Effect of milling variables on pasting properties and texture of chickpea flour gels

Chickpea is a pulse, highly acceptable and important staple food in many regions of the world. It is composed primarily of starch (33-47%) and protein (18-25%), and also contain lipids, fiber, vitamins, minerals, and other micronutrients, such as phenolic compounds. The ball mill has emerged as a physical method for modifying the physicochemical and technological properties of proteins and starch, enabling a diversification of their applications in food products. The aim of this study was to evaluate the influence of ball milling parameters (rotation speed, treatment time, and ball ratio) on the pasting properties and firmness of chickpea flour gels. Chickpea flour (10.0% moisture, 3.4% ash, 22.1% protein, 4.1% lipid, and 60.4% carbohydrates) was treated in a ball mill under conditions established in a central composite design 2³, with three replicates at the central point, with the rotation speed (400-600 rpm), treatment time (10-30 min), and ball ratio (3:1-7:1 w/w, ball:flour) as variables. The pasting properties of the treated flours were evaluated by a Rapid Visco Analyzer (Standard 2 method with modifications) at 12% (total solids/w). The gels obtained were stored overnight under refrigeration for texture evaluation. Gel firmness was evaluated using a texturometer with an acrylic cylindrical probe (diameter: 25 mm) under the following conditions: pre-test speed: 2.00 mm/sec, test speed: 0.80 mm/sec, post-test speed: 2.00 mm/sec, and strain 40%. Statistical evaluation and mathematical models were obtained using Promitiza software. The results of pasting properties showed a reduction in peak viscosity (883-661 cP), trough viscosity (825-643 cP), and final viscosity (1039-1242 cP), and an increase in pasting temperature (80.0-81.2°C). Gel firmness decreased, with measurements ranging from 3.165 to 2.101 N, also being an indication of less retrogradation of the gel. The evaluation of the response surfaces (α = 5%) indicated that longer treatment time, higher rotation speed, and higher proportion of balls led to a decrease in RVA parameters, except for pasting temperature, and reduction in gel firmness. Treatment time was the most influential variable. Therefore, ball milling promoted modifications in the pasting properties of chickpea flour, resulting in lower viscosity pastes and softer gels. This modulation in the technological properties of flour can be explored in different products, especially in terms of texture characteristics.