Abstract

Palm wine is an alcoholic beverage consumed by rural as well as urban people in Cameroon. Palm wine has a shelf of just 48hours (Okafor,1977) and this research was aimed at determining if the glucose concentration of the fresh palm wine will decrease after pasteurization at a temperature of 65°c for 15mins.

A method to preserve palm wine for more than 6 months with the palm wine still maintaining its value without chemical treatment as proposed by Okafor (1977). Then it was found out that the fresh palm wine contains 3.489 mol/l of glucose measured by Benedict’s method.

When the fresh palm wine was pasteurized by heating at a temperature of 65°c for 15mins without any chemical treatment the glucose concentration of the pasteurized wine decreased to 0.806mol/l.

CHAPTER ONE

INTRODUCTION

1.1 Background

Palm wine contains many essential biomolecules like proteins, monosaccharides, vitamins, and some essential elements like potassium (k), Magnesium (Mg), nitrogen (N), and phosphorus (P). The concentration of the macro minerals is of the order K>Mg>N>P (Obahiagbon and Osagie, 2007).

The volume of palm wine produced in Cameroon varies seasonally with greater volumes produced in the month of June, July, August, and September when there is high rainfall, unfavorably low temperatures, and low demands. In addition to Cameroon, palm wine is also produced in many tropical countries like Nigeria and Ghana and it contributes significantly to their rural economy (Cunninghan, 1985).

Palm wine is a white effervescence alcoholic beverage that is produced from various species of palm trees the two mentioned properties are due to the presence of live bacteria and yeast (Gibbs- Russell et al, 1985). In Cameroon, palm wine is mostly produced from raffia palm and oil palm. It is produced in large quantities in areas like Momo division (Batibo, Widikum, and Ngie), Fako Division (Ndongo- Buea, mile 16, and Ekona mbenge) , Mezam Division (Bafut and Bali), and some areas in the central region of Cameroon.

Palm wine has a short shelf life of just two days (Okafor, 1978). This is because the sugar present in wine is converted to ethanol by the action of yeast in the absence of oxygen, a process known as fermentation (Okafor, 1978). Fermentation by yeast cell cells and other microbes starts on the palm wine immediately after it is collected from the palm sap.

Palm wine has been the earliest wine in consumption before the industrial revolution (FLLRO, 2007). In the past, it was consumed in rural areas only, but today, it is transported to urban areas, where it is then sold in limited quantities due to transportation problems and the method of preservation.

In Cameroon, most of the wine gets spoiled during the month of high production and less demand due to lack of storage facilities and the method of preservation, as a result, consumers turn to suffer from limited supply and high prices in the month of low production.

As a means to solve this problem, this research is design to determine the concentration of sugar(glucose) in palm wine before and after pasteurization, to see if palm wine can be preserved for a longer period of time without it getting worse so that it can be available in large quantities for consumption in times of low production and high demand.

1.2 Literature Review

1.2.1 Sources of palm wine

According to Ayyanwu (2006),  Palm wine is mostly produced from the fermented sap of tropical plants of the Palmae family, such as oil palm, coconut palm, date palm and raphia  palm. According to Ndon (2003), R. Hookeri is restricted to tropical rain forest, the ideal ecological condition for the Raphia palm.

Palm wine is known throughout the major parts of Africa under various names such as Mimbo in Cameroon and safufua in Ghana (Jespersen 2003). It is a popular drink consumed by more than 10 million people in West Africa (FAO 1998), because of the nutritional wealth of the non-fermented sap, it is often proposed to infants whose mothers cannot provide the necessary Brest milk for nursing (fantasy, 2003).

1.2.2 Biochemical composition of Palm Wine

According to Fafsnso (2003), palm wine contains sucrose (glucose +fructose) which gives it a characteristic sweet taste. In addition to sugar, palm wine also contains protein, amino acids, alcohol, and minerals.

The beverage, therefore, is a rich source of food nutrients and could serve as a sweetener in food preparation. Palm wine also contains many essential elements like sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), phosphorus (P), and Nitrogen(N). The concentration of these macro minerals are of the order K > Mg > N >  p >Na (Obahiagbon and Osangie, 2007)

According to Ezeagu (2003), palm wine contains values of 39.03, 59.63, and 62.65 mg\100ml protein, free amino acid, and lipids respectively, 3.40g\100ml ethanol. Mg, P and Zn were most abundant element while Pb, Cd, and Co was detected at nontoxic levels. Palm wine is milky in appearance; fresh palm wine is sweat and contains 11.5% of total sugar, 0.15% glucose, 9.5% fructose, and 0.05%rafinose.

During auto fermentation, quantitative analysis indicates that fresh unfermented sap contains 3.92%glu 10mg\ml vit c, 4mg\ml protein, and 0%alcohol. The pH of the sap falls from 7.0 to 4.5 in 120hours. Palm wine is also an important source of nicotinic acid (Cunnigham and Wehmeyer 2008)

1.2.3 Uses of palm wine

Palm wine has a strong cultural significance among Africans. It is used at important traditional ceremonies like marriages, worship rites, and other festivals. Although other types of wine are available, palm wine is irreplaceable for its well-known health benefits as well as its cultural significance among Africans, especially the people of West Africa (Toye, 2010)

Palm wine is an important solvent in herbal medical administration. Pregnant women consume it fresh for the sweetness and the nutrition while nursing mothers drink it warm to enhance breast milk production (Ekpe, 2006)

Palm wine tapping is the main occupation of people in the rural areas and this serves as their main source of income (FIIRO, 2007).

1.2.4 Fermentation of Glucose

Pasteur in 1857 described fermentation as the action of living organisms. According to him, the sugar present in palm wine is converted to ethanol and CO2 in the absence of oxygen by yeast cells and other microbes in the process known as fermentation.

C6H12O6 -2CH3 =   H2 OH + 2CO2

This reaction takes several steps; the glucose in several steps is converted first to pyruvate by glycolysis. The conversion of fructose to pyruvate occurs faster than other hexoses since step one in the glycolytic pathway catalyzed by hexokinase is bypassed.

The resultant pyruvate from glycolysis is then converted to ethanol and CO2 in a two-step process (Lehninger, 2004). In the first step, pyruvate is irreversibly converted to acetaldehyde by the action of pyruvate decarboxylase, with Mg2+ and thiamine pyrophosphate as co factor and coenzyme respectively.

1.3 Rationale

Fermentation starts on palm wine immediately after collection from the source, due to natural yeast in the air and other microbes which converts the sugar present in the palm wine to ethanol and carbon dioxide (CO2). If kept for more than two days, the ethanol is converted to vinegar and at this time it becomes sour and can no longer be consumed.

Due to the lack of preservation methods and storage facilities in Cameroon, the wine always gets spoiled during the month of high production and low demand.

To solve this problem this research is design to determine the concentration of sugar(glucose) in palm wine before and after pasteurization, to see if palm wine can be preserved for a longer period of time without it getting bad so that it can be available in large quantities for consumption in times of low production and high demand (Okafor,1978).

1.4 Overall Objectives

The overall objective here is to preserve palm wine for about six months without it getting worse.

Specific objective                                                                                                                                              

To determine and compare the concentration of glucose in fresh palm wine before and after pasteurization.

1.5 Hypothesis

Alternative hypothesis; the fructose concentration in fresh palm wine will change before and after pasteurization.

Null hypothesis; there will be no change in the fructose concentration of fresh palm wine before and after pasteurization.