Ana Kalušević

Aroma formation by immobilized yeast cells in fermentation processes

Immobilized cell technology has shown a significant promotional effect on the fermentation of alcoholic beverages such as beer, wine and cider. However, genetic, morphological and physiological alterations occurring in immobilized yeast cells impact on aroma formation during fermentation processes. The focus of this review is exploitation of existing knowledge on the biochemistry and the biological role of flavour production in yeast for the biotechnological production of aroma compounds of industrial importance, by means of immobilized yeast. Various types of carrier materials and immobilization methods proposed for application in beer, wine, fruit wine, cider and mead production are presented. Engineering aspects with special emphasis on immobilized cell bioreactor design, operation and scale‐up potential are also discussed. Ultimately, examples of products with improved quality properties within the alcoholic beverages are addressed, together with identification and description of the future perspectives and scope for cell immobilization in fermentation processes. Copyright

Encapsulation Systems in the Food Industry

Encapsulation is a useful tool to improve the delivery of bioactive and living cells into foods. Encapsulation aims to preserve the stability of the active compounds during processing and storage and to prevent undesirable interactions with the food matrix. In addition, encapsulation may be used to immobilise cells or enzymes in food processing applications, such as fermentation processes and metabolite production processes.

Effects of different carrier materials on physicochemical properties of microencapsulated grape skin extract

AbstractThe goal of this study was to investigate the characteristics of grape skin extract (GSE) spray dried with different carriers: maltodextrin (MD), gum Arabic (GA) and skim milk powder (SMP). The grape skin extract was obtained from winery by-product of red grape variety Prokupac (Vitis vinifera L.). The morphology of the powders, their thermal, chemical and physical properties (water activity, bulk and tapped densities, solubility), as well as release studies in different pH conditions were analyzed. Total anthocyanin content and total phenolic content were determined by spectrophotometric methods. MD and GA-based microparticles were non-porous and spherical, while SMP-based ones were irregularly shaped. The process of spray drying Prokupac GSE using these three carriers produced powders with low water activity (0.24–0.28), good powder characteristics, high yields, and solubility higher than 90%. The obtained dissolution/release profiles indicated prolonged release of anthocyanins and phenolic compounds in different mediums, especially from GSE/GA microparticles. These results have shown that grape skin as the main by-product of wine production could be used as a source of natural colorants and bioactive compounds, and microencapsulation as a promising technique for the protection of these compounds, their stabilization in longer periods and prolonged release.

Microencapsulation of anthocyanin-rich black soybean coat extract by spray drying using maltodextrin, gum Arabic and skimmed milk powder

Abstract Black soybean coat is insufficiently valorised food production waste rich in anthocyanins. The goal of the study was to examine physicochemical properties of spray dried extract of black soybean coat in regard to carrier materials: maltodextrin, gum Arabic, and skimmed milk powder. Maltodextrin and gum Arabic-based microparticles were spherical and non-porous while skimmed milk powder-based were irregularly shaped. Low water activity of microparticles (0.31–0.33), good powders characteristics, high solubility (80.3–94.3%) and encapsulation yields (63.7–77.0%) were determined. All microparticles exhibited significant antioxidant capacity (243–386 μmolTE/g), good colour stability after three months of storage and antimicrobial activity. High content of total anthocyanins, with cyanidin-3-glucoside as predominant, were achieved. In vitro release of anthocyanins from microparticles was sustained, particularly from gum Arabic-based. These findings suggest that proposed simple eco-friendly extraction and microencapsulation procedures could serve as valuable tools for valorisation and conversion of black soybean coat into highly functional and stable food colourant.

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.

6: Isolation, Purification and Encapsulation Techniques for Bioactive Compounds from Agricultural and Food Production Waste

Rice is a staple food in most Asian countries and a source of energy for 30 per cent of the world’s population (Muller-Fischer 2013). For human consumption, rice is usually processed by being milled and polished into white grain. Rice processing typically yields 56-58 per cent milled white rice (head rice), 10-12 per cent broken grain, 18-20 per cent husk and 10-12 per cent bran (Kahlon and Chow 2001). Head rice is the main commercial product, while the remaining categories constitute rice waste or by-products. Straw is also considered rice waste and its yield per ratio to grain is 1:6 (Schiere et al. 2004). Straw and husk are mainly used for non-food purposes, such as animal feed, craft art, chemical industries and amino acids (Matano et al. 2014, Van Soest 2006). Bran contains the majority of functional substances of rice grain and is unstable due to its oil and lipase content (Kahlon and Chow 2001). This paper provides a review of the bioactive compounds in rice waste and their extraction, isolation and utilisation.