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

Abstract

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.