Effects of high-pressure homogenization on the rheological properties of spray-dried aquafaba powder

Abstract

Aquafaba, the water obtained from chickpea cooking, has gained interest as a novel food foaming, emulsifying, or gelling agent. Applying proper unit operations to manufacture aquafaba powder with a longer shelf-life and improved functional properties than liquid aquafaba may further extend its usage in the food industry. In this study, spray drying of aquafaba was optimized, and high-pressure homogenization was used to improve the rheological properties of the reconstituted powder. The spray drying experiments at different inlet air temperatures (130, 150, and 170°C), feed rates (4, 6, and 8 mL/min), and aspiration rates (80, 90, and 100 m3/h) were conducted. Spray drying at 170°C inlet air temperature, 4 mL/min feed rate, and 92 m3/h aspiration rate was selected as the optimal process resulting in the highest product yield (46.34 ± 1.23%), protein (19.96 ±.29% d.b.), and saponin (96.47 ± 6.11 mg/g d.b.) contents, and minimum moisture level (3.21 ±.14% d.b.). High-pressure homogenization treatments at different pressure levels (80, 100, and 120 MPa) and the number of passes (2 and 4) were then applied to the solutions prepared from aquafaba powders at the least gelling concentration (20% w/v). The number of passes did not have any significant (p > 0.05) effect on the rheological properties, while homogenization at 120 MPa resulted in the highest viscosity (938.5 × 10−3 Pa s). The aquafaba gels obtained from homogenized solutions had storage modulus values of 7–9 times the loss modulus. The low-frequency dependence of the viscoelastic properties was also determined. High-pressure homogenization at increased pressure values and a low number of passes may be considered an optional tool for developing strong gels from aquafaba. Practical applications: Plant-based ingredients have been gaining increased interest in recent years, both from everyday consumers and the food industry. Alternative products may be developed with these materials to meet the demands of the clean-label food market. Aquafaba, the cooking water remaining after chickpea processing, is a potential plant-derived source. This study describes an optimized spray-drying process to obtain shelf-stable aquafaba powder and a high-pressure homogenization method to improve rheological properties. Based on the results presented here, it may be possible to prepare aquafaba gels and gel-like food products containing aquafaba.