Antioxidant effect of parsnip extract in stabilizing sunflower oil during storage and thermal conditions

Dissertation for receiving the master's degree "M.Sc"

in the field of food science and industry

Abstract

Oils and fats are oxidized during storage at high temperatures and their nutritional quality is reduced. The oxidation process of oils and fats and the formation of radicals Free radicals cause the development of cancer. These damages can be prevented by consuming antioxidant compounds found in fruits and vegetables such as alpha-tocopherol, glutathione, beta-carotene and ascorbic acid in the diet.  Diets rich in these antioxidant vitamins maintain health and reduce the risk of heart disease and cancer.  Synthetic antioxidants, especially BHA and BHT, are usually used to prevent the oxidation reaction. The toxic and carcinogenic effects of these synthetic antioxidants are known in humans. Also, synthetic antioxidants may cause swelling of the liver and affect liver enzyme activities. Therefore, considering the harmful effects of synthetic antioxidants and the beneficial effects of natural antioxidants in maintaining the health and safety of food and human body, in this study, the use of parsnip bark extract as a plant material and a natural source of antioxidants in sunflower oil was investigated. In this research, extraction was first performed from skin and pulp and the phenolic and tocopherol compounds present in the extract were determined, and then the extract was added in two concentrations of 400 ppm and 800 ppm to the sunflower oil sample without antioxidant, and then the sunflower oil samples formulated with this natural antioxidant were stored under temperature conditions of 30 degrees Celsius for 60 days in terms of oxidative stability by the parameters of acid number, peroxide number, color index and stability index. Oxidation at storage temperature at times of 45, 30, 15, 0 and 60 were compared with sunflower oil samples containing 100 ppm of synthetic antioxidant TBHQ. The results showed that the concentration of 800 ppm of parsnip peel extract was more effective than TBHQ and the concentration of 400 ppm of parsnip peel extract in 800 ppm in stabilizing sunflower oil. M of the extract is compared to lower concentrations of the extract. In the next step, sunflower oil containing 800 ppm of extract was compared with oil sample containing 100 ppm of synthetic antioxidant TBHQ under constant temperature conditions of 180 degrees Celsius for 24 hours and at time intervals of 4 hours, they were compared in terms of thermal stability parameters (acid number, conjugate number, carbonyl number, color index, oxidative stability index) and the results showed that parsnip bark extract with a concentration of 800 ppm and antioxidant Synthesis of TBHQ have worked almost similarly for oxidative stability, thus Parsley bark can be introduced as a good source of natural antioxidants and this effect is due to the tocopherol and phenolic compounds present in it. Keywords: Parsley bark extract, sunflower oil, oxidative stability. rtl;">1-Introduction

1-1-The importance of using medicinal plants

The necessity of studying the effective medicinal substances of the natural flora of plants is important. The effective substances and chemical elements in plants are very different, which can only be understood and classified through many experiments and experiences. Since the quantitative and qualitative tests of effective substances and medicinal chemical elements are very expensive, the modification of this category of plants is a very expensive and time-consuming task.

In this way, identifying the effective substances of medicinal plants is a very difficult task, and due to the complex metabolic activities inside the plant, it is not possible to quickly The characteristics of effective ingredients provided comprehensive and complete comments. It is noteworthy that effective ingredients and chemical elements change under the influence of different processes and even different environmental conditions of the place of growth. Oils are the richest source of energy among food components.From this point of view, these materials can play an important role in the case of people who suffer from a lack of food energy, such as many people from the deprived class. But on the other hand, their high consumption in people who do not have a problem in terms of energy intake can cause an increase in blood triglycerides, resulting in vascular diseases and heart failure. (7) Hydrogenated oils, in addition to having large amounts of saturated fatty acids, also contain large amounts of trans fatty acids. Hydrogenation also causes the formation of linoleic acid isomers, which, unlike natural linoleic acid, are no longer an essential fatty acid and lack the biological properties of this acid. If the amount of trans isomer in the oil is below 10%, it can be said that the oil is good for use. Considering the above, it can be concluded that, first of all, moderation should be observed in the consumption of oils, secondly, even if possible, liquid unsaturated oils should be used instead of hydrogenated oils or animal fats in the food plan, and lastly, during the process of frying food, the oil should not be exposed to high heat for a long time so that unwanted and toxic substances do not form in it. (7)

Oxidation of lipids occurs in foods that contain large amounts of fat and have a fat base, such as milk, meat products, oil, oilseeds, and also in foods that contain small amounts of fat, such as vegetables. Free radicals are able to damage the molecules of the body's biological systems and cause many diseases in living organisms, especially humans. (29) Most of these harmful compounds are produced as a result of food oxidation, especially fats, which not only endangers the health of the consumer, but also reduces the nutritional quality and creates an unpleasant taste and smell in these foods. (16) Antioxidants are used to prevent the action of free radicals. Antioxidants prevent the formation of free radicals in cells and play an important role in preventing cancer and protect against cell damage caused by free radicals. Today, the benefits of antioxidants are being talked about everywhere, from preventing heart diseases to reducing brain and eye damage. In order to prevent the action of free radicals, the body must have a defense barrier of antioxidants to prevent the action of free radicals and prevent the destruction of vital body cells. The action of antioxidants is affected by various conditions, including processing and storage and the environment of the relevant food. In addition to being safe, food antioxidants should not affect the color and taste of the food. They should be effective in low concentrations, easily mixed with oil, remain after the process, and remain stable in the final product. be and not too expensive. (Kopen 1983)

Although synthetic antioxidants work effectively during thermal processes and storage conditions, the use of these antioxidants is controversial due to their toxicity and food safety. Considering that synthetic antioxidants have adverse effects such as mutagenicity and cancer in the human body, they are gradually being removed from the list of consumed antioxidants. Concerns about the safety of antioxidants Synthetics such as BHA, BHT, and TBHQ, which are commonly used, have led to an increase in interest in natural antioxidants that exist in plants as secondary metabolites. Therefore, we must know ways to reduce the use of synthetic antioxidants, which is the extraction of natural antioxidants from plants. style="direction: rtl;">In the food industry and household use, a large amount of by-products are produced, the removal of which requires high oxygen. Plant materials that are produced as waste in this industry contain a high level of phenolic compounds that are harmful to the environment, but their positive effect on human health and their antioxidant properties have been proven. For example, 96% of citrus fruits in our country are used to produce juice, and their skin is a byproduct in the juice industry (Kang and Chala et al., 2006).