Kamal, Hina
(2024)
Food recycling: extraction and utilization of valuable protein from food waste.
PhD thesis, University of Nottingham.
Abstract
Approximately 61% of food waste (FW) originates at the (i) household, (ii) food service and (iii) distribution sectors. However, protein extraction from these FW sources remains limited and poorly understood. In fact, no formal studies on the extraction, optimisation, up-scaling and reutilisation of protein from these sources have been conducted thus far. Therefore, the core aim was to collectively extract protein from the “THREE” chief food waste gen¬eration outputs by employing green extraction methods and re-utilising it as a recycled prod¬uct. Briefly, FW was collected at three months interval as batches “FW-B1, FW-B2 and FW-B3” and subjected to continuous optimised parameters for each green extraction methods, namely enzymatic assisted extraction (EAE), ultrasonic assisted extraction (UAE) and liquid biphasic flotation (LBF) individually. Consequently, this study stands novel on the grounds that traditionally, many research studies have been applied to a singular food element only. Each extraction method was optimised at a laboratory scale in accordance to its working principle. A heuristic twin correlation of Plackett-Burman (PB) and Box-Behnken Response Surface Model (BB-RSM) was established. The highest protein yields 26.91% (FW-B1), 26.33% (FW-B2) and 28.29% (FW-B3) were acquired from the EA-BB-RSM design at: 300U/g enzyme concentration, pH 6, 100 rpm agitation and 55ºC for 30 min. The protein content was increased to 66.44% (FW-B1), 67.21% (FW-B2) and 67.08% (FW-B3) under UAE-BB-RSM with 80% solvent concentration, 1:25 solid/liquid ratio, 3% HCl ethanol acidity, 45ºC temperature, 50W ultrasonic power for 2h. However, regression coefficient and polynomial analysis of the variance model under LBF-BB-RSM had significant effects with increase in protein yield to 81.33% (FW-B1), 81.09% (FW-B2) and 80.11% (FW-B3). Comparatively all extraction methods (EAE, UAE and LBF) resulted in protein fractions with higher phase transition temperature. However, for enthalpy, all LBF samples showed small enthalpy changes with less than 1Jg−1, while both EAE and UAE extracted proteins exhibited higher enthalpy energy. Moreover, the intensity of reflections of the crystalline phase decreased with longer XRD treatment duration. Functional properties, predominantly solubility increased to 206.08 ± 0.11 in protein extracted after up-scaling the laboratory LBF-BB-RSM. In the current study, SuperPro Designer was used for evaluating the economic and sustainability performances for each EAE, UAE and LBF ex¬traction methods. The overall costs for EAE remained 38% higher than LBF and 19% higher than UAE. Similar patterns with application of hybrid extraction methods via (i) UAE + EAE, (ii) UAE + LBF, (iii) EAE + LBF produced accounting for 80%, 60% and 58% of the overall operating cost. Comparative analysis of each extraction method in reference to protein recovery, structural and functional modifications, along with economic and environmental sustainabil¬ity provides insight into the up scaling potential. Thus, an additional novelty of the study is in creating a continuous eco-friendly upscale LBF extraction model with protein recovery ˃ 80%. Moreover, the results of up-scaled extracted protein subjected to simulated gastric and intestinal digestion (SGID) imply the existence of shorter peptide (7-11 amino acids) with significant (P˂0.05) nutraceutical potential. For this reason, the current study explores the extracted protein valorisation potential by formulating different combinations of colloid system (extracted protein-starch-plasticizer) as “functional recycled packaging” called “extracted edible protein (EEP) coating. Overall, each of the EEP coating made with different extracted protein can be predicted with high confidence in water vapour permeability, solubility and thickness collectively. The level of transparency is evident from 20% EEP much like thickness. Additionally, the key chain in lightness was observed in 15% EEP (75.11 ± 0.03). Whereas increase in extracted protein concentrations including 20% (-9.63 ± 0.74) and 25% (-8.74 ± 0.14) were negative indicating a greenish colour with overall ▲ ˃ 3. Finally, silico analysis of the digested EEP concentrations with probiotic L.rhamnosus, lower concentrations (EEP 5%, 10% and 15%) upon in vitro digestion revealed the existence of shorter peptides (7-11 amino acids) with “AVVSPLKPCC, GMAGGPPLL, LTMPQWW, SQPWSFY and WNWGWLLWQL”. Thus, highlighting the potential of “food waste EEP coating” to induce synbiotic synergy with increase nutraceutical potency.
| Item Type: |
Thesis (University of Nottingham only)
(PhD)
|
| Supervisors: |
Ali, Asgar
Le, Cheng Foh |
| Keywords: |
food waste, enzymatic assisted extraction, ultrasonic assisted extraction, liquid biphasic flotation, protein structure, simulated gastric and intestinal digestion, total digestibility, bioactive peptides, nutraceutical potential, extracted edible protein coating |
| Subjects: |
Q Science > QK Botany |
| Faculties/Schools: |
University of Nottingham, Malaysia > Faculty of Science and Engineering — Science > School of Biosciences |
| Related URLs: |
|
| Item ID: |
78436 |
| Depositing User: |
Kamal, Hina
|
| Date Deposited: |
27 Jul 2024 04:40 |
| Last Modified: |
27 Jul 2024 04:40 |
| URI: |
https://eprints.nottingham.ac.uk/id/eprint/78436 |
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