Research proposal format

Analysis of Fatty Acids, Heavy Metal Concentrations, and Properties of Selected Oil Seeds Cultivated in West Nile, Uganda

LIST OF ABBREVIATIONS

AAS: Atomic Absorption Spectrophotometer
GC/MS: Gas Chromatography/Mass Spectrometry
MUFA: Monounsaturated Fatty Acids
PUFA: Polyunsaturated Fatty Acids
SFA: Saturated Fatty Acids
HDL: High-Density Lipoprotein
LDL: Low-Density Lipoprotein
FAMEs: Fatty Acid Methyl Esters
FAO: Food and Agriculture Organization
WHO: World Health Organization
EU: European Union
MRL: Maximum Residue Limit
EFSA: European Food Safety Authority
SR: Shear Rate
SA: Surface Area
PV: Peroxide Value
IV: Iodine Value
AV: Acid Value
AOAC: Association of Official Analytical Chemists
FFA: Free Fatty Acid
NAADS: National Agricultural Advisory Services
UK: United Kingdom
LDPE: Low-Density Polyethylene
RD: Relative Density
ASTM: American Society for Testing and Materials
AR: Analytical Grade
N: Normality
M: Molarity
SD: Standard Deviation
ND: Not Detected
MPL: Maximum Permissible Limit

ABSTRACT

This study investigated vegetable oils extracted from three oilseed varieties—sunflower (Helianthus annuus), sesame (Sesamum indicum), and peanut (Arachis hypogaea)—grown in the West Nile subregion of Uganda. The fatty acid composition, heavy metal content (cadmium (Cd), zinc (Zn), iron (Fe), and lead (Pb)), and physicochemical properties of the oils were analyzed using GC/MS, AAS, and AOAC standard methods, respectively.

Fatty acid analysis revealed the presence of oleic, linoleic, palmitic, stearic, behenic, lignoceric, and linolenic acids in all oils. Major fatty acids included oleic acid (44.06–44.12%), linoleic acid (30.29–31.51%), and palmitic acid (10.93–13.07%). The findings indicate that sesame, sunflower, and peanut oils are predominantly unsaturated, falling under the mid-oleic acid subclass. The polyunsaturated-to-saturated fatty acid ratios exceeded the FAO-recommended minimum of >1.

Heavy metal analysis detected iron and lead in all samples, with concentrations ranging from 2.330–14.982 mg/kg for iron and 1.944–2.126 mg/kg for lead. Sunflower oil contained the highest lead levels, while sesame oil had the highest iron content. Cadmium and zinc were undetectable in all samples. Notably, lead and iron concentrations exceeded the maximum permissible limits (0.1 mg/kg for Pb, 1.5 mg/kg for Fe). Elevated iron levels can accelerate fatty acid oxidation, compromising oil quality, while lead poses toxicity risks even at low concentrations.

Quality assessment demonstrated acceptable ranges for density, viscosity, iodine value (79.64–126.59 g I₂/100g), peroxide value (1.42–9.25 meq/kg), acid value, and saponification value.

Keywords: Fatty Acids, Heavy Metals, Vegetable Oils, Oil Properties

CHAPTER ONE

1.0 INTRODUCTION

1.1 BACKGROUND

Vegetable oils, derived from oil-bearing seeds or fruits, are essential in food processing, cooking, pharmaceuticals, and industrial applications. Common sources include soybean, sunflower, peanut, rapeseed (canola), sesame, and safflower (Nzikou et al., 2010). These oils consist of ~98% triglycerides (esters of glycerol and fatty acids) and 2% minor components (phosphatides, sterols, vitamins, pigments, and free fatty acids) (O’Brien, 2018). Nutritionally, they provide essential fatty acids and fat-soluble vitamins (A, D, E, K) (Koski et al., 2002).

Fatty acids play critical biological roles, serving as energy sources and structural components of cell membranes, influencing fluidity and permeability (Tiuca, 2017). Polyunsaturated fatty acids (PUFAs), such as omega-3 and omega-6, offer anti-inflammatory, antioxidant, neuroprotective, and cardiovascular benefits (Orosavova, 2015).

Fatty acid composition varies with plant genotype, geography, and agricultural practices (Maxia et al., 2009; Gecgel et al., 2007). For instance:

Sesame oil contains ~80% unsaturated fatty acids (oleic: 35.9–42.3%; linoleic: 41.5–47.9%) (Hwang, 2005).
Ugandan peanut oil comprises 39.71–55.89% oleic acid, 20.21–35.59% linoleic acid, and 11.91–17.16% palmitic acid (Musalima et al., 2019).
Sunflower oil has 14–43% oleic and 44–75% linoleic acids (Akkaya, 2018).

However, PUFAs are prone to oxidation, degrading oil quality (Rajko et al., 2010). Additional quality indicators include peroxide value, acid value, iodine value, and physical properties like viscosity and density (Mohammed & Alli, 2015).

Heavy metals (e.g., Cu, Zn, Fe, Pb) in oils stem from soil, manufacturing, and environmental pollution (Mendil et al., 2009; Zeiner et al., 2005). Muhammad et al. (2018) reported Cd (0.11 mg/kg), Pb (0.04 mg/kg), Fe (0.23 mg/kg), and As (0.12 mg/kg) in vegetable oils. These metals impair nutritional value, oxidative stability, and human health, causing organ damage (Unak et al., 2007). Chronic exposure may lead to neurological, muscular, or skeletal disorders (Jaishanka et al., 2014; Bernard, 2008).

This study evaluates fatty acids, heavy metals, and physicochemical properties of West Nile-derived oils.

1.2 PROBLEM STATEMENT

Environmental factors influence fatty acid composition and heavy metal contamination in oils. In West Nile, extensive fertilizer and pesticide use raises contamination risks (He, 2005). This study addresses gaps in regional data on oil quality and safety.

1.3 OBJECTIVES

General Objective

To analyze fatty acids, heavy metal concentrations, and properties of selected oil seeds from West Nile, Uganda.

Specific Objectives

Assess physicochemical properties of sunflower, sesame, and peanut oils from West Nile.
Determine fatty acid composition of the oils.
Quantify Cd, Zn, Fe, and Pb levels in the oils.

1.4 SCOPE

The study analyzed oils from Arua, Yumbe, Nebbi, and Zombo districts (August 2017–August 2018).

1.5 HYPOTHESES

No significant variation exists in the physicochemical properties of West Nile oils.
Fatty acid composition does not differ significantly across localities.
Heavy metal contamination in West Nile oils is negligible.

1.6 SIGNIFICANCE

Provides comparative data for consumers and policymakers.
Supports safety regulations for oil production and consumption.
Highlights heavy metal risks and oxidative stability concerns.