The influence of the dosage of Jerusalem artichoke fiber, a by-product of complex ethanol technology, on changes in the properties of rice extrudates

Jerusalem artichoke is a promising raw material for the alcohol industry. One of the by-products of the complex processing of Jerusalem artichoke into ethanol is dietary fibers, which is a dispersed fraction formed as a result of enzymatic hydrolysis and separation of the hydrolyzate into fractions. This product of enzymatic hydrolysis of Jerusalem artichoke can be in demand by the food industry as an ingredient with a high content of dietary fiber. The synergy of using Jerusalem artichoke fiber can be achieved in the production of products that combine traditional nutritional qualities and additional functional properties, which meets the main trends in the development of the food industry. Among such products, ready-to-eat products such as snacks and instant cereal products produced by extrusion technology are popular. Traditionally, the main raw materials for extruded products are starch-containing ingredients due to the peculiarities of their morphological structure and the ability to form a porous structure as a result of extrusion processing. Starchy raw materials after refining contain an insufficient amount of biologically active compounds and require additional enrichment by adding functional ingredients. The study examined the possibility of including Jerusalem artichoke fiber, the dispersed fraction formed during its complex processing of Jerusalem artichoke into alcohol, into the recipes of extruded products and its effect on the technological properties of the extrudates. The objects of the study were rice extrudates containing dried Jerusalem artichoke fiber up to 9%. Mixtures of rice cereals with different fiber content were prepared and extruded using Werner&Phleiderer Continua 37 laboratory twin-screw extruder under fixed operating parameters. Based on the results of the process, changes in dependent extrusion parameters such as torque, pressure, and temperature were assessed. The structural and mechanical properties, expansion coefficient, hardness, number of microfractures, hydration properties and changes in color characteristics were determined in the extrudates. Increasing the content of Jerusalem artichoke fiber up to 9% in extruded mixtures did not affect the change in extrusion modes and specific energy consumption. The temperature value varied in the range of 165-166 °C, pressure - 3.3-3.5 MPa. With an increase in the content of Jerusalem artichoke fiber, significant changes in the structural and mechanical properties were noted. The quadratic coefficient of expansion and hardness of the samples decreased from 11.2 to 7.8 and 13.2 N to 5.4 N, respectively. The number of microfractures characterizing porosity increased from 6.7 to 11.2. The hydration properties of the samples, water-holding capacity, solubility changed insignificantly. An increase from 7 to 8.5 sm3/g in swelling properties was found Increasing the dosage of fibers significantly affected the change in the color of the samples: the color became darker and acquired a brown tint. The results of the study show that increasing the content of Jerusalem artichoke fiber to 9% in the mixture largely affects the structural and mechanical properties of extrudates, which are significant in the development of snack products. The hydration properties of extrudates used as the basis for ready-to-eat cereals do not depend on the content of Jerusalem artichoke hydrolyzate.