CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND OF THE STUDY

Vegetables and fruits are essential foods in our diet and also have many compounds that are beneficial for health due to minor components which include phenolic substances (Francisco et al., 2012). The consumption of the tropical-subtropical fruit, avocado, has increased considerably in the last century throughout Nigeria. There seems to be potential for further increases in consumption in the future (Manuela, 2011).Nowadays, great importance has been attached to oils from fruits and seeds, this is because of their numerous functions and uses to mankind. Fats and oils from seeds act as insulators to the body. They serve as protective layer or covering for the internal organs such as heart and lung. They also serve as sources of energy to the body in the absence of carbohydrates (Akpabio et al., 2011).

Persea americana, commonly known as Avocado, is a fruit that contains a high value of oil and chlorophyll concentration which when extracted results to an oil of emerald green color (Genevive et al., 2013). The avocado fruit is rich in nutrients, high in proteins, antioxidants and dietary fiber is perhaps the most poorly conceived and misunderstood fruit of all times. This is mainly attributed to its high fat and calorie content and so most nutritionists and dieticians either advise against it or to use it “sparingly” (Kuinimeri, 2007). The presence of a ‘tree factor’ and C7 sugars has been hypothesized to act as inhibitors in the repining process of avocado fruit. Additionally, the content of sugars seems to decrease with fruit maturity. Also, in exceptional cases, avocados do not ripen until harvested although maturity does increase while the fruit remains on the tree (Manuela, 2011).

There had been many studies regarding the extraction of avocado pulp. Most of these have indicated the high amount of oleic acid present in avocado. Oleic acid is said to be an effective aid to lower serum cholesterol levels and low-density lipoproteins in the human body (Genevive et al., 2013). However, with the abundant production of avocado apple in Nigeria, 15% of avocado pear (pericarp/peels) is discarded as waste which ought to have been a potential source for the production of oils for industrial applications, specifically, the fruits’ pericarp that are reported to have antiviral, antibiotic and insecticidal properties and employed as a vermifuge and remedy for dysentery and in the production of cosmetics (Adama and Edoga, 2011).

 1.2  STATEMENT OF THE PROBLEM

Nowadays, great importance has been attached to oils from fruits and seeds, this is because of their numerous functions and uses to mankind. Due to this fact the demand for avocado oil has increased. This work will therefore focus on improving the production of the oil in large quantities to meet up the demand by investigating some parameters that would enhance better production.

 1.3 AIM

The aim of this work is to study the effect of solvent type and extraction time on the yield of Avocado pear seed oil using solvent extraction method.

The objectives of this work are:

1. To carry out seed preparation
2. To carry out solvent extraction process using soaking method
3. Finding out the oil yield of avocado pear by varying the solvent type and extraction time
   
   
   
   1.4 SCOPE OF THE STUDY
   

This study will be conducted on the seed of an Avocado Pear (Persea americana) and the method to be employed will be carried out in the laboratory using soaking method with hexane, diethyl ether and chloroform as solvents in determining the best possible yield with varying time intervals.

 
1.5 RELEVANCE OF THE STUDY

This study will give a full knowledge of the parameters to consider when carrying out a commercial production of oil from avocado pear seed in order to get a better yield. With this information, the production of avocado oil from the seed will be optimized by choosing the best solvent required for maximum extraction. This will provide better parameters to be used in the conversion of seed as a form of waste to useful products.