Effect of some treatments on colour parameters and antioxidant potentials of Corcorus olitorius broth

Abstract

Scientific research reports have revealed the high nutritional values, especially micronutrients, of leafy vegetables. African leafy vegetables are mostly harvested fresh and made into broths for immediate consumption. The effect of some preprocessing treatments on the Corcorus olitorius vegetable, an important African leafy vegetable, were assessed on colour parameters and antioxidant potentials of its broth. Freshly harvested leaves of C. olitorius were subjected to osmotic dehydration and steam blanching prior to drying, and direct drying. Two drying conditions of oven drying at 35°C for 24 h and tray-drying under prevailing laboratory environment conditions were separately employed before cooking into broths. Broth from fresh C. olitorius leaves served as control. Generally, pre-processing treatments increased the lightness (L*) index of the broth significantly (p<0.05) from 44.03 to 58.53. Greenness, shown by the negative a* values, and the yellowness, positive b values, significantly (p<0.05) decreased from -12.21 to -5.37 and 22.73 to 10.23, respectively. Antioxidant potentials, evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), also showed a general decrease with applications of pretreatments (67.90 to 37.77%). The results from this research is expected to guide on the selection of the pre-processing treatment(s) to obtain optimal nutritive quality from C. olitorius broth.