64
material depends upon the type of the food ingredients and the encapsulation methods, and can be used either individually or in combination. Various encapsulation
methods include electrospinning, gelation, extrusion, co-precipitation, coacervation, spray drying, freeze drying, layer-by-layer deposition, emulsion system, and
others (Wani et al. 2016). Different encapsulation methods result in different nano/
micro structures, which affects encapsulation efficiency and release properties of
core ingredients. The below sections will describe the applications of native, modified and resistant starch for encapsulation of various bioactive ingredients including
polyphenols, plant extracts, probiotics, vitamins and etc.
Native and Modified Starch as Encapsulating Agent
Starch is a renewable biopolymer and widely distributed in nature with a huge
diversity of industrial applications and among them its use as wall material for
encapsulation of bioactive compounds is of great interest. This technique involves
the packaging of sensitive functional ingredients within the matrix of wall materials
and ensures controlled release under specific conditions. It is widely used to safeguard the bioactive compounds from harsh environmental and gastrointestinal conditions. Functional ingredients can be encapsulated by various wall materials like
starch, dextrins, β-glucan, gum arabic, carboxymethyl cellulose, alginate, chitosan,
xanthan, pectin, zein and whey protein isolates; (Wani et al. 2016; Shah et al. 2016;
Gani et al. 2018; Ahmad et al. 2018), but starch is the predominant one. There has
been increasing interest of using starch in native and modified forms to encapsulate
food ingredients such as flavours, lipids, polyphenols, carotenoids, vitamins,
enzymes, and probiotics because starch is generally recommended as safe, available
at cost, non-allergenic and bland in taste. Some studies have observed higher encapsulation efficiency of starch and provided better protection of food ingredients (e.g.,
flaxseed oil and flavours) against unfavourable conditions than protein and gum
arabic based systems (Charve and Reineccius 2009; Tonon et al. 2012).
Some native starch granules have surface pores as well as channels in the granules (Huber and BeMiller 2000; Han et al. 2015) to encapsulate a range of bioactive
components including catechin, gallic acid, caffeine, ibuprofen (a water insoluble
drug), and amino acids. Other studies on encapsulation using starch include the
encapsulation of soy-based ferulic acid derivatives that have antioxidant properties
(Compton et al. 2007). Thymol and nisin encapsulated into a starch-based O/W
emulsion and found to have enhanced antibacterial efficacy in cantaloupe juice
(Sarkar et al. 2017). β carotene was encapsulated in Starch hydrogels and studied in
a simulated gastrointestinal tract including oral, gastric, and intestinal phases.
Compared with the oil-in-water emulsion systems with WPI (14%), the filled starch
hydrogels showed higher bio- accessibility of β-carotene. This was attributed to the
prevention of the fat droplets from aggregation by the starch hydrogels during oral
and gastric digestion. Catechin and folic acid were encapsulated in starch and studied for release behavior under simulated gastrointestinal conditions, the results
M. Ahmad et al.
material depends upon the type of the food ingredients and the encapsulation methods, and can be used either individually or in combination. Various encapsulation
methods include electrospinning, gelation, extrusion, co-precipitation, coacervation, spray drying, freeze drying, layer-by-layer deposition, emulsion system, and
others (Wani et al. 2016). Different encapsulation methods result in different nano/
micro structures, which affects encapsulation efficiency and release properties of
core ingredients. The below sections will describe the applications of native, modified and resistant starch for encapsulation of various bioactive ingredients including
polyphenols, plant extracts, probiotics, vitamins and etc.
Native and Modified Starch as Encapsulating Agent
Starch is a renewable biopolymer and widely distributed in nature with a huge
diversity of industrial applications and among them its use as wall material for
encapsulation of bioactive compounds is of great interest. This technique involves
the packaging of sensitive functional ingredients within the matrix of wall materials
and ensures controlled release under specific conditions. It is widely used to safeguard the bioactive compounds from harsh environmental and gastrointestinal conditions. Functional ingredients can be encapsulated by various wall materials like
starch, dextrins, β-glucan, gum arabic, carboxymethyl cellulose, alginate, chitosan,
xanthan, pectin, zein and whey protein isolates; (Wani et al. 2016; Shah et al. 2016;
Gani et al. 2018; Ahmad et al. 2018), but starch is the predominant one. There has
been increasing interest of using starch in native and modified forms to encapsulate
food ingredients such as flavours, lipids, polyphenols, carotenoids, vitamins,
enzymes, and probiotics because starch is generally recommended as safe, available
at cost, non-allergenic and bland in taste. Some studies have observed higher encapsulation efficiency of starch and provided better protection of food ingredients (e.g.,
flaxseed oil and flavours) against unfavourable conditions than protein and gum
arabic based systems (Charve and Reineccius 2009; Tonon et al. 2012).
Some native starch granules have surface pores as well as channels in the granules (Huber and BeMiller 2000; Han et al. 2015) to encapsulate a range of bioactive
components including catechin, gallic acid, caffeine, ibuprofen (a water insoluble
drug), and amino acids. Other studies on encapsulation using starch include the
encapsulation of soy-based ferulic acid derivatives that have antioxidant properties
(Compton et al. 2007). Thymol and nisin encapsulated into a starch-based O/W
emulsion and found to have enhanced antibacterial efficacy in cantaloupe juice
(Sarkar et al. 2017). β carotene was encapsulated in Starch hydrogels and studied in
a simulated gastrointestinal tract including oral, gastric, and intestinal phases.
Compared with the oil-in-water emulsion systems with WPI (14%), the filled starch
hydrogels showed higher bio- accessibility of β-carotene. This was attributed to the
prevention of the fat droplets from aggregation by the starch hydrogels during oral
and gastric digestion. Catechin and folic acid were encapsulated in starch and studied for release behavior under simulated gastrointestinal conditions, the results
M. Ahmad et al.