Background Aromatic plants may contribute for human health promotion due to their antioxidant properties and also by replacing added salt in foods. Phenolic compounds are one of the major groups contributing for aromatic plants properties, including the prevention of cancer, cardiovascular and neurodegenerative diseases. Scope and approach This review focuses on the main uses of aromatic plants generally recognized as safe (GRAS) and overviews the extraction, purification and analytical methods used to determine phenolics in these food matrices. The current state of the art is evaluated and future trends in the analysis of these compounds and food industry applications are discussed. Key findings and conclusions In general, aromatic plants are complex matrices regarding their content on phenolic compounds. Their composition can be affected by the chemical structure of the studied analytes, the selected methods, the composition/nature of the aromatic plant and storage conditions. The most usual separation technique to determine these compounds is High Performance Liquid Chromatography (HPLC) coupled with ultraviolet (UV) or diode array detectors (DAD), although the use of mass spectrometry (MS) detectors is increasing. The future trends include the use of more sophisticated and automated techniques in order to reduce both analysis time and the amount of solvents used. Food industry widely uses aromatic plants, but other industries like food packaging, cosmetics, perfumery and pharmaceutical can also benefit from their properties.

Advances in phenolic compounds analysis of aromatic plants and their potential applications

The aims of this research were first, to evaluate the antibacterial potential of commercial thyme essential oil against V. alginolyticus and V. parahaemolyticys and second, using the spray drying technique to produce microcapsules. chemical compounds of thyme oil and microcapsules were identified and quantified being thymol the chemical component present at the highest concentration. Oil-in-water (O/W) emulsions were prepared and the microcapsules were obtained with a spray dryer using maltodextrin as wall material (ratio 1:4). Thyme oil and the microcapsules exhibited antimicrobial activity against V. parahaemolyticus and V. alginolyticus. The spray drying process did not affect the antimicrobial activity of thyme essentialoil.

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Microencapsulation of essential thyme oil by spray drying and its antimicrobial evaluation against Vibrio alginolyticus and Vibrio parahaemolyticus.

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Dyeing of cotton fabric for improved mosquito repellency

Microcapsules encapsulating peppermint oil (L-Carvone) were fabricated via two-stage encapsulation processes (complex coacervation followed by spray drying) using three plant-based biopolymers (fungal chitosan, gum Arabic, and maltodextrin). Transglutaminase was introduced to the formulation to crosslink the coacervate formed during microcapsule wall development. The microcapsules were assayed for their physical, structural, morphological, mechanical, and barrier properties, using several analytical techniques, including light scattering, spectrophotometry, SEM, TEM, and a micromanipulation technique. The size of the microcapsules ranged from 10–125 µm, with a Sauter mean diameter of 37.8 ± 1.4 µm and shell thickness of 0.91 ± 0.15 μm. The microcapsules were spherical with a relatively smooth surface. Nile red was employed as a fluorescent dye dopant in the peppermint oil to assess the presence of oil in microcapsules after spray drying. A micromanipulation technique was used to quantify the mechanical properties of microcapsules, such as rupture force (0.6 ± 0.1 mN) and nominal rupture stress (2.1 ± 0.3 MPa). Static oil leakage from dry microcapsules was negligible after storage for 50 days. The release rates of the oil from the microcapsules to aqueous ethanol solutions (5–20% w/w) were measured, and the effective diffusivity was quantified (Deff = 4.210−12 m2 s–1). These results show that the two-stage encapsulation processes could be an eco-friendly and sustainable methodology for the manufacture of active oil containing microcapsules, with potential applications in food, personal care, and cosmetics products. Furthermore, the use of plant based materials will overcome the growing issues associated with the consumer turning away from animal based products in favour of vegan alternatives.

Microcapsules with a fungal chitosan-gum Arabic-maltodextrin shell to encapsulate health-beneficial peppermint oil

Encapsulation is a versatile technology (comprising about 20–25% of the total flavor market) and is the preferred means to protect volatile flavor compounds. It can be utilized to add specific functionalities (physicochemical stability, functionality, safety, and organoleptic qualities) to a flavoring material. A retro-design approach is used to design flavor encapsulation where the knowledge of physical and chemical properties are fundamental. Various process variables impact the physical (e.g. internal and surface morphology, size, and wall thickness), mechanical (mechanical strength), and structural properties (flowability, glass transition temperature, degree of crystallinity and permeability) of encapsulated flavors, and thus impact their overall quality. For this reason, much effort has focused on development of reliable analytical techniques to characterize flavor encapsulates. This chapter reviews the general concepts and principles of existing tools used for the physical, chemical, and microbiological characterization of encapsulated flavors and provides recommendations and examples leading to a better understanding of their performance characteristics.

Testing Tools and Physical, Chemical, and Microbiological Characterization of Microencapsulated Systems

Microencapsulation is one of the quality preservation techniques of sensitive substances used in food and pharmaceutical industries. Peppermint oil was encapsulated with gum arabic, maltodextrin, and a blend,(1:1 by mass) of gum arabic and maltodextrin by spray drying. The drying gas was hot air at an inlet temperature 200 0 C. No valuable changes were detected in the chemical composition of peppermint oil after encapsulation. The materials giving the highest flavor retention during drying were gum arabic and the (1:1)blend, as they provided acceptable oil retention (81% and 80%) ,respectively. The results showed the high safety of encapsulated peppermint oil, as biological evaluation showed that serum glucose, cholesterol and aminotransferases enzymes exhibited no significant change as compared to control mice. Meanwhile, creatinine (mg/dl) was significantly, but slightly, increased from 0.8 to 1.07 mg/dl after feeding diet containing encapsulated peppermint oil.

M. Aly

Papers

Microencapsulation Of Peppermint Oil By Spray Drying