Evaluation of Changes in Protein Quality of High-Pressure Treated Aqueous Aquafaba.

Chickpea cooking water (CCW), known as aquafaba, has potential as a replacement for egg whites due to its emulsion and foaming properties which come from the proteins and starch that leach out from chickpeas into the cooking water. High pressure (HP) processing has the ability to modify the functional characteristics of proteins. It is hypothesized that HP processing could favorably affect the functional properties of CCW proteins by influencing their structure. The objective of this study to evaluate the effect of HP treatment on the associated secondary structure, emulsion properties and thermal characteristics of CCW proteins. A central composite rotatable design is used with pressure level (227-573 MPa) and treatment time (6-24 min) as HP variables, and concentration of freeze dried CCW aquafaba powder (11-29%) as product variable, and compared to untreated CCW powder. HP improves aquafaba emulsion properties compared to control sample. HP reduces protein aggregates by 33.3%, while ß-sheets decreases by 4.2-87.6% in which both correlated to increasing protein digestibility. α-helices drops by 50%. It affects the intensity of some HP treated samples, but not the trend of bands in most of them. HP treatment decreases Td and enthalpy because of increasing the degree of denaturation.

Reduction in soaking time and anti-nutritional factors by high pressure processing of chickpeas.

High pressure (HP) treatment was applied to Kabouli chickpeas to reduce soaking time and anti-nutritional factors, and enhance their quality. Chickpeas were subjected to HP treatment at 100-600 MPa with single and multiple cycles (up to 6) with 10 min holding time as soak-treatments with or without prior soaking at 40 °C for 2 h. HP treatment alone resulted in 89.1% hydration while a combination of pre-soaking followed by HP treatment resulted 93.8% hydration; however overnight soaking (12 h) of chickpeas at room temperature resulted only in 42.5% hydration. Texture softness and color brightness were enhanced by HP treatment with or without pre-soaking (2 h at 40 °C) as compared to overnight soaked chickpeas. HP treatment reduced tannin to 25 mg CE/100 g and phytic acid to 0.2% levels which were about one fifth of their content in raw chickpeas and significantly lower than in overnight soaked product. Scanning electron microscopy revealed that 600 MPa HP treated samples showed larger pore sizes and bigger starch granules corresponding with the higher hydration rates. Fourier transformation infrared spectroscopy results also showed a difference between raw and HP treated chickpeas. Overall, HP treatment was effective in reducing the anti-nutritional factors and soaking times and enhanced quality factors.

Effect of high pressure processing on structural and functional properties of canned aquafaba.

Aquafaba is chickpea cooking water. It has great functional properties since it consists of starch and protein. High pressure processing (HPP) is proven to modify the functionality of starch by keeping its integrity. The objective of this study was to check if HPP can improve structural and functional properties of canned aquafaba. HPP treatments were given at pressure levels: 200, 259, 400, 542, and 600 MPa with holding time between 5 and 30 min. After HPP, part of the samples was freeze dried for crystallinity and particle size analysis and the fresh part used for rheological, functional properties, and colour. HPP enhanced functional properties, mostly foaming stability which increased from 50.5 to 67 min. Rheological properties were enhanced mainly for consistency coefficient from 0.6 to 1.4 Pa.s. Crystallinity dropped slightly compared to control sample, while the colour got brighter, from 27.5 to 49.6. Processing time and pressure intensity did not contribute in increasing particle size. The combination of high intensity and long pressurization time resulted the smallest particle size (90 µm).