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More than 820 million people in the world are suffering from hunger and 1.3 billion from food insecurity. People experiencing food security have sufficient access to safe, sufficient and nutritious food in both quality and quantity. In Africa, food insecurity is on the rise because of population increase, global warming and desertification. There is a need for droughtresilient crops which will be less impacted by climate change as only climate-smart food systems can lead to food security. The cactus pear is capable of providing sustainable food production in arid and semi-arid areas. Cactus pears (Opuntia ficus-indica) produces young and edible cladodes known as nopalitos. Nopalitos are a source of sustainable, economic and nutritious food and could be an important food source to livestock and human alike. In Mexico, nopalitos are a traditional food, eaten fresh or cooked in dishes enjoyed through many generations. The aim of the study was to identify the most ideal size, cultivar and harvesting season for optimal eating qualities. The characteristics of nopalitos from the two cultivars (Fusicaulis and Morado) were compared to be able to select the most ideal eating cultivar. Nopalitos were also compared to different well-known vegetables to describe the texture, taste and juiciness. Consumers are reluctant to try unknown food, therefore, a description of how nopalitos taste was attempted in this study. The ideal post-harvest handling, the preferred cooking methods and the optimal cooking times to use in cooking instructions and recipes for South African consumers were determined in this study. Physicochemical characteristics (length, weight, width, diameter, surface area, volume, colour, firmness, compressibility, TA, pH, TSS, mucilage, moisture and viscosity) of Fusicaulis and Morado nopalitos were determined and compared between size (9 cm, 12 cm, 15 cm, 18 cm, 21 cm and 24 cm), two seasons (autumn and spring) and over two years (2017 & 2018). The nopalitos were, University of the Free State (UFS)

English: Cactus pear plants (Opuntia ficus-indica and Opuntia robusta) are edible plants that grow and thrive in the semi-arid area of the Free State, South Africa, yet are unknown food sources. Cactus pear cladodes could be developed into a crop that could offer solutions in terms of food security, yet are ignored and underutilized in South Africa. Extensive research done abroad on the nutritional and therapeutic properties of cladodes and mucilage verified its high potential for human consumption. The development of mucilage into a commercial nutraceutical food product offers an opportunity to add value to the crop while providing a healthy product that could significantly enhance the well-being of the South African consumer. A successful, easy, inexpensive and chemical free extraction process was developed, yet cladodes were not equal in terms of the amount of quality of mucilage. Thus, the most appropriate cultivar for optimal mucilage yield and quality from forty-two local cultivars had to be selected and cladode harvesting time established. It was found that mucilage yield was not a consequence of cladode size or moisture content, but of cultivar and viscosity. Seven cultivars were selected that proved to have the lowest viscosity while commercially viable in South Africa (O. ficus-indica cultivars namely Algerian, Meyers, Morado, Ficus-Indica, Gymno-Carpo, Tormentosa, Turpin). The eighth cultivar represented a different species (O. robusta Robusta). Further morphological and rheological investigations revealed that the dormant stage (dormant months) would be the optimal harvesting time, while the selection of cultivars were narrowed down to four (O. ficus-indica Algerian, Morado, Gymno- Carpo and O. robusta Robusta). Mucilage (native and freeze-dried powders) from all cultivars showed non-Newtonian, pseudoplastic tendencies. Higher viscosity mucilage was time dependent, rheopectic and had yield stress tendencies. Fluctuations in temperature, pH, concentration, Afrikaans: Die turksvy (Opuntia ficus-indica en Opuntia robusta) is eetbare plante wat groei en floreer in die semi-droë area van die Vrystaat, Suid Afrika. Dit is egter ‘n onbekende voedsel bron. Turksvye kan ontwikkel as ‘n gewas waarvan die kladode ‘n oplossing kan bied in terme van voedselsekuriteit, tog word dit geïgnoreer en is onderbenut in Suid Afrika. Uitgebreide internasionale navorsing oor die voedings- en terapeutiese eienskappe van kladodes en slymgom het die potensiaal daarvan vir menslike gebruik bevestig. Die ontwikkeling van slymgom in ‘n kommersiële voedingsproduk bied ‘n geleentheid om waarde tot die gewas te voeg, terwyl dit ‘n gesonde produk kan lewer wat baie voordelig kan wees vir die welstand van die Suid-Afrikaanse verbruiker. ‘n Suksesvolle, maklike en chemies-vrye onttrekkingsproses is ontwikkel, tog het die kladodes nie dieselfde kwaliteit slymgom gelewer nie. Daarom moes vasgestel word watter kultivar die mees geskikste kultivar is in terme van die optimale slymgom opbrengs en kwaliteit uit 42 plaaslike kultivars. Die beste oestyd vir die kladodes moes ook bepaal word. Daar is bevind dat die opbrengs van slymgom nie bepaal word deur die gewig of vog inhoud van die kladodes nie, maar deur die kultivar en viskositeit van die slymgom. Sewe kultivars met die laagste viskositeit, wat nogsteeds kommersieël lewensvatbaar is in Suid Afrika, is geïdentifiseer (O. ficus-indica kultivars: Algerian, Meyers, Morado, Ficus-Indica, Gymno-Carpo, Tormentosa, Turpin). Die agtste kultivar verteenwoordig ‘n ander spesie (O. robusta ‘Robusta’). Verdere morfologiese en rheologiese ondersoeke het getoon dat die dormante groeistadium die optimale oes tyd is, en dat die vier beste kultivars O. ficus-indica: Algerian, Morado, Gymno-Carpo en O. robusta: Robusta is. Slymgom (natuurlike slymgom en gevriesdroogde slymgom) van al die kultivars het nie-Newtoniese en pseudoplastiese neigings getoon. Slymgom met’n hoër viskositeit was tyd afhanklik, rheopeuties en het vl

English: Different coloured cactus fruit, peel, seeds and cladodes were studied for antioxidant content and -capacity in fresh products. Fruit and cladodes from seven different cultivars from the O.ficus-indica spp. and one of O. robusta spp. were collected representing the four colours of fruit available namely, green, pink, orange and purple. It was found that fresh cactus pear fruit and cladodes contained exceptionally high levels of Ascorbic acid, Total Phenolics and Betalains and modest amounts of Carotene. Antioxidant potential remained at very high levels regardless of the specific antioxidant content. The highest antioxidant content and -capacity were found in purple (O.robusta Robusta) fruit and cladodes, attributed to the high levels of Betalains. Ascorbic acid, working synergistically with Phenolics, was found to provide almost as much antioxidant capacity to orange fruit coloured cultivars. It was thus found that cultivars with purple and orange fruit and cladodes were the best in regards to antioxidant content as well as -potential. Five cultivars, representing the four colours were further investigated by processing into different products in order to determine the influence that preservation techniques had on the antioxidant content and potential in the fruit, peel and cladodes. Juice, dried products, chutneys, whole preserves and pickles were prepared from the fruit (pulp), peel and cladodes of the five different coloured cultivars that attained the highest values in the fresh study. Betalains were retained in processed products; Ascorbic acid was mostly preserved in the processed products that involved minimal heat treatments, while Carotene and Phenolics increased after processing. Processed cladodes, more than fresh cladodes, from all the cultivars, were concluded to provide an excellent source of antioxidants and could be suggested for products such as cladode flour and pickles. The peel in general was found to contain very similar antioxidant co, Afrikaans: Verskillende kleure turksvy vrugte, skille, sade en kladodés was bestudeer In hierdie studie vir antioksidant inhoud en -kapasiteit. Vrugte en kladodes van sewe verskillende Opuntia ficusindica kultivars en een O. robusta kultivar, wat die vier vrug kleure (groen, pienk, oranje en pers) insluit, is gebruik. Die bevindinge dui daarop dat vars turksvy vrugte en kladodes, baie hoë vlakke van askorbiensuur, fenole en betalaiene asook laer karoteen vlakke bevat, maar die antioksidant potensiaal bly hoog ongeag die spesifieke antioksidant waardes. Die heel hoogste antioksidant inhoud en -potensiaal vlakke is gevind in die pers (0. robusta Robusta) kultivar, in die vrugte sowel as die kladodes. Hierdie hoë vlakke is toegeskryf aan die hoë betalaien inhoud. Askorbiensuur, in samewerking met fenole, het die antioksidant potensiaal vlakke aan die ander kleure en veral aan oranje vrugte verskaf. Daar is dus gevind dat pers en oranje kultivars die beste keuse is vir antioksidant inhoud en -waarde. In die verdere studie is vyf kultivars, wat steeds die vier turksvy kleure verteenwoordig, verwerk in verskillende produkte sodat bepaal kan word of die antioksidante steeds teenwoordig sal wees na prosessering in die vrugte, skille en kladodes. Sap, gedroogde produkte, blatjang, heel ingelegde produkte en piekels (suurtjies) was voorberei van die vrugte, skille en kladodes van die vyf kultivars wat die beste resultate gelewer het in die eerste deel van die studie. Daar is gevind dat betalaiene behoue gebly het, askorbiensuur was meestal behou in die prosesse waar minder hitte toegevoeg is, terwyl karoteen en fenole toegeneem het tydens prosessering. Geprosesseerde kladodes, eerder as vars kladodes, van enige kultivar is 'n uitstekende bron van antioksidante en daarom word dit hoogs aanbeveel vir die gebruik in produkte soos turskvy kladode meel en piekels. Die skil, oor die algemeen, het dieselfde hoë antioksidant inhoud as die vrug en behoort ingesluit te word in produkte