SUBMERGED FERMENTATION BIOCONVERSION OF AIR-CLASSIFIED STARCH-RICH PULSE FLOURS TO PROTEIN-RICH PRODUCTS
| dc.contributor.advisor | Tanaka, Takuji | |
| dc.contributor.advisor | Korber, Darren | |
| dc.contributor.committeeMember | Nickerson, Michael | |
| dc.contributor.committeeMember | Ai, Yongfeng | |
| dc.contributor.committeeMember | Tar'an, Bunyamin | |
| dc.creator | Arasaratnam, Lashmitha | |
| dc.date.accessioned | 2023-04-04T16:32:31Z | |
| dc.date.available | 2023-04-04T16:32:31Z | |
| dc.date.copyright | 2023 | |
| dc.date.created | 2023-03 | |
| dc.date.issued | 2023-04-04 | |
| dc.date.submitted | March 2023 | |
| dc.date.updated | 2023-04-04T16:32:32Z | |
| dc.description.abstract | Pulse starch is a low-value, often underutilized co-product of the pulse industry. This research focuses on the submerged fermentation of starch-rich pulse fractions by generally recognized as safe (GRAS) microbes that result in production of microbial biomass enriched in crude protein, converting low-value starch to higher-value microbial protein. Accordingly, starch-rich pulse fractions of yellow field pea, yellow lentil and faba bean flours were fermented by Lactobacillus plantarum or Aspergillus oryzae applied as single- and multi-strain cultures. The fermentation process converted starch into microbial protein, increasing protein levels in fermented flour. The protein content of starch-rich yellow pea, yellow lentil and faba bean flours increased from 7.8% to 10.2%, 16.5% to 18.5% and 14.5% to 16.4% respectively. However, the increase in protein content was not sufficient to make the fermented substrates reach the targeted level of >45% protein. This was likely due to the shortage of nitrogen as starch-rich flours have 80% or above carbohydrate. The addition of inexpensive, commonly available nitrogen compounds was tested to increase protein. The starch-rich flours were supplemented with ammonium sulphate, ammonium phosphate or urea at varying concentrations (15 g/L – 35 g/L) over the fermentation time course to aid in de novo microbial protein synthesis. It was found that nitrogen supplementation aided microbial growth during fermentation and resulted in higher protein yield than when no additional nitrogen was added. Supplementation of urea at 35 g/L resulted in highest protein yield in all three pulse flours, resulting in final protein levels above 45%. The protein-rich fermented substrates were then further analyzed for proximate composition including starch, ash, lipid and moisture contents and in vitro protein digestibility (IVPD). It was found that as the protein content increased, the starch and lipid levels in the fermented substrates decreased. The overall protein digestibility of substrates fermented by L. plantarum was also improved and significantly higher (p<0.05) compared to A. oryzae and L. plantarum-A. oryzae co-culture fermented samples. Overall, this research highlights that fermentation by GRAS microbes for single cell protein (SCP) production is a highly efficient method to increase value of under-utilized starch-rich by-products in the pulse industry, as SCP can be used as an alternative for conventional food and feed. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | https://hdl.handle.net/10388/14553 | |
| dc.language.iso | en | |
| dc.subject | Submerged fermentation | |
| dc.subject | Single cell proteins | |
| dc.subject | Lactobacillus plantarum | |
| dc.subject | Aspergillus oryzae | |
| dc.title | SUBMERGED FERMENTATION BIOCONVERSION OF AIR-CLASSIFIED STARCH-RICH PULSE FLOURS TO PROTEIN-RICH PRODUCTS | |
| dc.type | Thesis | |
| dc.type.material | text | |
| thesis.degree.department | Food and Bioproduct Sciences | |
| thesis.degree.discipline | Applied Microbiology | |
| thesis.degree.grantor | University of Saskatchewan | |
| thesis.degree.level | Masters | |
| thesis.degree.name | Master of Science (M.Sc.) |