College of Agriculture and Environmental Sciences

Effect of preservatives and storage conditions on quality of Marula (Sclerocarya birrea) fruit juice

2026-06-22T10:43:33Z

Effect of preservatives and storage conditions on quality of Marula (Sclerocarya birrea) fruit juice Gosh, Lekhuleni Isobel Lerato The aim of the United Nations Sustainable Development Goals (SDGs) is, among other things, to eradicate hunger and malnutrition and guarantee that all people have access to sufficient nutrient-dense food by 2030. The introduction of underutilised indigenous fruit species such as marula (Sclerocarya birrea subsp. caffra), which is reported to be abundant in vitamin C and minerals needed by humans for the fulfilment of their recommended daily dietary requirements, seems to be a reliable strategy to achieve these goals. This multi-disciplinary study was conducted to investigate (i) the impact of geographical region on the physicochemical properties of marula fruits and juice, and (ii) the effect of a treatment combination of preservatives and storage conditions on the physicochemical properties, mineral retention and microbial activities of 100% marula fruit juice. The aim of the study was therefore to establish the most suitable preservatives and storage conditions for processed marula fruit juice, for the purpose of the future commercialisation of this product. Fruit and its juice utillised for for the analysis of physicochemical properties including calcium, iron, fruit mass, total soluble sugars, total flavonoids, and vitamin C were harvested from Bushbuckridge, Giyani and Tzaneen, all of which are classified as lowveld regions of South Africa. The effect of treatment combinations (preservatives and storage settings) on quality, including phytochemicals and minerals, was assessed by subjecting marula fruit juice to preservatives (sodium metabisulphite and sodium benzoate) and storage conditions (4, 6, and 10˚C) for a duration of 20 days. Concerning the assessment of microbial activity, the spread plate count approach was employed, encompassing incubation, enumeration of colony-forming units, and species identification. For the physicochemical properties investigation, study revealed that fruits harvested in the Bushbuckridge region exhibited a greater mass (44.6 g) compared to those from other places. In comparison to other regions, the Tzaneen region fruit had a higher total soluble sugar concentration of 12.9 ˚Brix. Regarding the impact of varying presevatives and storage conditions on quality retention, results demonstrated that the combination of sodium benzoate and a storage temperature of 10˚C resulted in the highest preservation of total flavonoid content (2.49 mg QE/ml) after 20 days, compared to other treatments. Retention of higher vitamin C content (83.26 mg/100 ml) was noted under the treatment combination (+ positive control - pasteurized at 10˚C). For minerals, the treatment iv combination of sodium benzoate and 4˚C yielded enhanced calcium retention (81.3 mg/L) relative to alternative treatments. The maximum retention of iron content (33.1 mg/L) was recorded with the treatment combination of sodium benzoate and 4˚C, in comparison to other treatments. Regarding microbiological quality, juice samples treated with sodium metabisulphite, irrespective of storage conditions, exhibited the lowest yeast count (3.2 x 102 cfu/ml) in comparison to other treatments. Therefore, regional variances, the use of preservatives, and low storage temperatures all have a direct impact on marula fruit and juice. As a result, marula fruit juice manufacturers should take these factors into account since they have a direct impact on the juice's marketability and potential for commercialisation.; Inhloso yeMhlabuhlangene Tinjongo Tekutfutfukisa Letisimeme (SDGs) kutsi, emkhatsini waletinye tintfo, kucedza indlala kanye nekungadli kahle kanye nekucinisekisa kutsi bonkhe bantfu bayakhona kutfola kudla lokwenele lokunemsoco ngemnyaka wa 2030. Kwetfulwa kwetinhlobo tetitselo temdzabu letingakasetjentiswa kahle letifana nemaganu imarula (Sclerocarya birrea subsp. caffra), letisetjentiswa kancane. kuvithamin C kanye nemaminerali ladzingwa bantfu kwentela kugcwalisa tidzingo tabo tekudla letinconyiwe tetinsuku tonkhe, kubonakala ngatsi lisu leletsembekile lekufeza lemigomo. Lolucwaningo lolunetifundvo letiningi lwentelwe kuphenya (i) umtselela wesigodzi sendzawo etimphahleni tephysicochemical tetitselo temarula kanye nejusi, kanye (ii) nemphumela wenhlanganisela yekwelapha yetintfo letilondvolotako kanye netimo tekugcina etimphahleni tephysicochemical, kugcinwa kwemaminerali ejusi yemarula 100%. Inhloso yalolucwaningo bekukusungula tintfo letifanele kakhulu tekugcina kanye netimo tekugcina ijusi yetitselo temarula lecubunguliwe, ngenhloso yekutsengisa lomkhicito esikhatsini lesitako. Titselo kanye nejusi yato lesetjentiselwa kuhlatiya tintfo temtimba letifaka ekhatsi ikhalsiyamu, i-ayoni, bukhulu besitselo, shukela loncibilikako lophelele, ema flavonoids laphelele kanye nevithamin C kwavunwa eBushbuckridge, eGiyani nase Tzaneen, konkhe loku kuhlukaniswe njengetindzawo letiphansi eNingizimu Afrika Umphumela wekuhlanganiswa kwekwelapha (tintfo letilondvolotako kanye netindzawo tekugcina) ngelizinga, kufaka ekhatsi emakhemikhali etitjalo kanye nemamineral, kwahlolwa ngekubeka ijusi yetitselo temarula ngetintfo letilondvolotako (isodium metabisulphite kanye nesodium benzoate) kanye netimo tekugcina (4, 6, kanye na 10 ̊C) sikhatsi lseingemalanga langu-20. Mayelana nekuhlolwa kwemsebenti wetintfo letincane, indlela yekubala emapuleti lasakateke yasetjentiswa, lefaka ekhatsi kufukamela, kubalwa kwemayunithi lakha emakoloni kanye nekukhonjwa kwetinhlobo. Kuloluphenyo lwephysicochemical, lolucwaningo lwaveta kutsi titselo letivunwe esigodzini sase Bushbuckridge tikhombisa bukhulu lobukhulu (44.6 g) uma kucatsaniswa naleto letivela kuletinye tindzawo. Uma kucatsaniswa naletinye tifundza, sitselo sesigodzi sase Tzaneen besinesibalo lesiphakeme sashukela loncibilikako lesiphelele lesingu 12.9 ̊Brix. vi Mayelana nemtselela wetintfo letehlukene tekugcina kanye netimo tekugcina ekugcineni lizinga, imiphumela yakhombisa kutsi kuhlanganiswa kwesodium benzoate kanye nelizinga lekushisa lekugcina la 10 ̊C kwaholela ekugcineni lokusetulu kwalokucuketfwe kweflavonoid lephelele (2.49 mg QE/ml) ngemuva kwemalanga lamashumi lamabili (20), uma kucatsaniswa naletinye tindlela tekwelapha. Kugcinwa kwe vithamin C lesetulu (83.26 mg/100 ml) kwaphawulwa ngaphansi kwekuhlanganiswa kwekwelashwa (+ kulawula lokuhle - pasteurized ku 10 ̊C). Kumaminerali, inhlanganisela yekwelapha ye-sodium benzoate kanye na 4 ̊C kwakhicita kugcinwa kwe khalsiyamu lokukhulisiwe (81.3 mg/L) uma kucatsaniswa naletinye tindlela tekwelapha. Kugcinwa lokukhulu kwe-ayoni (33.1 mg/L) kwabhalwa ngekuhlanganiswa kwekwelapha kwesodium benzoate kanye na 4 ̊C, uma kucatsaniswa naletinye tindlela tekwelapha. Mayelana nelizinga letintfo letincane, emasampula ejusi laphatfwe ngesodium metabisulphite, kungakhatsaleki kutsi timo tekugcina, tikhombisa sibalo lesiphansi semvubelo (3.2 x 102 cfu/ml) uma kucatsaniswa naletinye tindlela tekwelapha. Ngako-ke, kwehluka kwesifundza, kusetjentiswa kwetintfo letilondvolotako kanye nelizinga lekushisa leliphansi kwekugcina konkhe kunemitselela lecondzile esitselweni semarula kanye nejusi. Ngenca yaloko, bakhiciti bejusi yetitselo temarula kumele batsatse letintfo njengoba tinemtselela locondzile ekutsengiseni kwejusi kanye nemandla ekutsengisa.; Xikongomelo xa Swikongomelo swa Nhluvukiso lowu Yisekaka Emahlweni (tiSDG) swa United Nations, exikarhi xin'wana, i ku herisa ndlala na nsiko na ku tiyisisa leswaku vanhu hinkwavo va na mfikelelo wa swakudya leswi nga tala swiaki swa mirhi swo ringanela hi kwalomuya ka 2030. Ku sungula ku tirhisiwa kwa mixaka ya mihandzu ya xintu leyi tirhisiwaka switsongo yo tanihi makanyi (Sclerocarya birrea subsp. caffra), leyi yi vikiwaka ku va yi tele yi vhitamini ya C na timinerali leswi dingiwaka hi vanhu ku fikelela swilaveko wa vona swa madyelo ya siku na siku leswi bumabumeriwaka, swi tikomba swi ri qhinga ro tshembeka ku fikelela swikongomelo leswi. Ndzavisiso lowa marhavinyingi wu endleriwile ku lavisisa (i) nkhumbo wa xifundza xa ndhawu ya misava hi mayelana na swihlawulekisi swa fizikokhemikali swa mihandzu ya makanyi na juzi ya makanyi (ii) xitandzhaku xa nkatsaniso wa makhomelo wa swisivelakubola na swiyimo swa vuhlayiselo, na nhlayiso wa timinerali na migingiriko ya switsongwatsongwana ya 100% ta juzi ya mihandzu ya makanyi. Hikokwalaho, xikongomelo xa ndzavisiso lowu a ku ri ku tumbuluxa swisivelakubola leswi ringaneleke swinene na swiyimo swa vuhlayiselo swa juzi ya mihandzu ya makanyi leyi phurosesiweke, hi xikongomelo xa vubindzurisi bya nkarhi lowu taka wa xikumiwa lexi. Muhandzu na juzi ya wona leswi tirhisiweke eka nxopaxopo swihlawulekisi swa fizikokhemikali ku katsa na khalisiyamu, ayoni, ntiko wa mihandzu, machukela lama n'okaka hinkwawo, tifulavhonoyidi hinkwato na vhitamini ya C swi hlengeletiwile eBushbuckridge, Giyani na Tzaneen, hinkwaswo swa swona swi ntlawahatiwa tanihi swifundza swa le timbalankoveni ta Afrika-Dzonga. Xitandzhaku xa mikatsaniso ya makhomelo (swisivelakubola na tindhawu ta vuhlayiselo) eka risima, ku katsa na tifayitokhemikali na timinerali, xi kamberiwile hi ku endla juzi ya mihandzu ya makanyi yi va na swisivelakubola (sodium metabisulphite na sodium benzoate) na swiyimo swa vuhlayiselo (4, 6, na 10˚C) ku ringana nkarhivunavi wa 20 wa masiku. Hi mayelana na makambelelo ya nghingiriko wa switsongwatsongwana, nhlayelo wa puleti yo hangalasela wu tirhisiwile, leswi katsaka andziso wa switsongwatsongwana, nhlayelo wa tiyuniti leti vumbaka tikholoni na ntiveko wa mixaka ya swihanyi. Eka vulavisisi bya fizikokhemikali, ndzavisiso lowu wu paluxe leswaku mihandzu leyi hlengeletiweke eka xifundza xa Bushbuckridge yi kombe ntiko lowukulu wa (44.6 g) loko wu pimanisiwa na lowuya wa le tindhawini tin'wana. Hi ku viii pimanisiwa na swifundza swin'wana, xifundza xa Tzaneen xi vile na nkhuvangano wa machukela lama n'okaka hinkwawo wa 12.9 ˚Brix. Hi mayelana na nkhumbo wa swisivelakubola leswi hambanaka na swiyimo swa vuhlayiselo eka nhlayiso wa risima, mivuyelo yi kombise leswaku nkatsaniso wa sodium benzoate na mahiselo ya vuhlayiselo ya 10˚C wu vange nhlayiso wa henhlahenhla wa vundzeni wa tifulavhonoyidi hinkwato (2.49 mg QE/ml) endzhaku ka 20 wa masiku, loko ku pimanisiwa na makhomelo man'wana. Nhlayiso wa vundzeni bya vhitamini ya C bya le henhla (83.26 mg/100 ml) byi lemukiwile ehansi ka nkatsaniso wa makhomelo (+ vulawurinene - ku hisisa kufika eka 10˚C). Eka timinerali, nkatsaniso wa makhomelo wa sodium benzoate na 4˚C swi nyike nhlayiso wa khalisiyamu lowu antswisiweke (81.3 mg/L) loko ku fananisiwa na makhomelo man'wana. Nhlayiso wa mpimohenhla wa vundzeni bya ayoni (33.1 mg/L) wu rhekodiwile eka nkatsaniso wa makhomelo wa sodium benzoate na 4˚C, hi ku pimanisiwa na makhomelo man'wana. Hi mayelana na risima ra ntivoswitsongwatsongwana, tisampulu ta juzi leti cheriweke sodium metabisulphite, swi nga ri na mhaka swiyimo swa vuhlayiselo, ti kombe nhlayelo wa xiviriso wa le hansihansi (3.2 x 102 cfu/ml) hi ku pimanisiwa na makahomelo man'wana. Hikokwalaho, mihambano ya swifundza, ntirhiso wa swisivelakubola na mahiselo ya vuhlayiselo ya le hansi hinkwaswo swi na nkhumbo wo kongoma eka mihandzu ya makanyi na juzi ya makanyi. Hikokwalaho, vamaki va juzi ya mihandzu ya makanyi va fanele ku tekela enhlokweni swihlohloteri leswi tanihileswi swi nga na nkhumbo wo kongoma eka vumaketeki bya juzi leyi na vuswikoti bya vubindzuriseki. Abstract in English with Swazi and Tsonga translations

Determination of the nutritional and phytochemical composition of monsonia burkeana (special tea) and its potential anti-proliferative effects on cancer cell lines

2026-06-17T14:23:14Z

Determination of the nutritional and phytochemical composition of monsonia burkeana (special tea) and its potential anti-proliferative effects on cancer cell lines Ngwenya, Sandile Manzi Traditional medicinal plants have long been used to treat ailments in humans and animals. Africa is rich in such plants, many of which have been studied for bioactivities like anticancer, antimicrobial, and anti-inflammatory effects, though many remain uncharacterized. Monsonia burkeana (“special tea”) is widely consumed for its health benefits, usually as a decoction. Its antimicrobial properties are known; however, its phytotoxicity and antiproliferative activities remain underexplored. Elucidating these could benefit both traditional medicine and the pharmaceutical industry. This study aimed to investigate the effects of drying methods on the nutritional composition of special tea, identify bioactive compounds in its crude extract, and evaluate antiproliferative activities in cancer cell lines, offering insights for pharmaceutical development and commercial potential. The specific objectives included assessing nutritional composition, profiling bioactive compounds, and testing cytotoxicity against lung, colorectal, and liver cancer cell lines. Samples from Sekhukhune, Lanseria, Brits, and Rietondale were dried using shade, oven, and freeze-drying methods. Nutritional elements were analyzed by inductively coupled plasma mass spectrometry (ICP-MS), phytochemicals profiled using nuclear magnetic resonance (NMR), liquid chromatography-mass spectrometry (LC-MS), and gas chromatography-mass spectrometry (GC-MS), and anticancer properties evaluated through the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and caspase-3 activity assays. The results demonstrated a consistent elemental composition across all regions, with all 24 elements present in each sample and collection region. NMR analysis identified phenols, alkyls, esters, and ethers, while GC×GC/TOF-MS detected various bioactive compounds, including oxalic acid, β-caryophyllene, caryophyllene oxide, phytol, squalene, and vitamin E. LC-MS analysis confirmed the presence of additional key phytochemicals such as castalagin, vescalagin, acutissimin B, epicatechin, citroside, trifolin, 1,6-digalloyl-beta-D-glucopyranose, 5,7-dihydroxy-2-(4-hydroxy-3-methoxyphenyl)-3-{[3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy}-4H-chromen-4-one, and puerarin 4',6''-diacetate. The MTT assay revealed significant cytotoxic activity against lung and liver cancer lines, however, activity against the colorectal cancer cell line was lower compared to that demonstrated against the other two cancerous cell lines. In conclusion, the combination of essential micro- and macronutrients, bioactive phytochemicals, and demonstrated cytotoxic effects against cancer cell lines highlights the medicinal value of M. burkeana plants. The study provides strong evidence that Monsonia burkeana is a promising alternative for cancer treatment. These findings not only validate its traditional use and benefits over the years but also highlight its potential for pharmaceutical applications.

Investigation of egg quality characteristics of Ross 308 broiler breeder chickens

2026-06-16T17:33:16Z

Investigation of egg quality characteristics of Ross 308 broiler breeder chickens Nkune, Achy Poultry products such as chicken eggs and meat continue to have an important economic impact and are important to the growth of a country`s economy. Moreover, poultry products are globally consumed in greater quantities than any other source of animal protein, because they are reasonably priced. Ross 308 broiler chicken is the best breed of chicken nationally which was bred specifically for meat. Poultry breeders focus on egg characteristics in their selection process for reproduction, because poor egg quality results in economic losses during production. This study was conducted to investigate the characteristics of egg quality traits, the correlations among these factors, how the egg weight influences egg quality traits, and to estimate the weight of the egg from egg quality traits in Ross 308 broiler breeder chickens. A total of 1000 eggs were purchased from Daybreak Farm in Bela Bela Local Municipality, Limpopo province of South Africa to conduct the study. Eight external traits of egg quality, including egg length, egg width, shell weight, shell index, shell surface area, unit surface shell weight and shell ratio, and five internal egg quality traits such as yolk weight, albumen weight, albumen ratio, yolk ratio and yolk/albumen. The descriptive statistics were used to quantify the egg quality traits, and the correlation between weight and quality traits of egg was investigated using Pearson`s correlation, One-way Analysis of Variance (ANOVA) was applied to investigate which egg quality traits are affected by egg weight and stepwise regression analysis was used to come up with best fit model to predict egg weight from egg quality traits. The descriptive statistics revealed that egg weight had a minimum and maximum value of 32.59 g and 98.25, g respectively. Egg length had a minimum value of 46.61 mm and a maximum value of 70.36 mm, and yolk weight had a minimum value of 5.31 g and a maximum value of 34.02 g. One-way ANOVA revealed that egg weight has a substantial effect (p < 0.05) on egg length, egg width, shell weight, shell index, shell surface area, unit surface shell weight, shell ratio, yolk weight, albumen weight, albumen ratio, yolk ratio and yolk/albumen. Pearson’s correlation findings displayed that egg weight had a highly positive, remarkable association (p < 0.01) with egg length, egg width, shell weight, unit surface shell weight, albumen weight, yolk weight, yolk ratio and yolk/albumen. In addition, negative correlation (p > 0.05) was identified between egg weight and shell index, shell ratio and albumen ratio. Stepwise regression findings revealed that the model, including yolk weight, yolk ratio, albumen ratio and albumen weight, was the best-fitted model (R2 = 1.00 and RMSE = 0.05) for estimation of egg weight. The model including yolk weight, albumen weight and yolk ratio was the second best (R2 = 1.00 and RMSE = 0.34). The study concludes that the improvement of yolk weight, yolk ratio, albumen weight and albumen ratio might improve the egg weight of the Ross308 broiler chicken breed. The results of this study may be useful to farmers in considering egg quality traits during breeding to improve the egg weight of Ross 308 broiler breeder chickens.

Determinants of biogas adopton and its impact on livehoods: evidence from Domboshava, Zimbabwe

2026-06-16T15:24:19Z

Determinants of biogas adopton and its impact on livehoods: evidence from Domboshava, Zimbabwe Chawarika, Admire This study investigates the socio-economic determinants of biogas technology adoption among livestock farmers in Domboshava, Zimbabwe and examines its impact on rural livelihoods. Despite Zimbabwe's potential for renewable energy technologies, biogas adoption remains limited, particularly in rural areas facing persistent energy poverty. This research addresses key knowledge gaps regarding technology uptake barriers and livelihood outcomes in developing country contexts. The study employed a mixed-methods targeting randomly selected 368 respondents, however 370 livestock farming households were interviewed and formed the basis for the analysis utilizing descriptive statistics, binary logistic regression, multinomial logistic regression and multiple linear regression for analysis. Qualitative methods, comprising institutional mapping and stakeholder analysis, were employed to complement the quantitative findings, drawing on data from 25 key informant interviews. Socio-economic variables included gender, age, education, remittances, asset ownership, non-farm income, land size, livestock units, energy costs, access to credit and extension services. A composite livelihood index was developed to measure multidimensional welfare outcomes. Analysis using binary and multinomial logistic regression revealed that off-farm income, land size, access to credit, gender, livestock units, energy costs, and extension services significantly influenced biogas adoption, while energy costs and livestock ownership were relatively weak predictors. Similarly, farmers’ plans to adopt biogas were strongly affected by income, land size, credit access and the availability of information. Multiple linear regression further indicated that biogas adoption significantly enhances household livelihoods, particularly in terms of energy security, income diversification and overall welfare. Based on these findings, the study proposes a tailored institutional framework that emphasizes coordinated roles for government, NGOs, financial institutions and local communities to promote biogas adoption and its contribution to sustainable livelihoods. Policy recommendations include targeted financial mechanisms, improved extension services, gender-sensitive strategies and cross-sectoral coordination. These insights offer valuable guidance for scaling renewable energy solutions and advancing sustainable rural development in Zimbabwe and Africa.