Call number: LD2668 .T4 1985 C64 / Master of Science

Color formation in oils during frying is one of the most noticeable degradation reactions that occur in the frying oil. Degradation reactions cause formation of products that positively and negatively impact the nutritional and sensory qualities of both the food being fried and the frying oil. The origins of these pigment forming reactions in the oil and the factors affecting these reactions are not well understood. Assessments of the mechanisms, the components involved and external conditions affecting oil darkening were conducted. The effect of basic food ingredients, commercially sold and laboratory formulated breading and battering, preformed lipid hydroperoxides and phospholipids on color formation and oil degradation of the frying oil were investigated. Protein products, specifically whey protein, caused both the fastest darkening and thermo-oxidative deterioration of the frying oil. This breakdown was aided further through the addition of minor food materials such as glucose and amino acids as well as lipid hydroperoxides in concentrations greater than 5 % of the frying oil. Nonenzymatic browning is the main reaction causing color formation in the frying oil and utilizes carbonyls from the food product such as starches, sugars and lipid oxidation products as starting materials alongside amino groups from proteins and amino acids. Breading ingredients contributed to oil color formation due to particles from the food crust breaking off into the frying oil to further accelerate browning reactions. Increasing the temperature of the frying oil provided additional stimulus for color forming and thermo-oxidative reactions to progress at a faster rate. / xv, 184 leaves : ill. ; 29 cm

The demand for deep fried chips by public and the number of people entering the fast food industry in the form of fast food outlets has increased tremendously. Frying oils are very expensive and are the most important ingredient used in the preparation of fried foods. Due to high oil costs and lack of knowledge, frying oils are used to their maximum. This has resulted in the abuse of deep fried chip cooking oils. The overall quality of the deep fried chip cooking oil used in the South Central Operational Entity of the eThekwini Municipality is not known but abused cooking oils have been identified by Environmental Health Practitioners (EHP's) during routine inspections of fast food outlets. Considering all of the above, the objectives of the proposed research were: (l) Determine the overall prevalence of the use of abused deep fried chip cooking oils at fast food outlets in the South Central Operational Entity of the eThekwini Municipality. (2) Determine in which supervision areas in the South Central Operational Entity the use of abused cooking oil is most prevalent. (3) Determine current/reported practices in preserving the quality of chip oil. (4) Make appropriate recommendations to owner/managers of the fast food outlets and to Environmental Health Practitioners. The study design was observational utilizing a Rapid Epidemiological Assessment (REA) technique, with both a descriptive and analytical component. All fast food outlets making deep fried chips in the South Central Operational Entity registered with the eThekwini Health Department at the time of the study were included in the study population. The Lot Quality Assurance Sampling (LQAS) method was used to determine the overall prevalence of the use of abused oil and to determine supervision areas reached the predetermined service target. A total of 100 fast food outlets were sampled. An oil sample from each fast food outlet, which was taken and sent to a laboratory where an Oxifrit Test was done on every oil sample taken. The Oxifrit Test was the benchmark in this study. EHP's of eThekwini Municipality collected further data by means of an observational checklist and a closed-ended questionnaire, which aimed to establish cooking oil preservation practices. The study revealed that 60 of the outlets had oil that was acceptable whereas 40 had oil that was unacceptable (abused oil). In the multivariate analysis the only factors significantly associated with abused oil were the condition of the fryer and frequency of oil change. Supervision Areas 6, and 4 had more abused deep fried chip cooking oil than average in the South Central Operational Entity. For further prioritization, Supervision Areas 6 and 4 fell below the decision rule for majority of acceptable oil preservation practices, thus Supervision Areas 6 and 4 will be targeted for intervention. Intervention will include education, monitoring and ultimately enforcing the law by EHP's to ensure safe use of deep fried chip cooking oil in the South Central Operational Entity within eThekwini Municipality. / Thesis (M.P.H.)-University of KwaZulu-Natal, 2006.