Effect of Germination and Fermentation on the Nutrient Contents, Functional and Antioxidant Activities of Pigeon Pea (Cajanus cajan) Flour

Abstract

Effect of germination and fermentation on the nutrient contents, functional and antioxidant activities of pigeon pea (Cajanus cajan) flour were investigated. The pigeon pea seeds were sorted, cleaned and processed into germinated, fermented and raw flours. The flour samples obtained were analyzed for proximate composition, mineral contents, antinutrient contents, functional properties and antioxidant/free radical scavenging properties using standard methods. The results of the proximate composition showed that the moisture content within the range of 9.62±0.02-9.96±0.01, crude protein content 16.63±0.01-24.17±0.01, crude fibre content 1.41±0.01-2.59±0.01, lipid 4.33±0.01-5.61±0.01, ash content 1.62±0.01-2.17±0.01, carbohydrate 56.80±0.02 - 62.47±0.01 and energy values 366.91 - 374.40kcal/100g. The result of elemental mineral analysis showed magnesium as the major mineral element in the sample (91.32±0.02 to 123.75±0.04mg/g), calcium (96.02 ± 0.02 - 110.14 ± 0.003mg/g), phosphorus (39.11 ± 0.02 - 46.12 ± 0.03mg/g), sodium (8.63 ± 0.02 - 12.61 ± 0.001mg/g), Iron (3.08 ± 0.02 - 4.11 ± 0.001mg/g) and zinc (2.04 ± 0.01 - 3.17mg/g) respectively. The result of the functional properties showed optimal gelatinization temperature ranged from 73.610C - 89.410C, emulsion capacity, 11.88 - 43.42%, foam stability,28.22 to 65.81%, foaming capacity,15.83 to 21.11%, bulk density,0.53 - 0.71g/ml, water absorption capacity, 1.11 and 1.51ml/g while oil absorption capacity,0.84 - 1.14ml/g. The sensory properties of the moi-moi from the processed flours showed that the colour test, (6.33 -7.53), flavour (7.63 to 7.75), taste (5.13 to 5.53), mouth-feel (7.25 to 7.36), overall acceptability (6.93±0.04 - 8.83±0.04). The results of the phenolic content ranged from 20.13mg\GAE, 53.43mg\GAE and 42.64mg\GAE for raw processed, malted and fermented samples respectively. The results of the 1,1-diphenyl-2-picrylhydrazyl (DPPH) antioxidant activity of ethanolic extracts showed IC50values of 0.810, 1.177 and 1.014mg\ml for the raw, malted and fermented seed extracts respectively. The moisture, crude protein and fibre contents was significantly increased (p>0.05) during germination and fermentation whereas lipid, carbohydrate, ash and energy values were significantly (p<0.05) decreased by the processing techniques. Germination increased the emulsion capacity, foaming capacity whereas fermentation reduced the foaming capacity of pigeon pea flour. Malting and fermentation significantly (p>0.05) increased the % scavenging properties of pigeon pea extract though that of germination was higher. Malting and fermentation significantly (p<0.05) decreased the sensory properties of moi-moi produced. Based on the result obtained, regular consumption of pigeon pea will be a proactive measure against heart diseases and other related disorders in the human body.