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The influence of processing parameters for protein extraction and downstream processing of brewers’ spent grain to produce a dried protein powder product
Thesis (MEng)--Stellenbosch University, 2024.
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867613879208509440 |
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| access_status_str | Open Access |
| author | Tromp, Megan Caley |
| author2 | Goosen, Neill Jurgens |
| author_browse | Goosen, Neill Jurgens Tromp, Megan Caley |
| author_facet | Goosen, Neill Jurgens Tromp, Megan Caley |
| author_sort | Tromp, Megan Caley |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description |
Thesis (MEng)--Stellenbosch University, 2024. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/131938 |
| institution | Stellenbosch University (South Africa) |
| last_indexed | 2026-06-10T12:43:09.148Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/131938 The influence of processing parameters for protein extraction and downstream processing of brewers’ spent grain to produce a dried protein powder product Tromp, Megan Caley Goosen, Neill Jurgens Stellenbosch University. Faculty of Engineering. Dept. of Chemical Engineering. Brewing industry -- By-products Proteins -- Separation Agricultural wastes UCTD Thesis (MEng)--Stellenbosch University, 2024. ENGLISH ABSTRACT: Brewers’ spent grain (BSG) is a valuable yet underutilized by-product of the beer brewing process which is presently used as an ingredient in ruminant livestock feed. BSG is, however, a food-grade material which has made it of interest as an alternative protein source to combat food scarcity and the environmental impact of current food systems. The recent interest in BSG as a protein source has resulted in work being conducted using various methods of protein extraction, with a common method being enzymatic hydrolysis. This type of extraction has been reported to improve the techno-functional properties of the resulting protein hydrolysates including protein solubility, ease of digestibility as well as sensory attributes including decreased bitterness which contribute to the desirability and quality of the final food product within which the protein hydrolysate is incorporated. This study was aimed at producing a dried protein powder product from the brewery by-product BSG via enzymatic hydrolysis, and to determine the powder properties. This was achieved by investigating the effect of varying enzymatic hydrolysis reaction conditions to produce BSG protein hydrolysates (BSG-PHs) using two proteolytic enzymes, namely Protamex® and Flavourzyme® and, thereafter, determining the optimum combination of process conditions. Subsequently the amino acid profiles and molecular weight distributions of the BSG-PHs were determined. Finally, optimal downstream processing conditions were established by means of recovery analysis and adsorption behaviour to produce a stable final powdered protein product. Optimum processing conditions of enzymatic hydrolysis were determined based on highest resulting protein recoveries and degree of hydrolysis (DH). Optimum conditions for hydrolysis performed with the aid of Protamex® were a temperature of 65°C, a pH of 8.5 and an E/S dosage of 0.625% (g enzyme / g protein dry weight basis) and an extraction time of 150 minutes. This resulted in a protein recovery of 33.9% and DH of 19.2%. Molecular weight distributions of this hydrolysate confirmed the gradual breakdown of larger molecular weight proteins and peptides, with the final hydrolysate produced from Protamex® aided hydrolysis constituting of 62.5% falling either above or below molecular weights associated with bitterness. Amino acid profile analyses confirmed the presence of all essential amino acids. Top performing powders produced from the spray drying of the BSG-PH produced with Protamex® had a protein recovery of 77.37% and protein content of 43.21%. This powder was produced at spray drying conditions of air inlet temperature of 200°C, air flowrate of 64 m³/hr, feed flowrate of 0.06 L/hr and a maltodextrin concentration of 5%. Recommended storage conditions were established to be below a water activity of 0.843. Further investigation into the pre-treatment of BSG prior to enzymatic hydrolysis is recommended with the aim of increasing protein recovery during the extraction stage. Furthermore, to increase spray drying recoveries, the macronutrient composition of the fraction of hydrolysate feed lost in the drying chamber and exhaust should be determined to identify where and how protein is lost during the drying stage. Transition glass temperature studies are also recommended to acquire a well-rounded understanding of required storage conditions. Sensory analysis should also be undergone to provide insight into potential consumer response to a BSG powdered protein product. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Masters 2025-04-29T13:35:30Z 2025-04-29T13:35:30Z 2024-12 Thesis https://scholar.sun.ac.za/handle/10019.1/131938 Stellenbosch University xvi, 140 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Brewing industry -- By-products Proteins -- Separation Agricultural wastes UCTD Tromp, Megan Caley The influence of processing parameters for protein extraction and downstream processing of brewers’ spent grain to produce a dried protein powder product |
| title | The influence of processing parameters for protein extraction and downstream processing of brewers’ spent grain to produce a dried protein powder product |
| title_full | The influence of processing parameters for protein extraction and downstream processing of brewers’ spent grain to produce a dried protein powder product |
| title_fullStr | The influence of processing parameters for protein extraction and downstream processing of brewers’ spent grain to produce a dried protein powder product |
| title_full_unstemmed | The influence of processing parameters for protein extraction and downstream processing of brewers’ spent grain to produce a dried protein powder product |
| title_short | The influence of processing parameters for protein extraction and downstream processing of brewers’ spent grain to produce a dried protein powder product |
| title_sort | influence of processing parameters for protein extraction and downstream processing of brewers spent grain to produce a dried protein powder product |
| topic | Brewing industry -- By-products Proteins -- Separation Agricultural wastes UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/131938 |
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