INTRODUCTION

Tropical fruit wine-making in the country started during the early 1980's, explored and spearheaded specifically by the Institute of Food Science and Technology (now Food Science Cluster) of the University of the Philippines-Los Baños (UPLB).

Given that our fruits are abundant, readily available and inexpensive, securing consistent and low-cost supply to the Philippine fruit wine industry is highly feasible. A variety of substrates aside from grapes has now been utilized in the Philippines.

OBJECTIVES

The primordial purpose of this study by exploiting the fermentative ability of yeasts to produce Guyabano wines is to offer a relative simple avenue for reducing wastage of Guyabano fruits in low utilization environment and in places where the production of Guyabano is low or nonexistent. Graviola wine are readily storable and can be used for production processes even when the fruit is out of season.

The following are the objectives of Graviola (Guyabano) winemaking among 3 key areas:

WINEMAKERS: The student (winemakers) will learn and master the basic of wine making.

PRODUCT: To produce desirable taste of fine Graviola (Guyabano) wine.

CONSUMERS: To appreciate the taste and health benefits of Graviola (Guyabano) wine and help

promote homemade production and eventually for commercialization.

INGREDIENTS AND MATERIALS

1 Kilogram ripe soursop “guyabano” fruit (Annona muricata)

Baker’s yeast ( Saccharomyces cerevisiae)

4 Liters purified drinking water

1 Kilogram refined sugar

Fermentation vessels

Siphoning devices

Strainer

Cooking pot

METHODOLOGY

1. Meticulous fruit selection- Only the best quality and ripe guyabano fruits were used in this product to produce good quality tasting wine.

2. Extraction of aroma and taste- Ripe guyabano fruit pulp(excluding the skin and seeds) was soaked and boiled adding 4 litters of water and 1 kilogram of refined sugar. Allow to cool for 24 hours.

3. Fermentation- The wine / sugar mixture (must) is now ready to start fermenting. Yeast can replicate and grow by breaking down sugar into alcohol and carbon dioxide (CO2). It does not need oxygen (O2) to complete this process. This is called an anaerobic process. If oxygen or air is allowed to get to the wine, oxidation can occur, whereby, alcohol combines with oxygen to create acetic acid (vinegar). There is a bacterium called acetobacter that carries enzymes that rapidly promote this process. Baker’s yeast (1 teaspoon) was added as fermenting agent due to unavailability of wine yeast. Fermentation process is expected to be rapid for 2-3 days with more bubbles appearing on top of the vessel. Oxidation is unlikely to occur during this stage so only an airlock mechanism which can allow CO2 be expelled in the vessel was used and not necessarily an airtight one.

4. Racking/Siphoning- In 2-3 days bubbling may have subsided and the mixture was ready for siphoning. It was then transferred to another fermenting vessel with now an airtight lock using a cork cup fitted on the lid. Siphoning/ racking (approx. every 2 weeks for 2-3 months) were done several times until no observable residues were seen. It is also important to reduce the amount of air space above the fermenting wine when the fermentation process slows down.

5. Refining- To stop the fermentation the wine was heated to about 55°-60°C (thermal death point for bread yeast).For finer/clearer wine an egg white was added and allowed the remaining sediments to settle for 3-4 days. 2-3 more racking follows.

6. Bottling- The product is a medium-sweet guyabano wine with lesser alcohol content. If given more time for aging process, it is expected to yield a considerable increase in alcohol by volume content. Once clear, wine is ready for bottling. If you intend to age the wine it must be kept in a cool dark place with a constant temperature around 13°C.

RESULTS

CONCLUSION

Fermentation of Graviola (Guyabano) wine using baker’s yeast S. cerevisiae resulted into desirable sweet taste wine, it is therefore concluded that the source of the yeast is thus an important factor in the determination of quality wine characteristics. It was believed that the longer the fermentation period and its aging period, the better the taste hence the higher quality of wine will be produced. Moreover, the students realized that they can be good winemakers even it was just self-taught, although wine production entails extensive training and expertise but good & acceptable wine can be obtained by just learning the basic.