Microencapsulation of L. acidophilus (La-05) and B. lactis (Bb-12) and evaluation of their survival at the pH values of the stomach and in bile

Abstract

Microcapsules were prepared using the probiotic microorganisms Lactobacillus acidophilus (La-05) and Bifidobacterium lactis (Bb-12) and the spray drying technique and cellulose acetate phthalate as the wall material. This study evaluated the resistance of these microorganisms to drying at three temperatures and also the in vitro tolerance of the free and microencapsulated form to pH values and bile concentrations similar to those found in the human stomach and intestine. With an air entry temperature of 130 degrees C and exit temperature of 75 degrees C, the number of viable cells of B. lactis was practically unaltered, whereas the population of L. acidophilus was reduced by two logarithmic cycles. B. lactis was more resistant to the drying process than L. acidophilus under all conditions tested. The morphology of the microcapsules was determined by scanning electron microscopy and the microcapsules presented a rounded external surface containing concavities, a continuous wall with no apparent porosity, average size of 22 microm, moisture content varying from 5.3 to 3.2% and water activity between 0.230 and 0.204. After inoculation into HCl solutions with pH values adjusted to 1 and 2, incubated anaerobically at 37 degrees C, and plated after 0, 1 and 2 h of incubation, microcapsules were effective in protecting the microorganisms, while the populations of both free microorganisms were eliminated after only 1 h at the acidic conditions. Microencapsulated B. lactis and L. acidophilus, both free and microencapsulated, were also resistant after 12h to bile solutions.

Technology and potential applications of probiotic encapsulation in fermented milk products

“…It was demonstrated that encapsulation of B. pseudolongum in cellulose acetate phthalate using emulsion method protected bacteria from acidic environment (simulated gastric environment) (Rao et al, 1989). In another study, B. lactic and L. acidophilus were encapsulated in cellulose acetate phthalate polymer using spray-drying technique (Favaro-Trindale and Grosso, 2002). This method was effective in protection of both these probiotic bacteria from low pH media similar to human stomach.…”

Physicochemical Properties and Excipient Compatibility Studies of Probiotic Bacillus coagulans Spores

“…Upon ingestion of meal gastric pH at first increases and then returns back to the fasting pH values within 3-4 hours [25]. Some of the reported protective strategies to address the pH instability are microencapsulation by enteric polymers like cellulose acetate phthalate [26], coating of probiotics with lipidic excipients like waxes [16], mixing with resistant starch [27] and symbiotic microencapsulation by emulsion spray drying technique [28].…”

Encapsulation Technology to Protect Probiotic Bacteria

“…Encapsulation is a process to entrap active agents within a carrier material and it is a useful tool to improve living cells into foods, to protect [3,4,5,6,7], to extend their storage life and to convert them into a powder form for convenient use [8,9,10,11]. In addition, encapsulation can promote controlled release and optimize delivery to the site of action, thereby potentiating the efficacy of the respective probiotic strain.…”