HISTOLOGICAL CHANGES IN THE LUNGS AND HEART DUE TO DIETARY OXIDIZED GROUNDNUT OIL.

CHAPTER ONE INTRODUCTION 1.1 Background of the study The most commonly used industrial frying oils are based on partial hydrogenation, which has the benefit of high oxidative stability. Most foods are subjected to processing before being consumed with the goal of enhancing palatability as well as facilitating quick digestion (Sanders 1993).Prominent amongst these processing methods is hydrogenation process especially in he production of margarines and shortenings (Egbung et al.,2012 and Odutuga et al.,1997). Ologan (2002) reported persistent use of reprocessed thermoxidised oils that are predisposed to auto oxidative deterioration in most middle income countries of the world due to its low cost. Different food processing techniques have been found to have adverse effects on consumers. Groundnut oil is extracted from groundnut(Arachis hypogea),a member of the plant family, leguminosae, with a vine like growth form containing pinnate compound leaves of 5 to 7 leaflets(Blackmon and Reynolds,1986).Almost every part of the plant is useful, the kernels are used for candy production when roasted, it is also consumed as a delicacy especially when used in preparing soups in some African communities such as Bekwarra in Cross River State ,Nigeria (Isleib and Wyne,1992,Omagu 2013).The oil can be used as shortening agents or a base for confectionery and for peanut butter as well as for deep frying such as French fries and chicken (Shankarappa et al.,1996). Odutaga and Ajayi 1998 reported a reduction in the concentration of ALP and the loss of enzyme in conditions of deficiency of Zinc and essential fatty acids. There was significant increase (p<0.05) in levels of haemoglobin in rats fed thermoxidised groundnut oil (Ani et al., 2015) .Despite these reported literature information on groundnut oil, there is paucity of information on the biological effects of groundnut oil on the heart tissue hence the present study was designed to evaluate the effect of thermoxidised groundnut oil on the aminotransferase activity in the heart tissue of Wistar rats. 1.2 Statement of the problem Most foods are subjected to processing before being consumed to improve their palatability and in some cases enhance their digestion (Sanders, 1993). Various food processing techniques have been found to leave deleterious effects on the processed foods and fats and oils are no exception (Gurr and James, 1975; Kubows, 1992, Ononogbu, 2002). Although fat and oil serve as the principals and inexpensive source of essential fatty acids and vitamins, during processing, they are Materials and Methods subjected to oxidative degradation (Alexander, 1978; Frankel, 1980; Kubows, 1992; Ologan, 2002). In the economically developing nations of the world, the intermittent use of reprocessed thermoxidised oil is common and uninhibited. Moreover, the semi-refined oils, which are predisposed to auto-oxidative deterioration, even without thermal processing, are the most cheaply and readily available. The compounds formed as a result of thermal oxidation are of special interest, since deep fried fat is continuously or repeatedly used at elevated temperatures in the presence of air and moisture. The peroxides and hydro peroxides do not survive the heating process while the non-volatile products that remain in the oil are absorbed into the food and subsequently ingested (Thomson and Aust, 1983). Degradative products that accumulate have been shown to be potentially toxic (Izaki et al., 1984; Okiy, 1988; Isong et al., 1996; Odutuga et al., 1997; Odutuga et al., 1999; Jimoh and Odutuga, 2002). Although the high level of unsaturation of fatty acids (FA) contained in vegetable oils is appreciated by nutritionists, it causes severe technological problems, because of their high susceptibility to oxidation. The fats oxidation degrades the organoleptic quality of food, reduces its nutritional value.(Yoshikawa et al., 2000).Most of the studies that have been carried out have involved the use of highly abused oxidized oils whose mode of oxidation cannot be compared to normal culinary practices (Andrew et al., 1960; Fujimoto et al., 1984; Mac Gregor et al., 1988). In this study therefore, groundnut oil was thermally oxidized in a way to simulate normal culinary practice, characterized and its effect on the activity of Na K ATPases in selected rat tissues was + + investigated. 1.3 Objective of the study The objective of this study is focused on histological change in the lungs and heart due to dietary oxidized groundnut oil. 1.4 Significance of the study Groundnut oils are an integral part of a human diet as they are used in almost all types of culinary practices. They serve as sources of lipids with a significant nutritive value and health benefits which can be attributed to their fatty acid compositions and biological antioxidants. However, cooking oils are usually subjected to thermal oxidation which occurs when fresh cooking oil is heated at high temperatures during various food preparations. Repeated use of cooking oils in the commercial food industry is also common to maximize pro t. Thermal oxidation of edible oils had since attracted great attention of nutritionist and researchers given the deteriorative effect such as generation of very cytotoxic compounds, loss of carotenoid, phe-nolics and vitamins thus reducing the overall antioxidant properties of the oils. Practically, findings of this study will be use for nutritionist, health practitioner and the general public as the outcome of the study will throw light on the healt risk associated to too much usage of oxidized groundnut oil in cooking.This is because products of the oxidation processes can contribute in the aging of an organism and in the aetiology of cardiovascular diseases and cancer Theoretically, , the result of this study will add to the general body of knowledge, serve as the reference material to scholars and student and may call for further in-depth of researchers on the topic. 1.5 Scope and Limitation of the study The study is focused on histological change in the lungs and heart due to dietary oxidized groundnut oil. Fresh groundnut was purchased from Taminus market, Plateau. Female albino Wistar rats weighing between 90 – 140 grammes were obtained from the National Veterinary and Research Institute.