Nutritional composition of dried fishes from Bangladesh and functional properties of their protein isolates
| dc.contributor.author | Sun, Huan | |
| dc.contributor.examiningcommittee | Utioh, Alphonsus (Food and Human Nutritional Sciences) | |
| dc.contributor.examiningcommittee | Johnson, Derek (Anthropology) | |
| dc.contributor.supervisor | Aluko, Rotimi | |
| dc.date.accessioned | 2024-09-19T13:25:26Z | |
| dc.date.available | 2024-09-19T13:25:26Z | |
| dc.date.issued | 2024-09-18 | |
| dc.date.submitted | 2024-09-18T18:34:41Z | en_US |
| dc.date.submitted | 2024-09-18T21:48:33Z | en_US |
| dc.degree.discipline | Food and Human Nutritional Sciences | |
| dc.degree.level | Master of Science (M.Sc.) | |
| dc.description.abstract | Dried fishes (DFs) are considered to be rich in protein, fat, ash and easy to store as well as transport at room temperature. However, they have been neglected for a long time with respect to their nutritional quality, consumption safety and their potential as an innovative food ingredient. To alleviate the serious public health challenge posed by malnutrition and find new possibilities for the food industry, it is particularly important to study the nutritional profile of dried fish and explore their functional characteristics to pave the way for subsequent industrial applications. Therefore, this study explored the nutrient composition of seven different DFs (Bombay duck: BD, Harpadon nehereus; ribbon fish: RF, Trichiurus iepturus; white sardine: WS, Escualosa thoracata; freshwater barb: FB, Puntius spp.; Ganges River sprat: GR, Corica soborna; fermented barb: FM, Puntius spp.; fermented anchovies: FA, Setipnna spp.) collected from four cities (Cox’s Bazar: C; Dhaka: D; Mymensingh: M; Sylhet: S) in Bangladesh. In addition, further investigation was conducted on determining the functional properties of dried fish protein isolates (DFPIs) from Dhaka at neutral pH (7.0), thereby to broaden the value-addition of DFs and explore potential applications of the isolated proteins as ingredients in the food industry. We found that two small indigenous DFs, WS and GR, showed good potential as a protein source because both of them contained more than 75% protein, in which the essential amino acids (EAA) content accounted for 50% of the total amino acids, and the scores of various individual EAAs exceeded 100. In addition, there were significantly (p<0.05) lower contents of sodium and higher potassium in WS and GR, making them good sources of these minerals. An excellent fatty acid profile was detected in WS based on the high levels of EPA (6-7%), DHA (~19%) and other n-3 fatty acids (total n-3 fatty acid: 32-35%), making it a great source of health-promoting essential fatty acids. All the DFs analyzed in this study are good sources of vitamin B12. However, the presence of high levels of heavy metals in several of the DFs, except for WS, is not desirable due to potential adverse effects on human health. In addition, a relatively high cholesterol content (0.17-0.25 µg/g) in GR also limits its promotion potential among consumers as a source of healthy nutrients. In terms of DFPIs’ functional proprieties, it was found that the high concentration of NaCl contained in DFs increased the ionic strength of the extraction environment and caused the isoelectric point (IP) to move towards to acidic direction (pH 4.5). Under neutral pH conditions, BD-D exhibited higher solubility (85.03±1.06%), relatively stable heat coagulability (6.23 ± 0.41 %), excellent water/oil holding capacity (water holding: 7.00 ± 0.47 g/g; oil holding: 20.13 ± 0.14 ml/g), as well as strong gelling ability (least gel concentration: 3%) and emulsifying properties (oil droplets size of 2-3.5 μm; emulsion stability: 70-100 %). Far-UV CD results reflect that β-sheet (20-35%) and random coil (35-46%) are the predominant secondary structures of DFPIs, indicating highly denatured structures. The almost zero ellipticity in the near-UV spectrum also implies that except the GR, most of the tertiary structures in DFPIs are also unfolded. The polypeptide profile lacked the characteristic band of myofibrillar protein at 200 kDa. Instead, the broad bands at 37-25 and 15-10 kDa indicate that the myofibrillar and sarcoplasmic protein of DFPIs have been degraded into shorter peptides with low molecular weights. | |
| dc.description.note | October 2024 | |
| dc.identifier.uri | http://hdl.handle.net/1993/38623 | |
| dc.language.iso | eng | |
| dc.rights | open access | en_US |
| dc.subject | Dried fish | |
| dc.subject | Nutritional quality | |
| dc.subject | Micronutrients | |
| dc.subject | Heavy metals | |
| dc.subject | Dried fish protein isolates | |
| dc.subject | Functional properties | |
| dc.subject | Emulsions | |
| dc.subject | Structural properties | |
| dc.subject | Bangladesh | |
| dc.title | Nutritional composition of dried fishes from Bangladesh and functional properties of their protein isolates | |
| dc.type | master thesis | en_US |
| local.subject.manitoba | no | |
| oaire.awardTitle | Dried fish matters: Mapping the social economy of dried fish in South and Southeast Asia for enhanced wellbeing and nutrition | |
| oaire.awardURI | https://www.sshrc-crsh.gc.ca/results-resultats/recipients-recipiendaires/2017/partnership_grants_nov-subventions_partenerial_nov-eng.aspx | |
| project.funder.identifier | http://dx.doi.org/10.13039/501100000155 | |
| project.funder.name | Social Sciences and Humanities Research Council of Canada |