Principal investigator

Dr Maryna de Wit

Dr Maryna de Wit 

deWitM@ufs.ac.za
+27 51 401 3261
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Qualifications and background


MSc and PhD done in Dairy chemistry and biochemistry (1997-2003) Fruit and vegetable processing and biochemistry (2004-) 

NRF C3 rated researcher

Areas of Interest


Food chemistry, specifically the chemical changes in foods during processing, with a special interest in fruits, vegetables and dairy products. Team member of Dairy chemistry and biochemistry group 

Project leader of plant food processing (fruit and vegetables)

This group mainly focuses on cactus pears and all its human food applications:

  • Nutritional analysis of the fruit and cladodes, including processed products
  • Novel food ingredients from cactus pears: mucilage, colorants (betalains) and cactus pear seeds oil

Team member of Dairy chemistry and biochemistry group

Highlights / News

Dr Maryna de Witt was appointed in 2017 as boardmember of the international CACTUSNET: Coordinator for Agro-processing and Post-harvest Technology of the Sub-Saharan Africa Region FAO-ICARDA CactusNet, [Food and Agricultural Organization (FAO) of the United Nations (UN) and International Center for Agricultural Research in the Dry Areas (ICARDA) and International Technical Cooperation Network on Cactus Pear (Cactusnet)]

Research

Betalains (colourants) from prickly pears
Prickly pear betalains (colourants)

Prickly pear cladodes showing mucilage
Prickly pear cladodes showing mucilage

Prickly pear mucalage
Prickly pear mucilage

Research on cactus pears is valuable, since increased droughts necessitates exploration of under-utilized crops that can withstand harsh  environmental conditions as is increasingly being observed in South Africa. SA is the only country in the world where 42 different cultivars of spineless cactus pears, originally from the American Burbank collection, are found and propagated. The importance of this plant to humans and animals is immense. In many parts of the world it is the only food available for humans and animals and it provides water, nutritional and functional ingredients.

The current research aim is to explore the utility of cactus pears as part of mainstream human nutrition in arid and impoverished regions. This includes using the plant as both fruit and vegetable, utilizing waste products and by-products as well as its application as functional ingredients.

Cactus pear seed oil
Cactus pear seed oil

Marshmallows from prickly pear mucilage
Marshmallows from mucilage

Nopalitos (young cladodes) as vegetables
Nopalitos (young cladodes) as vegetables

Recent Featured Publications

Cactus pear antioxidants: a comparison between fruit pulp, fruit peel, fruit seeds and cladodes of eight different cactus pear cultivars (Opuntia ficus-indica and Opuntia robusta)
M de Wit, A du Toit, G Osthoff and A Hugo
May 2019. Journal of Food Measurement and Characterization, Vol 7(3), pp 2347–2356. DOI 10.1007/s11694-019-00154-z (Impact factor: 1.181) Abstract

Mucilage powder from cactus pears as functional ingredient: influence of cultivar and harvest month on the physicochemical and technological properties
A du Toit, M de Wit, H J Fouché, M Taljaard, SL Venter and A Hugo
March 2019. Journal of Food Science and Technology, Vol 56 (5), pp 2404–2416. DOI 10.1007/s13197-019-03706-9 (IF 1.797). PDF 

Antioxidant properties of fresh and processed cactus pear cladodes from selected Opuntia ficus-indica and O. robusta cultivars    
A du Toit, M de Wit, G Osthoff and A Hugo
September 2018. South African Journal of Botany, Vol 118, pp. 44-51. DOI 0.1016/j.sajb.2018.06.014 
(IF 1.340). PDF

Relationship and correlation between antioxidant content and capacity, processing method and fruit colour of cactus pear fruit  
A du Toit, M de Wit, G Osthoff and A Hugo
August 2018. Food and Bioprocess Technology, Vol 11(8). pp. 1-9. DOI 10.1007/s11947-018-2120-7 
(IF 2.998) PDF

Cultivar and harvest month influence the nutrient content of Opuntia spp. Cactus pear cladode mucilage extracts
A du Toit, M de Wit and A Hugo
April 2018 Molecules, Vol 23(4), 916 DOI 10.3390/molecules23040916 (IF 3.098) PDF

South African cactus pear seed oil: A comprehensive study on 42 spineless Burbank Opuntia ficus-indica and Opuntia robusta cultivars
M de Wit, A Hugo and N Shongwe
March 2018. European Journal of Lipid Science and Technology, Vol 120(3),1700343. DOI 10.1002/
ejlt.201700343 (IF 2.145) Abstract

Quality assessment of seed oil from selected cactus pear cultivars (Opuntia ficus-indica and Opuntia robusta)
M de Wit, A Hugo and N Shongwe   
June 2017 Journal of Food Processing and Preservation, Vol 41(3), e12898 DOI 10.1111/jfpp.12898
(IF 1.51) Abstract

Effect of cultivar, season and locality on lipid content and fatty acid composition of cactus pear seed oil       
M de Wit, A Hugo, N Shongwe and R van der Merwe
2016 South African Journal of Plant and Soil, Vol 33(4), pp. 279-288. DOI 10.1080/2571862.2016.
1141335 (IF 0.55) PDF


FACULTY CONTACT

Faculty Manager: Velaphi Makgwahla
T: + 27 51 401 3199
E: makgwahlamvt@ufs.ac.za

Marketing Manager: Elfrieda Lötter
T: +27 51 401 2531
E: lottere@ufs.ac.za

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