| Author | Ong-Ard Praepanitchai |
| Call Number | AIT Diss no.FB-19-01 |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Food Engineering and Bioprocess Technology, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. FB-19-01 |
| Abstract | In this study, Lactobacillus plantarum (TISTR 050) was encapsulated in sodium alginate (SA)soy protein isolate (SPI) based hydrogel beads by extrusion gelation technique and further incorporated in mango juice to develop as probiotic-based functional beverage. The probioticencapsulated beads were evaluated by scanning electron microscopy (SEM) for surface morphology, Fourier transform infrared (FTIR) and differential scanning calorimetry (DSC). The beads were also studied for viability of encapsulated probiotics under in vitro simulated gastric and intestinal conditions, and under heat treatment (50, 63 and 72 °C). Further, the encapsulated probiotics incorporated in mango juice were investigated for survival of probiotics, and the changes in pH, total acid, polyphenol content, reducing sugar, and total antioxidant capacity of juice during storage under refrigerated (4 °C) conditions.
The encapsulated beads with the combinations of sodium alginate-soy protein isolate (SA-SPI) provided better protection to L. plantarum in gastric conditions compared to bead encapsulated with sodium alginate (SA) alone. The bile salt concentrations of 0.5 and 1.0 % (w/v) did not have diminishing effects on the survival level of the probiotics encapsulated in the SA-SPI beads even after 6 h of incubation. The probiotics encapsulated in the SA-SPI beads survived longer relative to those encapsulated in the SA beads and the non-encapsulated probiotics subjected to heat treatment at 50, 63 and 72 °C. However, increasing the concentrations of soy protein isolate (SPI) from 2 to 12% (w/v) did not significantly influence the survival level of the probiotics encapsulated in the SA-SPI beads under heat treatments.
The hydrogel beads made of 1% SA and 8% SPI (Bead F) containing probiotics was chosen to incorporate with mango juice. The application of encapsulated bead of L. plantarum in mango juice under pasteurization process showed the successful resistance to thermal conditions (72 °C for 90 s). The pH of the pasteurized mango juice with hydrogel beads containing probiotic cells was remained almost constant, (4.60-4.70) during 91 days of storage at 4 °C. But in case of mango juice with free probiotic cells, the pH of mango juice was reduced very quickly to 3.85 from pH 4.70 during the same period of storage at 4 °C. The acidity of mango juice with L. plantarum free cell was increased from 1.25% to 3.25% during storage at 4 °C for 91 days. For pasteurized mango juice with encapsulated L. plantarum TISTR 050 bead (pasteurized together both mango juice and encapsulated bead), the acidity slightly increased from 1.25% to 1.50% during experimental period. The storage of mango juice did not show any effect on total polyphenols content (TPC) during storage at 4 °C for 91 days. The TPC of mango juice with probiotic free cell showed the highest increase from 1.33 mg GAE/mL to 1.74 mg GAE/mL when compared with another treatment. In case of pasteurized mango juice with encapsulated bead (pasteurized together both mango juice and encapsulated bead), TPC was slightly increased from 1.35 mg GAE/mL to 1.47 mg GAE/mL. The concentration of total sugar in all treatment of mango juices with free cell/encapsulated bead significantly increased because of the action of enzymes in fruit juice. The DPPH free radical scavenging capacity of the mango juice without probiotic decreased little, but mango juice with L. plantarum can increase the DPPH free radical scavenging during 91 days of storage at 4 °C. |
| Year | 2019 |
| Corresponding Series Added Entry | Asian Institute of Technology, Dissertation; no. FB-19-01 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Food Engineering and Bioprocess Technology (FB) |
| Chairperson(s) | Anal, Anil Kumar; |
| Examination Committee(s) | Athapol Noomhorm;Thammarat Koottatep;Loc Thai Nguyen
; |
| Scholarship Donor(s) | AIT Fellowship ; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2019 |