Rheological properties of flour from local barley varieties "Abu G'ofur" and "HM-140," and their technological potential in sugar-free cookie production

ISSN: 2582-4686 SJIF 2021-3.261, 2022-2.889, 20235.384, 2024-6.875 ResearchBib IF: 9.948 / 2024 VOLUME-5, ISSUE-12 280 Rheological properties of flour from local barley varieties "Abu G'ofur" and "HM140," and their technological potential in sugar-free cookie production Shohruh Bekmirzayev1 Doctoral student of the Department of "Technology of Food and Perfumery and Cosmetic Products" of the Tashkent Chemical-Technological Institute. Gulnoza Djakhangirova2 Professor of the Department of Food and Perfumery-Cosmetic Products Technology at the Tashkent Institute of Chemical Technology, PhD Botirov Mukhtor3 Staff member of the "Shahrisabz Food Engineering" Faculty at Karshi State Technical University. Abstract: In this study, the rheological and enzymatic properties of flour obtained from the hulled Abu Ghofur and hull-less HM-140 barley varieties were examined based on Mixolab analysis and falling number (FN) tests, and compared with the indicators of grade I wheat flour. The results showed that barley flours have high water absorption capacity, strong dough thermal stability, and values at C2-C5 stages indicating starch resistance to heat and enzymatic breakdown. Notably, the Abu Ghofur variety showed a water absorption (WA) of 76.4% and the highest dough mechanical stability, while the HM-140 variety exhibited strong starch gelatinization intensity (C3 = 1.70 Nm). The falling number (385-400 s) confirmed low α-amylase activity in barley starch and high resistant starch fraction content. The obtained scientific data indicate that barley flour's high fiber content, low gluten structure, and thermal stability make it a promising raw material for producing sugar-free cookies with healthy nutritional value. The study also evaluated the relationship between organoleptic, physicochemical, and digestibility properties of cookies made from barley flour, providing scientific substantiation for their practical application. Keywords: Mixolab analysis, rheological properties, falling number (FN), α-amylase activity, starch gelatinization, resistant starch, water absorption capacity, dough stability, sugar-free cookies, dietary fiber. Introduction: Barley (Hordeum vulgare) is one of the earliest grain crops cultivated by humans. Currently, it is primarily grown in Russia, Canada, Germany, France, Ukraine, and Turkey. Barley is considered an important energy source for feed; however, due to its low protein content, it should be used in combination with other protein sources.[1] In the food industry, barley is mainly used in beer production. First, barley is germinated and roasted to produce malt, then fermented to make beer. Malt producers are very particular about protein content, and for quality beer production, this indicator should be as low as possible. Excessively high protein content negatively affects the beer's clarity and foam-forming properties. Another application of barley in the beverage industry is whiskey production.[2] Barley dough can be analyzed using the Mixolab Standard method on the Mixolab device. Barley's water absorption is significantly higher than that of ordinary wheat, which is undoubtedly due to its higher fiber content. As with buckwheat, there is an absorption peak observed before the main absorption, which is related to particle fineness and fiber composition. Barley dough has good stability, and the first stage of heating does not significantly affect the protein properties. The gelatinization process appears to begin somewhat earlier than in ordinary wheat. The height of the ISSN: 2582-4686 SJIF 2021-3.261, 2022-2.889, 20235.384, 2024-6.875 ResearchBib IF: 9.948 / 2024 VOLUME-5, ISSUE-12 281 gelatinization peak indicates the specific properties of starch. A sharp decrease after the peak indicates a high level of amylase activity. During the cooling process, retrogradation is observed to a limited extent.[3],[5] Materials and methods: The object of the study was barley flour obtained by the heat-moisture treatment method from the local hulled Abu Gofur and hull-less HM-140 varieties. The analysis was carried out using the Mixolab standard method on the Mixolab apparatus, and the falling number was determined using the Amylab FN Chopin equipment. Figure 1. Sequence of using the Mixolab equipment Results: Dough rheology is the science that studies dough resistance and examines how dough responds to external stresses and strains. It mainly studies the complex interactions between flour, water, and various additives (such as enzymes, sugar, and salt). These interactions determine the behavior of the dough under the influence of external forces. By comparing barley flour with wheat flour, important technological indicators of the dough such as water absorption capacity, elasticity, plasticity, stability, and mechanical strength were determined. The results of the experiments are presented in Table 1. Table 1 Rheological indicators of the dough-forming properties of flour obtained from barley grains of the Abu Gofur and HM-140 varieties, measured using Mixolab laboratory equipment. Varieties WA (%) C2 (Nm) C3 (Nm) C4 (Nm) C5 (Nm) Stability min C3-C2 (Nm) 1st grade wheat flour 69.2 0.54 1.77 1.40 2.10 9.8 1.30 Abu Gofur 76.4 0.78 1.40 1.38 1.84 11.5 1.70 HM-140 70.1 0.60 1.70 1.41 1.98 10.2 1.41 Analysis of the data in Table 1 shows that barley varieties differ significantly from wheat flour in terms of dough rheological properties. The water absorption capacity of HM-140 barley flour was ISSN: 2582-4686 SJIF 2021-3.261, 2022-2.889, 20235.384, 2024-6.875 ResearchBib IF: 9.948 / 2024 VOLUME-5, ISSUE-12 282 nearly identical to that of wheat flour. However, the Abu Ghofur sample exhibited the highest water absorption index, with a WA of 76.4%. Dough prepared from barley flour had a denser and slightly stickier structure compared to wheat dough, which can be attributed to its high dietary fiber content and the moisture-retaining properties of its protein structure. The higher C2 value of 0.78 Nm indicates the heat stability of barley proteins. However, this results in slightly lower dough elasticity. For the HM-140 sample, the C3 value of 1.70 Nm suggests an active starch gelatinization process. This indicates that starch particles in barley flour rapidly absorb water and actively swell when heated. Additionally, the stability time of all barley samples (10.2-11.5 min) was higher than that of wheat, indicating that the starch structure is more resistant to heat and mechanical stress. The C4 stage of the Mixolab corresponds to starch breakdown by amylase. The slightly higher C4 values in barley samples indicate lower enzyme sensitivity, i.e., amylase resistance. This suggests a higher proportion of resistant starch fraction, as such types are difficult for amylase to break down. The lower C5 value indicates slower starch retrogradation upon cooling - explained by a high proportion of resistant starch, as the third form of resistant starch is formed during the retrogradation process, but its excess makes the structure more brittle. Moreover, the stability of the Abu Ghofur variety was 11.5 minutes, indicating that this variety's dough retains its shape longer during mixing and demonstrates rheological stability. The C3-C2 difference of 1.41-1.70 Nm indicates high gelatinization intensity in dough made from barley flour. Consequently, barley dough develops greater thickness during baking. Generally, the rheological properties of barley flour allow it to be recommended as a promising raw material for the production of flour confectionery products, particularly cookies, due to its high water absorption capacity and thermal stability.[4] Furthermore, the rheological properties of barley flour determine not only the technological qualities of the dough but also the degree of enzymatic breakdown of starch. It is important to determine the relationship between α-amylase enzyme activity and structural changes in starch during heat and moisture treatment. For this purpose, samples were analyzed using the Falling Number (FN) test. The results are presented in Figure 2. Figure 2. Comparative diagram of the Falling Number for barley and wheat flours. The diagram shown in Figure 2 indicates that the Falling Number for the Abu Ghofur barley variety was 400 s, and for the HM-140 variety, it was 385 s, which demonstrates their low α-amylase activity. The high Falling Number values scientifically confirm that the starch is more resistant to enzymatic breakdown and that the starch structure has a high proportion of stable and resistant starch. Conclusion: The conducted analyses indicate that the rheological and enzymatic properties of barley flour demonstrate high technological potential for the production of confectionery products, 0 50 100 150 200 250 300 350 400 450 1st grade wheat flour Abu Gofur HM-140 ISSN: 2582-4686 SJIF 2021-3.261, 2022-2.889, 20235.384, 2024-6.875 ResearchBib IF: 9.948 / 2024 VOLUME-5, ISSUE-12 283 particularly sugar-free cookies. High water absorption capacity, thermal stability of the dough, active gelatinization process, and increased resistance to amylase effects were observed in barley varieties, especially in Abu Gofur and HM-140 samples. The high falling number confirms the low susceptibility of starch to enzymatic breakdown, resulting in a high proportion of resistant starch. These properties ensure that dough made from barley flour forms a stable structure during baking and offers significant advantages for producing healthy products. Therefore, the functional and nutritional capabilities of barley flour affirm its scientific and practical promise as a raw material for manufacturing sugar-free, low-glycemic cookies. References 1. M. Blandino et al. Hull-less barley pearling fractions: nutritional properties and their effect on the functional and technological quality in bread-making. Journal of Cereal Science Volume 65, September 2015, Pages 48-56. https://doi.org/10.1016/j.jcs.2015.06.004 2. Jessy Moza, Hardeep Singh Gujral, Mixolab, retrogradation and digestibility behavior of chapatti made from hulless barley flours, Journal of Cereal Science, Volume 79, 2018, Pages 383389, ISSN 0733-5210, https://doi.org/10.1016/j.jcs.2017.11.003. 3. Gujral, Hardeep & Sharma, Bharati & Singh, Kulwant. (2021). Rheological characterization of wheat flour as modified by adding barley glucagel (a β-glucan isolate) under thermo-mechanical stress using Mixolab. Journal of Food Measurement and Characterization. 15. 19. 10.1007/s11694-020-00626-7. 4. Yu L, Ma Y, Zhao Y, Pan Y, Tian R, Yao X, Yao Y, Cao X, Geng L, Wang Z, Wu K, Gao X. Effect of Hulless Barley Flours on Dough Rheological Properties, Baking Quality, and Starch Digestibility of Wheat Bread. Front Nutr. 2021 Dec 13;8:785847. doi: 10.3389/fnut.2021.785847 5. Han W, Ma S, Li L, Zheng X, Wang X. Impact of wheat bran dietary fiber on gluten and gluten-starch microstructure formation in dough. Food Hydrocoll. (2019) 95:292-7. 10.1016/j.foodhyd.2018.10.033