Bioprocessing of rice bran to isolate peptide for its value addition. | |
| Author | Kittima Triratanasirichai |
| Call Number | AIT Thesis no.FB-15-03 |
| Subject(s) | Bioactive compounds. Enzymatic analysis Microbiological--Techniques. |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Food Engineering and Bioprocess Technology, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. no.FB-15-03 |
| Abstract | Rice bran is one of the by-products from milled rice that normally used as a raw material for oil extraction. Many ways have been used to extract the protein including enzymatic, alkaline, physical and fermentation processes. Fermentation was very old technology but not often applied, it gives acceptable protein yield and can produce functional protein similar like enzymatic hydrolysis or sometimes even better. Therefore the aim of this study was to hydrolyze the rice bran protein into their smaller molecules or peptides and oligopeptides thus reducing the molecular weight and size. The study also focused on controlled gastrointestinal passage of those extracted peptides. Rice bran was fermented by Bacillus subtilis TISTR 1528 (FB) and Lactobacillus plantarum TISTR 926 (FL). The suitable ratio was evaluated and found that the fermentation time that gives highest protein content is at 36 hours for both culture (FB: 12.70%, FL: 9.91%). The properties were also determined, including: chemical composition, amino acid profile, molecular weight and degree of hydrolysis. Antioxidant activity (DPPH radical scavenging; DPPH and total phenolic content; TPC) and Angiotensin I-converting enzyme inhibitory were analyzed as well. The result found that the amino acid profileof the fermented sample (FB) is rich in glutamic acid, arginine, alanine and aspartic acid. In the sample also present the essential amino acid in intermediate level. The fermentation supposed to create a smaller protein molecule and high antioxidant and functionality, found that the molecular weight of both sample are the same (10-70 kDa). However, the antioxidant activity is decreasing for FB sample as fermentation time become longer and slightly increase for FL sample. The antioxidant activity of samples was related to amount of TPC present in sample and the TPC of both sample had the same trend as in antioxidant activity. The degree of hydrolysis is related with the growth of culture and production of protease, where it help taken out more protein from rice bran, at 36 hours found to be the highest. Even though, the cultures used for fermentation are different but it produced the same type of protein, which confirm by Fourier Transform Infrared Spectroscopy (FTIR). The peaks are the same and it appeared at almost same wavelength. Angiotensin I-converting enzyme inhibitory was another test that was carried out, FB sample has percent ACE inhibition of 29.79% and FL have 23.40%. The powder sample was then subjected to multilayer encapsulation in order to protect the peptides from digestion or hydrolysis in gastric acid and intestinal acid. Multilayer encapsulation composed of sodium alginate-chitosan interaction, sodium alginate (2%) and powder sample (1%) was dropped into hardening solution containing 0.4% chitosan. The bead then transfer to other layers including chitosan and sodium alginate (0.08%), respectively. The physical properties of multilayer encapsulated bead was measured also (particle size, swelling index and encapsulation efficiency), in each properties both beads sample show no significant different. The Scanning Electron Microscopy (SEM) was analyzed for bead sample to observe the surface, the surface of dry bead are not smooth but rough and have dent but in fresh bead the surface is smooth andround. Lastly, the encapsulated beads were subjected to release study to ensure the protection of peptides. The bead was first incubated in simulated gastric fluid (SGF) for 4 hour and being transferred to intestinal fluid (SIF). The result showed that during there was no release of bioactive peptides during 4 hr in SGF but once transferred to SIF, the beads start to breakdown and completely disintegrated within 15 min. From the result, it show that fermentation process is suitable to produce rice bran protein with high recovery and protein content but its not suitable for producing antioxidant purpose. The multilayer encapsulation does help protect peptides from gastric acid and release in the intestine where it is being absorbed. |
| Year | 2015 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. no.FB-15-03 |
| Type | Thesis |
| 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;Loc Thai Nguyen; |
| Scholarship Donor(s) | Royal Thai Government Fellowship; |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2015 |