Kirkiana Fruit Research Articles

The effect of incorporating herbal (Lippia javanica) infusion on the phenolic, physicochemical, and sensorial properties of fruit wine.

The use of medicinal herbs in food processing to improve food quality and human health is growing in sub‐Saharan Africa. Herbal infusions have perceived medicinal benefits. This study investigated the effect of incorporating L. javanica extract on the phenolic, physicochemical, and sensory properties of a Uapaca kirkiana fruit‐based wine. The fruit and L. javanica were analyzed for proximate, pH, total soluble sugars (TSS), total sugar, titratable acidity, phenolics, and antioxidant activity (AOA). The prepared substrate was fermented at optimized fermentation temperature of 23°C, pH of 3.4, inoculum concentration of 9.5% (v/v) (Saccharomyces cerevisiae), and L. javanica extract concentration of 10% (v/v). The produced wine had a pH, total sugar, TSS, total acidity, and vitamin C content of 3.1 ± 0.2, 3.0 ± 0.1 g/L, 4.8 ± 0.1%, 5.9 ± 0.01 g/L, and 4.4 ± 0.1 mg/100 g, respectively. The wine had 12.2 ± 2.1 mg GAE/g, 0.06 ± 0.01 mg/g, and 1.8 ± 1.1 mg CE/g total phenols, tannins, and flavonoids, respectively. The alcohol, free sulfur dioxide (SO2), AOA, and color values of the produced wine were 10.2 ± 0.1 alcohol by volume (ABV)%, 58.1 ± 1.2 mg/L, 73.1 ± 0.1 EC50 mg/L, and 40.4 ± 2.1% yellow, respectively. The flavor, color, and overall acceptance of the produced wine were rated as “good” and were significantly different (p < .05) from control wine. The addition of L. javanica extracts enhanced total phenol, color, and sensory properties of the wine. The utilization of U. kirkiana fruit by incorporating L. javanica infusion can reduce postharvest losses and improve nutrition and health.

Extraction and Characterization of Pectin from Snot Apple (Azanza garckeana) Fruits with Potential Use in Zimbabwe

ABSTRACT Azanza garckeana (snot apple) is an underutilized indigenous fruit of southern Africa. The study was aimed at determining the functional characteristics and potential use of extracted pectin from A. garckeana (snot apple) fruits from Zimbabwe. A. garckeana (snot apple) fruits were collected from a semi-arid communal area of Nhema, Zimbabwe. Pectin properties were determined using standard methods. Fruit jam was formulated with 53% (w/v) U. kirkiana fruit pulp, 45% (w/v) sugar, 1.5% (w/v) A. garckeana pectin, 0.5% (w/v) citric acid. The optimum extraction conditions were 90°C for 90 minutes at pH 3. Pectin yield was 9.21 ± 0.1% to 18.1 ± 0.1% and 10.1 ± 0.1 to 20.2 ± 0.2% for dried and fresh A. garckeana fruits respectively. Physicochemical properties of the pectin were (% w/w) degree of esterification (DE) 72.1–80.3, methoxyl content 6.1–6.8, anhydrouronic acid (AUA) content 60.3–67.6, moisture content 3.1–2.2, ash content 0.9–0.7 for dried and fresh fruits. Equivalent weight range was 816.7–848.2 mg/mol. Jam had total soluble solids (68.2 ± 0.1%), total titratable acid (2.1 ± 0.2 g/L), moisture content (32.6 ± 1.3%) and pH (3.4 ± 0.1). Jam’s overall acceptance score was 6. There was no significant difference in aroma, spreadability, taste, and texture of both jams at P < 0 .05. Pectin extracted from A. garckeana (snot apple) fruits has good functionality properties with potential for applications in food processing, especially in jam production.

Probiotic Potential, Iron and Zinc Bioaccessibility, and Sensory Quality of Uapaca kirkiana Fruit Jam Fermented with Lactobacillus rhamnosus Yoba.

Uapaca kirkiana is an underutilised indigenous fruit tree (IFT) found in the miombo ecological zone in sub-Saharan Africa. Furthermore, sub-Saharan Africa is home to many nutritionally insecure people who suffer from micronutrient deficiency. The incorporation of probiotic strains in jams as a possible way of enhancing mineral accessibility, food quality, and health is limited in Africa. This study monitored the probiotic potential, bioaccessible iron and zinc, and organoleptic properties of U. kirkiana fruit jam fermented with L. rhamnosus yoba. U. kirkiana fruits were collected from semiarid rural areas of Zimbabwe. The L. rhamnosus yoba strain was obtained from the Yoba for Life Foundation, Netherlands. Mineral and biochemical properties of the probiotic jam were analysed using AOAC standard methods. The U. kirkiana fruit tree was ranked first as a food resource by most rural populations in Zimbabwe. The probiotic jam formulation had 55% (wt/vol) U. kirkiana fruit pulp, 43% (wt/vol) sugar, 1.25% (wt/vol) pectin, 0.5% (wt/vol) citric acid, and 0.25% (wt/vol) L. rhamnosus yoba strain. The probiotic jam had 6.2 ± 0.2 log CFU/mL viable L. rhamnosus yoba cells. Iron and zinc content (mg/100 g w.b.) was 4.13 ± 0.22 and 0.68 ± 0.02 with pH 3.45 ± 0.11, respectively. Nutrient content was g/100 g w.b., carbohydrate 66 ± 4.1, fat 0.1 ± 0.01, crude protein 0.2 ± 0.01, ash 0.7 ± 0.02, and crude fiber 0.3 ± 0.01. Bioaccessible iron and zinc were 6.55 ± 0.36% and 16.1 ± 0.50% and increased by 4% and 2% in the probiotic jam, respectively. Mineral bioaccessibility and nutrient content were significantly different (p < 0.05) in jam with 0.25% L. rhamnosus yoba. Jam acceptance rating was 83%. The probiotic jam can be used as a sustainable food containing probiotic with potential nutritional and health benefits.

Bioactive compounds and functional potential of Uapaca kirkiana (Muell. arg.) fruits

Consumption of Uapaca kirkiana indigenous fruit by the local populace is growing in popularity because of the acclaimed health and functional benefits. The aim of the study was to determine the bioactive compounds and functional properties of the U. kirkiana fruit. Besides the fruit’s pulp yield, the bioactive phytochemical constituent, physicochemical properties and functional characteristics of the pulp were analysed. The sugar, starch, minerals, and ascorbic acid constituents of the fruit pulp were, respectively determined using the following instruments: brix refractometer, megazyme kit, inductive coupled plasma-optical emission spectrometer and 2,6- dichlorophenolindophenol (DCPIP) titration test. The total phenolic content (TPC), tannin, and flavonoid contents were evaluated using Folin Ciocalteau test, tannin binding test and vanillin test, respectively. The average weight of the U. kirkiana fruits harvested from three regions having different climatic conditions ranged from 23.56 to 34.20 g per fruit. The mean pulp weight was from 12.15 g/100 g to 15.09 g/100 g per fruit. The biochemical and functional parameters obtained include total titratable acid (0.3 - 0.48 g/kg), antioxidantactivity (34.96 - 36.68%), vitamin C (15.74 - 16.63 mg/100 g), dry matter content (28.81 - 29.38%), pH (4.3 - 4.6) and sugar content (20.29 - 21.87 g/100 g). Fructose was the dominant sugar (10.12-11.0 g/100 g). Preliminary phytochemical screening of the pulp indicated the presence of tannins, flavonoids, amino acids and carbohydrate content. Total phenolic content ranged from 67.0 to 82.5 µg GAE/g. The essential elements constituent evaluation of the pulp revealed that Fe content was 11.3 - 12.2 mg/100 g, K (383.07 - 439.8 mg/100 g), Mg (28.7 - 35.1 mg/100 g), Ca (16.4 - 17.3 mg/100 g), P (13.4 - 15.1 mg/100 g), Na (9.08 - 9.78 mg/100 g), Cu (0.8 - 0.94 mg/100 g) and Zn (0.87 - 0.94 mg/100 g). This study, besides establishing U. kirkiana fruit as a good source of micronutrients (Fe, Cu, Zn), reveals that the fruit is also an excellent source of phenolic compounds, vitamin C and sugars, hence use as a dietary supplement may combat some nutritional deficiencies. We, therefore, recommend U. kirkiana fruits to be used to produce nutritive functional foods with health benefits such as probiotic jams and as an additive. Key words: Indigenous fruit, micronutrients, phenolic, pulp, phytochemicals, U.kirkiana, megazyme kit

The potential of Uapaca kirkiana fruit jam for the delivery of Lactobacillus rhamnosus yoba as a probiotic food

Probiotics are important in enhancing food quality, reducing incidences of diarrhoea and promoting good health. A fruit jam is an ideal food to deliver probiotics because it is easy to produce, a good source of sugar, and most rural population consume it. A probiotic jam was developed using an underutilised fruit, U. kirkiana, to benefit the resource-poor population in southern Africa. U. kirkiana fruit is found abundant in most semi-dry rural areas of Zimbabwe. Ripe U. kirkiana fruits were obtained from preferred domesticated trees by households residing in semi-dry rural areas of Zimbabwe. The fruits were pulped by removing seeds, mashing and sieving through an 800 μM sieve. Pectin content of the pulp was determined. A probiotic jam was developed using the formulation 55 % (wt/vol) pulp, 43 % (wt/vol) sugar, 1.5 % (wt/vol) pectin, and 0.5 % (wt/vol) citric acid. The fruit pulp was mixed with sugar in a stainless steel pot and cooked at 110 °C. Citric acid was added and stirred whilst cooking until it reached 55 oBrix. Pectin was added and the jam was continuously stirred until it reached 68 oBrix. The jam was inoculated with 0.25 % L. rhamnosus yoba and left to propagate for 24 hours, while bacterial growth was monitored. The physicochemical and functional properties (pH, total soluble solids, sugars, total titratable acidity, iron content, zinc content, and vitamin C), and L. rhamnosus yoba viability in the probiotic jam was analysed. The probiotic jam had vitamin C, total titratable acidity, total soluble solids, and moisture content of 0.34 ±0.02 mg /100 g FW, 2.2 ± 0.11 g / L FW, 68.5 ± 0.2 % FW, and 34.8 ± 1.2 % FW, respectively; iron and zinc content of 4.13 ± 0.52 mg /100 g FW and 0.36 ± 0.02 mg /100 g FW, respectively; high fructose and sucrose content of 12.84 ± 0.21 g /100 g FW and 24.61 ± 0.12 g /100 g FW, respectively; and a total titratable acidity content of 2.2 g / L at day 0 (after production), 2.37 ± 0.01 g / L FW at day 4, and 2.48 ± 0.02 g / L FW at day 7 of storage (25 °C). The probiotic jam had 6.2 ± 0.2 Log CFU / mL viable cells on point of consumption. U. kirkiana fruit jam can potentially deliver live L. rhamnosus yoba cells as a probiotic food. Key words: Probiotic food, vitamin C, fruit jam, L. rhamnosus yoba, pectin, U. kirkiana fruit, sub-Saharan Africa

Multivariate Analyses of Functional and Chemical Properties of Uapaca Kirkiana Fruits from Zimbabwe

ABSTRACT The correlation between the functional and chemical properties of U. kirkiana fruit pulp was studied. The functional and chemical properties of the fruit pulps were determined and data were analyzed by regression and principal component analysis (PCA) to show correlations and variances. Results showed a 51.4% variance, PC 1 had a 37.31% variance. PC 2 showed a 14.17% variance. Antioxidant activity (AOA), Cu, vitamin C, total titratable acid (TTA), and Mg had a positive variance in PC 1. TTA and pH were significant and correlated in PC 1. Titratable acidity and pH had a variability of 69% and 74%. Iron and Ca were significant and correlated in PC 2. Phosphorus and AOA were positively correlated. Pulp yield had a weak positive correlation with dry matter, Ca, K, and Zn content. Fruits from Bikita were grouped according to pH levels, AOA, Cu, vitamin C, TTA, and phosphorus content. Fruits in Kazangarare were high in Fe and Ca and grouped together. Magnesium content was significant in fruits obtained from Gokwe. Phosphorus and TTA had significant effect (p < 0.01; p < 0.05) on pulp yield. The results provide useful data about relationship, chemical composition variation of U. kirkiana fruit pulp obtained at the different regions of Zimbabwe.

Natural Plant Resources for Sustainable Development: Insights from Community Use in the Chimanimani Trans-Frontier Conservation Area, Mozambique

In rural African communities, wild plant species are a valuable resource that are often threatened by agricultural conversion and overexploitation. To understand the harvest and sale of wild plant species that provide fruits and raw materials for artisanal products, this study used ethnobotanical and socio-economic methods to engage communities in the Chimanimani Trans-Frontier Conservation Area, Mozambique. Use was dependent on local availability and market accessibility. Incomes are made from Uapaca kirkiana fruits in some communities and Strychnos madagascariensis in others; some earn money from Cyperus spp. mats whilst others use Phragmites mauritianus. Less marketed items included baskets made from numerous species (including Oxytenanthera abyssinica) and wooden implements (e.g. made from Pterocarpus angolensis) which are used to process, store and transport maize. Conservation and development could potentially benefit from value-addition activities, new management systems (like agroforestry), or population protection and restoration. This should include analysis of population extents and production levels.

Effect of propagule type and fruiting time on Uapaca kirkiana fruit and seed size, seed germination and seedling growth

Uapaca kirkiana grafts and marcots are alternative viable seed sources and seed size is independent of propagule type. Studies on seed germination and seedling growth of Uapaca kirkiana derived from different propagules have been limited. The objectives were to assess variations in fruit and seed weight, germination ability of seed from grafts, marcots and natural forest stand. It was also to assess the effects of fruit and seed size, and collection time on seed germination. Trees from natural forest stand were significantly (P < 0.0001) taller and had thicker stem diameters at breast height than the rest. Fruit diameters, seed germination, seedling height, root collar diameter, leaf number and seedling survival significantly (P < 0.0001) varied with propagule type. Significantly (P = 0.0275) large seed was obtained from asexual propagules (grafts and marcots) in November, while in December large seed was from natural forest stand. Germination of seed derived from grafts was rapid and consistent. Seedlings derived from asexual propagules were superior in height, survival and root and leaf number. It can be concluded that seed size is independent on propagule type and that large (heavy) seed is superior in germination and seedling growth. Grafts and marcots are alternative viable seed sources for raising seedlings.

Consumer preferences for Uapaca kirkiana fruits in Zambia

Zambian farmers and other stakeholders have identified Uapaca kirkiana as a priority indigenous fruit tree species for domestication. Successful domestication of trees depends on understanding and expanding the market demand for tree products. This study aims at creating a better understanding of consumer preferences for U. kirkiana fruit in Zambia. The study was conducted in the Chipata and Ndola districts of Zambia through a process of questionnaire surveys. A total of 188 consumers were consulted regarding their perception and buying behaviour of indigenous fruits. The study reveals that there is a strong demand for the fresh and secondary products of the U. kirkiana fruit in Zambia. Among the six principal reasons for the direct consumption of the fruit is its sweetness and nutritional value. Jam, butter and syrup are the most desired processed products from U. kirkiana fruit.Indigenous fruit marketing in Zambia is mostly informal and at a nascent development stage. Fruit sellers can improve their marketing efforts by considering the demands of consumers. National market development strategies can assist with the promotion of indigenous fruits and also focus on the processing of such fruits.

Indigenous knowledge of rural communities in Malawi on socio-economic use, propagation, biology, biodiversity and ecology of Uapaca kirkiana Muell. Arg

Uapaca kirkiana Muell Arg. is one of the most popular indigenous fruit trees in the Miombo woodlands of southern Africa. An investigation into existing indigenous knowledge and socio- economic use of this fruit tree was conducted in Malawi. The survey revealed that U. kirkiana fruits contribute considerably to livelihood as a food supplement and for income generation among local communities. However, U. kirkiana trees are not widely cultivated due to lack of improved planting materials and difficulties in establishment outside their natural habitats. The results from the survey indicate that fruits are the main non-timber products that contribute to demand for domestication and the attributes preferred by the rural communities for improvement are mainly related to fruit taste and yield. Poor management and anthropogenic activities have resulted in the destruction of forest reserves and the local people do not have maximum stewardship of U. kirkiana trees in the forest reserve. The indigenous knowledge on U. kirkiana trees provides a valuable basis for domestication, propagation and improvement of fruit and tree attributes, and management issues on both co-managed and government forest reserve.

Histological Evaluation of Early Graft Compatibility in Uapaca kirkiana Müell Arg. Scion/Stock Combinations

Compatibility of scion and stock combinations in Uapaca kirkiana fruit trees has not been evaluated despite noticeable growth irregularities. The objectives of this study were to determine graft compatibility of scion/stock combinations and possible causes of graft incompatibility. Scion, stock, and graft union diameters were measured. Stem sections comprising the graft unions were immersed in formalin acetic acid and then washed in sterile water. These were transversely dissected across the unions and examined under using light microscope. There were considerable growth disorders at the unions, which included significant overgrowth of stocks and unions and constricted unions. There were cracks in the bark across the union in many graft combinations. Anatomic and histological studies showed accumulation of phenol deposits and necrotic tissues, and there was no continuity of vascular tissues above the union. There were also differences in proliferation of callus tissues among grafted partners. Continuity in wood and bark tissues below the unions supported growth of partially compatible partners, whereas isolated parenchymatous tissues at the union supported growth of incompatible partners. There were many necrotic tissues and unfilled areas above the union. Accumulation of phenolic and necrotic cell deposits, poor or a high level of callusing at the union, and possibly specific incompatibility reactions were implicated as the causes of graft incompatibility in U. kirkiana trees.

Harvesting and postharvest handling practices and characteristics of Uapaca kirkiana (Muell. Arg.) fruits: a survey of roadside markets in Malawi

Uapaca kirkiana (Muell. Arg.), a highly valued indigenous fruit species, is being domesticated to increase its utilization in southern Africa. Vendors, who were also the fruit gatherers, that were selling U. kirkiana fruits at roadside markets in Dedza, Malawi, were interviewed on four occasions during the marketing season (October 2003–January 2004) and fruit samples were concurrently sampled from each vendor. Information was obtained on when and how the fruits had been harvested and handled. Timing of fruit harvest was based on experience, aided by indicators such as occurrence of first heavy rains, natural abscission, size and color changes. Harvesting by knocking down unripe fruits from trees was practiced throughout the␣season, but naturally abscised fruits were also gathered in December and January. Fruits harvested when mature but unripe required incubation in soil, plain and woven plastic bags or clay-pots. The incubation method changed and the duration of incubation decreased between October (3–4 days) and January (≤2 days). Fruit samples were evaluated for damage, color and soluble solids concentration (SSC). Fruit SSC and color lightness/brightness (L*) increased from 10.1 to 16.4% (P<0.01) and from 45.7 to 50.5 units, (P<0.01), respectively. Higher SSC values were generally associated (R 2=0.68, P<0.001) with increasing pulp color intensity. Cracking, at 48%, constituted the most common form of damage in sampled fruits. On average, fruits were saleable for only 3–4 days, this being attributed to inherent fruit characteristics combined with immaturity at harvest, and damage during harvesting and storage in hot dry conditions. Lack of appropriate harvesting and handling techniques were associated with fruit darkening, drying, rotting and other postharvest problems.

Analysis of phenolic compounds including tannins, gallotannins and flavanols of Uapaca kirkiana fruit

Tannins and phenolic acids were extracted from Uapaca kirkiana unripe pulp, seed coat, peel and embryo, as well as from ripe pulp, seed coat, embryo and peel portions of the fruit. Extraction was done using 50% methanol. More tannins were detected in the embryos of both ripe and raw fruit. Both ripe and raw seed coat contained the least amounts of tannins. The flavanoids and gallotannins also followed the same trend, with most of them in the embryos of both, the ripe and raw, fruit portions whilst the least were found in the seed coat. Tannins were, however lost during sun-drying compared to oven-drying, even though the differences were not very large. Also, raw fruits showed high concentrations of tannins compared to the ripe fruits. Hydroxybenzoic acid was found in the peel and pulp but none was detected in the seed coat or in the embryo. Similar phenolic acids were detected in the seed coat, except for caffeic acid and protocatechuic acid, detected in the embryo by both the UV florescence and Folin spray.

Income and labour productivity of collection and use of indigenous fruit tree products in Zimbabwe

Rural people in Africa periodically rely on wild fruits to supplement their diet and to generate cash income. However, scientific evidence on the economics of using indigenous fruit tree (IFT) products is scarce. The objective of the study was to fill in some of the gaps for which farm-household surveys were conducted in Zimbabwe during 1999-2000. Gross margins and returns to labour in collection, use and sale of products of Uapaca kirkiana (Muell. Arg., Wild Loquat), Strychnos sp. (S. cocculoides (Baker) and S. spinosa (Lam.), Monkey Orange) and Parinari curatellifolia (Planch. ex. Benth., Fever Tree) were compared with other farming activities. A random sample of over three hundred households in the Murehwa Communal and the Takawira Resettlement Areas was interviewed to gather income and expenditure data. Additionally, income, expenditure and labour allocation of 39 households were closely monitored for one year. Results indicated that the majority of rural households benefited from consumption and sale of indigenous (IF), although the extent varied among households. Within the households, children were the main consumers of fruits. Marketing of IF are carried out by women who used the receipts to purchase household goods. While U. kirkiana fruits were more important in generating cash income than others, fruits of P curatellifolia were important for home consumption during periods of food shortages. The gross margins for collection of IFT products were lower than for livestock and crop production. However, returns to labour from collection and use of IFT products were considerably greater than from other activities including gardening and livestock rearing. The study indicates that collection of IFT products is an efficient labour allocation strategy in Zimbabwe.