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.