Dovyalis Caffra Research Articles

Isolation and characterization of Streptococcus agalactiae inducing mass mortalities in cultured Nile tilapia (Oreochromis niloticus) with trials for disease control using zinc oxide nanoparticles and ethanolic leaf extracts of some medicinal plants

BackgroundStreptococcus agalactiae (Group B streptococcus, GBS) induces a serious infection that can harm not only aquatic life but also humans and other animals. In a fish farm in southern Egypt, Nile tilapia (Oreochromis niloticus) has developed an epidemic with clinical symptoms resembling piscine streptococcosis.ResultsInitial microscopic inspection of the affected fish brain and kidney indicated the presence of Gram-positive cocci. S. agalactiae was effectively isolated and identified using nucleotide homology of the 16S rRNA and species-specific PCR. The partial 16S rRNA sequence was deposited in the GenBank database at the NCBI and given the accession number MW599202. Genotyping using RAPD analysis indicated that the isolates in the present study belonged to the same genotypes and had the same origin. The challenge test, via immersion (9.2 × 107, 9.2 × 106, and 9.2 × 105 CFU/ml for 1 h) or intraperitoneal injection (4.6 × 107, 4.6 × 106, and 4.6 × 105 CFU/fish), elicited clinical symptoms resembling those of naturally infected fish with a mortality rate as high as 80%. The ability to create a biofilm as one of the pathogen virulence factors was verified. Zinc oxide nanoparticles and the ethanolic leaf extracts of nine medicinal plants demonstrated considerable antibacterial activities against the tested S. agalactiae strain with low minimum bactericidal concentrations (MBC) and minimum inhibitory concentrations (MIC). The ethanolic leaf extracts from Lantana camara and Aberia caffra showed potent antibacterial activity with MBC values of 0.24 and 0.485 mg/ml, and MIC values of 0.12 & 0.24 mg/ml, respectively.ConclusionThis study isolated S. agalactiae from O. niloticus mortalities in a fish farm in Assiut, Egypt. The pathogen persists in fish environments and can escape through biofilm formation, suggesting it cannot be easily eliminated. However, promising findings were obtained with in vitro control employing zinc oxide nanoparticles and medicinal plant extracts. Nevertheless further in vivo research is needed.

Leaf gas exchange, water use, and yield of Marula (Sclerocarya birrea) and Kei Apple (Dovyalis caffra): South African indigenous fruit trees with domestication potential

Conventional crop production is expected to decline in the future in sub-Saharan Africa due to the rising costs of inputs, soil degradation, and increasing water scarcity related to climate variability and change. South Africa has more than 30 species of indigenous fruit trees that are adapted to grow under harsh conditions, yet these species are currently underutilized. Their cultivation is constrained by the lack of detailed ecophysiological information required to develop effective management strategies that optimize tree performance. In this study we investigated how two species with domestication potential namely Marula (Sclerocarya birrea) and Kei apple (Dovyalis caffra) responded to climate and soil factors over a period of two years (2019–2021). Photosynthesis, transpiration, and yield were quantified for mature trees growing in experimental orchards in the Mpumalanga Province of South Africa. Leaf gas exchange data were collected at selected intervals during the growing season using an infrared gas analyser while whole tree transpiration rates were quantified using the heat ratio method of monitoring sap flow. These data were used to parameterize a big leaf Penman-Monteith (PM) model to estimate the transpiration dynamics of individual trees at the daily time step. S. birrea's transpiration responded strongly to both climatic and soil water content variations while the water use of D. caffra was driven mostly by climatic factors. Transpiration rates averaged 0.30 L/m2 of leaf area for S. birrea while that of D. caffra was around 0.45 L/m2. Both species exhibited significant alternate bearing with yield of individual trees fluctuating by more than 50 % between successive years. For the 2019/20 season, water productivity (grams of fruit per litre of water transpired) varied between 6.2 and 17.4 g/L for S. birrea and between 24.3 and 41.7 g/L for D. caffra. Whole tree transpiration by both species were accurately predicted using the PM model albeit with different parameters for each species. This study demonstrates that a simple PM model can accurately estimate the water requirements of these species in other growing regions.

Cytotoxic evaluation of Dovyalis Caffra leaf extract-mediated hematite-(Fe2O3) nanoparticles for biological applications

Although hematite (Fe2O3) nanoparticles are gaining attention for biomedical purposes due to their unique properties, eco-friendly synthesis using plant extracts is being explored due to toxicity concerns of the resulting material. This study explores the use of plant extracts (Dovyalis caffra leaf extracts) for the synthesis of Fe2O3 nanoparticles alongside their cytotoxicity profile using human embryonic kidney cells (HEK293) and human cervical cancer cells (HeLa). The physicochemical properties of the prepared nanoparticles were established using x-ray diffraction (XRD) and microscopy techniques, confirming their crystalline nature and spherical morphology with minimal agglomeration. Using the MTT assay approach, the cytotoxicity profile of the nanoparticles revealed dose-dependent cytotoxic effects, with higher specificity towards cancer cells and very low toxicity towards the human cell line, suggesting safe usage as biomedical agents. While the standard drug 5-Fluorouracil possessed significantly higher cytotoxicity, its unwanted high toxicity towards normal human cells makes the Fe2O3 nanoparticles a better choice. These findings suggest the potential of Dovyalis caffra leaf extract-mediated Fe2O3 nanoparticles for biomedical applications, emphasizing their low toxicity towards normal human cells and specificity towards cancer cells.

Ethnomedicinal Uses, Phytochemistry, and Anticancer Potentials of African Medicinal Fruits: A Comprehensive Review.

Africa is home to diverse medicinal plants that have been used for generations for the treatment of several different cancers and, presently, they are gaining interest from researchers as promising approaches to cancer treatment. This review aims to provide a comprehensive review of dietary and medicinal African fruits including their traditional uses, botanical description, ethnobotanical uses, bioactive phytochemical compositions, and anticancer properties investigated to date in vitro, in vivo, and in clinical studies. Data on recent updates concerning the traditional uses and anticancer properties of these fruits were collected from a myriad of available publications in electronic databases, such as Web of Science, PubMed, ScienceDirect, Scopus, SpringerLink, and Google Scholar. The results suggest that approximately 12 native or commercially grown African fruits belonging to different plant species, including Tribulus terrestris, Xanthium strumarium, Withania somnifera, Xylopia aethiopica, Abelmoschus esculentus, Carissa macrocarpa, Carpobrotus edulis, Syzygium cumini, Kigelia Africana, Annona muricata, Persea americana, and Punica granatum, have been reported for their potential as treatment options for the management of cancer. We further found that approximately eight different fruits from native plant species from Africa, namely, Sclerocarya birrea, Dovyalis caffra, Parinari curatellifolia, Mimusops caffra, Carpobrotus edulis, Vangueria infausta, Harpephyllum caffrum, and Carissa macrocarpa, have been widely used for the traditional treatment of different ailments but somehow failed to gain the interest of researchers for their use in anticancer research. In this review, we show the potential use of various fruits as anticancer agents, such as Tribulus terrestris, Xanthium strumarium, Withania somnifera, Xylopia aethiopica, Abelmoschus esculentus, Carissa macrocarpa, Carpobrotus edulis, Syzygium cumini, Kigelia Africana, Annona muricata, Persea americana, and Punica granatum; unfortunately, not enough reported research data have been published to gain thorough mechanistic insights and clinical applications. Additionally, we discuss the possibility of the utilization of potential phytochemicals from fruits like Persea americana and Punica granatum in anticancer research, as well as future directions.

Attributes, uses, and management of Dovyalis caffra (Kei apple) A Review of literature

The objective of this review is to explore information about D. caffra and get good ideas about future research requirements and development activities. Dovyalis caffra (Warb.) (Kei apple) which belongs to the family Flacourtacea is a thorny evergreen tree/shrub native to the Kei River area of southwest Africa and abundant in the wild around the eastern Cape, Kaffraria, and Natal. It is now found distributed in many countries of the world including Ethiopia. Propagation of D. caffra is mostly by seed but its propagation is also possible vegetatively using stem cuttings. Propagation by stem cuttings is preferred to propagation by seed for faster, lesser cost, and easier establishment and to counteract the challenges posed by the storage behavior of the recalcitrant nature of seeds. D.caffra has many uses such as live fences, fodder for livestock, traditional medicine, and food for human beings. It has also allelopathic chemicals that suppress or control the growth of weeds in its vicinity. D.caffra can be managed by pruning and trimming. The purpose of the management is to keep live fences in good condition including shape and appearance, to avoid dead and diseased wood, to maintain and improve flower display, and to make the plants take small space. Studies regarding this valuable species are very limited in Ethiopia but some studies done in agroforestry, especially in home gardens show a high frequency of the species since it is used widely in live fences and to some extent as food.

Effect of Mature Stages on Phenolic Contents, Antioxidant Activities and Mineral Distribution in Different Parts of Kei Apple Fruit

This study aimed to evaluate the concentrations of the heavy metals, macro and micro-elements as well as the distribution of phenolic constituents in different parts of half-ripe and full-ripe kei apple fruits. For mineral analysis, fruit samples were digested and analyzed using inductively coupled plasma optical emission spectrometry (ICPOES). The colorimetric determination of total polyphenolic contents (TPs) and the antioxidant capacity using DPPH and total antioxidant capacity (TAC) assays were done using aqueous alcoholic extracts. Also, the phenolic profiles were identified and quantified using high performance liquid chromatography (HPLC). The results showed that the highest antioxidant activity using DPPH and TAC and total phenolic content were detected in the pulp of full-mature fruits and its values were 2.03 mg GAE/g d.w, 22.61 mg AAE/g d.w and 26.24 mg GAE/g d.w, respectively. Average of mineral concentrations in dried samples (in μg/g), were ranged between: 6,164.99 to 18,339.61 (K); 2,538.06 to 3,488.92 (Ca); 749.26 to 2,110.12 (Mg); 82.13 to 733.36 (Fe); 22.74 to 58.02 (Zn); 6.43 to 11.85 (Mn); 10.17 to 20.02 (Cu); 1.86 to 8.73 (Ni) and much lower concentrations of Co, Pb and Cd. The key phenolic constituents of the fruit harvested in different times were 4-hydroxy benzoic acid, chlorogenic acid and catechol. Overall, harvesting of kei apple fruit in the first week of June indicates the full maturity of the fruit with characteristic higher phenolics, antioxidant capacity without any deterioration in most of elemental minerals.

Are South African Wild Foods the Answer to Rising Rates of Cardiovascular Disease?

The rising burden of cardiovascular disease in South Africa gives impetus to managerial changes, particularly to the available foods in the market. Since there are many economically disadvantaged groups in urban societies who are at the forefront of the CVD burden, initiatives to make healthier foods available should focus on affordability in conjunction with improved phytochemical diversity to incentivize change. The modern obesogenic diet is deficient in phytochemicals that are protective against the metabolic products of sugar metabolism, i.e., inflammation, reactive oxygen species and mitochondrial fatigue, whereas traditional southern African food species have high phytochemical diversity and are also higher in soluble dietary fibres that modulate the release of sugars from starches, nurture the microbiome and produce digestive artefacts that are prophylactic against cardiovascular disease. The examples of indigenous southern African food species with high horticultural potential that can be harvested sustainably to feed a large market of consumers include: Aloe marlothii, Acanthosicyos horridus, Adansonia digitata, Aloe ferox, Amaranthus hybridus, Annesorhiza nuda, Aponogeton distachyos, Bulbine frutescens, Carpobrotus edulis, Citrullus lanatus, Dioscorea bulbifera, Dovyalis caffra, Eleusine coracana, Lagenaria siceraria, Mentha longifolia, Momordica balsamina, Pelargonium crispum, Pelargonium sidoides, Pennisetum glaucum, Plectranthus esculentus, Schinziophyton rautanenii, Sclerocarya birrea, Solenostemon rotundifolius, Talinum caffrum, Tylosema esculentum, Vigna unguiculata and Vigna subterranea. The current review explains the importance of phytochemical diversity in the human diet, it gives a lucid explanation of phytochemical groups and links the phytochemical profiles of these indigenous southern African foods to their protective effects against cardiovascular disease.

Chemical and antioxidant characterization of Dovyalis caffra and Dovyalis abyssinica fruits in Kenya

This study aimed at chemical characterization of Dovyalis caffra (Hook.f. & Harv.) Sim. and Dovyalis abyssinica (A. Rich.) Warb. fruits from Kinamba Town (KT) in Laikipia county and Gitoro Forest (GF) in Meru county of Kenya. All analysed fresh fruit samples had low pH values averaging at 2.67. Other tests showed D. abyssinica-GF to be significantly inferior to D. caffra-GF and D. caffra-KT in terms of TSS, TSS:TTA ratio, and ascorbic acid content. Based on these parameters, D. caffra-KT presents itself with a higher potential for direct consumption as compared to D. caffra-GF. Proximate analysis of dried fruit pulps demonstrated D. abyssinica-GF to be significantly higher in ash content and significantly lower in protein and fat contents compared to the other two samples. There were insignificant difference in the fibre and carbohydrate contents of all the fruit samples. In phytochemical analysis, D. caffra-GF recorded the highest total polyphenol content of 1845 mg Gallic acid equivalent (GAE)/100 g while D. abyssinica-GF reported the lowest figure of 1128 mg GAE/100 g. Flavonoid and simple phenols fractions were in the range of 18.15–26.85% and 73.15–81.85% respectively in all fruit samples. As for antioxidant activity, D. caffra-GF recorded significantly high scores in both DPPH and CUPRAC assays, and D. abyssinica-GF the lowest. The range of DPPH and CUPRAC scores for all samples was 1995–4993 mg l-ascorbic acid/100 g and 1384–2303 mg l-ascorbic acid/100 g respectively. The current study presents the nutritional and health potential of D. caffra and D. abyssinica fruits. This forms a good basis for future adoption and exploitation of these fruits.

Ecofriendly synthesis of silver nanoparticles using Kei-apple (Dovyalis caffra) fruit and their efficacy against cancer cells and clinical pathogenic microorganisms

Green fabrication has become a safe approach for producing nanoparticles. Plant-based biogenic synthesis of silver nanoparticles (AgNPs) has emerged as a possible alternative to traditional chemical production. In this paper, we provide a low-cost, green synthesis of AgNPs utilizing using Kei-apple (Dovyalis caffra) fruit extract. Ultraviolet–visible (UV–Vis) spectroscopy, Fourier Transform Infrared (FTIR), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), Scanning-Electron Microscope (SEM), and Dynamic Light Scattering (DLS) analyses were used to characterize green produced AgNPs. The formation of AgNPs was shown to have a surface resonance peak of 415 nm in UV–visible spectra, and FTIR spectra verified the participation of biological molecules in Synthesis of AgNPs. The TEM revealed that the biosynthesized AgNPs were mostly spherical in form, with size range of 12–53 nm. XRD diffractogram was used to demonstrate the face cubic centre (fcc) character of AgNPs. Excellent anticancer activity of AgNPs was recorded where more than 80% of Prostate Cancer (PC-3) cell lines was inhibited by 100–150 µg/mL of AgNPs, while 38% only was recorded using AgNO3 and 55.62% was recorded D. caffra fruit extract at 150 µg/mL. Destructions of PC-3 cell was observed as a result of exposed to AgNPs, followed by D. caffra fruit extract, while minor alterations were recorded as exposed to AgNO3. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging using AgNPs was three fold using fruit extract at 100 µg/mL indicating good antioxidant activity. Excellent inhibitory activity of AgNPs was recorded against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus fumigatus with inhibition diameter zone 28.22 ± 0.25 mm, 23.21 ± 0.35 mm, 27.25 ± 0.03 mm, 28.40 ± 0.15 mm, 29.23 ± 0.44 mm, and 9.52 ± 0.5 mm, respectively compared with AgNO3. D. caffra fruits considered a promising and safe source for fabrication of AgNPs with multi-biological functions.

Phenolic profiling and antioxidant evaluation of extracts from Southern African indigenous fruits byproducts

The call to build climate-resilient food systems in Africa has revived interest in indigenous fruits, which, however, remain under-researched. In this study, the phenolic content and antioxidant profiles of seed and pulp of ethanolic extracts from eight Southern African indigenous fruits were evaluated using UPLC-ESI-Q-TOF/MS and four antioxidant assays. Total phenols and hydroxycinnamic acids were highest in Dovyalis caffra (Kei apple) seed (5084.5 and 3403.83 mg/kg). Flavonoids were most abundant in Colpoon compressum (Colpoon) seed (1127.23 mg/kg), while hydrolysable tannins were highest in Syzygium guineense (Water pear) seed (666.13 mg/kg). Proanthocyanidins were abundant in Harpephyllum caffrum (Wild plum) pulp while anthocyanins were highest in Olea africana (Wild olive) pulp. Hierarchical clustering heatmap analysis showed similar concentration and diversity in the composition of reported compounds. Syzygium guineense seed had the lowest DPPH values. ORAC values were highest in O. africana pulp while H. caffrum pulp had the highest FRAP values and lipoxygenase inhibition capacity. In conclusion, the study revealed a diverse profile of phenolics in indigenous fruits extracts, to which their bioactivity is attributed. Specifically, H. caffrum pulp and S. guineense seed have potential as natural sources of phenolic antioxidants for food application.

Biogenic Synthesis of CuO, ZnO, and CuO-ZnO Nanoparticles Using Leaf Extracts of Dovyalis caffra and Their Biological Properties.

Biogenic metal oxide nanoparticles (NPs) have emerged as a useful tool in biology due to their biocompatibility properties with most biological systems. In this study, we report the synthesis of copper oxide (CuO), zinc oxide (ZnO) nanoparticles (NPs), and their nanocomposite (CuO–ZnO) prepared using the phytochemical extracts from the leaves of Dovyalis caffra (kei apple). The physicochemical properties of these nanomaterials were established using some characterization techniques including X-ray diffraction analysis (XRD), ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). The XRD result confirmed the presence of a monoclinic CuO (Tenorite), and a hexagonal ZnO (Zincite) nanoparticles phase, which were both confirmed in the CuO–ZnO composite. The electron microscopy of the CuO–ZnO, CuO, and ZnO NPs showed a mixture of nano-scale sizes and spherical/short-rod morphologies, with some agglomeration. In the constituent’s analysis (EDX), no unwanted peak was found, which showed the absence of impurities. Antioxidant properties of the nanoparticles was studied, which confirmed that CuO–ZnO nanocomposite exhibited better scavenging potential than the individual metal oxide nanoparticles (CuO, and ZnO), and ascorbic acid with respect to their minimum inhibitory concentration (IC50) values. Similarly, the in vitro anticancer studies using MCF7 breast cancer cell lines indicated a concentration-dependent profile with the CuO–ZnO nanocomposite having the best activity over the respective metal oxides, but slightly lower than the standard 5-Fluorouracil drug.

Anticancer, antioxidant, antiviral and antimicrobial activities of Kei Apple (Dovyalis caffra) fruit

Secondary plant metabolites remain one of the key sources of therapeutic agents despite the development of new approaches for the discovery of medicinal drugs. In the current study, chemical analysis, and biological activities of Kei apple (Dovyalis caffra) methanolic extract were evaluated. Chemical analysis was performed using HPLC and GC–MS. Antiviral and anticancer effect were assessed using the crystal violet technique and activity against human liver cells (HepG2), respectively. Antibacterial activity was tested with the disc diffusion method. The obtained results showed that chlorogenic acid (2107.96 ± 0.07 µg/g), catechin (168 ± 0.58 µg/g), and gallic acid (15.66 ± 0.02 µg/g) were the main bioactive compounds identified by HPLC techniques. While, compounds containing furan moieties, as well as levoglucosenone, isochiapin B, dotriacontane, 7-nonynoic acid and tert-hexadecanethiol, with different biological activities were identified by GC–MS. Additionally, inhibition of 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) scavenging was 79.25% at 2000 µg/mL, indicating its antioxidant activity with IC50 of 728.20 ± 1.04 µg/mL. The tested extract exhibited potential anticancer activity (58.90% toxicity) against HepG2 cells at 1000 µg/mL. Potential bacterial inhibition was observed mainly against Escherichia coli and Proteus vulgaris, followed by Staphylococcus aureus and Bacillus subtilis with a diameter of growth inhibition ranging from 13 to 24 mm. While weak activities were recorded for fungi Candida albicans (10 mm). The extract showed mild antiviral activity against human coronavirus 229E with a selective index (SI) of 10.4, but not against human H3N2 (SI of 0.67). The molecular docking study's energy ratings were in good promise with the experiment documents of antibacterial and antiviral activities. The findings suggest that D. caffra juice extract is a potential candidate for further experiments to assess its use as potential alternative therapeutic agent.

Evaluation of antimicrobial and synergistic effects of some medicinal plant extracts on antimicrobial resistant organisms

Background: To evaluate antimicrobial activity of ten plant extracts on antimicrobial resistant organisms and investigate interactions of these extracts with antimicrobials against resistant organisms. Methods: The antimicrobial potential of ethanolic leaf extract of Aberia caffra Hook. f. & Harv., Azadirachta indica L., Dodonaea viscosa L., Ficus nitida L., Lanatana camara L., Myrtus communis L., Olea europaea L., Ruta graveolens, Schinus terebinthifolius Raddi and Vitex agnus-castus L. was investigatedagainst eleven drug resistant organisms by agar well diffusion method. The interaction of these extracts with antimicrobials was assessed. Results: Ethanolic extracts of Dodonaea viscosa leaves had antibacterial activity against ESBL-producing Escherichia coli (E. coli) quinolone resistant Salmonella typhi (S. typhi) andESBL and carbapenemase-producing Klebsiella pneumonia (K. pneumonia).Schinus terebinthifolius Raddi leaves showed antibacterial activity against ESBL and carbapenemase-producing K. pneumoniae and fluconazole resistant C. albicans. Myrtus communis leave extracts demonstrated activity against ESBL-producing E. coli and fluconazole resistant A. fumigatus. Ruta graveolens L. revealed activity against quinolone resistant S. typhiand fluconazole resistant A. fumigatus. Vitex agnus-castus, Aberia caffra Hook. f. &Harv.andAzadirachta indica L. leaf extracts had activity against ESBL-producing E. coli. Olea europaea L. had activity against quinolone resistant A. baumannii. Ruta graveolens L. and Myrtus communis L. were the only extracts showing synergistic effect in association with voriconazole against fluconazole resistant A. fumigatus. Conclusion: Tested plant leaf extracts had great potential as antimicrobial agents against at least one drug resistant microorganism. Isolation of active components and further studies are needed to evaluate the efficacy and toxicity of these products.

Proximate Analyses and Amino Acid Composition of Selected Wild Indigenous Fruits of Southern Africa.

A literature survey revealed that several wild indigenous Southern African fruits had previously not been evaluated for their proximate and amino acid composition, as well as the total energy value (caloric value). Fourteen species including Carissa macrocarpa, Carpobrotus edulis, Dovyalis caffra, Halleria lucida, Manilkara mochisia, Pappea capensis, Phoenix reclinata, and Syzygium guineense were analyzed in this study. The nutritional values for several species such as C. edulis, H. lucida, P. reclinata, and M. mochisia are being reported here for the first time. The following fruits had the highest proximate values: C. macrocarpa (ash at 20.42 mg/100 g), S. guineense (fat at 7.75 mg/100 g), P. reclinata (fiber at 29.89 mg/100 g), and H. lucida (protein at 6.98 mg/100 g and carbohydrates at 36.98 mg/100 g). Essential amino acids such as histidine, isoleucine, lysine, methionine, phenylalanine, tryptophan, and valine were reported in all studied indigenous fruits. The high protein content in H. lucida was exhibited by the highest amino acid quantities for histidine. However, the fruits are a poor source of proteins since the content is lower than the recommended daily intake. The jacket-plum (Pappea capensis), on the other hand, meets and exceeds the required daily intake of lysine (0.0003 g/100 g or 13 mg/kg) recommended by the World Health Organization.

Effect of alcoholic and acetous fermentations on the phenolic acids of Kei-apple (Dovyalis caffra L.) fruit.

The Kei apple is a tree found on the African continent. Limited information exists on the effect of alcoholic and acetous fermentation on the phytochemicals of Kei apple. The fruit has increased concentrations of l-malic, ascorbic, and phenolic acids among other compounds. Juice was co-inoculated with Schizosaccharomyces pombe (Sp) and Saccharomyces cerevisiae (Sc) to induce alcoholic fermentation (AF). Acetous fermentation followed AF, using an acetic acid bacteria (AAB) consortium. Saccharomyces cerevisiae + Sp wines and vinegars had the highest pH. Total acidity, soluble solids and l-malic acid decreased during AF and acetous fermentation, and was highest in Sc wines and vinegars. Volatile acidity (VA) concentration was highest in Sp vinegars but was not significantly different from Sc and Sc + Sp vinegars. Gallic acid was highest in Sp wines and vinegars, whereas syringic acid was highest in Sc wines and vinegars. The Sc + Sp wines were highest in caffeic, p-coumaric, and protocatechuic acids. Schizosaccharomyces pombe vinegars were highest in caffeic and p-coumaric acids. Highest concentrations of ferulic and sinapic acids were found in Sp and Sc wines, respectively. Chlorogenic acid was most abundant phenolic acid in both wines and vinegars. Saccharomyces cerevisiae + Sp and Sc fermentation had a positive effect on most phenolic acids; Sc + AAB had an increased effect on syringic and chlorogenic acids, whereas Sp + AAB resulted in an increase in gallic, caffeic, and p-coumaric acids. The AAB selected had minimal performance with respect to VA production in comparison to commercial vinegars. Acetic acid bacteria selection for acetous fermentation should therefore be reconsidered and the decrease of certain phenolic acids during acetous fermentation needs to be investigated. © 2021 Society of Chemical Industry.

Two alcoholic sources in the preparation, chemical characterization and acceptability of artisanal dovialis liqueurs

ABSTRACT: This study evaluated two alcoholic sources in the preparation, chemical characterization, and acceptability of homemade Kei apple liqueurs. Kei apple fruits were harvested from 4-year-old plants and immediately transported to the laboratory. The liqueur prepared with vodka + fruits without the epicarp was named L1;the liqueur prepared with sugarcanespirit+ fruits with the epicarp and sliced was named L2. The infusion or alcoholic maceration stage was then performed, mixing the fruits with the alcoholic liquid. After the preparation of the alcoholic extract, the chemical characterization of the final products was performedand after 60 days, the sensory analysis and acceptabilityof the product were conducted. The experimental design was entirely randomized, in a 2 × 2factorial scheme (two types of fruits ×.two types of alcohol), containing three samples of liqueurs per replicate and six replicates per experimental plot. The liqueurs suited the parameters fixed by the Brazilian legislation for the chemical evaluation of these products. As for sensory analysis, L1 had good acceptability from tasters, with apurchase intention by 71% of them.

Prioritization of indigenous fruit tree species with domestication and commercialization potential in KwaZulu-Natal, South Africa

Indigenous fruit tree species (IFTs) can play a crucial role in poverty alleviation and as a source of food in South Africa. Although these species contain nutrient-rich edible fruits that are also locally processed to food products such as jams and jellies, they are still underutilized and also harvested from the wild. This study aimed to prioritize in northern KwaZulu-Natal, IFTs with domestication and commercialization potential. A literature survey and focus groups were used to list tree species that produce edible fruits with this potential. Plant experts, through focus groups and reference group meetings, further ranked fruit trees using a scorecard method based on various attributes. A total of 29 prioritized IFTs was obtained, of which the Sapotaceae was the most represented family with a maximum of four species. Based on scorecard assessment, the most preferred species in descending order were Strychnos spinosa Lam., Garcinia livingstonei T.Anderson, Englerophytum magalismontanum (Sond.) T.D.Penn, Sclerocarya birrea (A.Rich) Hochst., Dovyalis caffra (Hook.f. & Harv) Hook.f., Vangueria infaustia Burch. and Berchemia zeyheri (Sond.) Grubov. Strychnos spinosa was ranked as the first most important IFTs with a final score of 151, whereas Berchemia zeyheri was ranked the least with the final score of 146.1. However, the final scores of all most preferred species were relatively similar to one another. The top seven species identified in this study should be considered as a baseline for future IFTs development programmes such as domestication, whereby these species are introduced to small-holder farmers and food processing industries.

ZnO nanoparticles mediated by aqueous extracts of Dovyalis caffra fruits and the photocatalytic evaluations

The rising interests in the green routes to the synthesis of nanoparticles stemmed from different benefits of the approach including eco-friendliness, cost effectiveness, and non-toxicity with living tissues. This study presents the synthesis and evaluation of the photocatalytic properties of biomediated ZnO nanoparticles (NPs) obtained using Dovyalis caffra fruit extracts as reducing and capping agents. The ZnO nanoparticles were characterized using UV–vis spectroscopy, x-ray diffraction (XRD) analysis and transmission electron microscopy. The XRD result showed that the synthesized ZnO NPs have a hexagonal wurtzite structure, while the TEM images showed a rod-like morphology, arranged in bundles. The average size of the ZnO NPs, estimated from the TEM images, were 10.4 and 34.1 nm for the width and length respectively. The optical band gap energy (3.43 eV) obtained from the absorption spectrum revealed a blue shift compared to the bulk. The evaluation of the photocatalytic potential of the synthesized ZnO NPs showed an effciency of 71% against MB dyes.

Sex determination in Kei-apple (Dovyalis caffra) using molecular markers and flow cytometry

The Kei-apple (Dovyalis caffra) is an indigenous fruit with excellent nutritional characteristics that renders it a suitable candidate for novel food and beverage products. As an indigenous species, the Kei-apple has been studied only to a limited extent with particular emphasis on fruit characteristics important for agro-processing applications. A specific knowledge gap in the published literature relates to the inability to distinguish between male and female trees at the juvenile stage. This limitation hampers orchard management plans which require a specific ratio of male:female trees to ensure adequate pollination and fruit production. Furthermore, collection of specimens from the wild is also compromised by the inability to distinguish between sexes. Therefore, the present study investigated the suitability of two complementary methods, i.e. characterisation using molecular markers and DNA content analysis via flow cytometry, in order to distinguish between male and female trees. The molecular markers allowed for the identification of putative male and female specific markers and the DNA content analysis revealed differences in the average estimated nuclear DNA content of male and female trees. However, molecular markers did not allow for sex discrimination in 100% of the tested samples (i.e. in 70–94%) and the difference in the DNA content between the sexes was small. This may be resolved by testing additional markers or refining the flow cytometry method, however, until such time, it is recommended that future applications use both methods to limit the risk of misidentifications.

Bio-inspired synthesis and cytotoxic evaluation of silver-gold bimetallic nanoparticles using Kei-Apple (Dovyalis caffra) fruits

This work presents the synthesis and cytotoxic properties of monometallic nanoparticles (NPs) of Ag, Au and their AuAg bimetallic nanoparticles (BNPs) using Kei apple fruit extract. The BNPs were prepared by varying the concentrations of the plant extract and the precursor salts (AgNO3 and HAuCl4). UV–visible spectroscopic methods showed surface plasmon resonance around 430 and 532 nm for the Ag and Au NPs respectively. The plasmon bands of the BNPs were recorded around 540 nm. Powder X-ray diffraction (pXRD) analysis and transmission electron microscopic (TEM) studies showed the crystalline nature and monodispersity associated with the monometallic nanoparticles. However, a clear evidence of polydispersity was apparent in the case of the bimetallic nanoparticles. The anticancer assay of the synthesized nanoparticles showed promising activities with the BNPs exhibiting higher potential with respect to the reaction conditions. The BNPs synthesized using higher volume of the fruit extract (AuAg BNPs3) gave the best anticancer properties against breast cancer MCF7 cell line whereas the AuNPs gave an IC50 of 105 μM as the least potent nanoparticles.