Food Science and Technology Project Topics

Physico-chemical Properties of Soybean Oil

Physico-chemical Properties of Soybean Oil

Physico-chemical Properties of Soybean Oil

Chapter One

The Objective of the study

Thus, this research study will focus on the effects of physico-chemical properties on soybeans oil production.


 Soybean Oil and Healthy Benefits

Mono-unsaturated Fatty Acid and Poly-unsaturated Fatty Acid and Inflammation

High fat intake has been associated with adipose tissue inflammation (Weisberg et al., 2003;Todoric et al., 2006), and furthermore, low, moderate and high-fat diets have suggested that the amount of fat present in the diet is less important than the nature of fat consumed (Field et al., 2007, Mozaffarian et al., 2011). Various studies have assessed whether diets containing certain proportions of MUFA and PUFA might affect obesity parameters. While PUFA (n-3) is believed to be beneficial to health, high intakes of PUFA (n-6) without a concurrent increase in PUFA (n-3) have showed detrimental effects on cardiovascular events and even death (Ramsden et al., 2010, 2013). Many changes in fatty synthase, adiponectin metabolism, and short-chain fatty acid receptors GPR41 and GPR43 have been observed in animals fed high-fat diets with different amounts of MUFA and PUFA (Enns et al., 2014). These findings indicate that different types of fatty acid-rich diets (e.g. soybean oil) regulate adipokines and proteins involved in adipose tissue metabolism and inflammation.

Soybean Oil and Diabetes

Insulin resistance is one of the metabolic alterations characterized by an abnormal response of circulating insulin which is associated with glucose intolerance and decreased glucose uptake by peripheral insulin responsive tissues. Therefore, insulin resistance precedes the onset of type 2 diabetes mellitus (T2DM) (Bonadonna and De Fronzo, 2001). Mono- or polyunsaturated fatty acids have been described to improve insulin sensitivity (Coll et al., 2008) and to exert anti-obesity action (Sekiya et al., 2003). Furthermore, shifting from a diet rich in saturated fatty acids to one rich in monounsaturated fatty acids ameliorates insulin sensitivity in healthy people (Bonadonna and De Fronzo, 2001).

A recent study showed that animals treated with 100 µL soybean oil for 7 days developed insulin resistance, and the expression of GLUT4, a transmembrane glucose transporter, was 60% lower in adipose tissue while no effects were observed in skeletal muscle (Poletto et al., 2010). It has been shown that low amount of soybean oil, rich in both linoleic and alpha linolenic acids (LA and ALA), ameliorates the diabetic phenotype and restores Δ6 desaturase levels (LeikinFrenkel et al., 2004). In contrast, an experimental study found that high-fat diet containing soybean oil is able to increase body mass, length, and retroperitoneal fat mass, when administered during the first 60-days-old. In addition, a severe reductionof the pancreatic islets area was observed in these animals (Da Costa et al., 2013).  A study with normotensive healthy subjects found that soybean oil, olive oil, and lipid free similarly increased glucose and insulin concentrations during parenteral infusion. However, no changes were observed for lipid profile, inflammatory and oxidative stress biomarkers, or immune functions between soybean oil- and olive oil-based lipid emulsions (Siqueira et al., 2011).

Soybean Oil and Cardiovascular Disease

Soybean oil can be enriched with (n-3) stearidonic acid (SDA) to allow efficient conversion to longer chain eicosapentaenoic acid (EPA). EPA possesses distinct biological properties that generally impart properties to cells and tissue, which underlie their ability to promote health and prevent disease (Deckelbaum and Torrejon, 2012). Although active in some areas of human biology, mechanisms of EPA actions are perhaps best defined in cardiovascular disease. The long chain EPA can alter cell membrane structure and fluidity as well as decreasing the amount of membrane occupied by lipid rafts (Yaqoob and Shaikh, 2010). The (n-3) fatty acid (FA) and their derivatives are important molecules in chemotaxis and immune and inflammatory response. Importantly, (n-3) FA decreases blood pressure and alters vascular resistance (Sudheendran et al., 2010). Some cardiovascular benefits have been reported for (n-3) FA in terms of reducing arrhythmias, providing TG-lowering effects, and providing antithrombotic and anti-inflammatory as well as antihypertensive effects (Sudheendran et al., 2010).

In a variety of experimental studies, animal models fed a high-fat diet rich in (n-3) FA decreased dyslipidemia, cholesterol delivery to the arterial wall, arterial pro-inflammatory processes, and increased arterial anti-inflammatory biomarkers. Also, LDL uptake can be affected by different types of dietary FA (Rumsey et al., 2002), in which the uptake of cholesterol esters from LDL can lead to cholesterol deposition within cells and tissues, thereby contributing to atherosclerosis. Satisfactorily, high-fat diets rich in (n-3) FA negatively regulate selective uptake and decrease whole-particle LDL uptake, with a severe LDL reduction in the aortic media layer (Chang et al., 2009). Growing evidences have pointed out that oxidative stress leads to vascular damage and plays a critical role in the cardiovascular diseases such as hypertension (Fearon and Faux, 2009).

High production of reactive oxygen species (ROS) is increased during hypertension in both experimental and clinical models of hypertension (de Champlain et al., 2004). After comparing the effects of canola oil and soybean oil ingestion upon antioxidant activities, Papazzo et al., (2011) reported that soybean oil promoted elevation in superoxide dismutase, glutathione peroxidase and catalase activities, total cholesterol and low-density lipoprotein cholesterol. In contrast, malondialdehyde and 8-isoprostane concentrations were significantly lower after the ingestion of canola oil compared to the soybean oil.  Parenteral infusion of Soybean oil significantly reduced brachial artery flow-mediated dilatation from baseline – 23% at 4 h and – 25% at 24 h; in contrast, administration of olive oil, lipid free, and saline did not change either systolic blood pressure or flow (Siqueira et al., 2011).





The oil was purchased from Oja Oba in Owo, Ondo State Nigeria. Various chemicals Hydrochloric acid (HCl), sodium hydroxide (NaOH), potassium hydroxide (KOH), idobromine (IBr), sodium thiosulphate (Na2S2O3), potassium iodide (KI), and acetic acid (CH3COOH) were used to determine the physico-chemical properties of the oil, the analysis was carried out in chemistry laboratory of Food Science and Technology, Rufus Giwa Polytechnic Owo, Ondo State, Nigeria.

 Determination of Physico-chemical Properties of Oil

The determinations of physicochemical parameters of seed oils for refractive index, acid value, iodine value, saponification value, peroxide value, and free fatty acid are always carried out according to the methods of AOAC (1990).




Table 4.1: Physicochemical Properties of Soybean Oil





The study revealed the physicochemical properties of soybean oil. The results shows the oil samples are of good quality and are suitable for consumption, domestic use such as frying and in industrial usage. Furthermore, the oil samples can be useful for the other purposes such as soap making due to their high saponification values. Since the samples contain low acid value, therefore they contain low levels of free acids which also suggest low levels of hydrolytic and lipolytic activities. Low level of peroxide values suggests strong presence or high levels of antioxidants which reduce spoilage by oxidative rancidity.


            Based on the research, soybean oil is recommended for consumption and can be implemented in the frying of food products since they are less liable to oxidative rancidity which causes off odour and flavor in food. The results reveal that soybean oil can be used for soap making hence, found its usage in both domestic and industrial purposes.

However, further research should be made on the proximate and fatty acid composition of soybean oil.


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