| Author | Koirala, Sushil |
| Call Number | AIT Thesis no.FB-19-09 |
| 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.FB-19-09 |
| Abstract | Goat milk proteins have gained increasing attention especially the bioactive peptides released from the parent proteins. Specifically, the interest in bioactives of goat milk is intensifying due to its reduced allergenicity compared with bovine milk. In this study, proteins of goat milk were extracted by various methods in order to gain knowledge on their potent hydrolysates and peptides. Firstly, optimization of ultrasonication process using Box-Behnken design showed that pH and ultrasonication time had a significant effect (p<0.05) on the protein extraction process, while amplitude had no significant effect (p>0.05). The increase in protein concentration from ultrasonication was 27.15% from 19.37 mg/mL (control) to 24.63 mg/mL. Secondly, enzymatic hydrolysis was carried where, protease hydrolysates at 2.5% (w/w) showed significantly higher (p<0.05) protein concentration and degree of hydrolysis compared with pepsin hydrolysates. The results also showed that at the optimal conditions, ultrasonic pretreated samples had higher protein concentration and degree of hydrolysis than with untreated samples for both enzyme hydrolysates showing the effects of ultrasonication on structure and conformation of proteins. Similarly, among enzymatic hydrolysis using commercial enzymes (neutral protease and pepsin) and fermentation using probiotic starter cultures (Lactobacillus helveticus TISTR 6792 and Bifidobacterium lactis 6E11 (IN-0596), the fermentation process had better extraction of protein and its corresponding degree of hydrolysis. The water-soluble peptide extract (WSPE) by fermentation using both probiotic starter culture was fractionated using RP-UHPLC and obtained peptide fractions were analyzed for bioactive potential. IC50 which is half maximal inhibition concentration values representing the concentration of sample required to inhibit 50% of the schizont maturation, were calculated by implementing linear regression between inhibitor concentration and percent inhibitions. DPPH radical scavenging analysis showed antioxidant abilities in all fractions with Bifidobacteria fermented peptide fractions showing highest antioxidant ability at 1.23 mg/mL. The values of IC50 were lower for enzymatically hydrolyzed peptide fractions than fermentation, further stamping fermentation as an ideal method for the production of peptides. Similarly, ACE-inhibitory activity was also assessed where Lactobacilli fermented sample had the highest ACE-inhibitory activity of around 0.18 mg/mL. The results show the potential of bioactive peptides from goat milk to be used as food additive and natural ACE-inhibitors with possible food and biomedical industrial applications. |
| Year | 2019 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no.FB-19-09 |
| 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) | Loc Thai Nguyen ;Datta, Avishek ;Wai Prathumpai; |
| Scholarship Donor(s) | Asian Institute of Technology Fellowship; |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2019 |