Variations in Antioxidant Activity, Physical, Chemical and Selected Antinutritional Factors of Two Pigeon Pea (Cajanus cajan (L)) Varieties as Affected by Processing Methods

Abstract

This study evaluated the variations in antioxidant activity, physical, chemical and antinutritional properties of two pigeon pea varieties (white and brown) as affected by processing methods (boiling, roasting and sprouting). The processing methods revealed significant (p<0.05) variations in the results of tested parameters. The unprocessed white pigeon pea variety had the highest gelatinization temperature (84 °C), trypsin inhibitor (9.04 Tiu/ng), polyphenols (137.05 mgGAE/100 g) and ABTS (141.10 μmTrolox/g), while the unprocessed brown variety retained higher concentrations of bulk density (0.71 g/g), phytate (2.55%), tannin (0.94 mg/100 g), FRAP (7.86 mmol/100 g) and total flavonoid (1.02 mgQE/100 g) contents, respectively. Boiled white pigeon pea variety had the highest moisture (11.60%), fat (5.19%), oil absorption capacity (2.97 mg/ml), DPPH (103.25%), and magnesium (80.65 mg/100 g), whereas roasted white pigeon pea variety showed significantly (p<0.05) higher concentrations in water absorption capacity (2.25 g/ml), swelling index (3.51%), and wettability (59.70%). Roasted brown pigeon pea variety exhibited greater ash (5.04%), fiber (5.31%), protein (24.36%), and oil absorption capacity (2.97 mg/ml) than other treatments, respectively. On the other hand, the sprouted white pigeon pea variety had the highest carbohydrate (60.09%), calcium (124.00 mg/100 g) and iron (11.38 mg/100 g) content. From the variety and processing methods, the study shows that the white variety of pigeon pea was a good source of proximate, minerals and functional values, while the brown variety had the highest antinutrients and antioxidant activities. Hence, pigeon pea is a good source of nutrients and that differences in nutrient values are due to variety and processing treatments.