Organogel-nanoemulsion containing nisin and D-limonene and its antimicrobial activity

Oleogels-Innovative Technological Solution for the Nutritional Improvement of Meat Products

Food products contain important quantities of fats, which include saturated and/or unsaturated fatty acids. Because of a proven relationship between saturated fat consumption and the appearance of several diseases, an actual trend is to eliminate them from foodstuffs by finding solutions for integrating other healthier fats with high stability and solid-like structure. Polyunsaturated vegetable oils are healthier for the human diet, but their liquid consistency can lead to a weak texture or oil drain if directly introduced into foods during technological processes. Lately, the use of oleogels that are obtained through the solidification of liquid oils by using edible oleogelators, showed encouraging results as fat replacers in several types of foods. In particular, for meat products, studies regarding successful oleogel integration in burgers, meat batters, pâtés, frankfurters, fermented and bologna sausages have been noted, in order to improve their nutritional profile and make them healthier by substituting for animal fats. The present review aims to summarize the newest trends regarding the use of oleogels in meat products. However, further research on the compatibility between different oil-oleogelator formulations and meat product components is needed, as it is extremely important to obtain appropriate compositions with adequate behavior under the processing conditions.

A Systematic Review on Nanoencapsulation Natural Antimicrobials in Foods: In Vitro versus In Situ Evaluation, Mechanisms of Action and Implications on Physical-Chemical Quality

Natural antimicrobials (NA) have stood out in the last decade due to the growing demand for reducing chemical preservatives in food. Once solubility, stability, and changes in sensory attributes could limit their applications in foods, several studies were published suggesting micro-/nanoencapsulation to overcome such challenges. Thus, for our systematic review the Science Direct, Web of Science, Scopus, and Pub Med databases were chosen to recover papers published from 2010 to 2020. After reviewing all titles/abstracts and keywords for the full-text papers, key data were extracted and synthesized. The systematic review proposed to compare the antimicrobial efficacy between nanoencapsulated NA (nNA) and its free form in vitro and in situ studies, since although in vitro studies are often used in studies, they present characteristics and properties that are different from those found in foods; providing a comprehensive understanding of primary mechanisms of action of the nNA in foods; and analyzing the effects on quality parameters of foods. Essential oils and nanoemulsions (10.9-100 nm) have received significant attention and showed higher antimicrobial efficacy without sensory impairments compared to free NA. Regarding nNA mechanisms: (i) nanoencapsulation provides a slow-prolonged release to promote antimicrobial action over time, and (ii) prevents interactions with food constituents that in turn impair antimicrobial action. Besides in vitro antifungal and antibacterial, nNA also demonstrated antioxidant activity-potential to shelf life extension in food. However, of the studies involving nanoencapsulated natural antimicrobials used in this review, little attention was placed on proximate composition, sensory, and rheological evaluation. We encourage further in situ studies once data differ from in vitro assay, suggesting food matrix greatly influences NA mechanisms.

A novel promising delivery system for cuminaldehyde using gelled lipid nanoparticles: Characterization and anticancer, antioxidant, and antibacterial activities

This work aimed to develop a novel nanoencapsulation system for food colloidal formulations using gelled lipid nanoparticles (GLNs) to improve the functionality, stability, and bioactivity of cuminaldehyde as a highly volatile and poor hydrophilic food additive. Cuminaldehyde-loaded GLNs with diameters of 117-138 nm were fabricated through a hot emulsification process with monoglyceride (10 and 15 g/100 g lipid phase) as a lipid gelator at two concentrations of cuminaldehyde (500 and 1000 mg/L). All samples remained stable towards macroscopic phase separation and creaming during 28 days of storage at 4 °C, which could be related to the rigid structure of dispersed particles in the gelled state and retarding droplet movement. Moreover, all samples were stable to creaming after subjecting to the environmental changes including temperature (30, 60, and 90 °C for 30 min), ionic strength (100, 200, and 300 mM NaCl), and pH (3, 5, and 7). Measurement of apparent viscosity showed non-Newtonian shear thinning nature in all samples, which was more pronounced at higher concentrations of the gelator. Interestingly, higher cytotoxic effects of cuminaldehyde against human lung and colorectal cancer cells were observed after encapsulation within GLNs. However, weak toxicity was also found against normal peripheral blood mononuclearcells.On the other hand, the antioxidant activity and lipid oxidation stability were improved by increasing cuminaldehyde concentration, while it was reduced at higher monoglyceride concentration. All samples exhibited stronger antibacterial activity against Bacillus cereus than Eschershia coli. These findings suggest the significant potential benefits of GLNs as novel nanocarriers to enrich various food and beverage formulations with essential oils, flavors, and aromas.

Journey of Limonene as an Antimicrobial Agent

Injudicious consumption of antibiotics in the past few decades has arisen the problem of resistance in pathogenic organisms against most antibiotics and antimicrobial agents. Scenarios of treatment failure are becoming more common in hospitals. This situation demands the frequent need for new antimicrobial compounds which may have other mechanisms of action from those which are in current use. Limonene can be utilized as one of the solutions to the problem of antimicrobial resistance. Limonene is a naturally occurring monoterpene with a lemon-like odor, which mainly present in the peels of citrus plants like lemon, orange, grapefruit, etc. The study aimed to enlighten the antimicrobial properties of limonene as per previous literature. Advantageous contributions have been made by various research groups in the study of the antimicrobial properties of limonene. Previous studies have shown that limonene not only inhibits disease-causing pathogenic microbes, however, it also protects various food products from potential contaminants. This review article contains information about the effectiveness of limonene as an antimicrobial agent. Apart from antimicrobial property, some other uses of limonene are also discussed such as its role as fragrance and flavor additive, as in the formation of nonalcoholic beverages, as solvent and cleaner in the petroleum industry, and as a pesticide. Antibacterial, antifungal, antiviral, and anti-biofilm properties of limonene may help it to be used in the future as a potential antimicrobial agent with minimal adverse effects. Some of the recent studies also showed the action of limonene against COVID-19 (Coronavirus). However, additional studies are requisite to scrutinize the possible mechanism of antimicrobial action of limonene.

Oleogel-Based Systems for the Delivery of Bioactive Compounds in Foods

Oleogels are semi-solid materials containing a large fraction of liquid oil entrapped in a network of structuring molecules. In the food industry, these formulations can be used to mimic fats and to deliver bioactive compounds. In the last decade, there has been increasing interest in these structures, not only from a scientific point of view, i.e., studying new molecules, methodologies for gelification, and new structures, but also from a technological point of view, with researchers and companies exploring these structures as a way to overcome certain challenges and/or create new and innovative products. One of the exciting applications of oleogels is the delivery of functional molecules, where the incorporation of oil-soluble functional compounds can be explored not only at the macroscale but also at micro- and nanoscales, resulting in different release behaviors and also different applications. This review presents and discusses the most recent works on the development, production, characterization, and applications of oleogels and other oleogel-based systems to deliver functional molecules in foods.

Lipid-Based Nanostructures for the Delivery of Natural Antimicrobials

Encapsulation can be a suitable strategy to protect natural antimicrobial substances against some harsh conditions of processing and storage and to provide efficient formulations for antimicrobial delivery. Lipid-based nanostructures, including liposomes, solid lipid nanoparticles (SLNs), and nanostructured lipid nanocarriers (NLCs), are valuable systems for the delivery and controlled release of natural antimicrobial substances. These nanostructures have been used as carriers for bacteriocins and other antimicrobial peptides, antimicrobial enzymes, essential oils, and antimicrobial phytochemicals. Most studies are conducted with liposomes, although the potential of SLNs and NLCs as antimicrobial nanocarriers is not yet fully established. Some studies reveal that lipid-based formulations can be used for co-encapsulation of natural antimicrobials, improving their potential to control microbial pathogens.

Design of gel structures in water and oil phases for improved delivery of bioactive food ingredients

Gels are viscoelastic systems built up with a liquid phase entrapped in a three-dimensional network, which can behave as carriers for bioactive food ingredients. Many attempts have been made to design gel structures in the water phase (hydrogels, emulsion gels, bigels) or oil phase (organogels, bigels) in order to improve their delivery performances. Hydrogels are originated from proteins or polysaccharides, which are suitable for the delivery of hydrophilic ingredients. Organogels are mainly built up with the self-assembling of gelator molecules in the oil phase, and they offer good carriers for lipophilic ingredients. Emulsion gels and bigels, containing both aqueous and oil domains, can provide accommodations for lipophilic and hydrophilic ingredients simultaneously. Gel structures (e.g. rheology, texture, water holding capacity, swelling ratio) can be modulated by choosing different gelators, modifying gelation techniques, and the involvement of other ingredients (e.g. oils, emulsifiers, minerals, acids), which then alter the diffusion and release of the bioactive ingredients incorporated. Various studies have proved that gel-based delivery systems are able to improve the stability and bioavailability of many bioactive food ingredients. This review provides a state-to-art overview of different gel-based delivery systems, highlighting the significance of structure-functionality relationship, to provide advanced knowledge for the design of novel functional foods.

Ethnobotany, phytochemistry and pharmacology of Arctotis arctotoides (L.f.) O. Hoffm.: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Arctotis arctotoides (Asteraceae) is part of the genus Arctotis. Arctotis is an African genus of approximately 70 species that occur widely in the African continent with diverse medicinal values. This plant is used for the treatment of indigestion and catarrh of the stomach, epilepsy, topical wounds and skin disorders among the ethnic groups in South Africa and reported to have a wide spectrum of pharmacological properties.

AIM OF THE REVIEW

The aim of the present review is to appraise the botany, traditional uses, phytochemistry, pharmacological potential, analytical methods and safety issues of A. arctotoides. Additionally, this review will help to fill the existing gaps in knowledge and highlight further research prospects in the field of phytochemistry and pharmacology.

MATERIALS AND METHODS

Information on A. arctotoides was collected from various resources, including books on African medicinal herbs and Zulu medicinal plants, theses, reports and the internet databases such as SciFinder, Google Scholar, Pubmed, Scopus, Web of Science, and Mendeley by using a combination of various meaningful keywords. This review surveys the available literature of the species from 1962 to April 2017.

RESULTS

In vitro and in vivo studies of the medicinal properties of A. arctotoides were reviewed. The main isolated and identified compounds were reported as sesquiterpenes, farnesol derivatives, germacranolide, guaianolides and some steroids, of which, nine were reported as antimicrobial. Monoterpenoids and sesquiterpenoids were the predominant essential oil compound classes of the leaves, flowers, stems and roots. The present review revealed potential pharmacological properties such as anti-oxidant, antibacterial, antifungal and anticancer activities of plant extracts as well as isolated compounds. Moreover, the review reports the safety profile (toxicity) of the crude extracts that had been screened on brine shrimps, rats and human cell lines.

CONCLUSIONS

The present review has focused on the phytochemistry, botany, ethnopharmacology, biological activities and toxicological information of A. arctotoides. On the basis of reported data, A. arctotoides has emerged as a good source of natural medicine for the treatment of microbial infections, skin diseases, anti-inflammatory and anticancer agents and also provides new insights for further isolation of new bioactive compounds, especially the discovery of antimicrobial, anti-inflammatory and anticancer novel therapeutic lead drug molecules. Additionally, intensive investigations regarding pharmacological properties, safety assessment and efficacy with their mechanism of action could be future research interests before starting clinical trials for medicinal practices.

Exploring the anti-quorum sensing activity of a d-limonene nanoemulsion for Escherichia coli O157:H7

In this study, a d-limonene nanoemulsion was developed by using a spontaneous emulsification method and its potential to inhibit the quorum sensing (QS)-regulated properties of Escherichia coli O157:H7 (E. coli) were revealed. The results in this study showed that d-limonene nanoemulsion inhibited E. coli biofilm formation through the suppression of curli and extracellular polymeric substance (EPS) production without inhibiting cell growth, and decreased swimming and swarming ability. Further analyses showed that d-limonene nanoemulsion interfered with auto-inducer 2 (AI-2) communication and repressed the expression of curli related genes and AI-2 importer genes in E. coli. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1979-1986, 2018.

Development of β-Carotene-Loaded Organogel-Based Nanoemulsion with Improved In Vitro and In Vivo Bioaccessibility

β-Carotene (BC), a naturally occurring lipophilic carotenoid, is beneficial for human health. However, its water solubility and bioavailability are low. In this study, organogel-based nanoemulsion was successfully prepared to improve the loading amount, solubility, and bioavailability of BC. Corn oil was selected as the oil phase for the organogel as a result of the greatest release amount of BC. Tween 20 was optimized as the emulsifier based on the highest extent of lipolysis and BC bioaccessibility. The nanoemulsion was a better alternative than the organogel according to both the extent of lipolysis and BC bioaccessibility. Cellular uptake of BC was significantly improved through organogel-based nanoemulsion compared to BC suspension. Caveolae-/lipid-raft-mediated route was the main endocytosis pathway. Pharmacokinetic results confirmed that the in vivo bioavailability of BC in nanoemulsion was 11.5-fold higher than that of BC oil. The information obtained suggested that organogel-based nanoemulsion may be an effective encapsulation system for delivery of insoluble and indigestible bioactive compounds.