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Section 7. Food and Beverage
Section 7. Food and Beverage
Mamatov Sherzod Mashrabjanovich, Dodaev Kuchkor Odilovich, Choriev Abdusattor Zhuraevich. Tashkent Institute of Chemical Technology E-mail: sherzod_mamatov@mail.ru
Study of changes in the content of ascorbic acid at thermoradiation dried vegetables
Abstract: Intensification of the process carried out IR vacuum drying on the example of potatoes, carrots and onions, experimental by selecting one of the test methods pre-infrared, microwave and infrared-microwave treatments. The main attention is paid to the degree of preservation components of dried vegetables. The data on the study of the safety of vitamin C.
Keywords: potatoes, carrots, onions, vitamin C, pre-treatment, drying, infrared drying.
Introduction. One of the reliable methods of food preservation and to meet the growing demand for them is their drying.
In world practice all ways: convection, freeze, dielectric, conductive, thermoradiation, drying vegetable raw materials with inherent advantages and disadvantages. The quality of the dried product and the economic performance of the industrial organization of drying depends largely on the duration of drying.
Organization drying useful when used as a source of heat energy converters, which are available in a wide range in a variety of configurations. They are environmentally friendly, automatically adjustable, easy to provide them security.
IR rays are absorbed by the active moisture in the product, but not absorbed by the tissue product itself, so the removal of moisture can be accomplished at a temperature of40-70 0 С, which allows to retain biologically active substances, including vitamins, natural color and flavor of the original raw material.
Units are not always drying plant material, including using infrared rays may be provided regulating process parameters depending on the degree of grinding of raw materials, the specific energy delivered to the feedstock, and the duration of the IR energy supply [1; 2].
Objects and methods. The influence ofpretreatment process of vacuum drying IR vegetables at a residual pressure in the drying chamber, equal to 40 kPa. IR vacuum drying is carried out by pulse-discontinuous mode, with decreasing levels of energy supply. Experiments were car-
ried out on the example of drying potatoes, carrots and onions. Experiments include two phases:
— The first phase is briefly pulsed pretreatment in electromagnetic fields IR, microwave and infrared ranges with microwave heat flux density at 18-20 times the density at the primary drying;
— In the second stage is carried out infrared drying with the vacuum heat flux wound 1,5 kW/m 2.
The results of assessments of changes in the average moisture content ofthe drying object and speed ofthese changes were subjected to regression analysis. The concentrations of ascorbic acid performed by HPLC. The results showed that the pre-treatments used to vacuum drying IR vegetable essential, but to varying degrees affect the basic process for most vegetables.
These results indicate that the ascorbic acid content in the samples dried potato IR two hour vacuum drying with IR pretreatment constitute 72.4 mg% and pretreated in a microwave electromagnetic field of the microwave and IR ranges, respectively, and 60.1 mg% 64.2 mg% while IR-vacuum drying without pretreatment — 65.1 mg%.
Display the residual amount of vitamin C in the sample of dried potatoes obtained by vacuum drying IR IR pretreatment above.
Figure 2 shows the dynamics of decrease of vitamin C in the dry matter at different temporal boundaries drying. It points to reduce the loss of vitamin C in the samples of dried potatoes obtained by vacuum drying IR with IR pretreatment.
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Study of changes in the content of ascorbic acid at thermoradiation dried vegetables
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Time, min
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Fig. 1. the graphics changes of vitamin C from the Fig.2. Schedules of decreasing of vitamin C in a solid time of drying in samples of the dried potatoes time of drying in samples of the dried potatoes
Figure 3 shows a graph of the growth mass fraction of ascorbic acid in the samples of carrot drying process.
The current standard GOST 52622-2006 on “Dried vegetables" are general specifications, providing the vitamin C content of 10 mg per 100 g of dried product [3; 4].
Ascorbic acid in an IR vacuum drying pretreatment with an electromagnetic field in the IR and IR bands in the microwave for 2.5 hours, significantly greater than the recommended GOST 52622-2006 and is respectively 28.5 and 25.46 mg%, with a pre-treatment in the electromagnetic field of microwave proportion of vitamin C is only 23.6 mg%. During IR vacuum drying without pretreatment long period of heating is not conducive to the preservation of significant vitamin C. For 2.5 hours drying is 22.4 and 3:00-16.1 mg%.
From these graphs in Figure 3 it is clear that for each drying method are temporary borders, after which ends increase in the share of vitamin C. For drying IR vacuum system with pre-treatment in an electromagnetic field infrared, microwave and infrared-microwave bands — this time is 2.5 hours, without pretreatment — 3 hours. If they are exceeded, the content of ascorbic acid is reduced.
This increases the contact surface of the product with air or oxygen, oxidation reactions leading to a quantitative
loss of valuable components. This can be explained by the fact that after the passage of these temporary borders product “dry out”. He becomes brittle skeleton particles gives micro cracks [5].
Dynamics of changes in quantitative indicators of ascorbic acid content in the dry matter, the curves of which are shown in Figure 4 can determine the loss of vitamin C in the considered methods of drying samples carrots. These curves can perform calculations of loss of vitamin C on the borders of the optimal time for each drying method.
These graphs show that the least loss of vitamin C are observed in samples dried carrots obtained after using an electromagnetic field treatment to IR drying.
The sequence of changes in the content of vitamin C, which changes the curves shown in Figure 5, shows the existence of a certain number of patterns of change in the ascorbic acid during the drying of samples selected for drying vegetables.
Vitamin C in the concentrated samples of dried onions and reaches a maximum after drying of 2.5 hours — 46.8% at mg IR with vacuum drying using IR pretreatment. It is more desired to GOST 52622-2006 (12,00% mg) four times. The maximum content of ascorbic acid using microwave pretreatment of dried samples achieved within 2.5 hours and was
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Section 7. Food and Beverage
40.1 mg%, with a combined pretreatment process (RF-IC) — 38.4, and without pretreatment — 42 3 mg%. Further drying bow without pretreatment for 3 hours
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Fig. 3. Graphic changes the content of vitamin C of time drying in samples of dried carrots
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leads to a decrease in the amount of ascorbic acid to 37.8 mg%. The advantages of the IR-IR with vacuum drying pretreatment vividly show the digital data.
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Time, min
♦ without pretreatment —■— with IR treatment - ■ with microwave treatment
—x- - with IR-microwave treatment
Fig. 4. the graphics changes the content of vitamin C in a solid time of drying in samples of dried carrots
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0 100 200
Time, min
> without pretreatment —■— with IR treatment - ■ with microwave treatment
—*■ - with IR-microwave treatment
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Fig. 5. the graphics changes the content of vitamin c in drying time in samples of dried onion
Fig. 6. the graphics changes the content of vitamin c in a solid time of drying in a drying of onion
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Study of changes in the content of ascorbic acid at thermoradiation dried vegetables
By analogy in Figure 6 shows the change of quantitative indicators vitamin C content in the dry matter in samples of dried onion in the drying process.
Conclusion. It was established experimentally that when using dried cascade IR pretreatment facility and subsequent vacuum drying, infrared vitamin C content in potatoes, carrots and onions is respectively 72.4; 28.4 mg and 46.8% with the required residual moisture content of 10-14%.
Based on these charts, we can conclude that the smallest loss of vitamin C are observed in samples dried onions obtained by vacuum drying IR with IR pretreatment.
References:
1. Ilyasov S. G., Krasnikov V. V. Methods for determination of optical and thermo radiation characteristics of foods. - M.: Food Industry, 1972. -175 p.
2. Ilyasov S. G., Krasnikov V. V. Physical basis of infrared irradiation of food. M.: Food Industry, 1978. - 359 p.
3. Mamatov Sh. M. Process optimization of drying vegetables and fruits//Modern problems of mathematical modeling and computational methods: Ukrainian scientific conference. - Exactly (Ukraine), 2013. - 189 pp.
4. Mamatov Sh., Choriev A., Dodaev Q Babayarov F. Mathematical modeling and optimization the drying process of agricultural products//International Conference on European Science and Technology. — Wiesbaden (Germany), 2012. - P. 256-261.
5. Mamatov Sh. M. Application of mathematical model for optimizing the process of drying vegetables and fruits//IV of the All-Russian conference on chemical technology with the international participation. - Moscow (Russia), 2012. - P. 330-332.
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