EXPLORING THE COLOR OF PLANT POWDERS USING COMPUTER COLORIMETRY

The level of development of infrastructure of the agrarian market of Ukraine is determined by the state of food safety and socio-economic development of the country, since the agrarian sector, formed on the basis of wide application of contemporary innovative and information technologies, can become one of the profitable directions in the development of economy. Drying is characterized by technological effectiveness, efficiency and eco-friendliness of the production [1]. Dry production has high food nutritious value and possesses many advantages: mass and volume of the products decreases considerably with the storage and preliminary preparation, as well as the need for boxes, warehouses and separate production premises, which makes transportation easier and cheaper. Therefore, expansion of assortment of the processed fruit and vegetable production due to increasing the share and variety of the assortment of dry fruits and vegetables nowadays is expedient and promising. In future, due to an increase in the consumption of production by the enterprises of food industry, as well as development of culture of consumption of dry vegetables, fruits and nuts by the population of the country, a further increase and development of market both in the quantitative and in the qualitative indicators is expected. Powders are one of the promising forms of dry plant products [2, 3]. Fruit and vegetable powders, having rich chemical composition, in particular, can be used in the technologies of whipped sweet dishes for the purpose of their enrichment, assortment expansion, intensification of processes, forming high sensory properties. In recent years, it has been established by many studies that the risk of diseases, caused by negative environmental effect, is substantially reduced with the use of food ration, enriched by the complex of biologically active materials, in particular, vitamins, bioflavonoids, microelements, pectic substances of the fruit and vegetable raw material [4]. Сolor is the key index of quality and consumer properties of foodstuffs with the use of plant powders. Sweet whipped dishes, in particular, sambuc, form a special group of culinary products, the composition of which implies creation of slightly acidic medium. In connection with this, a relevant direction of studies is exploring biotransformation of pigments of vegetable and fruit powders in the given multi-component food systems in the course of technological process of making dishes and culinary products.


Introduction
The level of development of infrastructure of the agrarian market of Ukraine is determined by the state of food safety and socio-economic development of the country, since the agrarian sector, formed on the basis of wide application of contemporary innovative and information technologies, can become one of the profitable directions in the development of economy.
Drying is characterized by technological effectiveness, efficiency and eco-friendliness of the production [1].Dry production has high food nutritious value and possesses many advantages: mass and volume of the products decreases considerably with the storage and preliminary preparation, as well as the need for boxes, warehouses and separate production premises, which makes transportation easier and cheaper.
Therefore, expansion of assortment of the processed fruit and vegetable production due to increasing the share and variety of the assortment of dry fruits and vegetables nowadays is expedient and promising.
In future, due to an increase in the consumption of production by the enterprises of food industry, as well as development of culture of consumption of dry vegetables, fruits and nuts by the population of the country, a further increase and development of market both in the quantitative and in the qualitative indicators is expected.Powders are one of the promising forms of dry plant products [2,3].Fruit and vegetable powders, having rich chemical composition, in particular, can be used in the technologies of whipped sweet dishes for the purpose of their enrichment, assortment expansion, intensification of processes, forming high sensory properties.In recent years, it has been established by many studies that the risk of diseases, caused by negative environmental effect, is substantially reduced with the use of food ration, enriched by the complex of biologically active materials, in particular, vitamins, bioflavonoids, microelements, pectic substances of the fruit and vegetable raw material [4].
Сolor is the key index of quality and consumer properties of foodstuffs with the use of plant powders.Sweet whipped dishes, in particular, sambuc, form a special group of culinary products, the composition of which implies creation of slightly acidic medium.In connection with this, a relevant direction of studies is exploring biotransformation of pigments of vegetable and fruit powders in the given multi-component food systems in the course of technological process of making dishes and culinary products.

Literature review and problem statement
Sweet whipped dishes are heterogeneous systems, which are obtained by whipping a foaming agent with the subsequent introduction of flavour, aromatic and coloring substances into the mixture [5].
Varieties of the assortment of sambuc, their flavour qualities and the content of substances useful for organism are created by introduction of additional ingredients, which make changes in the colour of these dishes [6].The use of vegetable and fruit powders in the technological process of

EXPLORING THE COLOR OF PLANT POWDERS USING COMPUTER COLORIMETRY A . N i e m i r i c h
PhD, Associate Professor* Е-mail: avnemirich@mail.ru

O . P e t r u s h a
PhD* Е-mail: petrushaoo@ukr.net

O . V a s h e k a
PhD* Е-mail: oksana.vasheka@meta.ua

L . T r o f y m c h u k
Department of Molecular and avant-garde gastronomy** Е-mail: Danilyak1006@mail.ru
The majority of plant powders can be used for creating new products.Nevertheless, depending on the final use, the pigment composition of the powders must be considered [8].
For controlling the used raw material, sensory assessment of products is frequently used [9].This method is not accurate enough because of possible subjectivity of the views of a taster [10].
The progressive development of digital technology gave rise to formation of the new direction -the method of computer colorimetry, the essence of which lies in the description of the color of objects in the system of сolor coordinates according to the results of processing digital images of the tested sample [11].Thus, the results obtained by the researchers [12] showed that the measurement of сolor coordinates by the method of processing the image of the sample may be used for controlling the tendency of change in the chromaticity of food products.
This method was used for controlling the process of drying fish [13], assessment of quality of tomatoes [14] and ham [15], etc.
However, literary sources do not reveal the possibility of applying the method of computer colorimetry of finished dishes and culinary products while using the plant raw material, which predetermines the relevance of the chosen direction of the study.

The aim and the tasks of the study
The aim of the work was to prove experimentally a possibility of using the method of computer colorimetry for the quality control of plant powders.
To achieve the set goal, it is necessary to solve the following tasks: -to explore сolor of plant powders in the dry and restored state with the use of computer colorimetry; -to examine influence of the pigments of plant powders on the color of finished dishes by the method of computer colorimetry; -to propose the sequence of assessment of the quality, namely, color of the finished products by the method of computer colorimetry.

Materials and methods of determining chromaticity of plant powders by the method of computer colorimetry
The powders from cabbage, obtained by new prospective method of drying with the mixed heat supply (TUU 10.3-01566330-279:2012) were selected as tested materials.The sample for the comparison in this case was the powder from cabbage of traditional convective method.The powders from spinach and apples of low-temperature drying (LTD), peaches and strawberries of cold spray drying (CSD) of the Swiss company «OBIPEKTIN AG», CH-9220 BISCHOFSZELL were also analyzed.The studies evaluated the powders from fruits of sea buckthorn of convective drying (TU 9164-089-38826547-2014), which are the concentrate of biologically active substances, structuring agents, color-forming and aromatic natural additives in the technology of sweet whipped products -sambuca and cream.
Detailed description of the procedure of computer colorimetry, which was used for evaluating the сolor of plant powder, is represented in [18,19].The assessment of сolor of the image of the tested powders was conducted in two models of color: RGB (Fig. 1, a

Results of studies of сolor of plant powders and meals made with their use by the method of computer colorimetry and discussion of these results
The obtained digital images of powders in the native state and in the state, restored in water, were assessed for the value of coordinate magnitudes in the RGB and CIELab systems (Fig. 2).In each tested sample, an equal area of ~288 mm 2 , which corresponds to the square of 235×235 pixels, was analyzed.General view of digital images of the restored powders is shown in Fig. 3.The average value of сolor coordinates of the analyzed areas (Fig. 3) is represented in Table 1.
It is clear from the obtained data (Table 1) that the restored powders from cabbage have higher values of the color saturation index -С ab units.The powder from cabbage has varieties of pigments, which determine color; however, their concentration brings the color of the powder close to white color.This is clearly seen by the сolor coordinates in the RGB system, which, correspondingly, tend to maximum value.It should be noted that the powder from cabbage, obtained by drying with the mixed heat supply, has saturated color, which is observed by the values of the coordinates, which are decreased in comparison with the powder from cabbage, obtained by convective drying.The restored powders from spinach, apples, strawberries and sea buckthorns have somewhat other properties, since in the dry state their index of color saturation is higher than in the native state.This may be caused by the composition of pigments of the raw material.Thus, the powder from spinach is characterized by the saturated green color (Fig. 2), caused by content of chlorophyll, which is evident from the higher value of the green component -G ~142 un., in comparison with the blue component -B ~92 un.However, the red component -R has somewhat lower value in comparison with the green one; however, its value is determined by the presence of the pigment carotene.
The powder from strawberries contains the pigments anthocyans and flavonoids.The color of anthocyans ranges from bright red to violet, and the color of flavonoids ranges from yellow to orange.The red component does not reflect the presence of such pigments.However, examining the values of coordinate systems of CIELab, it is clear (Table 1) that the color of the native and restored powder from strawberries lies in the plane of red-orange shades.This regularity proves the presence of anthocyans and flavonoids.The size of the component of the coordinates of color "+a" (the plane of red color Fig. 1, b) remains constant for both samples of powder from strawberries.
Apples, as well as powders from them, are characterized by a wide range of content of natural pigments: riboflavin, chlorophyll, carotene, anthocyan and tannin.Their concentration in the pulp of apples does not give them bright color, and is mainly characterized by the yellowish-white shade (prior to the beginning of oxidation processes).
Yellow color in the RGB system has the values of coordinates R=255, G=255 and B=0, white color -R=255, G=255 and B=255, respectively (Fig. 1, a).By the results of obtained values of coordinates, it is seen that the сolor of powder from apples tends to yellow-white color.
The shift of color to yellow is proved by the value of magnitudes of CIELab, and, namely, «+b» (Table 1 and Fig. 1, b).The values of smaller magnitudes of coordinates remain the same for the restored powder.This is explained by the better capability for hydration.The values of the yellowness index increase as well.
It should be noted that all plant powders in the restored state have a smaller value of lightness -L in comparison with the dry powder (Fig. 4).The linear dependency of this change, depending on a plant powder, has a different slope angle.
The most significant difference of lightness is observed for the powder from spinach -magnitude L decreases by ~59 % (Fig. 1, b) and for the powder from strawberries it decreases by ~44 %.For other plant powders, the lightness decreases on average by 21 %.This decrease is explained by the fact that during the restoration of powders, the pigments fully demonstrate their properties of coloring.
Сolor is one of the indices, which will make it possible to estimate the content of additives of the plant powder to a culinary product.In further studies, the color of foam structures, sambuc and creams made from sour cream with added plant powders, was determined (Table 2).It is necessary to note the decrease in the magnitude of color saturation of sambuc in comparison with the restored powders (Fig. 5), which is caused, first of all, by decrease in the concentration of powders and, correspondingly, the pigments (which form the color of product).

Fig. 4. Magnitudes of lightness of plant powders in native and restored state
It is clear from Fig. 5 that in the foam systems with addition of 25 % of powder from peach, the сolor of product becomes lighter, i. e., the magnitudes of сolor coordinates of RGB increase (Fig. 1, a).With the increase in the amount of added plant powder and, respectively, of the pigment, the value of coordinates shift in the direction of restored powder.This situation is characteristic for all plant powders and, consequently, for the products made with their use.
Adding the powder from strawberries 25 % and 50 % shifts the magnitude of coordinates from the plane of red color to the plane of orange color, with the corresponding change in the value of the coordinate "+a" from 19 to 4, and that of the coordinate «+b» from 20 to 18 (with the addition of 25 %) (Table 2 and Fig. 1, a).An increase in the quantity of added powder from strawberries to sambuc somewhat changes the magnitude of the red component of сolor coordinates in the RGB system by 4 units, but in the CIELab system, the red component "+a" remains constant with a decrease in brightness.The powder from sea buckthorn in the cream made of sour cream demonstrates less intensive color against the background of the white component of the sour cream components, which is proved by an increase in the values of the RGB coordinates.If we examine the obtained values of coordinates in the CIELab system, it should be noted that the magnitude of green and yellow component «-а» and «-b» remained the same.
It was found that adding powders to the formulation composition of sambuc gives it attractive color in all added concentrations in comparison with the control.
Thus, the сolor of meals was defined with the use of computer colorimetry to prove that plant powders retain the ability to give attractive color to products and to improve their sensory properties.

Тable 2
Сolor coordinates of sambuc and cream made of sour cream depending on the type of added powder In accordance with this method, digital images of sambuc and cream made of sour cream were obtained with subsequent determining the chromaticity coordinates and calculation of the corresponding indices, which are represented in Table 2.
A study of сolor of plant powders in different states and in the composition of multi-component food system, using the method of computer colorimetry, makes it possible to estimate transformation of coloring substances in the course of technological process of making whipped sweet meals.However, for detailed estimation of color of prepared meals, it is necessary to consider and preliminarily study color-forming peculiarities of main ingredients of the formulation, which requires additional measures to control innovative products.
The accessibility of the method makes it possible to use it for evaluating quality, controlling technological process of preparing meals and culinary products with the use of traditional and innovative ingredients, including vegetable and fruit-andberry powders.Conducting corresponding studies might be rather expedient since it would make it possible to widen the concept of coloring pigments during their transportation and storage, which allows predicting the shelf life of food products.

Conclusions
1.By the method of computer colorimetry, сolor of plant powders was studied, as a result, it was established that the сolor of restored powders from cabbage and from apples is more intensive than that of native powders.However, powders from spinach, strawberries and peach have such color properties that are more expressed in the dry state than after the restoration, which is caused by pigment composition of the raw material.
2. By using the method of computer colorimetry, the effects of pigments of plant powders on the color of prepared meals was explored, which, in turn, makes it possible to control finished products by the сolor index of the ingredient that is added to the product.In this case, the limits of variation of each component in the RGB system must not exceed ±10 units and for the CIELab system, ±6 units.
3. The sequence of assessing the color of prepared meals and culinary products implies measuring the color of the main ingredients of the formulation with subsequent consideration of the influence of each of them on the final result of this indicator.

Introduction
Deep processing of raw materials using the processes of cryomechanodestruction opens up a possibility of the more complete use of biological potential of plant raw materials (higher by 45-55 % than when using existing methods) and manufacturing a new generation of natural nanoproducts for healthy nutrition.
The relevance of development of nanotechnologies, based on applying the processes of cryomechanochemistry and cryomechanodestruction that make it possible to maximally preserve and extract biologically active substances (BAS) of the original raw materials, is caused by the need to address a global problem that is currently observed in many countries of the world.The problem is the imbalances and deficiency (by 50 %) in the food rations of population of vitamins, high-

Fig. 2 .
Fig. 2. Digital images of the tested samples of powder of spinach: a -in native state; b -in restored state

Fig. 3 .
Fig. 3. Digital images of the restored samples of plant powders: a -from cabbage of convective drying; b -from cabbage of drying with mixed heat supply; c -from spinach; d -from apples; e -from peaches; f -from strawberries; g -from sea buckthorn

Fig. 5 .
Fig. 5. Change in magnitudes of сolor coordinates of powder from peach in native and restored state as well as in foam system

Table 1
Сolor characteristics of native vegetable and fruit powders and of those restored in water