EFFECT OF WATER-HEAT TREATMENT ON SPELT GRAIN FLOUR QUALITY

UDК [664.7:633.11] DOI: https://doi.org/ V. Liubych, Dr of Agricultural Sciences, Professor, Е-mail: LyubichV@gmail.com https://orcid.org/0000-0003-4100-9063 ResearcherID: W-8897-2018 Scopus Author ID 57190382174 V. Zheliezna, PhD of Agricultural Sciences, Senior Teacher, Е-mail: valieriia.voziian07@gmail.com https://orcid.org/0000-0002-1874-2155 ResearcherID: AAL-5479-2020 Scopus Author ID: 57195525104 Uman National University of Horticulture, 1, Institute Street, Uman, Cherkasy region, 20305, Ukraine Tel. +38047 4432011


Introduction
Wheat is the most widely grown crop in the word because of its unique protein characteristics. Now there is an active 'search', revival, improvement and introduction into production of 'antique cereals'forgotten grain cereals. One of these species is spelt wheat (Triticum spelta L.), an ancient, almost extinct species of wheat with a hexaploid chromosome set (2n = 42) [1,2]. Spelt wheat is undemanding to growing conditions, so it is common in organic farming in most Western European countries (Germany, Belgium, Switzerland, France, Spain) and the United States. [3,4]. The high adaptive properties of this culture have been confirmed by studies of 22 research institutes in nine countries of the European Union participating in SESA project [5].
Spelt wheat is almost a perfect combination of the vitamins, minerals, proteins, carbohydrates and fats essential for human body. Compared to soft wheat, it is richer in proteins, unsaturated fatty acids and dietary fibers [6,7]. Organic substances contained in spelt have a high level of solubility, so they are easily and quickly absorbed by the human body [8]. Its grain contains special soluble carbohydrates -micropolysaccharides, which are able to strengthen the immune system, lower cholesterol and regulate blood coagulation processes [9,10]. The peculiarity of spelt wheat grain is the balanced placement of valuable components in the shells and endosperm, which makes it possible to use simple and complex grain grindings [11,12].

Literary review
Compared to soft wheat, spelt wheat grain has thicker shells that are less tight to the aleurone layer [13]. However, the groove of spelt wheat grain is wide and reaches about half of the cross section of endosperm and is relatively big in the top part [14,15].
Spelt flour is inferior to wheat by the baking quality, but it can be useful in the manufacture of bakery products of improved chemical composition, for dietetic nutrition [16,17]. High quality characteristics and softgrain consistency of spelt grain provide high quality confectionery and grits with excellent taste properties. Thus, the complex of useful features and properties of spelt wheat determined its widespread practical use and encouraged for different scientific researches [18]. Flour quality depends on the technological properties of grain. Yield and quality of flour vary depending on weather and agrotechnical conditions of cultivation [19]. The conversion of spelt wheat into flour will help to expand the range of this product. In addition, it has high biological value [9,12].
In a context of market economy, the main indicator of effective enterprise performance is the demand for products, which is formed to a greater extent by the quality of manufactured products. Marketing techniques and promoting of low quality products can only produce short-term sales improvements. Therefore, the optimization of flour production from new varieties of spelt wheat grain was carried out taking into account the main indicators of flour quality (ash content and linen), which predetermine the quality of the manufactured bakery products.

Formulation of the problem
The aim of the study is to determine the effect of water-heat treatment on the quality of spelt wheat flour.
To solve this goal, the following tasks were set: to conduct literature review and scientific experiment, make a statistical analysis of the obtained data, make mathematical models, establish the optimal parameters of water-heat treatment depending on flour quality.

Materials and methods
The experimental part of the work was carried out in the laboratory of 'Quality evaluation of grain and grain products' of the Department of Technology of Storage and Processing of Grain of Uman National University of Horticulture. For research, we used spelt winter wheat grain of Zoria of Ukraine variety. Flour quality was investigated depending on water-heat treatment ( Table 1). To do this, the grain was used with a moisture content of 13,0 % to 17, 0% with an interval of 0,5 %, softened from 5 h to 30 h with an interval of 5 h. For laboratory grinding of spelt wheat grain, MVR-000342.90 roller machine was used, which allows to obtain wheat flour in accordance with DSTU 46.004-99 of wheat flour. The technical characteristics of the roller machine are shown in Table 2. The minimum weight of grain sample should be 1 kg.
The principle of roller machine operation is that grain after water-heat treatment is loaded into the receiving hopper 2 (Fig. 1). Through the feed valve 3 grain is directed to the roller 4. Weight, kg 350 The yield of flour,% 75-85 After grinding the receiving product is separated on a sieve separator 5 of a drum type. The separator descent, if necessary, is directed to re-treatment through the pneumatic conveyor system 1.
Measurements accuracy and data reliability were mathematically substantiated at each stage of the research. The replicates of each experiment were treated with descriptive statistics to determine variation coefficient. In case of poor data variation of the samples of each experiment, their average was determined, which was used for mathematical modeling. The arrays of data, obtained from the averages, were checked for correct distribution. Correctly distributed data were processed by basic statistics methods and incorrectly distributed -by non-parametric ones. Correlation and regression analyses were used during statistical processing. Obtained functional dependencies were checked for the absence of autocorrelation by Darbin-Watson statistics method [20].
Due to the duplication of experiments, the reproducibility of experimental data was checked. The hypothesis of noise dispersion persistence was tested using the Kohren criterion [20]. Testing of this hypothesis allowed to assert the homogeneity or heterogeneity of a number of variances. Mathematical modeling used data in which the number of variances was homogeneous.
The method of full factorial experiment is based on the assumption that any continuous function under study y= f(x 1, x 2 ,...,x n ) with all derivatives at a given point with x 01 , x 02 , ..., x 0n coordinates can be decomposed into Taylor series: ... ,..., , [15].

Results and discussion
Studies have shown that ash content of the products after the first grinding was lower than after the second one. This is due to a quality deviation of the intermediate product coming into the second grinding.
The variation coefficients of analytical replicates for the results after the first grinding varied from 4,65 to 14,18, and for the results after the second one -from 2,44 to 13,43. This indicates little or minor variation. Therefore, the average data from the research results can be used for mathematical modeling. The theory of correct distribution of sample data was rejected, and therefore the relationship between the parameters of water-heat treatment and flour ash content was carried out using nonparametric statistics (determining Spearman correlation coefficient).
With 95 % probability, it can be stated that there was an inverse correlation between the parameters of water-heat treatment and ash content (Table 3).  The relationship between water-heat treatment and flour ash content can be described by the following linear dependencies: Z 1 =1,641249-0,061686X 1 -0,005239X 2 (2) Z 2 =1,813573-0,064253X 1 -0,003174 X 2 where Z 1 and Z 2 -ash content after the first and second grindings; X 1 -grain moisture, % X 2 -duration of softening, min. An important indicator of mathematical model quality is the presence or absence of autocorrelation of residuals. As a result of statistical analysis, the Darbin-Watson method found a positive autocorrelation of the residuals of the 3 d function. This meant that the selected model was incorrect or lacked of a statistically significant relationship. For the first equation, the autocorrelation of residuals was not detected.
Taking into account the high statistical reliability of first equation, the corresponding dependence can be represented graphically (Fig. 2). The lowest flour ash content after the first grinding of spelt grain can be obtained with the highest grain moisture content and the maximum duration of its softening.

Fig. 2 -Relationship between parameters of water-heat treatment of spelt wheat grain and flour ash content after the first grinding
The correlation and influence of the factors were determined using beta and partial correlation coefficients (Fig. 3). For the first grinding, grain moisture content before grinding had the highest influence on flour ash content. After graphical representation of the 4 th function, it was found that the effect of moisture and the duration of its effect on grain during the second grinding were similar to the first one (Fig. 4). The influence of moisture on the milling products during the second pass resulted in a greater effect than the duration of softening. In general, flour ash content in a production using two milling systems is most influenced by grain moisture content. Obviously it can be explained by the fact that the formation of microcracks in grain endosperm depends on forces between water and its structural parts. Moisture content increase weakens bonds between shells and grain endosperm, which helps them to separate better during the second grinding. Therefore, the reaction of spelt wheat grain to water-heat treatment is similar to the known regimes for soft-milled wheat grain type.
The tendency of flour whiteness change depending on the modes of water-heat treatment varied similarly to ash content. Due to the fact that the sample data were not correctly distributed, the relationship between factors was found using non-parametric statistics methods (Table 4). According to Cheddock scale, the relationship between flour whiteness and the duration of softening was directly noticeable, and with grain moisture content -straight high, which made it feasible to carry out further studies. The theory of linear dependence between these indicators was rejected because the residuals of obtained models had autocorrelation. After interpreting the dependencies in the form of second-order functions, it was found that the formula of the dependence of flour whiteness after the first grinding, moisture content and duration of softening had autocorrelation of residuals similar to linear. This indicates that relevant models may have unaccounted for significant variables that influenced the process, model cycle, process performance could respond to delayed conditions, and so on. Therefore, to calculate partial correlation coefficients for the corresponding dependence, look for relationships and the power of effect was inappropriate.
The graphical representation of function shows that the duration of softening had the greatest influence on flour whiteness at the lowest grain moisture content (Fig. 5). At the moisture content of 14,0-17,0 %, the effect of softening duration decreased. The research results were unevenly distributed, so the use of non-parametric statistics was a priority. It was assumed that there was a straight line connection between the coefficient of endosperm use (Coef. U) and the duration of softening, whereas the tendency to change depending on moisture content was curvilinear. Curvilinear dependencies were also observed between the parameters of water-heat treatment and complex efficiency criterion (Complex U). Therefore, the approximation was performed using second-and thirdorder polynomials.
Graphical representation of 2 d and 3 d functions is shown in Fig. 6.
It has been proved that the greatest effect on the performance of flour production was due to grain moisture content. Thus, increasing moisture content from 13,0 % to 15,0 % rose endosperm use coefficient from 94,5 % to 99,0 or more by 4,5 points. High endosperm use coefficient was at 15,5 % spelt wheat grain moisture content. Further increase in moisture content to 16,0-17,0% had a negative effect on this indicator, as it decreased to 93,7-95,6 %. In all studied samples, increase in the duration of softening at grain moisture content of 15,0-15,5 % increased the endosperm use coefficient.

Conclusions
Therefore, there is high correlation between the parameters of water-heat treatment of spelt wheat grain and flour quality. The use of water-heat treatment significantly influences the complex criterion of flour milling production efficiency. Grain moisturizing and softening contribute to an increase in the complex criterion by 22-40 % compared to 13 % moisture content (40,8 %). Its largest value was recorded by the longest duration of softening -57,0-57,2 %. It is the lowest in grain moisture content before grinding -13,0-14,5 % -40,8-46,8 %.
The use of water-heat treatment causes an improvement in spelt wheat grain flour production process. It improves the processing of spelt wheat by classic technology. According to the performance indicators of flour milling production in low productivity enterprises, moisturizing of spelt wheat grain is optimal up to 15,0-15,5 %, followed by its softening for 10-15 hours. It is advisable to further study the effect of crushing and water-heat treatment parameters of the developed flour milling process on spelt wheat grain.