ANALYSIS OF VEGETABLE OIL PROCESSES, INFLUENCE OF EXCESSIVE ALKALINE CONSUMPTION IN THE REFINING OF SUNFLOWER AND SOY OILS ON THE QUALITY INDICATORS OF THE FINISHED PRODUCT

ABSTRACT

In the processes of refining and deodorization of vegetable oils, the raw materials required to obtain a high-quality product are also required to be high. Improper or insufficient handling at any stage of the process can result in a change in the quality of the oil involved in refining or deodorization. In this article, several types of methods of refining and deodorization of vegetable oils are studied.

АННОТАЦИЯ

В процессах рафинации и дезодорации растительных масел сырье, необходимое для получения качественного продукта, также должно быть высоким. Неправильное или недостаточное обращение на любом этапе процесса может привести к изменению качества масла, используемого для рафинации или дезодорации. В данной статье изучено несколько видов методов рафинации и дезодорации растительных масел.

Keywords:  refining, deodorization, vegetable oils, sunflower, peroxide, iodine, alkali, cottonseed, acid number.

Ключевые слова: рафинация, дезодорация, растительные масла, подсолнечное, перекись, йод, щелочь, хлопковое, кислотное число.     

Today, based on modern technology, there are a number of methods of vegetable oil processing: oil hydration, physical and chemical refining, bleaching and deodorization.

Regardless of which method is used, each method is carried out according to a specific technological scheme. A technological scheme refers to a set of logically connected technological processes. A technological process is defined as processes carried out under the influence of various factors (pressure, temperature, vacuum, humidity, etc.).

Technological process change is affected by some mechanical, heat, moisture and chemical reactants, and the process changes its direction.

In the processes of refining and deodorization of vegetable oils, the raw materials required to obtain a high-quality product are also required to be high. Improper or insufficient handling at any stage of the process can result in a change in the quality of the oil involved in refining or deodorization.

After the independence of our republic, part of the land was allocated for planting grain crops. As a result, in recent years, the volume of delivery of cotton seeds to the processing industry has reached 1.5 million per year. reduced to tons.  Oil companies are supplied with cotton seeds by only 55-60%. This requires the search for new types of fat-protein raw materials and suitable agricultural crops for industrial processing. Solving this problem is related not only to the prospects for the development of the mixed feed industry. One such crop is sunflower, which contains 33-57% fat and 20.8% protein. Oil obtained from sunflower seeds is not inferior to cottonseed oil in terms of taste and quality [1].

With this in mind, theoretical and experimental research aimed at improving the technology of cleaning and deodorizing vegetable oils, including sunflower oil, is relevant for the industry.

In order to increase the nutritional value and technological properties of oils and fats, they are subjected to various stages of purification - refining. A complete cleaning cycle includes the following main processes: removal of phosphatides, waxy substances, free fatty acids, coloring substances and odors [4].

Deodorization is the removal of specific taste and odor characteristics, resulting in "denatured" oils and fats that cannot be distinguished or identified by taste or smell. Deodorization is of great importance in the process of preparing oils for the production of margarine, mayonnaise, preserves and salad oils.

The different qualities of fats and oils encountered in refining, as well as the diversity of requirements for refined products, show that in each individual case, it is necessary to use different stages of technological processes of refining or different combinations of separate operations. This, in turn, emphasizes the importance of process samples that include exemplary hydration, neutralization, and bleaching [3].

The development of the refining regime of any vegetable oil, including sunflower oil, leads to the development of methods for the separation of lean substances with the participation of glyceride oils. At the same time, methods for the separation of phosphatides in a continuous and continuous process are sufficiently well developed [2].

In these methods, such a level of separation of phosphatides is achieved that it is considered sufficient from the point of view of preparation of fats for the hydrogenation process. The method of neutralization of free fatty acids with alkaline solutions does not cause any difficulties. The most difficult way to get a well-clarified refined oil.

Sunflower oil is one of the best types of vegetable oils. It has a low freezing point and a high percentage of unsaturated fatty acids.  It is added to salads, vinaigrettes, various sauces and dressings are prepared from it, fish and vegetables are fried, and it is used in various pastries. Sunflower oil is sold in unrefined, refined and deodorized form. Refined sunflower oil - transparent, golden or pale yellow in color, does not form sediments during storage, has a weak smell of seeds.

The following concentrations of alkali solution were used to determine the effect of alkali solution concentration and its excess on yield and quality indicators of refined extractable sunflower oil:

Figure 1. Concentrations of alkali solution

The results of the study on the effect of the concentration of the alkaline solution and its excess on the yield and quality indicators of refined extractable sunflower oil are presented in Table 8.

Figure 2. The effect of alkali solution concentration and its excess on the quality parameters of refined extractable sunflower oil

As a result, the concentration of alkali solution and its increase leads to a decrease in the acid and color number of refined sunflower oil, and reduces the separation of refined sunflower oil.

At the same concentration of alkali solution of 150 g/l, with the increase of alkali from 20% to 30%, the acid number of refined oil is from 0.4 mg KOH to 0.18 mg KOH, the color number of iodine is 30 mg and 25 mg, and the oil reduces the extraction from 96.5% to 94.3%.

At a concentration of 200 g/l with a 20% excess of alkali, the acid value of the refined oil is 0.35 mg KOH, the color value is 30 mg iodine, and the oil separation is 95.2 %. In the same volume, the concentration of the alkaline solution is more than 20%, the color number remains at the same volume of 30 mg of iodine, the separation of refined oil increases to 96.3%. 

In relatively strict conditions of refining, a 50% increase in the concentration of an alkali solution of 300 g/l reduces the acid number to 0.15 mg KOH, and the color number to 25 mg iodine, and the oil separation is 93.5%.

The analysis of the research results showed that to refine the sunflower oil obtained by this extraction method, it is necessary to use an alkali solution with a concentration of 150 g/l, more than 30%, while the refined sunflower oil is 94.3%, acid number 0, 18 mg of KOH and the color number is 25 mg of iodine.

After refining in an alkaline solution, oils retain a soapy taste if the soap is poorly washed off, and the oil acquires an earthy taste when large amounts of bleaching earth are used or from prolonged contact with it.

Therefore, we studied the deodorization process of refined sunflower oil according to the following data: Color - 15 mg / iodine, acid number - 0.6 mg KOH/g, peroxide number - 12 mmol a.k. / kg. The influence of the duration of the deodorization process on the quality indicators of sunflower oil during the deodorization process was studied. The deodorization process was carried out under production conditions in steam heated to 230 °C for 60-90 minutes at 2-3 mm Hg of residual pressure in a periodic deodorizer. The obtained results are presented in figure 3.

Figure 3. The obtained results

It follows that increasing the duration of the process leads to a decrease in the acid, color and peroxide numbers of the deodorized oil. During 85 and 90 min, the acid number was 0.3 and 0.25 mg KOH/g, 8 and 6 mg iodine color, and the peroxide number was 4 mmol active oxygen/kg.. These indicators correspond to the requirements of GOST-1129-2013. The analysis of the research results made it possible to determine that in order to deodorize this extracted sunflower oil, periodic deodorization should be carried out for 85-90 minutes with heated steam at a temperature of 230 °C, while the residual pressure in the deodorizer does not exceed 2-3 mm of the mercury column.

References:

1. Кодиров З. З. Влияние концентрации NaOH и избытка щелочи на состав продукта при рафинировании хлопкового, соевого, подсолнечного масла // Universum: технические науки. – 2021. – №. 3-3 (84). – С. 50-52.
2. Кодиров З. З. Физико-химические изменения и нормативные требования к хранению и доставке растительных масел населению //Universum: технические науки. – 2021. – №. 10-3 (91). – С. 8-12.
3. Кодиров З. З., Кодирова З. А. Влияние влаги при хранении высококачественного рафинированного, дезодорированного хлопкового, подсолнечного и соевого масел //Universum: технические науки. – 2020. – №. 10-2 (79). – С. 25-27.
4. Усманов Б. С., Кодиров З. З. Влияние солнечных лучей на состав продуктов при хранении высококачественных растительных масел //Universum: технические науки. – 2021. – №. 2-2 (83). – С. 92-95.