfactant) and their stability either on storage or under stressing conditions was affected by the used extract and surfactant. Formulations protected the extracts from the degradation caused by UV exposition, were biocompatible against keratinocytes, protected them against oxidative damages induced using hydrogen peroxide and inhibited the release of nitrite induced in macrophages using the lipopolysaccharide inflammatory stimulus. The overall results underlined the key role played by the composition of the formula to achieve a suitable cosmeceutical for skin care but even for the prevention of premature aging and chronic damages caused by the stressing conditions.

A comprehensive review of nano-delivery system for tea polyphenols: Construction, applications, and challenges

Tea polyphenols (TPs) are important bioactive compounds in tea and have excellent physiological regulation functions. However, the extraction and purification of TPs are key technologies affecting their further application, and the chemical instability, poor bioavailability of TPs are major challenges for researchers. In the past decade, therefore, research and development of advanced carrier systems for the delivery of TPs has been greatly promoted to improve their poor stability and poor bioavailability. In this review, the properties and function of TPs are introduced, and the recent advances in the extraction and purification technologies are systematically summarized. Particularly, the intelligent delivery of TPs via novel nano-carriers is critically reviewed, and the application of TPs nano-delivery system in medical field and food industry is also described. Finally, the main limitations, current challenges and future perspectives are highlighted in order to provide research ideas for exploiting nano-delivery carriers and their application in TPs.

Nano-Strategies for Enhancing the Bioavailability of Tea Polyphenols: Preparation, Applications, and Challenges

Tea polyphenols (TPs) are among the most abundant functional compounds in tea. They exhibit strong antioxidant, anti-inflammatory, and anti-cancer effects. However, their instability and low bioavailability limits their applications. Nanotechnology, which involves the use of nanoscale substances (sizes ranging from 1 to 100 nm) to improve the properties of substances, provides a solution for enhancing the stability and bioavailability of TPs. We reviewed the preparation, performance, effects, and applications of different types of TPs nanocarriers. First, we introduced the preparation of different nanocarriers, including nanoparticles, nanoemulsions, nanomicelles, and nanolipids. Then, we discussed various applications of tea polyphenol-loaded nanocarriers in functional ingredient delivery, food quality improvement, and active food packaging. Finally, the challenges and future development directions of TPs nanocarriers were elucidated. In conclusion, a nano-strategy may be the “key” to break the application barriers of TPs. Therefore, the use of nano-strategies for the safe, stable, and efficient release of TPs is the direction of future research.

Preparation of Water-in-Oil Nanoemulsions Loaded with Phenolic-Rich Olive Cake Extract Using Response Surface Methodology Approach

In this study, we aimed to prepare stable water-in-oil (W/O) nanoemulsions loaded with a phenolic-rich aqueous phase from olive cake extract by applying the response surface methodology and using two methods: rotor-stator mixing and ultrasonic homogenization. The optimal nanoemulsion formulation was 7.4% (w/w) of olive cake extract as the dispersed phase, and 11.2% (w/w) of a surfactant mixture of polyglycerol polyricinoleate (97%) and Tween 80 (3%) in Miglyol oil as the continuous phase. Optimum results were obtained by ultrasonication for 15 min at 20% amplitude, yielding W/O nanoemulsion droplets of 104.9 ± 6.7 nm in diameter and with a polydispersity index (PDI) of 0.156 ± 0.085. Furthermore, an optimal nanoemulsion with a droplet size of 105.8 ± 10.3 nm and a PDI of 0.255 ± 0.045 was prepared using a rotor-stator mixer for 10.1 min at 20,000 rpm. High levels of retention of antioxidant activity (90.2%) and phenolics (83.1–87.2%) were reached after 30 days of storage at room temperature. Both W/O nanoemulsions showed good physical stability during this storage period.

Strategies of confining green tea catechin compounds in nano-biopolymeric matrices: A review

Catechins are polyphenolic compounds which abundantly occur in the plants, especially tea leaves. They are widely used in nutraceutical and pharmaceutical formulations due to their capability of lowering the risk of developing various diseases. Nevertheless, low stability, loss of antioxidant and antimicrobial activities hinder the direct application of catechins in food formulations. To surmount this pervasive challenge, bioactive ingredients should be entrapped in a biopolymeric matrix. Thus, nanoencapsulation technology would be an appropriate strategy to improve the stability of these bioactive compounds and to protect them against degradation. Among different types of nanocarriers, biopolymer-based nanovehicles has captured a lot of attention in both industry and academia due to their safety and biocompatibility. This revision enlarges upon the various types of biopolymeric nanostructures used for accommodation of catechins, namely nanogels, nanotubes, nanofibers, nanoemulsions and nanoparticles. Last but not least, the applications of the entrapped catechins in the food industry are highlighted.

Formulation and Preparation of Water-In-Oil-In-Water Emulsions Loaded with a Phenolic-Rich Inner Aqueous Phase by Application of High Energy Emulsification Methods

Currently, industry is requesting proven techniques that allow the use of encapsulated polyphenols, rather than free molecules, to improve their stability and bioavailability. Response surface methodology (RSM) was applied in this work to determine the optimal composition and operating conditions for preparation of water-in-oil-in-water (W/O/W) emulsions loaded with phenolic rich inner aqueous phase from olive mill wastewater. A rotor-stator mixer, an ultrasonic homogenizer and a microfluidizer processor were tested in this study as high-energy emulsification methods. Optimum results were obtained by means of microfluidizer with 148 MPa and seven cycles input levels yielding droplets of 105.3 ± 3.2 nm in average size and 0.233 ± 0.020 of polydispersity index. ζ-potential, chemical and physical stability of the optimal W/O/W emulsion were also evaluated after storage. No droplet size growth or changes in stability and ζ-potential were observed. Furthermore, a satisfactory level of phenolics retention (68.6%) and antioxidant activity (89.5%) after 35 days of storage at room temperature makes it suitable for application in the food industry.

Emulsion gels as delivery systems for phenolic compounds: Nutritional, technological and structural properties

Polyphenols have interesting antioxidant properties and could help prevent certain diseases. Emulsion gels (EGs) have characteristics that make them a promising alternative system for supplying several bioactive compounds simultaneously, among them polyphenols. We produced four EGs containing olive oil, soy protein and a cold gelling agent based on alginate. One basic formulation (ES) contained only these ingredients and was used as a reference, while the other three also contained different solid polyphenol extracts from grape seed (G), grape seed and olive (O) or grape total (T), called ESG, ESO and EST, respectively. The corresponding EGs were prepared by mixing soy protein, alginate, water and one of these types of polyphenol extract (G, O or T), using a homogenizer. Then, the olive oil was gradually added to the mixture and finally, each mixture was placed in a metal container under pressure and chilled for 24 h until they formed an EG. The composition (including concentrations of phenolic metabolites), and technological and structural properties of these EGs were evaluated. Hydroxytyrosol was identified in all the EGs, but ESO showed the highest (P < 0.05) content. The EGs with added polyphenols showed contents of gallic acid, flavanol monomers and derivatives, with ESG showing the highest (P < 0.05) content. All the EGs showed optimal thermal stability, while colour and texture parameters were significantly influenced by the type of polyphenol extract added. No significant differences in the frequency or half-bandwidth of the 2923 and 2853 cm^-1 infrared bands were observed.

Development and Characterization of Nano-emulsions Based on Oil Extracted from Black Soldier Fly Larvae

Insect-based biorefinery is seen as a potential alternative approach to manufacturing foods, feeds, and fuel because of the increasing demand for renewable and sustainable products. Insect oil and protein are the two major components that can be quantitatively obtained from insect farming. However, very few attempts have been conducted to utilize insect oil for the production of value-added products. In this study, the oil extracted from the black soldier fly (Hermetia illucens) larvae (BSFL) was used as a novel feedstock for preparing nano-emulsions. The nano-emulsions were prepared with BSFL oil, hydrogenated lecithin (HL), and d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) in water using pre-homogenization followed by ultrasonication. The morphology and the particle size of nano-emulsions were affected by ratios of HL to TPGS. Moreover, the nano-emulsions showed a nearly Newtonian liquid behavior and the presence of TPGS was able to improve the storage stability of HL nano-emulsions. The addition of TPGS could eliminate the phase transition region of HL nano-emulsions but did not provide a significant change for the molecular mobility in the HL nano-emulsions. In summary, the BSFL oil could be used as a renewable feedstock for formulating nano-emulsions from the aspect of high value-added applications and physicochemical characteristics of the nano-emulsions could be adjusted by the mixed surfactant ratio, surfactant to oil ratio, and oil content. Graphical Abstract The physicochemical characteristics and optimization of nano-emulsions based on black soldier fly larvae oil were investigated.