Applications of spray-drying in microencapsulation of food ingredients: An overview

Microencapsulation is a rapidly expanding technology which is a unique way to package materials in the form of micro- and nano-particles, and has been well developed and accepted within the pharmaceutical, chemical, food and many other industries. Spray drying is the most commonly used encapsulation technique for food products. A successful spray drying encapsulation relies on achieving high retention of the core materials especially volatiles and minimum amounts of the surface oil on the powder particles for both volatiles and non-volatiles during the process and storage. The properties of wall and core materials and the prepared emulsion along with the drying process conditions will influence the efficiency and retention of core compounds. This review highlights the new developments in spray drying microencapsulation of food oils and flavours with an emphasis on the encapsulation efficiency during the process and different factors which can affect the efficiency of spray drying encapsulation.

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Encapsulation Efficiency of Food Flavours and Oils during Spray Drying

Encapsulation efficiency and oxidative stability of flaxseed oil microencapsulated by spray drying using different combinations of wall materials

Production of instant soymilk powders by ultrafiltration, spray drying and fluidized bed agglomeration

Carbon nanotubes are promising materials for various applications. In recent years, progress in manufacturing and functionalizing carbon nanotubes has been made to achieve the control of bulk and surface properties including the wettability, acid–base properties, adsorption, electric conductivity and capacitance. In order to gain the optimal benefit of carbon nanotubes, comprehensive understanding on manufacturing and functionalizing carbon nanotubes ought to be systematically developed. This review summarizes methodologies of manufacturing carbon nanotubes via arc discharge, laser ablation and chemical vapor deposition and functionalizing carbon nanotubes through surface oxidation and activation, doping of heteroatoms, halogenation, sulfonation, grafting, polymer coating, noncovalent functionalization and nanoparticle attachment. The characterization techniques detecting the bulk nature and surface properties as well as the effects of various functionalization approaches on modifying the surface properties for specific applications in catalysis including heterogeneous catalysis, photocatalysis, photoelectrocatalysis and electrocatalysis are highlighted.

Carbon nanotube catalysts: recent advances in synthesis, characterization and applications.

Encapsulation of oil in powder using spray drying and fluidised bed agglomeration

Many active components (anti-oxidants, aromas) are lipophilic substances, available in liquid form and have to be protected from the environment. Encapsulation of oil drops into a solid matrix is regarded as an efficient protection method and a means of formulating liquid compounds in a solid dosed form. The aim of this study is to investigate the feasibility of encapsulation of a vegetable oil (ISIO4®, 5% w/w dry matter) used as a model into a mixture of maltodextrin and acacia gum. Encapsulation was completed in three stages, i.e. emulsification, spray drying and fluid bed agglomeration. Optimal operating conditions for spray drying and agglomeration were identified. Powders were characterized before and after agglomeration in terms of oil content and protection (dispersion into the matrix, surface oil content, oxidation) and powder handling properties (flowability, wettability, friability). The proposed encapsulation method provided powders where oil droplets were well dispersed and protected (oil droplets diameter lower than 1 μm in reconstituted emulsions, less than 2% of the total oil content at the particle surface, oil oxidation lowered compared to unprotected oil). Agglomeration did not change oil encapsulation properties of the spray-dried powder but considerably improved its wettability. Industrial relevance Encapsulation of active components finds many applications in food industry for aromas, vitamins, anti-oxidants, etc. used in powdered foods (soups, instant drinks and sauces), prepared meals and food complements with a market in constant increase. It is also widely used in pharmaceutical, chemical and cosmetics industries where products are different but techniques are similar. This study aimed to test the combination of spray drying and fluidised bed agglomeration to encapsulate sensitive lipid-based compounds into dosed powders to provide protection and storage stability and render their use easier.

M. Fuchs

Papers

Encapsulation of oil in powder using spray drying and fluidised bed agglomeration

Oil encapsulation by spray drying and fluidised bed agglomeration