Bojana Balanč

Novel approaches in nanoencapsulation of aromas and flavors

Abstract In recent years, people’s dietary habits become more oriented toward healthy, safe, and, at the same time, tasty food. The perception of food taste is mostly affected by the addition of flavors and aromas during processing. Due to sensitivity of flavors and aromas in their native form, aroma encapsulation is already well established in the food industry. The benefits ascribed to encapsulation are reflected in easier handling of liquid flavors by its conversion into a dry form, improved stability when exposed to oxygen, light, and/or elevated temperatures, improved shelf-life, decreased release of volatile flavor components, masking of off-flavors and off-tastes, ability to impact textural properties of final products, and prolonged/controlled release. Among numerous encapsulation methods, spray drying has been predominantly used for encapsulation of flavors and aromas. However, the innovations in the field of encapsulation, particularly galloping nanotechnologies, have gained considerable attention from the food sector in the past decade, with applications for aromas as well as for other food compounds. This chapter reviews the current state of knowledge on nanoencapsulation of aromas and flavors, overviewing the processes and techniques utilized for coacervation, nanoprecipitation, molecular inclusion, and production of nanoparticulate formulations such as nanoemulsions, liposomes, solid–lipid nanoparticles (SLNs), and nanostructure lipid carriers (NLCs). Furthermore, the chapter gives insight into physicochemical and morphological characteristics of aroma nanoencapsulates, summarizing advantages and limitations of aroma nanoscale formulations versus microparticle formulations produced by conventional microencapsulation technologies. Finally, a critical prospect of potential application of aroma nanoencapsulates in real food products will be given, supported by examples available in literature.

Influence of ultrasound probe treatment time and protease type on functional and physicochemical characteristics of egg white protein hydrolysates

ABSTRACT The objective of this study was to discover the relationship between the ultrasound probe treatment (UPT) on egg white proteins (EWPs) before EWPs hydrolysis by different proteases, and the functional properties of the obtained hydrolysates. To fulfill this goal, the protein solubility, foaming, and emulsifying properties were studied as a function of the UPT time and then related to the surface characteristics and structural properties. The changes in the hydrolysates microstructures and macromolecular conformation, induced by the UPT, were followed using scanning electron microscope analyzis (SEM) and Fourier transforms infrared spectroscopy (FTIR). The results showed that UPT influenced (P < 0.05) the proteolysis of egg white proteins for all examined treatment times. Alcalase hydrolysates (AHs) and papain hydrolysates (PHs) were found to have a higher solubility, as a consequence of their relatively higher foaming, and emulsifying properties compared to the untreated hydrolysates. The changes in surface hydrophobicity, sulfhydryl content and surface charge of AHs and PHs indicated unfolding of EWPs affected by ultrasound. SEM analyzis showed that UPT destroyed the microstructures of AHs and PHs, while FTIR spectra indicated remarkable changes in the macromolecular conformation of AHs and PHs after UPT. This study revealed that by combining ultrasound pre‐hydrolysis treatment under controlled conditions with thoughtful proteases selection, hydrolysates with improved functional properties could be produced, enhancing utilization of EWPs in food products.

Comparative Effects of Span 20 and Span 40 on Liposomes Release Properties

Abstract Liposomes are known as convenient carriers for a broad range of actives. The release rate of actives can be adjusted/controlled by the addition of different surfactants. The aim of this study was to compare the effects of two surfactants, Span 20 and Span 40, on liposomes release properties. In particular, the study shows how the membrane modification affects the mass transfer resistances and liposome size compared with the common liposomes. The aqueous extract of thyme was used as a model substance. It is a valuable source of natural antioxidants – polyphenols. The diffusion of polyphenols from native thyme extract (un-encapsulated) and from different types of liposomes was conducted using Franz diffusion cell. The results were approximated with Fick’s second law and they implied that liposomes modified with Span 20 provided the slowest release of polyphenolic compounds due to the highest value of mass transfer resistance (2.523 × 106 s/m).

Encapsulation of resveratrol in spherical particles of food grade hydrogels

The paper reports about the preparation and characterization of hydrogel particles containing liposomes loaded with resveratrol as an active compound. The materials used for preparation of the particles were chosen to be suitable for food industry. Different polymer concentrations affect particles shape, size, size distribution, as well as the release kinetics of resveratrol. The diameter of particles varied from 360 to 754 μm, while the narrow size distribution was observed for all types of particles. Release studies were performed in Franz diffusion cell and the results showed the prolonged release of resveratrol from all samples, but the sample with the highest content of polymer (2.5% w/w) in particular stood out. The research provides useful information about liposomes containing active compound encapsulated in hydrogel matrices and offers the basis for its application in the food industry.