A review on the encapsulation of bioactive components using spray‐drying and freeze‐drying techniques

Abstract

Bioactive compounds are a type of chemical substance found in plant sources. Lycopene, carotenoids, phytochemicals, phenolic compounds, and anthocyanin are a few bioactive compounds. These compounds are rich in antimicrobial, antioxidant, and free radical‐scavenging properties. But these compounds are easily degraded. In order to enhance the chemical stability and the retention properties of functional ingredients, encapsulation is indispensable. This paper reviews the two important methods of encapsulation of bioactive components and the novelties in these techniques. Spray‐drying and freeze‐drying techniques are commonly used for encapsulation in the food and pharmaceutical industries. The former is a quick and high‐temperature process, while the latter is a time‐consuming and low‐temperature procedure. The inlet temperature during spray drying is maintained between 120 and 190°C, whereas during freeze drying, a temperature of −80°C to −20°C is maintained. For effective encapsulation, the optimization of the process conditions such as the temperature, pressure, feed rate, airflow rates, and selection of wall materials are essential. In this paper, the influence of these parameters on encapsulation efficiency and product stability is also discussed. Practical Applications The spray‐drying and freeze‐drying techniques find their application in the food and chemical industries for the purpose of encapsulation and drying. The former technique helps transform liquid foods to powder and thereby extending their shelf life. The encapsulation of some biologically active components helps better retention and delivery of the components. Spray drying is a technique in which liquid foods are converted to powdered form. These techniques have been used for a very long time in the dairy industry. But in recent times, they have been used in the pharmaceutical industries as well. Their main application in the pharmaceutical industry is drug delivery. Freeze drying is a low‐temperature encapsulation process which is mainly used for the encapsulation of functional foods. The most commonly spray‐dried active materials include oleoresins, natural food colors, natural antioxidants, lipids, flavors, and functional foods. Probiotic sources such as bacterial cultures are the main freeze‐dried products. In this review, the practical applications of the techniques are elaborated.

Microencapsulation of Erythrocytes Extracted from Cavia porcellus Blood in Matrices of Tara Gum and Native Potato Starch

“…The study of color is relevant to the organoleptic properties of products fortified with iron encapsulants [ 28 , 31 ]. In addition, they are affected by the natural color of the wall materials used [ 16 , 56 , 57 ], and the amount of these used in spray drying [ 58 , 59 ], which would cause changes in the color shades due to non-enzymatic browning reactions at high temperatures [ 60 , 61 ]. Another essential aspect to consider would be the possible caramelization of carbohydrates due to the effect of high temperatures, which would contribute to a more significant darkening of the products obtained [ 62 , 63 ].…”

“…Food fortification and oral iron supplementation are the most used mechanisms for the prevention and treatment of anemia, and they are performed to protect and release the mineral at the right time and place [ 15 ], with encapsulation being the most used method, which allows inhibiting the different mechanisms of reaction and degradation of bioactive compounds, during the incorporation of ingredients to food systems, this process allows protecting the nucleus with various matrices such as starches, maltodextrins, gums, lipids, carbohydrates, proteins and antioxidants [ 16 ]. The most commonly applied encapsulation methods in the food industry are emulsification [ 17 ], gelation [ 18 ], extrusion [ 19 ], spray drying [ 20 ] and lyophilization [ 21 ], and there are also chemical encapsulation techniques such as coacervation, co-crystallization, interfacial polymerization, ionic gelation, polymeric incompatibility, liposome entrapment and molecular inclusion [ 22 ].…”

Microencapsulation of a Commercial Food-Grade Protease by Spray Drying in Cross-Linked Chitosan Particles

“…Microencapsulation by means of spray drying is a topic of great interest, as demonstrated by the increasing number of scientific articles published and patent applications submitted in the last decade [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. Spray drying is a preservation and controlled release technology that is commonly applied in the food industry [ 10 , 19 , 20 , 21 ], mainly due to being a relatively low-cost technique that is reproducible, rapid, and easy to scale-up, when compared with other microencapsulation technologies [ 22 , 23 ]. Spray drying has been used in the food science field to encapsulate flavours, bioactive and functional compounds, probiotics, enzymes, or even cells [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ].…”

“…Spray drying is a preservation and controlled release technology that is commonly applied in the food industry [ 10 , 19 , 20 , 21 ], mainly due to being a relatively low-cost technique that is reproducible, rapid, and easy to scale-up, when compared with other microencapsulation technologies [ 22 , 23 ]. Spray drying has been used in the food science field to encapsulate flavours, bioactive and functional compounds, probiotics, enzymes, or even cells [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ]. A crucial step in developing spray-dried microcapsules for food applications is the choice of the encapsulating material, since its properties (i.e., solubility and emulsifying properties) determine the encapsulation efficiency and stability of the microcapsules [ 34 ].…”

Granulation of Silicon Nitride Powders by Spray Drying: A Review

“…It is widely used in the food industry to produce freeze-dried products such as milk powder. Spray drying is also used in the pharmaceutical industry for the dehydration of saturated solutions and the isolation of the active substances contained in them in powder form [ 42 ]. Finally, this method is used for the manufacture of spherical non-agglomerated and monodisperse metastable ceramic powders and their compositions [ 43 ].…”