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Effects of pre-treatments to preserve quality attributes and prolong shelf-life of dried pomegranate arils
Thesis (MScAgric)--Stellenbosch University, 2021.
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| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2021
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| _version_ | 1867614130485067776 |
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| access_status_str | Open Access |
| author | Mokapane, Faith Moleboheng |
| author2 | Fawole, Olaniyi Amos |
| author_browse | Fawole, Olaniyi Amos Mokapane, Faith Moleboheng |
| author_facet | Fawole, Olaniyi Amos Mokapane, Faith Moleboheng |
| author_sort | Mokapane, Faith Moleboheng |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2021. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/110330 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:47:08.513Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/110330 Effects of pre-treatments to preserve quality attributes and prolong shelf-life of dried pomegranate arils Mokapane, Faith Moleboheng Fawole, Olaniyi Amos Opara, Umezuruike Linus Stellenbosch University. Faculty of Agrisciences. Dept. of Horticulture. Pomegranate (Punica granatum L.) -- Quality -- South Africa Fruit -- Drying -- Effect of temperature on Pre-treatment Pomegranate industry -- South Africa Pomegranate -- Phytochemical analysis Pomegranate -- Effects of chemical treatments UCTD Thesis (MScAgric)--Stellenbosch University, 2021. ENGLISH ABSTRACT: The pomegranate fruit (Punica granatum L.) is a lucrative horticultural crop, which is rich in nutrients and phytochemical compounds. Fruit with physical defects such as sunburn and cracks pose a threat to the competitiveness of the South African pomegranate industry. Such fruit are undesirable to consumers and are thus regarded as second grade or waste. Fruit waste may be prevented by drying arils for marketing as healthy snacks. However, the process of dehydration involves heat application that may degrade beneficial phytochemicals and textural components of the fruit. The aim of this study was, therefore, to investigate the potential of pre-treatment use for the development of dried pomegranate arils. The pre-treatments under study were blanching at different temperatures and duration as well as chemical pre-treatments of ascorbic acid and citric acid at different concentrations and dipping times. Pre-treatments significantly affected drying characteristics. Blanching at higher temperatures (85 or 100 °C) for longer dipping times of 30 s increased the percentage moisture loss and drying rate. In contrast, chemical pre-treatments were found to have higher effective moisture diffusivity (Deff). The parabolic drying model had a better fit for all pre-treatments based on higher root mean square error (RMSE), chi-square (χ2) and coefficient of determination (r2). Citric acid (0.2 and 0.4 %) and 100 °C (10 s and 20 s) blanching pre-treatments had significant effects on the rehydration capacity. A further study on storage of dried arils revealed that quality parameters were significantly affected by pre-treatment application. Red colour (a*) of arils improved from the beginning of storage to month 5, with citric acid pre-treatment having the highest value. As storage progressed, dried arils became less sticky across all pre-treatments. Untreated arils were significantly harder (higher maximum compression force) while blanching at 100 °C for 20 s resulted in arils with the lowest compression force. Soluble solids (SS) content of arils decreased with increase in storage duration, and untreated arils retained the highest SS content. Blanched arils had increased acetic acid, while untreated samples had the highest abundance of furfural. In summary, this study showed the potential for the use of pre-treatments to produce dried arils with better retention of phytochemical content (TPC and TFC). Application of blanching pre-treatments at higher temperatures reduced drying time and aril texture but did not retain the red colour of dried arils. Overall, citric and ascorbic acid pre-treatments, respectively, maintained arils redness and total anthocyanin content. Future studies may focus on combining treatments to produce an additive effect, and a more extended storage trial may be explored to simulate long-term storage and handling as commonly practised in industry. AFRIKAANSE OPSOMMING: Die granaatvrug (Punica granatum L.) is 'n winsgewende tuinbougewas wat ryk is aan voedingstowwe en fitochemiese samestellings. Hoë temperature het ‘n negatiewe impak op die Suid- Afrikaanse granaatbedryf se kompeterendheid aangesien dit tot sonbrand en krake kan lei. Verbuikers beskou die vrug dan as ongewens en dit word as tweede-graadse vermorsing geklassifiseer. Vermorsing van die granaatvrug kan voorkom word deur die sade uit te droog en te verkoop as ‘n gesonde versnappering. Die dehidrasie proses om die vrugte uit te droog benodig hoë temperature, maar dit het ‘n negatiewe invloed op die tekstuur en die fitochemiese samestelling van die vrug. Dus, die doel van die studie was om die moontlike opsies van vooraf-behandeling metodes te ondersoek wat gebruik kan word vir die uitdroging van die granaatvrug. Blansering by verskillende temperature en blanstye, asook die chemiese vooraf-behandeling van askorbiensuur en sitroensuur by verskillende konsentrasies en dompeltye was ondersoek. Die vooraf-behandelings het die uitdroging eienskappe van die granaat sade beïnvloed. Blansering by hoër temperature (85 of 100 ° C) vir langer dompeltye van 30 sekondes, het die persentasie vogverlies en uitdrogings tempo verhoog. Daar is gevind dat chemiese vooraf-behandeling 'n hoër effektiewe vogdiffusie (Deff) het. Die paraboliese droog model was die beste gepas vir al die vooraf- behandeling metodieke, gebaseer op die hoër wortel van gemiddelde kwadraatfout (WGKF), chi- kwadraat (χ2) en die doeltreffendheid van bepaling (r2). Vooraf-behandeling met sitroensuur (0,2 en 0,4 %) en blansering by 100° C (10 en 20 s) het 'n beduidende effekte op die rehidrasievermoë gehad. ‘n Verdere studie oor die stoor van gedroogde granaat sade het aan die lig gebring dat verskeie kwaliteitsparameters beïnvloed word deur vooraf-behandeling metodieke. Die rooi kleur (a*) van die sade het verbeter vanaf die begin van stoor tot die vyfde maand van storing, waar die sitroensuur vooraf-behandeling metodiek die hoogste waarde getoon het. Hoe langer die sade gestoor was, hoe minder klewerig het die sade geword. Dit het gebeur vir al die vooraf-behandeling metodieke. Sade wat nie vooraf-behandel was nie, was aansienlik harder (hoër maksimum kompressiekrag), terwyl blansering by 100 °C vir 20 s gelei het tot sade met die laagste kompressiekrag. Die oplosbare vastestowwe (OVS) inhoud het afgeneem met die verlenging van die stoor tydperk vir vooraf- behandelde sade, waar sade wat nie vooraf-behandel was nie, ‘n hoë OVS inhoud behou het. Blansering het asynsuur verhoog, terwyl ‘furfural’ in groot hoeveelhede geïdentifiseer was in die onbehandelde granaat sade. Ter opsomming, die studie het gewys hoe verskeie vooraf-behandelings metodieke gebruik kan word om gedroogte granaat sade met beter fitochemiese inhoud te produseer. Die gebruik van blansering as ‘n vooraf-behandeling metodiek by hoë temperature, het die droogtyd asook die tekstuur-hardheid verminder, maar dit het nie die rooi kleur van die saad behou nie. Oor die algemeen het sitroen- en askorbiensuur, onderskeidelik,die rooi kleur en fitochemiese inhoud gehandhaaf. Toekomstige studies kan fokus op die kombinering van verskeie vooraf-behandelings metodieke om ’n saamgestelde effek te lewer. Om langtermyn stoor en handeling soos in industrie gewond te simuleer, die invloed van langer stoor tydperke kan ook verder ondersoek word. Masters 2021-03-08T11:45:20Z 2021-04-22T10:14:25Z 2021-09-08T03:00:13Z 2021-03 Thesis http://hdl.handle.net/10019.1/110330 en_ZA Stellenbosch University ix, 95 pages : illustrations (some color) application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Pomegranate (Punica granatum L.) -- Quality -- South Africa Fruit -- Drying -- Effect of temperature on Pre-treatment Pomegranate industry -- South Africa Pomegranate -- Phytochemical analysis Pomegranate -- Effects of chemical treatments UCTD Mokapane, Faith Moleboheng Effects of pre-treatments to preserve quality attributes and prolong shelf-life of dried pomegranate arils |
| title | Effects of pre-treatments to preserve quality attributes and prolong shelf-life of dried pomegranate arils |
| title_full | Effects of pre-treatments to preserve quality attributes and prolong shelf-life of dried pomegranate arils |
| title_fullStr | Effects of pre-treatments to preserve quality attributes and prolong shelf-life of dried pomegranate arils |
| title_full_unstemmed | Effects of pre-treatments to preserve quality attributes and prolong shelf-life of dried pomegranate arils |
| title_short | Effects of pre-treatments to preserve quality attributes and prolong shelf-life of dried pomegranate arils |
| title_sort | effects of pre treatments to preserve quality attributes and prolong shelf life of dried pomegranate arils |
| topic | Pomegranate (Punica granatum L.) -- Quality -- South Africa Fruit -- Drying -- Effect of temperature on Pre-treatment Pomegranate industry -- South Africa Pomegranate -- Phytochemical analysis Pomegranate -- Effects of chemical treatments UCTD |
| url | http://hdl.handle.net/10019.1/110330 |
| work_keys_str_mv | AT mokapanefaithmoleboheng effectsofpretreatmentstopreservequalityattributesandprolongshelflifeofdriedpomegranatearils |