Probiotics viability and stability is a core challenge for the food processing industry. To prolong the viability of probiotics (Lactobacillus acidophilus), gelatin (GE)-chitosan (CH) polyelectrolytes-coated nanoliposomes were developed and characterized. The average particle size of the nanoliposomes was in the range of 131.7-431.6 nm. The mean zeta potential value of the nanoliposomes differed significantly from -42.2 to -9.1 mV. Scanning electron micrographs indicated that the nanoliposomes were well distributed and had a spherical shape with a smooth surface. The Fourier transform infrared spectra revealed that the GE-CH polyelectrolyte coating has been effectively applied on the surface of nanoliposomes and L. acidophilus cells were successfully encapsulated in the lipid-based nanocarriers. X-ray diffraction results indicated that nanoliposomes are semicrystalline and GE-CH polyelectrolyte coating had an influence on the crystalline nature of nanoliposomes. Moreover, the coating of L. acidophilus-loaded nanoliposomes with GE-CH polyelectrolytes significantly improved its viability when exposed to simulated gastrointestinal environments. The findings of the current study indicated that polyelectrolyte-coated nanoliposomes could be used as an effective carrier for the delivery of probiotics and their application to food matrix for manufacturing functional foods.
The objective of this study was to evaluate agricultural wastes as immobilizers for probiotics in liquid foods, such as soy milk. Probiotic strains were initially evaluated for acid and bile tolerance and the ability to produce alpha-galactosidase. Rinds of durian, mangosteen, and jackfruit were dried, ground, and sterilized prior to immobilization of selected strains ( Lactobacillus acidophilus FTDC 1331, L. acidophilus FTDC 2631, L. acidophilus FTDC 2333, L. acidophilus FTDC 1733, and Lactobacillus bulgaricus FTCC 0411). Immobilized cells were inoculated into soy milk, and growth properties were evaluated over 168 h at 37 degrees C. Soy milk containing free cells without agrowastes was used as the control. Immobilized probiotics showed increased growth, greater reduction of stachyose, sucrose, and glucose, higher production of lactic and acetic acids, and lower pH in soy milk compared to the control. The results illustrated that agrowastes could be used for the immobilization of probiotics with enhanced growth, utilization of substrates, and production of organic acids.
This study explored the potential of soluble dietary fiber (SDF) from agrowastes, okara (soybean solid waste), oil palm trunk (OPT), and oil palm frond (OPF) obtained via alkali treatment, in the nanoencapsulation of Lactobacillus acidophilus . SDF solutions were amended with 8% poly(vinyl alcohol) to produce nanofibers using electrospinning technology. The spinning solution made from okara had a higher pH value at 5.39 ± 0.01 and a higher viscosity at 578.00 ± 11.02 mPa·s (P < 0.05), which resulted in finer fibers. FTIR spectra of nanofibers showed the presence of hemicellulose material in the SDF. Thermal behavior of nanofibers suggested possible thermal protection of probiotics in heat-processed foods. L. acidophilus was incorporated into the spinning solution to produce nanofiber-encapsulated probiotic, measuring 229-703 nm, visible under fluorescence microscopy. Viability studies showed good bacterial survivability of 78.6-90% under electrospinning conditions and retained viability at refrigeration temperature during the 21 day storage study.