A Review on the Quality of Palm Oil (Elaeis guineensis) Produced Locally in Imo State, Nigeria

Over 70 % inhabitants of Imo state pend on palm oil for their cooking, frying etc. The study reviews available data on palm oil quality produced locally in Imo state with a view of providing up-to-date information and identify research gaps that could have health consequences on consumers. Peer reviewed scientific articles were reviewed and a meta-analysis of four different scientific research databases, PubMed, Web of Science, Google Scholar and Directory for OpenAccess Journals was conducted. The result showed that palm oil produced locally in Imo state has average of pH (4.73), acid value (28.3 mg/KOH), FFA (14.15 mg/KOH), smoke point (115C), iodine value (1.68 wijj’s), saponification value (197.07 mgKOH/g), ester value (168.77), moisture content (0.44 %), density (0.89 g/ml), SG (0.91), peroxide value (17.75 mEq./kg), refractive index (1.46 Bx) and viscocity (60.04 cps). Overall palm oil is highly degraded and of poor quality since major quality indicators are not within Nigerian Industrial Standard and Standard Organization of Nigeria. Also, there is a dearth of information/data available on quality of palm oil produced locally in Imo state especially on its microbial status. Food scientist should look in that direction to enhance proper understanding of the quality of palm oil. Introduction Palm oil is an edible oil, reddish in colour derived from the fruits of the oil palm Elaeis guineensis, which is indigenous in West Africa [1-3]. The oil palm tree is a perennial tree crop, which produces the highest quantity of oil when compared to other oil producing plants [4-5]. The crop is unique in that it produces two types of oil. The fleshy mesocarp produces palm oil, which is used mainly for its edible properties and the kernel produces palm kernel oil, which has wide application in the oleochemical industry [5-6]. Palm oil consumption in 2015 was estimated at 35% globally [7] making it the highest consumed vegetable oil. Like most vegetable oils, palm oil is mainly composed of triglycerides or triacylglycerols which represent 95% of the total weight constituents [8-9]. It also contains minor compounds such as diacylglycerol, mono glycerol and free fatty acids (FFA) issued from the biosynthesis and / or hydrolysis of triacylglycerols, sterol, tocopherol, pigments and metal ions are also represented [10]. The majority of fatty acids are palmitic acid followed by oleic acid [11-13]. The benefits of palm oil are numerous and at the same time it present health implications from use of poor palm oil. The janus behavior of palm oil is majorly due to its chemistry. Certain properties make it deteriorate faster and so could constitute a health problem when consumed. Palm oil has been used in food preparation for over 5,000 years [14]. The nutritional and health implications have been reviewed and well documented [14-15]. Palm oil has good resistance to oxidative deterioration and its better ability to withstand high temperatures has made it so useful in frying than most alternative oils [16-17]. In addition, it is rich in antioxidant such carotenoids, tocopherols and tocotrienol which when consumed enhance immune function by a variety of Sustainable Food Production Submitted: 2018-06-14 ISSN: 2624-876X, Vol. 4, pp 40-50 Revised: 2018-09-03 doi:10.18052/www.scipress.com/SFP.4.40 Accepted: 2018-10-02 2018 SciPress Ltd, Switzerland Online: 2018-12-20 SciPress applies the CC-BY 4.0 license to works we publish: https://creativecommons.org/licenses/by/4.0/ mechanisms, and can improve cardiovascular health [14]. Carotenoids also play an important potential role by acting as biological antioxidants, protecting cells and tissues from the damaging effect of free radicals through pollutants exposure to cigarette smoke, industrial pollution, stress, unbalance diets, pesticide and insecticide residues in food and water, and many other negative environmental influences [18]. Degenerate diseases such as heart disease and cancer, as well as general ageing are associated with buildup of free radicals in the body. These natural antioxidants act as buffers against free radicals and are believed to play a protective role in cellular ageing, atherosclerosis, cancer, arthritis, and Alzheimer’s disease [19]. Other additional benefit is their use in cosmetics [20-21]. They have been blended into mayonnaise and salad oil [22] and have been used so well in soap production. The aim of this study is to review the available information on the quality of palm oil produced locally in Imo state Nigeria. It is believed that more than 70 % of palm oil users in Imo state uses locally produced palm oil for their domestic activities such as cooking, frying etc. This study is significant as it’s bringing into limelight the status of palm oil produced locally in terms of quality. The study also provides baseline information for further research on quality of palm oil produced locally in Imo state. Sources of Data The data/information was sourced from materials such as journals articles and conference/workshop/seminar papers and statistical bulletins. PubMed, Web of Science, Google Scholar and directory for open-access journals (DOAJ) were four scientific databases used to search for related articles using the keywords: palm oil, Imo state, quality (conducted in June 2018) produced limited (numbering 2) citations particular to Imo state while in total number of 74 papers was used in this review. Over 90% of literatures reviewed were obtained from backdoor searches through references confirming the scarcity of information on the subject matter. Study Area: Imo State, Nigeria The state lies in the South East of Nigeria. The state has 27 local government areas with its capital as Owerri which is also the largest city in the state. Its other major cities are Orlu and Okigwe. Imo occupies the area between the lower River Niger and the upper and middle Imo River. The state lies within latitudes 4°45'N and 7°15'N, and longitude 6°50'E and 7°25'E with an area of around 5,100 sq km [23]. There is atleast one local palm oil processing unit in each of the 27 local governments (Fig. 1). Example of such unit is Adapalm in Ohjai Egbema, while most others are not with name. Sustainable Food Production Vol. 4 41