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Development of a functional potato flour: from low-grade potatoes to potential novel food applications
Thesis (MScFoodSc)--Stellenbosch University, 2026.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2026
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| _version_ | 1869484205054885888 |
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| access_status_str | Open Access |
| author | Du Toit, Tanja |
| author2 | Van der Merwe, Debora |
| author_browse | Du Toit, Tanja Van der Merwe, Debora |
| author_facet | Van der Merwe, Debora Du Toit, Tanja |
| author_sort | Du Toit, Tanja |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScFoodSc)--Stellenbosch University, 2026. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/135779 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-07-01T04:11:11.287Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/135779 Development of a functional potato flour: from low-grade potatoes to potential novel food applications Du Toit, Tanja Van der Merwe, Debora Sigge, Gunnar Hayward, Stefan Stellenbosch University. Faculty of AgriSciences. Dept. of Food Science. Potato flour Functional foods Enzymes Potatoes -- Physiology Potatoes -- South Africa -- Classification UCTD Thesis (MScFoodSc)--Stellenbosch University, 2026. Du Toit, T. 2026. Development of a Functional Potato Flour: From Low-Grade Potatoes to Potential Novel Food Applications. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/563c829d-ea40-4429-a05d-62ea2c6af8b0 ENGLISH ABSTRACT: In South Africa, low-grade potatoes contribute significantly to food waste and economic losses, underlining the need for value-added uses within the food industry. The aim of this study was to develop a functional potato flour from low-grade potatoes and explore its potential for novel applications, while also evaluating key aspects of its commercial viability. Potato flour is commonly used as a thickening agent due to its high starch content, but its utilisation in other functional roles is still underdeveloped. Enzymatic hydrolysis, combined with either oven-drying or freeze-drying, was applied as the processing treatments to modify the functional properties of potato flour. The aim was to determine which treatment produced potato flour with the most versatile physicochemical and functional properties for novel food applications. Low-grade potatoes were processed into four flour treatments: untreated oven-dried (Un_OD), untreated freeze-dried (Un_FD), enzymatically hydrolysed oven-dried (EnzH_OD), and enzymatically hydrolysed freeze-dried (EnzH_FD). Before flour production, enzymatic hydrolysis was optimised using α-amylase (9.6 U/g) and glucoamylase (5 U/g), resulting in the highest glucose release of 5.61 mM. The functional properties of potato flour were significantly (p < 0.05) influenced by processing treatments. EnzH_OD flour had the highest a* (red) and b* (yellow) values due to Maillard browning, whereas freeze-dried flours retained higher L* (white) values associated with greater consumer acceptance. The EnzH_OD flour had a high bulk density, rendering it suitable for thickening functions, while the freeze-dried flours (Un_FD and EnzH_FD) had lower bulk densities with increased suitability for infant foods and baking. The Un_FD flour demonstrated extremely poor flowability associated with clumping and processing issues. The EnzH_OD potato flour had the lowest water holding capacity (160.8%) and oil-holding capacity (77.7%), indicating reduced functional performance, flavour retention and mouthfeel for bakery products. Water solubility was highest in the EnzH_OD (66.5%) and EnzH_FD (65.9%) due to enzymatic hydrolysis, increasing its potential for beverage applications. Overall, the EnzH_FD potato flour demonstrated the greatest application potential, supported by its enhanced functional properties and lightest colour. Nutritional analysis of the EnzH_FD potato flour revealed a protein content (10.7 g/100g) comparable to wheat flour and higher than most alternative flours, as well as fibre content (8.0 g/100g) exceeding wheat, rice, oat and maize flours. Mineral analysis showed higher total mineral content than wheat and commonly used gluten-free flours, with a notably high potassium content (1 731 mg/100g). Microbiological analyses of the potato flour, including Total Plate Count, Enterobacteriaceae, yeast and mould, Salmonella spp. and Bacillus cereus, were all below recommended limits, confirming safety for consumption over the 2.5 month testing period. Accelerated shelf-life testing (ASLT) at 25, 35 and 45°C over 42 days, based on total colour difference (ΔE), predicted a shelf-life of 2.2 months, after which browning would become visually noticeable. The results of this study indicate that the EnzH_FD potato flour is functionally enhanced, nutritionally valuable and microbiologically stable, supporting its commercial viability as a potential novel food product or application. These findings contribute to scientific knowledge on starch modification, product development within the gluten-free market and the sustainable management of low-grade potatoes. AFRIKAANSE OPSOMMING: In Suid-Afrika dra laegraadse aartappels beduidend by tot voedselvermorsing en ekonomiese verliese, wat die behoefte aan waarde-toevoegende benutting binne die voedselbedryf beklemtoon. Die doel van hierdie studie was om ’n funksionele aartappelmeel uit laegraadse aartappels te ontwikkel en die potensiaal daarvan vir nuwe toepassings te ondersoek, terwyl sleutelaspekte van die kommersiële lewensvatbaarheid daarvan ook geëvalueer is. Aartappelmeel word algemeen as ’n verdikkingsmiddel gebruik weens die hoë styselinhoud, maar die benutting daarvan in ander funksionele rolle is nog onderontwikkel. Ensiematiese hidrolise, gekombineer met óf oonddroging óf vriesdroging, is as verwerkingstegnieke toegepas om die funksionele eienskappe van aartappelmeel te modifiseer. Die doel was om te bepaal watter behandeling aartappelmeel met die mees veelsydige fisikochemiese en funksionele eienskappe vir nuwe voedseltoepassings lewer. Laegraadse aartappels is verwerk tot vier meelbehandelings: onbehandelde oonddroog (Un_OD), onbehandelde vriesdroog (Un_FD), ensiematies gehidroliseerde oonddroog (EnzH_OD) en ensiematies gehidroliseerde vriesdroog (EnzH_FD). Voor meelproduksie is ensiematiese hidrolise geoptimaliseer met behulp van α-amilase (9.6 U/g) en glukoamilase (5 U/g), wat gelei het tot die hoogste glukosevrystelling van 5.61 mM. Die funksionele eienskappe van die aartappelmeel is betekenisvol (p < 0.05) deur die verwerkingsbehandelings beïnvloed. Die EnzH_OD meel het die hoogste a* (rooi) en b* (geel) waardes getoon as gevolg van Maillard-verbruining, terwyl vriesgedroogde meele hoër L* (wit) waardes behou het, wat met groter verbruikersaanvaarding geassosieer word. Die EnzH_OD meel het ’n hoë bulkdigtheid getoon, wat dit geskik maak vir verdikkingsfunksies, terwyl die vriesgedroogde meele (Un_FD en EnzH_FD) laer bulkdigthede gehad het en meer geskik is vir babavoedsel en baktoepassings. Die Un_FD meel het uiters swak vloeibaarheid getoon, wat met klontvorming en verwerkingsprobleme geassosieer word. Die EnzH_OD meel het die laagste waterhouvermoë (160.8%) en oliehouvermoë (77.7%) getoon, wat op verminderde funksionele prestasie, geurretensie en mondgevoel in bakprodukte dui. Wateroplosbaarheid was die hoogste in EnzH_OD (66.5%) en EnzH_FD (65.9%) as gevolg van ensiematiese hidrolise, wat die potensiaal vir dranktoepassings verhoog. Oor die algemeen het die EnzH_FD-aartappelmeel die grootste toepassingspotensiaal getoon, ondersteun deur verbeterde funksionele eienskappe en die ligste kleur. Voedingsanalise van die EnzH_FD aartappelmeel het ’n proteïeninhoud (10.7 g/100 g) getoon wat vergelykbaar is met koringmeel en hoër is as die meeste alternatiewe meele, asook ’n veselinhoud (8.0 g/100 g) wat dié van koring-, rys-, hawer- en mieliemeel oortref. Minerale-analise het ’n hoër totale mineraalinhoud as koring en algemeen gebruikte glutenvrye meele getoon, met ’n besonder hoë kaliuminhoud (1 731 mg/100 g). Mikrobiologiese ontledings van die aartappelmeel, insluitend totale plaattelling, Enterobacteriaceae, gis en mif, Salmonella spp. en Bacillus cereus, was almal onder die aanbevole perke, wat veiligheid vir verbruik oor die 2.5-maande toetsperiode bevestig het. Versnelde rakleeftydtoetsing by 25, 35 en 45°C oor 42 dae, gebaseer op totale kleurverskil (ΔE), het ’n rakleeftyd van 2.2 maande voorspel, waarna verbruining visueel waarneembaar sou word. Die resultate van hierdie studie dui daarop dat die EnzH_FD aartappelmeel funksioneel verbeter, voedingswaardig en mikrobiologies stabiel is, wat die kommersiële lewensvatbaarheid daarvan as ’n potensiële nuwe voedselproduk of toepassing ondersteun. Hierdie bevindings dra by tot wetenskaplike kennis oor styselmodifikasie, produkontwikkeling binne die glutenvrye mark en die volhoubare benutting van laegraadse aartappels. Masters 2026-04-10T08:09:26Z 2026-04-10T08:09:26Z 2026-03 Thesis https://scholar.sun.ac.za/handle/10019.1/135779 en Stellenbosch University v, 115 pages : illustrations, maps application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Potato flour Functional foods Enzymes Potatoes -- Physiology Potatoes -- South Africa -- Classification UCTD Du Toit, Tanja Development of a functional potato flour: from low-grade potatoes to potential novel food applications |
| title | Development of a functional potato flour: from low-grade potatoes to potential novel food applications |
| title_full | Development of a functional potato flour: from low-grade potatoes to potential novel food applications |
| title_fullStr | Development of a functional potato flour: from low-grade potatoes to potential novel food applications |
| title_full_unstemmed | Development of a functional potato flour: from low-grade potatoes to potential novel food applications |
| title_short | Development of a functional potato flour: from low-grade potatoes to potential novel food applications |
| title_sort | development of a functional potato flour from low grade potatoes to potential novel food applications |
| topic | Potato flour Functional foods Enzymes Potatoes -- Physiology Potatoes -- South Africa -- Classification UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/135779 |
| work_keys_str_mv | AT dutoittanja developmentofafunctionalpotatoflourfromlowgradepotatoestopotentialnovelfoodapplications |