Nutrition & Food Science International Journal ISSN 2474-767X Research Article Nutri Food Sci Int J - Volume 4 Issue 1 November 2017 Copyright © All rights are reserved by Nwosu Caesar DOI: 10.19080/NFSIJ.2017.04.555626 Effect of Process Parameters on the Physical Properties of Watermelon Seed Oil under Uniaxial Compression Nwosu Caesar1*, Ozumba Isaac C1 and Kabir Abdullahi O2 1Agro-Industrial Development and Extension Department, National Centre for Agricultural Mechanization, Nigeria 2Agricultural and Bio systems Engineering Department, University of Ilorin, Nigeria Submission: May 01, 2017; Published: November 17, 2017 *Corresponding author: Nwosu Caesar, Agro-Industrial Development and Extension Department, National Centre for Agricultural Mechanization, Nigeria, Email: Abstract The effect of process parameters such as temperature and pressure on the physical properties of watermelon seed oil under uniaxial compression was studied. A laboratory mechanical oil expression piston-cylinder rig was used to express oil from watermelon seeds at different temperatures (100 °C, 110 °C, 120 °C and 130 °C) and different pressures (5000Kg, 5500Kg, 6000Kg and 6500Kg). The expressed oil was analyzed analysis using Analysis of variance (ANOVA). for Viscosity, Specific gravity, Refractive Index and Boiling Point using standard methods. The results obtained were subjected to statistical The results revealed that viscosity of the expressed oil consistently decreased with increase in heating temperature for all the pressure regimes under study and increased with increasing applied pressure for all temperature regimes under study. The results also showed that wasprocess also conditions revealed in did this not study affect that the while specific increasing gravity temperatureof the expressed reduces oil in Boiling a particular point, increasingpattern. The pressure study further increases revealed the Boiling that anpoint increase of oil mechanicallyin heating temperature expressed fromand appliedwatermelon pressure seed. results It is therefore in a corresponding concluded that significant for optimal increase physical in propertiesthe refractive of oil index expressed of the from expressed watermelon oil. It seeds, temperature and pressure must be regulated. Introduction and 7.5mg iron. It also contains the necessary amino acids such Vegetable oils are essential in meeting global nutritional as Leucine, Isoleucine, Tryptophan and Valine [3]. demands and are utilized for many food and Industrial purposes [1]. In Nigeria, vegetable oils are gaining popularity According to [4], watermelon seed oil contains high amounts in food, medical, cosmetic and soap making industries for of unsaturated fatty acids with linoleic and oleic acids as the the production of edible oils, drugs, pomade and toilet soaps major acids. Conventionally, the seeds are removed from the respectively. Although there is a wide range of vegetable oil sources, the Nigerian vegetable oil production is dominated by reduce its moisture content. Once dried, the seeds are then pod and then allowed to dry outside in the sun to significantly palm olein, groundnut and soya bean. pressed to extract the useful oil. In Nigeria, the traditional method of vegetable oil extraction is still in use; products from Watermelon seeds are one of the known oil bearing seeds this method have limited application due to poor quality of with high nutritional importance. Its oil is used in cooking oil obtained from this process. According to [5], the Nigerian and can be incorporated into the production of cosmetics vegetable oil production industry has been characterized by [2]. Watermelon seeds are rich sources of protein, vitamins low production capacity, low extraction rate of (12-18) % and B, minerals (such as magnesium, potassium, phosphorous, low quality of produced oil (FFA greater than 10%). sodium, iron, zinc, manganese and copper) and fat among others as well as phytochemicals. According to [2], its seed This low extraction rate and poor quality oil can be averagely consist of 31.9% protein, 4.4% carbohydrates, 57.1% attributed to the process and the equipment used for the expression. In view of the increasing awareness of the use of fat, 8.2% fiber, 6.2% ash, 130 mg calcium, 456mg phosphorus, Nutri Food Sci Int J 4(1): NFSIJ.MS.ID.555626 (2017) 001 Nutrition & Food Science International Journal watermelon seed oil; there is need to know the appropriate sets Experimental Design of parameters necessary for the optimum quality extraction In order to study the effects of process conditions such as of the oil. This study is therefore focused at investigating the heating temperature and applied pressure on the physical quality of oil recovered during mechanical expression of oil properties of oil mechanically expressed from watermelon from unshelled watermelon seed at different temperatures seeds; a suitable experimental design that incorporated and pressures. four levels of heating temperature (i.e., 100 °C, 110 °C, 120 Materials and Methods °C and 130 °C), four levels of applied pressure (i.e., 5000kg, 5500kg, 6000kg and 6500kg) was designed. A 4x4 factorial All experimental investigations were carried out in the Food Mechanization (NCAM), Ilorin, Nigeria. The average room experimental design in a Complete Randomized Block Design Processing laboratory of the National Centre for Agricultural at each level of the factors. The ranges of values of these factors temperature of the laboratory throughout the duration of the (CRBD) was used. Each test was performed in three replicates were obtained from literature search and preliminary test on experimental works was averagely 30 °C. watermelon oil expression. Material preparation Table 1: Design layout of 4x 4 Factorial Experiment under Complete Watermelon seeds used in this experiment was obtained Randomize Block Design (CRBD). from an open market in Ilorin, Kwara State, Nigeria. The unshelled seeds were sorted and cleaned to remove stones T1P1 T3P1 and other foreign materials. The moisture content of the seeds T1P2 T3P2 was determined using method prescribed by [6] and was found T1P3 T3P3 to be 4.25% wb. The seeds were then packed into air tight T1P4 T3P4 containers and placed in the laboratory. T2P1 T4P1 Experimental machines and instrumentation T2P2 T4P2 T2P3 T4P3 Key: T=Temperature;T2P4 T1=100 °C; T2=110 °C; T3=120T4P4 °C; T4=130 °C; P=Pressure; P1=5000kg; P2=5500kg; P3=6000kg; P4=6500kg Other important factors such as moisture content, particle size, heating time and pressing time were also obtained through preliminary investigations and were kept constant throughout the experiments in order to reduce the data to a reasonable size. The layout of the 4x4 factorial design experiments is as shown in Table 1. Sequence of Mechanical Oil Expression Before coupling the mechanical oil expression rig, a stainless steel wire mesh was placed at the bottom of the cylinder guide in order to cover the drainage area and at the same time serve Figure 1: Exploded view of the Model laboratory Mechanical Oil Expression Rig. a sample of 200g weight of unshelled watermelon seeds was as a filter during the oil expression process. After the coupling, In this study, a technique for heating oil seed sample poured into the press cage cylinder. The sample was then before and during expression was adopted. A laboratory heated for 30 minutes at 100 °C. Using the actuating lever of mechanical oil expression piston-cylinder rig, developed and the hydraulic press, the compression piston was moved down used by [7] was used for this experiment. The laboratory to compress the sample inside the press cage cylinder to a mechanical oil expeller is made up of three major components: pressure of 5000kg for 10 minutes. The oil expressed drains the compression piston, the press cage cylinder and the into the oil collector and was collected through the outlet pipe. supporting platform. A 600W electric band heater was installed round the press cage cylinder to serve as a heating On the expiration of the pressing time, the compression device for the expression process, while a thermocouple probe piston was lifted above the press cage using the actuating lever was used to monitor the temperature of the sample during of the hydraulic press and the resulting cake was discarded. preheating and expression process. The rig was adequately The same procedure was followed to carry out the experiment instrumented with a temperature controller to control the for three other heating temperature levels of 110 °C, 120 °C expression temperature, while the pressure for oil expression and 130 °C and three other applied pressure levels of 5500kg, was obtained from the hydraulic press via the instrumentation 6000kg, and 6500kg. Each experiment was carried out in three system (force measuring device) (Figure 1). replicates. How to cite this article: Nwosu C, Ozumba I C, Kabir A O. Effect of Process Parameters on the Physical Properties of Watermelon Seed Oil under 002 Uniaxial Compression. Nutri Food Sci Int J. 2017; 4(1): 555626. DOI: 10.19080/NFSIJ.2017.04.555626. Nutrition & Food Science International Journal Determination of physical properties of expressed oil refractive index and Boiling point. the expressed oil determined are viscosity, specific gravity, The physical characteristics (quality) of the expressed Results and Discussion oil at the various levels of heating temperatures and applied The summary of the results of the physical properties pressure were determined. The analyses were carried