The use of  non-traditional  grain  products,  such as Triticale, in various sectors of the food industry is currently attracting increasing attention of Russian researchers and manufacturers. The interest can be ex- plained by the increasing acreage, new Triticale va- rieties, and numerous studies of their technological, biochemical, and biological potential [1–7].

Triticale is a laboratory-made hybrid of wheat and rye. Its nutritional values are superior to those of both

* State Standard 34142-2017 Triticale flour. Specifications. Moscow:

Standartinform Publ., 2010. 8 p.

parental plants [1]. In Russia, Triticale grain is currently used in compound feed and alcohol production. Howe- ver, Triticale grain can substitute wheat baking flour as a very advantageous source of raw materials in the pro- duction of various pastries, e.g. cookies, biscuits, waf- fles, muffins, crackers, etc. Triticale flour can be used in the production of instant noodles and quick breakfasts, as well as dietary, therapeutic, and prophylactic bread varieties, e.g. wholegrain and multigrain bread [8–13]. In addition, Triticale grain can be used to manufacture mass-market pasta products. Other promising research areas are the technology of processing Triticale grain and bran for starch [15], dietary fibre [14, 16], and bio-

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logically modified products [17, 18]. However, there is currently no industrial production of high-quality Triti- cale flour in Russia.

Over the past decade, foreign scientists have focused mainly on the biology of Triticale cultivars, their biolo- gical safety and development, the origin of hexaploid trit- icale, industrial production of triticale, its competitive- ness with wheat, genomics, and biotechnology [19–28].

Until recently, Triticale grain has been considered as an analogue of rye, at least according to its technologi- cal properties [13]. However, Russian breeders have made it possible to develop and introduce new promising Tri- ticale varieties into agricultural practice. These varieties have a predominance of wheat genotype, which affects the phenotypic characteristics of Triticale kernels,  i.e. size, shape (sphericity coefficient ≥ 0.8), colour, as well as structural, mechanical, and technological properties [1].

The recent studies conducted have made it possible to obtain new data about the technological properties, biochemical composition,  and  varietal  characteristics of Triticale grain and its products. The studies resul- ted in new technologies of Triticale flours production, as well as a new grit variety with specific properties that will be in demand in the baking, macaroni, confec- tionery, starch, meat, and other food industries [2, 3, 5, 7, 29, 30].

The present research aims at developing an effective technological scheme for processing Triticale grain into high-quality baker’s grade flour.

STUDY OBJECTS AND METHODS

The experimental studies were conducted by the departments of complex grain processing and safety of grain and grain products at the All-Russian Scientific Research Institute for Grain and Products of its Proces- sing (V.M. Gorbatov Federal Scientific Centre for Food Systems of the Russian Academy of Sciences). The ex- periment involved samples of two Triticale varieties: Ramzes (harvest 2014) and Saur (harvest 2015). Both cultivars were bred at the Don Zonal Research Institute of Agriculture (Rostov region, Russia). Table 1 shows the initial quality indicators of Triticale grain. The grain was prepared for milling according to the previously es- tablished parameters of hydrothermal treatment [2].

The milling was carried out on two milling and sort- ing aggregates: with fluted rollers (RSA-4-2) and with fro- sted rollers (RSA-4). The intermediate products were en- forced in a laboratory sieve purifier. The set of sieves and the speed of the air flow depended on the size of the initial product. The milling products were sieved on a laboratory plansifter for 90 seconds. The parameters and regimes of milling corresponded to the ‘Rules for organizing and con- ducting the technological process at flour mills’.

A research conducted in the laboratory ‘Technolo- gy and equipment of the milling industry’ (2014–2015) showed that the processing of Triticale grain into baker’s grade flour is more similar to that of wheat in its tech- nological properties [1, 13]. The grit formation process is characterized by a significant number of grits that consist of pure endosperms. The research employed the method of analysis developed for intermediate products of grain milling at the All-Russian Scientific Research Institute for Grain and Products of its Processing. Ac- cording to the analysis, Triticale products were di- vided into 3 groups: the actual grits (particles of pure endosperm), clots of endosperm and shell, and tail-end products that differed in shape and colour.  The  ana- lysis proved the need for the introduction of sieve pu- rifiers [5]. The analysis also revealed a high content of grits in intermediate products of the high-quality mil- ling of Triticale grain. Hence, it was found recommen- dable to extract the grits. The use of sieve purifiers in the high-quality milling of Triticale grain made it possi- ble to increase the yield of top-quality flours, as well as to obtain granular substances and middling that can be used for pasta manufacturing.

The expediency of the extraction and enforcement of large-size grits of 560–950 micrometres (µm) was proved only for break I. It was revealed that middle-size grits (315–560 µm) were suspended during breaks I and II, while the small-size grits (224–315 µm) were sus- pended during breaks I, II, and III. The composition of the intermediate products of the fourth break was char- acterized mainly by the presence of bran particles with high ash content. Hence, it was found impractical for en- forcement in a sieve purifier.

Thus, we developed an advanced technological scheme for milling Triticale grain  with  a  sieve  puri- fier and sizing. The scheme was based on the principle of gradual milling and sorting. The construction of the tech- nological scheme was determined by the requirements for the finished products (quality and yield of flour), variety of grain, and productivity. The reduced technological scheme included four break systems (br.), six reduction systems (red.), and one scratch system (scr.) [22]. The technological process of the advanced scheme included four break systems, two sizing systems (sz.), three sieving (SV), and six reduction systems (red.) (Fig.1).

The break process of the advanced scheme con- sisted of the stage of grit formation (breaks I – II) and a scratch stage (break IV and reduction system VI). The sieving process involved a separate enforcing of large- size grits  of the  first break  (SV-1), medium-size  grits of break systems I + II (SV-2), and small-size grits of I + II + III breaks (SV-3) [5]. The parameters of the sie- ving process were characterized by extracting the tail- e-nd fraction in an amount of at least 80% of the ini-

Table 1. Basic quality indicators of Triticale varieties

Triticale variety                                                                                       Quality indicators

tial mass. The through product of the  sieve  purifier SV-1 was directed to the frosted rolls of the first roller mill of the sizing system. The through product of sieve purifiers SV-2 and SV-3 were combined and directed for the milling to the roller mill of the first reduction system. Tailings from the first and second sieving systems, which made up 15–20%, were combined and sent for additio- nal milling to the roller mill of the fifth reduction system. Tailings from the third sieving system were sent for addi- tional milling to the roller grinding machine of reduction system IV.

The break systems used fluted rollers that were fluted back on the back. All the reduction and sizing systems used roller machines with frosted rolls. The modes of milling were characterized by a total 75% extraction of large-size dunst products and flour on grinding mill of breaks I, II, and III. The extraction mode on the grinding mill of the first break was 25–30%. The extraction mode on the grinding mill of sizing systems I, II, and III was 25–30%. The removal on the grinding mill of reduction systems I, II, and III was at least 50%.

The whiteness of Triticale flour was determined by measuring the reflectivity of a compacted smoothed flour surface with a photoelectric device. To determine the ash content, the flour and bran were burnt, and the mass of the non-combustible residue was measured. The baking absorption and the rheological properties were measured by recording the consistency of dough in the process of its formation from water and flour. The change in the consistency of the dough during kneading was measured with the help of a Mixolab system (Chopin Technologies, France). The baking properties were measured by using the method of laboratory bread ba-king from Triticale flour. The method involved the vo-lume (cubic centime- tres) of bread made from 100 g of flour, as well as scoring the appearance and the bread crumb.

RESULTS AND DISCUSSION

The first stage of the research was devoted to stu- dying the basic milling properties of the initial Triticale grain samples. After laboratory milling, we selected four flows of Triticale flour that were obtained both with re- duced and advanced technological schemes.

Triticale flour varieties were formed by three flour flows: A, B, and C [3]. Stream A was the flour from the hcentral part of the endosperm obtained during reduc- tion systems I, II, and III + sizing system I (advanced scheme) and  the  flour  obtained  on  reduction  systems I, II, and III (reduced scheme). Stream B was the flour from the peripheral part of the endosperm and the su- baleurone layer obtained on the third and the fourth re- duction systems and on breaks I, II, and III. Stream C consisted of endosperm fragments and shells from other technological systems.

Tables 2 and 3 present the quality indicators of Tri- ticale flour flows of Ramzes and Saur varieties obtained according to different technological processing schemes. Figs. 2 and 3 show cumulative ash curves of the re- duction  and  quality  formation  processes  for  Ramzes and Saur flours. The cumulative curves (Figs. 1 and 2) demonstrate that the reduced scheme had three distinct stages of flour formation, where as the advanced tech- nological scheme had two stages. A  statistical analy- sis showed that cumulative curves can be represented as three and two linear segments for different milling schemes [3]. In case of Ramzes grain, the yield of T-70 Triticale flour (ash content ≤ 0.70%) was 40% for the reduced technological scheme. For the advanced tech- nological scheme, the yield of T-70 flour was 63%. The overall yield of flour was higher by 3.4% according to the  advanced  scheme,  as  compared  with  the  reduced scheme. However, the advanced scheme resulted in a 46% yield of T-60 flour variety, which has the lowest

Fig. 1. Technological process of the advanced scheme for processing Triticale grain into high-quality baker’s grade flour

Table 2. Quality indicators of Ramzes Triticale flour flows obtained according to different processing schemes

Product                                                        Whiteness, conventional units                                                  Ash content, %

Bran from:

Table 3. Quality indicators of Saur Triticale flour flows obtained according to different processing schemes

Bran from:

ash content (State Standard 34142-2017**). The reduced

scheme resulted in 0% of T-60 flour.

When processing Saur grain variety, the yield  of T-70 Triticale flour was 73% according to both schemes (Table 3). The overall flour yield increased by 0.6%. The advanced processing scheme resulted in obtaining 42% of Triticale flour with ash content ≤ 0.55%.

The second stage of the research featured the rheo- logical properties [31] of ten separate flows of Tritica- le flour from Saur grain variety, obtained according to the advanced technological scheme by using a Mixolab system (Chopin Technologie, France). The Chopin+ protocol  presupposes  5  research  phases.  Stage  I  lasts 8 min at 30°C; stage II lasts 15 minutes with a consis-

** State Standard 34142-2017. Triticale flour. Specifications. Moscow:

Standartinform Publ., 2010. 8 p.

tent increase in temperature at a rate of 4°C per minute from 30 to 90°C; stage III lasts 8 min at 90°C; stage IV lasts 10 min, with a consistent decrease in tempera- ture from 90 to 50°C; stage V lasts 5 min at 50°C. The rotational input in the analyzed points of the graph, from the point of view of biochemical processes, characte- rizes: formation of the dough (C1); dough dilution (C2); the maximum rate of starch gelatinization (C3); and the beginning and the end of the retrogradation of starch (C4 and C5). ά, β, and γ are the rates of biochemical re- actions (calculated values). The analysis also included the following indicators: the baking absorption of the dough, %; dough formation time, min; dough stability, min. The data of the integral evaluation of the rheolo- gical properties of the dough are visualized on the graph of the rotational input versus time in a particular tem- perature mode (Fig. 4, Tables 4 and 5) [31–33].

Fig. 2.Cumulative curves of ash content in Ramzes flour

Fig. 3. Cumulative curves of ash content in Saur flour

Time, min

The fourth reduction system

Fig. 4. Phases of rheological analysis of the dough and Mixolab profiles of Triticale Saur flour flows from different technological

systems.

The rheological analysis made it possible to create graphical profiles inherent in each flow of Triticale flour. Fig. 4 shows the phases of the rheological analysis of the dough and the Mixolab profiles of the three flour flows: break I, reduction systems I and IV, since they demon- strated the greatest differences.

The viscosity value was different: 2, 7, and 5 scores for break I, reduction system I, and break system IV, re- spectively. It should be mentioned that viscosity depends on the state of starch, the activity of amylases, and the peripheral parts that contain non-starchy polysaccha- rides. The amylase index depends on the amylolytic ac- tivity of the flour. The higher it is, the lower the activity of enzymes. The starch retrogradation index is related to the rate of staling of the finished product. Its high value indicates a faster rate of staling.

Table 4 demonstrates that the baking absorption increased from the first reduction system to the sixth reduction system, which was connected with a larger number of peripheral water-absorbing particles in the flour. The first, second, and third breaks also showed an increase in baking absorption. The  sizing  sys- tem occupied an intermediate position between the break and the reduction systems. Its baking absorption was 55.0%.

During the first stage (C1), the flow stability was uneven. However, the stability time tended to decrease from reduction systems I – VI, which could also be con- nected with an increase in the content of peripheral par- ticles and a decrease in the dough formation time.

At the second stage (C2) of the curve of the mi- xolabogram, one can observe the smallest rotational input, which is associated with the dough dilution and indirect- ly characterizes the state of the protein complex. Visco- sity increased from breaks I – III. The sizing system had the lowest viscosity. The reduction systems demonstrated an increase in rotational input followed by its decrease, which was apparently due to an increase in the share of peripheral fractions in the flour of these systems.

During the third stage (C3), the starch granules broke down and gelatinized, which led to an increase in rotational input. There was a clear dependence of the increase in the rotational inputon the grain-size compo- sition of the flour at the break system and its reduction at the reduction system.

During the fourth stage (C4), one could observe a gradual increase in the rotational input of the break sys- tems and its decrease during the final reduction systems. The highest rotational input was registered during the second reduction system.

Table 6 visualizes the rheological characteristics of the flows as six consecutive indices: the index of water absorption index, the mixing index, the gluten index, the viscosity index, the amylase index, and the starch retro- gradation index.

The fifth stage (C5) characterized the process of starch retrogradation during cooling and the rate of staling of the finished flour products. Here, the rotational input on the reduction systems fell significantly from 4.221 Nm on re- duction system I to 2.731 Nm on reduction system I.

Table 4. Main parameters of the phases of rheological analysis of the dough of individual flows of Saur Triticale flour

Table 5. Calculated values of reaction rates * for individual flows of Saur Triticale flour

*) α is characteristic of the dilution reaction rate expressed by the angle of the tangent to the mixolabogram from the moment the temperature rea- ches 30°C to the point C2; β is characteristic of starch gelatinization reaction rate, expressed by the angle of the tangent to the mixolabogram on the

C2 – C3 segment; γ is characteristic of the amylolysis rate, expressed by the angle of the tangent to the mixolabogram in the C3 – C4 segment.

Table 6. Indices of the Mixolab profiles for Saur Triticale flour

Flour sample from:                                                                       Indices of the Mixolab profiles

The analysis of the graphical profiles (Fig. 4, Table 5) showed that the highest value of the baking absorption index was registered in the flour from the sixth reduction system. The high water absorption capacity could be ex- plained by the fact that the system contained the largest number of peripheral parts of the kernels. The mixing index was related to the stability of the dough during kneading,  which  was  4.42  min  for  break  I  (1  score),

5.62 min for reduction system I (2 scores), and 5.65 min for reduction system IV (2 scores). The gluten index characterizes the stability of  protein  molecules  when the dough was heated from 30°C to 60°C. It is rather difficult to interpret the gluten index since two very important phenomena occurred while the dough was being heated. First, starch granules began to swell; se- cond, their structure remained unchanged, while the ef- fect of α-amylase was insignificant. The consistency of

At the third  stage of  the research,  we studied the samples of Ramzes and Saur Triticale flour from diffe- rent flows to determine the baking properties. To form a Triticale flour variety, three flows had to be formed on the basis of cumulative ash curves. These flows were three components of different anatomical parts of the kernels (Z – ash content, Y – yield). The first flow was Triticale flour from the central part of the endosperm, the second flow contained the peripheral part of the endo- sperm and the subaleurone layer, and the third flow was the flour from endosperm fragments and well-grin-ded shells. Below one can see the algorithm for the formation of three flows that form the Triticale flour varieties.

Flow formation for the Ramzes Triticale flour:

Milling 1 (reduced scheme):

Flow A – break II + reduction system III + reduction system I.

the dough changes due to the changes in the structure

of gluten proteins: hydrogen bonds break, stability of

Total: yield/ash content was 29.6/0.69; ZA 0.302×10–3 Y ; R2 = 0.82.

= 0,686 +

proteins improves, which is also related to their spatial

Flow B

A

– reduction system I + reduction system IV +

structure, and, ultimately,  the nature of  these protein

complexes [34, 35]. Such fractions of gluten proteins as

break III + break II + reduction system V.

Total:  yield/ash  content  35.8/0.80;  Z

=  0.615  +

gliadin and glutenin play a decisive role in gluten quali-

ty formation and its elastic properties. However, it is ne-

0.211×10–2

B