Еlasto-viscous characteristics of dough compositions with coconut fiber

Abstract

Background. Dough is a polydisperse colloidal system that behaves like an elastic-plastic body [1, p. 58]. This feature enables to carry out its many-sided analysis, but particularly structural and mechanical properties are mathematically describable. It allows, to a high precision, to predict the final quality of finished products and, if necessary, adjust their formulation.
An attractive appearance is one of the decisive factors for a consumer when choosing flour confectionery goods and breads, to a large extent it depends on their optimal texture. The effects of biologically active and non-traditional foods on the changes of gluten proteins and starch as the main dough texturizers have been highlighted in numerous publications.
Meanwhile, the properties of presscakes made from tropical foods remain insufficiently researched. Coconut fiber is among them. It was considered efficient to carry out an extended rheological analysis of test samples with coconut fiber added in 3, 5 and 7 % concentrations of flour weight.
The aim of the research is defining elasto-viscous characteristics of dough compositions with coconut fiber.
Material and methods. The basic product is first grade wheat flour and coconut fiber added in 3, 5 and 7 % concentrations of flour weight [12, p. 179]. Preparation of the samples followed by their handling was carried out on Brabender amylograph and Chopin alveograph by methods [13; 14]. Start and finish of gelatinization, rheological indexes of dough compositions were defined by decoding device-based curves – amylograms and alveograms.
Codes have been assigned for experimental samples: those tested with amylograph – Am-3, Am-5 and Am-7, alveograph – Alv-3, Alv-5 and Alv-7, respectively, according to content of the fiber, %. Dough compositions without coconut fiber were the etalons.
Results. Gelatinization maximum of dough compositions with the fiber was significantly lower – 1.7–2.3 times as compared to traditionally made dough. Addition of the fiber (3, 5, 7 %) makes pressure (P) index significantly rise, respectively, by 13.7, 30.1 and 53.4 % in comparison with the reference. The fiber in researched compositions significantly decreases their extensibility; the elasticity index of Alv-3 sample is at the limit of the reference, while for Alv-5 and Alv-7, respectively, it is by 8.5 and 14.9 % less as compared to the dough without the fiber. For researched compositions, the value of unit stress energy is insignificantly lower in comparison to the reference.
Conclusion. Inclusion of 3–7 % of the coconut fiber into formulation of dough semi-products variably influences their quality, depending on the ratio of flour and a liquid component. Elasticity of unleavened dough has risen by 13.7–53.4 %, whereas the value of stress energy is slightly less in comparison with the reference. Meantime, the viscosity of water-flour suspensions is significantly reduced – 1.7–2.3 times, which may indicate the inappropriateness of use of the fiber in production of dough with a high liquid content, like biscuit, choux, pancake, or waffle dough.
Further study of the changes in structural and mechanical properties of confectionery and bread dough is required, taking into account the interaction of all recipe ingredients in the presence of the supplement.