Lactobacillus plantarum immobilized onto soymilk residue (Okara) for the enhancement of soymilk fermentation and cell survival under simulated gastrointestinal conditions
- Published
- Accepted
- Subject Areas
- Biotechnology, Food Science and Technology
- Keywords
- Soymilk residue (Okara), natural immobilization carrier, Lactobacillus plantarum, fermented soymilk, isoflavones, survival, simulated gastrointestinal stress
- Copyright
- © 2016 Xiudong et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2016. Lactobacillus plantarum immobilized onto soymilk residue (Okara) for the enhancement of soymilk fermentation and cell survival under simulated gastrointestinal conditions. PeerJ Preprints 4:e2349v1 https://doi.org/10.7287/peerj.preprints.2349v1
Abstract
Cell immobilization is an alternative to microencapsulation for the maintenance of cells in a liquid medium. However, artificial immobilization carriers are expensive and pose a high safety risk. This study aimed to evaluate the potential of okara, a food-grade byproduct from soymilk production, as a natural immobilizer for L. plantarum 70810 cells. The study also aimed to evaluate the effects of okara-immobilized L. plantarum 70810 cells on soymilk fermentation, glucosidic isoflavone bioconversion, and cell resistance to gastrointestinal (GI) stress. Scanning electron microscopy revealed that the lactobacilli cells attached and bound to okara’s surface. Compared with the free cells (FL), immobilized Lactobacillus plantarum (IL) cells exhibited a significantly higher specific growth rate and shorter lag phase of growth, a faster decrease in pH and increase in titrable acidity, and a higher soymilk viscosity. Similarly, IL in soymilk showed higher productions of daizein and genistein compared with the control. Compared with FL, IL showed reinforced resistance to simulatedGI stress in vitro that included low pH, low pH plus pepsin, pancreatin, and bile salt. Our results indicate that okara is a new potential immobilization carrier to enhance the growth and glucosidic isoflavone bioconversion activities of L. plantarum in soymilk and improve cell survivability following GI transit.
Author Comment
This is a submission to PeerJ for review.
Supplemental Information
Image of okara(A)
Shows details of okara amplified 100 times by SEM
Image of okara （B）
Shows details of okara amplified 500 times by SEM
Image of okara and okara-immobilized L. plantarum 70810 cells (C)
Shows details of the suface of okara and okara-immobilized L. plantarum 70810 cells ampilifed 2000 times by SEM
Image of okara and okara-immobilized L. plantarum 70810 cells (D)
Shows details of the suface of okara and okara-immobilized L. plantarum 70810 cells ampilifed 2000 times by SEM
Cells count changes in soymilk containing free and immobilized L. plantarum 70810
Row data for analysis of microbial growth kinetics of L. plantarum 70810 in soymilk. FL: free L. plantarum 70810; IL:okara-immobilized L. plantarum 70810.
Fermentation parameters during soymilk fermentation
Raw data for analysis of Fermentation parameters during soymilk fermentation using free and immobilized L. plantarum 70810. FL: free L. plantarum 70810; IL:okara-immobilized L. plantarum 70810.
Change in soybean isoflavone content of soymilk
Liquid chromatogram and raw data for analysis of isoflavone content of soymilk inoculated with free and immobilized L. plantarum 70810. FL: free L. plantarum 70810; IL:okara-immobilized L. plantarum 70810.
Effect of acidic conditions on the survival L. plantarum 70810
Raw data of bacterial count for analysis of the effect of acidic conditions on the survival of free and immobilized L. plantarum 70810. FL: free L. plantarum 70810; IL:okara-immobilized L. plantarum 70810.
Effect of simulated gastric transit and pancreatic juice on the survival of L. plantarum 70810
Raw data of bacterial count for analysis of the effect of simulated gastric transit and pancreatic juice on the survival of L. plantarum 70810. FL: free L. plantarum 70810; IL:okara-immobilized L. plantarum 70810.
Effect of bile salts on the survival of L. plantarum 70810 body
Raw data of bacterial count for analysis of the effect of bile salts on the survival of free and immobilized L. plantarum 70810. FL: free L. plantarum 70810; IL:okara-immobilized L. plantarum 70810.
Cells count change of okara-immobolized L. plantarum 70810 under different ultrasonic condition
A, cells shedding from okara under different ultrasound power for 6 min at initial temperature of 10 °C. B, cells shedding from okara under ultrasound power of 160W for different time at initial temperature of 10 °C. C, cells shedding from okara under ultrasound power of 160W for 10 min at different initial temperature.