CC BY
16
Section 5. Chemistry
https://doi.org/10.29013/ESR-21-7.8-26-29
Farmonov Jasur, Tashkent Institute of Chemical Technology Karshi Engineering Economical Institute
Serkayev Kamar, Tashkent Institute of Chemical Technology
Samadiy Murodjon, Tashkent Institute of Chemical Technology Yangiyer branch
E-mail: samadiy@inbox.ru
Usmonov Ilkham,
Research and production enterprise "Ilm-fan texnologiyalar"
INVESTIGATION OF THE EFFECT OF HEAT TREATMENT ON THE RELEASE OF LINSEED OIL
Abstract. The article presents information on the effect of drying, that is, heat treatment on the extraction of linseed oil from flax seeds. The properties of oil at different drying temperatures are described in detail, moisture release at time intervals and the degree of oil release are determined depending on the duration of the drying process. The main parameters that determine oil recovery are seed oil content, drying temperature and drying time. It is concluded that it is technologically possible to increase the release of oil during heat treatment of flax seeds.
Keywords: flax seeds, linseed oil, heat treatment, drying, oil content, degree of extraction.
Introduction: Flaxseed oil, food, is obtained of the starch contained in it passes into dextrins, from flax seeds by cold pressing, which contrib- which are easily absorbed by the body, toxic subutes to the preservation of its healing properties. stances are destroyed. There is a slight denaturation Pressing with preliminary moisture-heat treatment of the protein, and due to the short processing time at high temperatures leads to significant losses of (30-150 sec.), The vitamin complex is almost com-vitamins. The preparation and processing of sesame pletely preserved. The effect of heat treatment in-and flax seeds into BAA oils involves the use of a creases the absorption of nutrients by 20-25%, and mechanical method of obtaining products, while a number of vitamins, including E, D, B4, in the the method of cold pressing with preliminary absence of intense lighting and an oxidizing agent, gentle heat treatment is used to impart functional are quite resistant to temperature [1]. properties. Gentle heat treatment has some posi- Due to the high content of omega-3 and ome-tive results. When the seeds are heated, up to 20% ga-6, flaxseed oil has beneficial medicinal proper-
ties, contributing to the normalization of metabolic processes in the body. Flaxseed oil, due to its unique composition, is used in medicine, and is now widely used in cooking. Flaxseed oil is perfectly combined with various oils and at the same time contains a large amount of omega-3 polyunsaturated fatty acids, without which the normal life of the human body is impossible. In addition, flaxseed oil has a high nutritional value, it increases the functioning of the immune system, stimulates the activity of the brain and other organs [2].
Flax seed has long been used in folk medicine due to its healing properties and a wide range of effects on various zones of the human body. The main nutrients that determine the biological value of flaxseed are: glycerides of linolenic (35-45%), linoleic (25-35%), oleic (15-20%), stearic (8-9%) acids, proteins (18-33%), carbohydrates (12-26%), organic acids [3].
Objects and Methods: The research was carried out on Central Asian flax with 38.10% oil content. Chemical analysis of the initial, intermediate and final products was carried out by known methods [4-6].
The oil content of seeds is understood as the content of crude fat and accompanying fat-like substances, which, together with the fat, pass into the ether extract from the studied seeds.
The essence of the methods for determining the acid number is to dissolve a certain mass of solvent oil in a mixture of solvents, followed by titration of the available free fatty acids with an aqueous or alcoholic solution of potassium or sodium hydroxide.
The method for the determination of moisture and volatile substances applies to oilseeds, cake, meal, and establishes the method of spectroscopy in the near infrared region, for the simultaneous determination of the following quality indicators:
- mass fraction of fat (in the measurement range from 1% to 60%);
- mass fraction of moisture and volatile substances (in the measurement range from 1% to 18%);
- mass fraction of protein (in the measurement range from 5% to 80%);
- mass fraction of fiber (in the measurement range from 2% to 50%).
Results and its discussion: Studies of the process of heat treatment of flax seeds for the yield of flaxseed oil in the temperature range from 80 to 130 °C for 30 minutes showed a decrease in seed moisture by 0.92% at a temperature of 80 °C, by 1.60% at 100 °C and by 2, 66% at 130 °C (Table 1). In this case, the oil yield increases from 19.60% without heat treatment to 25.52% when treated at a temperature of 100 °C and up to 28.82% at a temperature of 130 °C. Accordingly, the yield of cake with increasing temperature decreases from 80.40% without treatment and is 72.88% at a temperature of 100 °C and 68.51% at a temperature of 130 °C.
The decrease in the cake yield at a temperature of 100 °C is 9.35%, at a temperature of130 °C14.79, while the oil yield increases by 30.20% at a temperature of 100 °C and by 47.04% at a seed treatment temperature 130 °C.
Figure 1 shows data on the effect of the duration of the drying process of flax seeds on the removal of moisture at a drying temperature of 130 °C, from which it can be seen that the drying process at a temperature of 130 °C is completed within 45-50 minutes and the maximum amount of moisture removed from flax seeds is 6%. An increase in the heat treatment temperature to 140 and 150 °C increases the removal of moisture to 2.90 and 3.60%, the cake yield to 70.98 and 77.27%, respectively.
In this case, the oil yield decreases to 26.12 and 19.13%, which indicates the inadmissibility of increasing the heat treatment temperature above 130 °C.
The optimal conditions for heat treatment are 130 °C, the duration of heat treatment is 30 minutes. Under these conditions, 2.61% of moisture is removed, the cake yield is 68.51%, and the oil yield is 28.82%.
Table 1. - Influence of heat treatment temperature on oil extraction and cake yield at a heat treatment time of 30 min
№ Heat treatment temperature, °C Moisture release,% Oil cake yield,% Oil yield,%
1. Without heat treatment — 80.40 19.60
2. 80 0.92 78.82 20.26
3. 90 1.18 76.56 22.26
4. 100 1.60 72.88 25.52
5. 110 2.14 72.22 25.63
6. 120 2.47 70.18 27.34
7. 130 2.66 68.51 28.82
8. 140 2.90 70.98 26.12
9. 150 3.60 77.27 19.13
Time, min
Figure 1. Influence of drying time on the release of moisture from flax seeds at a temperature of 130 °C
80
30
20
0 10 20 30 40 50 60
Time, min
Figure 2. Influence of the duration of the pressing process and the temperature of heat treatment on the degree of oil recovery
Figure 2 shows the results of the effect of the drying time on the degree of oil recovery at a heat treatment temperature of 130 °C. With an increase in the duration of the drying process of flax seeds, the degree of oil extraction increases and reaches a maximum value of 75.64% at a time of 30 minutes, and then decreases rapidly. The optimal drying time for flax seeds at 130 °C is 25-35 minutes.
Table 2.- Influence of technological parameters
In this case, the degree of oil recovery is at least 65.6%. An increase in the duration of the drying process over 35 minutes leads to a decrease in the degree of recovery. With a process duration of 40 minutes, the recovery rate decreases to 52.5%, and with a heat treatment duration of 45 minutes, to 39.0%.
Table 2 shows the influence of technological indicators on the quality characteristics of the oil.
of the process on the quality characteristics of oil
№ Drying temperature, °C Drying time, min Oil yield,% Acid number Chromaticity Moisture,%
1. - - 19.60 0.48 40 1.71
2. 130 15 22.00 0.37 35 0.80
3. 130 30 28.82 0.26 30 0.11
4. 130 45 15.46 0.45 40 0.04
The table shows that the best indicators of flaxseed oil are observed at a seed drying temperature of 130 °C and a process duration of 30 minutes. In this case, the oil yield is 28.82%, the acid number decreases to 0.26, the color to 30, the moisture content does not exceed 0.11%.
Conclusions: Thus, the studies carried out have shown the possibility of increasing the degree of ex-
References
traction of flaxseed oil with the use of preliminary heat treatment. For this, the drying process must be carried out at a temperature of 130 °C and a process duration of 30 minutes. At the same time, the degree of oil extraction increases from 51.44% to 75.64%, the acid number decreases to 0.26, humidity to 0.11%, and color to 30.
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