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Identifying potentially valuable flavour fractions from South African botanical extracts using LC Taste as a rapid screening method
Thesis (MScFoodSc)--Stellenbosch University, 2020.
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Stellenbosch : Stellenbosch University
2020
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| _version_ | 1867613953781137408 |
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| access_status_str | Open Access |
| author | Van der Merwe, Emma |
| author2 | Sigge, G. O. |
| author_browse | Sigge, G. O. Van der Merwe, Emma |
| author_facet | Sigge, G. O. Van der Merwe, Emma |
| author_sort | Van der Merwe, Emma |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScFoodSc)--Stellenbosch University, 2020. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/109306 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA en_ZA |
| last_indexed | 2026-06-10T12:44:20.637Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2020 |
| publishDateRange | 2020 |
| publishDateSort | 2020 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/109306 Identifying potentially valuable flavour fractions from South African botanical extracts using LC Taste as a rapid screening method Van der Merwe, Emma Sigge, G. O. De Villiers, Andre J. Dovey, Martin Stellenbosch University. Faculty of AgriSciences. Dept. of Food Science. Botanical gardens -- South Africa Plant species -- Flavor and odor Plants -- Variation Liquid chromatography Plant extracts -- Analysis Bioactive compounds -- Biotechnology UCTD Thesis (MScFoodSc)--Stellenbosch University, 2020. ENGLISH ABSTRACT: The enormous variety of southern African botanicals offers unending opportunities for food and beverage applications. Considering the growing demand for botanical products and preparations as natural sources of flavour and/or functionality, the leaves of the botanical species, Moringa oleifera (Moringa), Warburgia salutaris (Pepperbark) and Cyclopia genistoides (Honeybush) and the fruit pulp of Adansonia digitata (Baobab) were analysed for potentially valuable flavours using the flavour screening technique, LC Taste® (Liquid Chromatography Taste®). Concentrated extracts of the preferred flavour from each botanical were prepared using exploratory steps. The concentration of ethanol (0%, 50%, 100%, v.v-1) in the aqueous solvent, the solid-liquid ratio (15%, 25%, 50%, w.v-1), the effect of sonication versus maceration with magnetic stirring, and the effect of the duration of the extraction time (3 h, 6 h, 24 h) at elevated temperature (70°C) on extraction efficiency were explored. The flavour extraction efficiency was evaluated based on sensory evaluation as well as relative peak intensities of the high performance liquid chromatography-diode-array detection (HPLC-DAD) signals. The preferred flavour was extracted from each botanical using 50% ethanol (v.v-1). Although the maximum solid-liquid ratio produced concentrated extracts, the ratio should ideally be further optimised per botanical. Maceration resulted in better extraction of flavour from Honeybush, Moringa and Baobab, while sonication extracted more flavour from Pepperbark. While 24 h extracted more flavour from Honeybush, the taste- and peak intensities of Pepperbark, Baobab, and Moringa, decreased with increasing extraction time at elevated temperature (70°C), suggesting that the compounds responsible for their flavour are relatively susceptible to thermal degradation. Extracts of each botanical was analysed via LC Taste®, optimising the HPLC parameters per botanical. One-minute fractions were collected in established fraction collection windows. The fractions were tested for the presence of Salmonella spp. based on International Organization for Standardization (ISO) 6579: - 1:2017 method, and for Bacillus cereus spores using an adapted version of the ISO 7932:2004 method. The fraction that gained the interest of the tasting panel was a pungent fraction from Pepperbark. To identify and quantify the compound(s) responsible for the characteristic heat, further chromatography was performed. The gas chromatography-mass spectrometry (GC-MS) results suggested that few aromatic compounds were isolated in the fraction. Liquid chromatography-electrospray ionisation–mass spectrometry (LC-ESI-MS) and tandem mass spectrometry (MS/MS) enabled the identification of the most abundant compound in the fraction, the pungent piperine-type alkaloid, piperanine. The current study marks the first report of piperanine in W. salutaris as well as in the genus Warburgia. Piperanine was extracted from the Pepperbark sample using ultrasound-assisted extraction (UAE) at 50°C with a solid-solvent ratio of 1:10, while a variety of solvents (100% ethanol and 50% aqueous ethanol (v.v-1); acidified aqueous solvents; pH 1.00, pH 4.00; pH 7.00) and extraction times (18 min and 3 h) were applied. The maximum yield, extracted in 3 h, using 50% aqueous ethanol, suggested that 0.412% (w.w-1) of the dehydrated leaves constitutes piperanine. This quantity is subject to natural variation and further investigation could improve extraction yields. Although piperanine was the likely sole contributor of pungency detected in the fraction isolated from the W. salutaris extract, a variety of other hot-tasting compounds, sesquiterpenes, have been associated with the Warburgia species. It is suspected that the initial extraction conditions of 50% aqueous ethanol (v.v-1) excluded the extraction of these compounds. Extracts of W. salutaris leaves with enhanced extraction yields of piperanine and pungent sesquiterpenoids, hold great potential for culinary applications as a novel flavour source with potential functionality. AFRIKAANSE OPSOMMING: Die suider Afrika plantdiversiteit bied oneindige geleenthede vir die gebruik in die voedselbedryf. Om die toenemende aanvraag vir botaniese bestandele as natuurlike bronne van geur en/of funksionaliteit aan te spreek, is die blare van die botaniese spesies, Moringa oleifera (Moringa), Warburgia salutaris (Peperbasboom) en Cyclopia genistoides (Heuningbos), asook die vrugte pulp van Adansonia digitata (Kremetart), geanaliseer met die geurkeuringstegniek, ‘LC Taste®’ (‘Liquid Chromatography Taste®’), om potensieel waardevolle geure te identifiseer. Eksperimentele stappe is gevolg om gekonsentreerde ekstrakte van die voorkeurgeur van elke spesie voor te berei. Die konsentrasie van etanol (0%, 50%, 100%, v.v-1) in die oplosmiddel, the verhouding van die plantmateriaal tot die oplosmiddel (15%, 25%, 50%, w.v-1), die effek van ultrasoniesebehandeling in vergelyking met maserasie met ‘n magnetisie roerder, en die effek van die die ekstraksietyd (3 h, 6 h, 24 h) by verhoogde temperatuur (70°C) op die ekstraksiedoeltreffendheid was bestudeer. Die ekstraksiedoeltreffendheid was geëvalueer gebaseer op sensoriese analises en op piekintensiteit van ‘hoë druk vloeistof chromatografie-diode-array detection’ (HPLC-DAD) seine. Die verkeurgeur was ge-ekstraheer van elke spesie met die 50% etanol (v.v-1). Alhoewel die maksimum plantmateriaal-oplosmiddel verhouding gekonsentreerde ekstrakte geproduseer het, moet die verhouding verkieslik geoptimiseer word per plantspesie. Met betrekking tot die ekstraksiemetodes, het maserasie tot beter ekstraksie gelei in die geval van Heuningbos, Moringa en Kremetart, terwyl ultrasoniese behandeling meer geur uit Peperbasboom ge-ekstraheer het. Terwyl 24 h meer geur ge-ekstraheer het uit Heuningbos, het die pieke- en die smaakintensiteit van Peperbasboom, Kremetart, en Moringa gedaal met verlengde tyd by verhoogde temperatuur (70°C). Dit suggereer dat die komponente verantwoordelik vir hul geur relatief sensitief is tot termiese afbreking. Gekonsentreerde ekstrakte van elke plantspesie is deur ‘LC Taste®’ gefraksioneer. Een-minuut fraksies is in die gevestigde fraksie-kolleksie tydperk gekollekteer en getoets vir die teenwoordigheid van Salmonella spp. gebaseer op die Internasionale Organisasie van Standaardisering (ISO) 6579: - 1:2017 metode, en vir Bacillus cereus spore met ‘n aangepaste weergawe van die ISO 7932:2004 metode om hul mikrobiese veiligheid te bewys voordat hulle deur ‘n sensoriese paneel geproe is. Die fraksie wat die paneel die meeste geïntriseer het was ‘n pikante fraksie van die Peperbasboom. Die gas chromatografie–massa spektromatrie (GC-MS) resultate van die fraksie het gedui dat min aromatiese komponente in die fraksie geïsoleer is. Vloeistof chromatografie–elektrosproei ionisasie–massa spektrometrie (LC-ESI-MS) en tandem massa spektrometrie (MS/MS) analises het gelei tot die identifisering van die volopste verbinding in die fraksie, die pikante piperine-analoog, piperanine. Die huidige navorsing is die eerste verslag van piperanine in W. salutaris, en die genus, Warburgia. Ultrasoniesebehandeling (UAE) by 50°C met ‘n plantmateriaal-oplosmiddel verhouding van 1:10, is toegapas om piperanine te ekstraheer, asook verskillende oplosmiddels (100% etanol en 50% etanol (v.v-1); pH-geadapteerde water; pH 1.00, pH 4.00; pH 7.00) en ekstraksietye (18 min en 3 h). Die maksimum opbrengs, ge-ekstraheer in 3 h met 50% etanol (v.v-1), dui dat 0.412% (w.w-1) van die gedroogte blare bestaan uit piperanine. Hierdie waarde is geneig tot natuurlike variasie en verdere navorsing kan die opbrengs verbeter. Alhoewel piperanine die enigste bydraer is tot die pikante smaak in die geïsoleerde fraksie, is ‘n reeks ander brandwarm komponente, geklassifiseer as sesquiterpenoÏedes, vantevore met die Warburgia spesie geassosieer. Die aanvanklike ekstraksie kondisie van 50% etanol (v.v-1) het moontlik die minder polêre komponente uitgesluit. Ekstrakte van W. salutaris blare met verhoogde konsentrasies van piperanine en die pikante sesquiterpenoÏedes, hou potensiaal vir voedselgebruik as ‘n onbekende bron van geur en die medisinale eienskappe. Masters 2020-11-20T20:41:46Z 2021-01-31T19:43:55Z 2020-11-20T20:41:46Z 2021-01-31T19:43:55Z 2020-12 Thesis http://hdl.handle.net/10019.1/109306 en_ZA en_ZA Stellenbosch University xiii, 147 pages : illustrations (some color) application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Botanical gardens -- South Africa Plant species -- Flavor and odor Plants -- Variation Liquid chromatography Plant extracts -- Analysis Bioactive compounds -- Biotechnology UCTD Van der Merwe, Emma Identifying potentially valuable flavour fractions from South African botanical extracts using LC Taste as a rapid screening method |
| title | Identifying potentially valuable flavour fractions from South African botanical extracts using LC Taste as a rapid screening method |
| title_full | Identifying potentially valuable flavour fractions from South African botanical extracts using LC Taste as a rapid screening method |
| title_fullStr | Identifying potentially valuable flavour fractions from South African botanical extracts using LC Taste as a rapid screening method |
| title_full_unstemmed | Identifying potentially valuable flavour fractions from South African botanical extracts using LC Taste as a rapid screening method |
| title_short | Identifying potentially valuable flavour fractions from South African botanical extracts using LC Taste as a rapid screening method |
| title_sort | identifying potentially valuable flavour fractions from south african botanical extracts using lc taste as a rapid screening method |
| topic | Botanical gardens -- South Africa Plant species -- Flavor and odor Plants -- Variation Liquid chromatography Plant extracts -- Analysis Bioactive compounds -- Biotechnology UCTD |
| url | http://hdl.handle.net/10019.1/109306 |
| work_keys_str_mv | AT vandermerweemma identifyingpotentiallyvaluableflavourfractionsfromsouthafricanbotanicalextractsusinglctasteasarapidscreeningmethod |