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Development of processing schemes for high-value utilization of pumpkin by-products
Thesis (MEng)--Stellenbosch University, 2023.
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| Format: | Thesis |
| Language: | en_ZA en_ZA |
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Stellenbosch : Stellenbosch University
2023
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| _version_ | 1867613914492043264 |
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| access_status_str | Open Access |
| author | Chifomboti, Lindah Phambala |
| author2 | Chimphango, Annie Fabian Abel |
| author_browse | Chifomboti, Lindah Phambala Chimphango, Annie Fabian Abel |
| author_facet | Chimphango, Annie Fabian Abel Chifomboti, Lindah Phambala |
| author_sort | Chifomboti, Lindah Phambala |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2023. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/129015 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA en_ZA |
| last_indexed | 2026-06-10T12:43:43.080Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/129015 Development of processing schemes for high-value utilization of pumpkin by-products Chifomboti, Lindah Phambala Chimphango, Annie Fabian Abel Stellenbosch University. Faculty of Engineering. Dept. of Chemical Engineering. Process Engineering. Pumpkin -- Processing Agricultural engineering Beta carotene Enzymatic extraction Cold pressing Vegetable oil presses Microwave pressing Extraction apparatus Thesis (MEng)--Stellenbosch University, 2023. ENGLISH ABSTRACT: Pumpkin use for production of high-value products including pre-processed cuts, has increased due to consumers’ preference for healthy lifestyles. This trend is generating substantial amounts of residues, mainly peels (rich in β-carotene and protein) and seeds (rich in oil and protein), without a proper disposal strategy. Thus, value can be added to the seeds and the peels by co-production of high-quality edible oils, β-carotene, and protein through an integrated multi-feedstock biorefinery concept. Edible oils are often recovered by cold pressing extraction (CPE) to preserve bioactive compounds. However, CPE has a low extraction efficiency (< 85%), and the edible oils produced lack oxidative stability, requiring the addition of synthetic antioxidants (β-carotene), which also serve as a pigmentation agent. Notably, vegetable oils are the preferred solvents for β-carotene extraction from plant biomass. In this study, novel processing schemes were developed and assessed for co-extraction of pumpkin seed oil (PSO) and β-carotene from pumpkin seeds and peels. Residues from the oil/β-carotene extraction (rich in protein) became feedstock for protein extraction (PE) through an enzyme (protease or viscozyme-L)-assisted hydrolysis. The objective was to increase PSO yields and oxidative stability through in-situ β-carotene extraction and enrichment, and to obtain protein as an additional high-value product in a sequential process with minimal processing steps. Microwave pre-treatment (MP) of the seeds and peels was employed to enhance PSO, βcarotene, and protein extraction. Three schemes were developed by the sequential integration of CPE and PE: (1) using microwaved seeds, (2) microwaved seed-peel mixture, and (3) untreated seed-peel mixture. Process conditions for CPE and in-situ enrichment with βcarotene (seed-to-peel ratio, 50 – 90 % w/w; microwave power, 200 – 600 Watts (𝑔. 𝑚2 103 𝑠𝑒𝑐3 ⁄ ); irradiation time, 120 – 240 sec; cold pressing pressure, 10 – 20 MPa), and PE from the press residue (liquid-to-solid ratio, 10 – 30 mL/g; enzyme dose, 1 – 3 % w/w; extraction time 2 – 5 h) were optimized for maximum yields in a three-level Box Behnken Design response surface methodology. The seed composition was ~54% crude oil and 35 % protein, and that of the peel ~11% protein and ~15 mg/ 100 g β-carotene. The CPE residues from mixed feedstock had 60.92 % protein. Microwave pre-treatment increased β-carotene, and protein extraction by 7.3-fold, and 38.65 % (protease-assisted extraction), respectively. The optimized CPE conditions were 80 % w/w seeds, 600 Watts (𝑔. 𝑚2 103 𝑠𝑒𝑐3 ⁄ ), 240 sec, and 20 MPa, providing 73.58 % recovery yield, and those of PE were 26.71 mL/g, 3 % w/w enzyme dose (viscozyme-L (5.0 pH, 55 °C)), 5 h; and 20.83 mL/g, 3 % w/w enzyme dose (protease (8.0 pH, 40 °C)), 4.24 h with 74.70% and 61.76% protein recoveries, respectively. Stellenbosch University https://scholar.sun.ac.za v PSOs extracted from the mixed feedstock were pigmented with β-carotene (~5.50 mg/ 100 g oil), and had higher oxidative stability at elevated temperatures (180 °C, 6 h) than unpigmented oils (2.01 mg/ 100 g oil), making them a suitable replacement for synthetic antioxidants in fortified-vegetable oils. Furthermore, protease (4.9 – 116.6 ± 1.18 mg/L) produced essential amino acids in higher concentrations than viscozyme-L (1.2 – 47.1 ± 2.47 mg/L). Thus, the microwave-assisted processing CPO scheme with pumpkin seed-peel mixture provides a potential multi-product pathway for obtaining maximum value from pumpkin residues. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Masters 2023-11-29T07:59:48Z 2024-01-08T19:18:44Z 2023-11-29T07:59:48Z 2024-01-08T19:18:44Z 2023-12 Thesis https://scholar.sun.ac.za/handle/10019.1/129015 en_ZA en_ZA Stellenbosch University xv, 132 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Pumpkin -- Processing Agricultural engineering Beta carotene Enzymatic extraction Cold pressing Vegetable oil presses Microwave pressing Extraction apparatus Chifomboti, Lindah Phambala Development of processing schemes for high-value utilization of pumpkin by-products |
| title | Development of processing schemes for high-value utilization of pumpkin by-products |
| title_full | Development of processing schemes for high-value utilization of pumpkin by-products |
| title_fullStr | Development of processing schemes for high-value utilization of pumpkin by-products |
| title_full_unstemmed | Development of processing schemes for high-value utilization of pumpkin by-products |
| title_short | Development of processing schemes for high-value utilization of pumpkin by-products |
| title_sort | development of processing schemes for high value utilization of pumpkin by products |
| topic | Pumpkin -- Processing Agricultural engineering Beta carotene Enzymatic extraction Cold pressing Vegetable oil presses Microwave pressing Extraction apparatus |
| url | https://scholar.sun.ac.za/handle/10019.1/129015 |
| work_keys_str_mv | AT chifombotilindahphambala developmentofprocessingschemesforhighvalueutilizationofpumpkinbyproducts |