Encapsulation of probiotic Lactobacillus acidophilus by ionic gelation with electrostatic extrusion for enhancement of survival under simulated gastric conditions and during refrigerated storage

Abstract

The probiotic Lactobacillus acidophilus was encapsulated in biodegradable and biocompatible capsules prepared by ionic gelation between phytic acid (PA) and chitosan (CS) with an electrostatic extrusion method. Calcium carbonate (CaCO 3 ) and starch were used as co-encapsulants for improvement of capsule stability. Capsules were characterised and evaluated for survival of encapsulated L. acidophilus cells in simulated gastric fluid (SGF) and during refrigerated storage. Loading capacity values of PA-CS capsules, PA-CS-starch capsules and PA-CS-CaCO 3 capsules were 8.20, 8.12 and 7.81 log CFU g À1 of wet capsule, respectively. Capsules showed particle sizes of 1.3-1.5 mm and a uniform spherical shape. PA-CS-CaCO 3 capsules were the most stable vehicles for the protection of probiotic cells against acidic damage, particularly at pH 1.5 and pH 2. L. acidophilus cells from PA-CS-CaCO 3 capsules showed only a 0.64 log CFU reduction in numbers after 2 h in pH 1.5 SGF conditions. The numbers of L. acidophilus encapsulated in PA-CS-CaCO 3 capsules were decreased by only 0.69 log CFU g À1 , while PA-CS capsules and PA-CSstarch capsule numbers were reduced by more than 1.45 log CFU g À1 after 4 weeks at 4°C. Addition of calcium carbonate to PA-CS capsules provided protection against acid injury via antacid and buffering effects for encapsulation of L. acidophilus.

Optimising chitosan–pectin hydrogel beads containing combined garlic and holy basil essential oils and their application as antimicrobial inhibitor

“…Analysis of drug dissolution from calcium pectinate beads has previously revealed that internal cross‐linked beads compacted the core, which decreased the drug release by 10–20% when compared to counterparts undergone cross‐linking of the surface (Pawar et al ., ). Chitosan‐coated beads were also expected to delay the release rate (Shi et al ., ; Kim et al ., ).…”

“…Kim et al . () noted that the loading efficiency of albumin in chitosan‐coated pectin beads was affected by the weight ratio of pectin‐to‐albumin and the concentration of CaCl 2 . The extent of the cross‐linking during gelation relies on the interaction between the negatively‐charged pectin (COO ‐ ) and positively‐charged calcium ions (Ca 2+ ) (Pawar et al ., ; Jaya et al ., ).…”

“…The particles comprise a core material as the internal phase, and a wall material as the coating phase (Bakry et al, 2016). Ionic gelation forms hydrogel by interaction between a charged polymer and an ion divalent with oppositely charge (Kim et al, 2017;de Moura et al, 2018). This technique can not only defend against volatilisation losses of EOs (Benavides et al, 2016) but also provide a porous matrix for releasing the active compounds (Singh et al, 2017).…”

“…Hydrogels based on polysaccharides, like chitosan and pectin, have been increasingly utilised in various fields (Kwiecie n & Kwiecie n, 2018). Since chitosan is positively-charged in low pH conditions (pH below its pK a ), it spontaneously associates with negatively-charged polyanions in solution to form polyelectrolyte complexes (Kim et al, 2017), which are favourable excipients in controlled release delivery systems (He et al, 2016). Pectin is an anionic heteropolysaccharide that mainly consists of linearly linked a(1?4)-D-galacturonic residues, with varying amounts of methyl-esterified carboxyl groups (Konovalova et al, 2017).…”

Review of electrospray observations and theory

“…Electrospraying was also used for encapsulation of probiotics (J. U. Kim, et al, 2016) and proteins (Xie & Wang, 2007). According to Xie and Wang (2007), electrospray should be a good option for encapsulation of antibiotics, enzymes and DNA fragments, too.…”