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Utilization of local fruit in wine making in Malawi

Timothy N. Ngwira
University of Malawi
Bunda College of Agriculture
P.O. Box 219, Lilongwe, Malawi

Abstract

Wine was made from the following indigenous and exotic fruits of Malawi: katope (Syzygium owarience) in December-January, guava (Psidium guajava) in January-April, chidede (Hibiscus sabdariffa) in June-September, bwemba (Tamarindus indica) in July-October and mango (Mangifera indica) in September-January. For katope and chidede, hot water extraction was carried out and the pH adjusted to pH 3.5. All the musts were treated with pectolytic enzyme to destroy pectins, which inhibit the clarification of the wine. White cane sugar, wine yeast nutrient, and commercial wine yeast were added to all the juice extracts. Aerobic fermentation was carried out for two days at 25oC in an open container. Fermentation started 2 hours after the yeast was mixed with the ingredients. After two days, anaerobic fermentation continued at the same temperature (25oC) until the wine was ready for bottling. The first racking occurred one week after the start of anaerobic fermentation, and subsequent rackings were at two-week intervals. Completion of fermentation and therefore the clarification of the wine occurred 4-6 months after the fermentation process started. The alcohol content of the wine ranged from 14 to 16%. The white guava gave the highest alcohol content and produced a dry wine. Mango and bwemba also produced white wines, chidede produced a rosé wine, and katope produced a red wine. The flavours of the wines were characteristic of the fruit used. The average Malawian palate preferred the semi-sweet wines.

Introduction

The African continent has many indigenous shrubs and trees, fruit-bearing varieties among them. A number of these fruit shrubs and trees, mostly the exotic ones, have been domesticated, and some are grown under agroforestry farming systems. The fruits produced by many of the indigenous shrubs and trees are edible. They grow and ripen within a very short period of the year, which leads to an overabundance of the fruit at that time, when the supply usually exceeds the demand. This situation is aggravated by the lack of storage facilities for fresh fruit or of fruit-processing facilities. In addition, some of the fruits, although edible, are not very palatable, contributing to their underutilization.

Producing wine from these indigenous fruits is one way to utilize the excess fruit or to improve its palatability. Wine has been made from the fruit of palms (Herzog et al. 1995), sour cherry (Vondracek et al. 1981), Rosa roxburghii (Liu-Jiunian 1982), cashew apple (Rao 1985) and bamboo (Mgheni 1983), among many indigenous others. The most common commercial wine is traditionally made from grapes.

In Malawi, Williamson (1975) documented many useful plants, among them katope (Syzygium spp.), bwemba (Tamarindus indica L.), guava (Psidium guajava L.), chidede (Hibiscus sabdariffa L.) and mango (Mangifera indica L.), all producing fruit at different times of the year. Wine making from indigenous fruits in Malawi was at one time commercial and Mulunguzi wine was made from masuku or wild loquat (Uapaca kirkiana Muell. Arg). Unfortunately production stopped, and no one in Malawi makes country wine on a commercial basis any more.

This study examined wine production from some fruits of Malawi throughout the year: katope (December-January), guava (January-April), chidede (June-September), bwemba (July-October) and mango (September-January). No attempt was made to use masuku in this study.

Materials and methods

Fruit

All the fruits were bought within Malawi. Katope was purchased in Lilongwe; guava was bought from the Bunda College orchard; chidede was harvested around the Bunda area in Lilongwe; bwemba was purchased in the Machinga area on the road to Mangochi; and the mangoes were purchased in Ntcheu District on the way to Balaka. The fruits purchased were fresh except for the bwemba fruits, which were dried.

Juice extraction

Juice was extracted by covering the fruit with 2 litres of boiling water per kilogram of fruit. The mangoes and the bwemba were peeled before they were scalded. The scalded fruit was cooled in a covered glass or plastic container, crushed, placed in a nylon juice extraction bag, and squeezed.

Pectin destruction

Pectolytic enzyme (pectolase) was added to the extracted fruit juice to help clarify the wine, as all the juices tended to be high in pectin. The enzyme was left to incubate with the juice for 24 hours.

pH monitoring

The pH of the resulting juice was determined using a narrow-range pH paper. The aim was to obtain a pH of around 3.5, which is an acceptable acidity for wines. Where necessary the pH was adjusted with either lemon juice or citric acid, or with potassium carbonate (K2CO3).

Aerobic fermentation

After the pH was adjusted, cane sugar from Malawi was added, as the sugar content of the fruit was low. The maximum alcohol produced in the absence of additional sugar would have been about 5%. The sugar added at fermentation was aimed to produce an alcohol content of 11-12%. Also added were wine yeast from a starter and wine yeast nutrient. The yeast was left to ferment aerobically for 48 hours at room temperature (25-27oC), during which time the must was stirred every 12 hours.

Anaerobic fermentation

After the 48 hr of aerobic fermentation, the must was poured into 25l scalded containers of glass or plastic, where anaerobic fermentation occurred over many months. The gas trap contained boiled water.

Racking

The first racking was usually one week after the start of the anaerobic fermentation with more racking following at longer intervals (two weekly rackings on the average), until fermentation stopped and the wine had cleared. Clearing normally started during the 4th month of fermentation, but some wines took up to 6 months to clear.

Bottling

Bottling was carried out after the wine had stopped fermentation and the wine had cleared. The best time for bottling was usually 6 months after fermentation.

Results and discussion

Acidity

The pH of katope and chidede extracts were acidic (pH 1.5) and had to be adjusted with K2CO3. Once adjusted, the pH remained the same until the end of fermentation.The pH of the other fruit (i.e., mangoes, guavas and bwemba) were normal for wine production (pH 3.5): S. owariense 2.5 ± 0.5, P. guajava 3.5 ± 0.5, H. sabdariffa .5 ± 1.0, T. indica 4.0 ± 0.5, M. indica 3.5 ± 0.5.

Fermentation

The yeast used in these fermentation trials was very active at 25-27oC, and fermentation started 2 hours after it was added. All the wines stopped fermenting after the alcohol content was above 12%. It was difficult to have clarity in the wine during the early part of fermentation. Katope tended to ferment faster (3.5 months) than the other fruits and was also faster in clearing. The slowest fermenting fruit was the mango, which took 5 months to clear. The seasonal temperatures influenced the rate of fermentation, which was faster during the hot season (August-December).

Alcohol content

Fermentation and clearing took longer in katope and white guava than in the other fruits. The mean alcohol content after the wine stopped fermenting was S. owariense 14% (range 12-16%), P. guajava (white) 16% (12-18%), P. guajava (red) 14% (16-18%), H. sabdariffa 12% (12-14%), T. indica 14% (12-14%), M. indica 14% (12-16%).

Colour of wine

Wine colour was related to the colour of the fruit pigment: S. owariense , red wine; P. guajava (white), white; P. guajava (red), white; H. sabdariffa, rosé; T. indica, white; M. indica, white. The intensity of the rosé and the red colour depended on how long the pectolase had been used to destroy the pectin; the longer the juice was incubated with the pectolase the deeper the colour of the wine.

Sweetness or dryness of wine

Although generally the sweetness of the wines depended on the quantity of cane sugar added to the must, the white guava normally gave a dry wine and the red guava a sweet wine. This must depend on the other sugars present in the red guava, which were not fermented by the yeast. This observation has also been made in white peach and red peach wines.

Wine preference

Although this has not been quantified yet, the majority of Malawians ask for wine that is either semi-sweet or sweet. On the other hand, expatriates normally prefer dry wine. Cultural differences in preference is of course an important consideration when the market for wines is being developed.

Commercialization

Commercial production of wine is possible from any of these locally available fruits. The fact that some of the shrubs and trees have found their way into agroforestry systems will make the fruit readily available for wine production. There is great potential in Malawi for commercial production of country wine. So far, the wine has advertised itself. Other fruits that have been used include peaches (Prunus persica L. Batsch), bananas (Musa paradisiaca L.), tangerines (Citrus reticullata Blanco), oranges (Citrus sinensis (L.) Osbeck), lemons (Citrus limon (L.) Burm), papayas (Carica papaya L.) and grenadillas (Passiflora edulis Sims). The commercial production of Mulunguzi wine from Uapaka kirkiana fruits in Malawi has been suspended currently.

To make commercial production of country wine in Malawi feasible, the following are needed: a reliable supply of wine yeast, yeast nutrient and pectolase;: wine bottles and corking materials; and the availability of large-scale equipment for commercial production.

References

Herzog F., Farah Z. & Amado R. 1995. Chemical composition and nutritional significance of wines from the palms Elaeis guineensis and Borassus aethiopum in the V-Baoule, Côte d'Ivoire. Tropical Science 35:30-39.

Liu-Jiunian. 1982. Studies on the stability of chaosihua rice wine (using glutinous rice and fruit of Rosa roxburghii as raw material. Food and Fermentation Industries 3:43-51.

Mgheni A.S.M. 1983. Bamboo wine from Oxytenanthera braunii. Indian Forester 109 (5):306-308.

Rao M.S.S. 1985. Scope for development of alcoholic beverage from cashew apple. Acta Horticulturae 108:160-164.

Vondracek J., Blazek J. and Kloutvor J. 1981. Evaluation of sour cherry varieties. Zahradnictvi 8(4):249-260.

Williamson J. 1975. Useful plants of Malawi. University of Malawi and Montfort Press, Limbe. Malawi. p 129-227.

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Plate 20. Tasting wines from fruits of Malawi during the conference poster session. (photo: A.B. Temu)

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