EVALUATION OF NUTRITIVE AND ANTIOXIDANT PROPERTIES OF BLANCHED LEAFY VEGETABLES CONSUMED IN WESTERN COTE D’IVOIRE

Abstract

African leafy vegetables are valuable sources of nutrients especially in rural areas where they contribute substantially to protein, minerals, vitamins, fibres and other beneficial nutrients. Five leafy  vegetable  species  (Abelmoschus  esculentus,   Celosia  argentea,  Ipomea  batatas,  Manihot esculenta and Myrianthus arboreus) that are used as soup condiments in Western Côte d’Ivoire were subjected to steam blanching in order to evaluate the effect of this processing method on their nutritive
value  and  antioxidant  properties.  The  result  of  the  study revealed  that  longer  time  of  blanching (higher  than  15  min)  caused  negative  impact  by  reducing  nutritive  value  but  positive  impact  by reducing anti-nutrients such as oxalates and phytates. The registered losses at 15 min were as follow:
ash  (3.78  –  55.81  %),  proteins  (0.1  -  10.79  %),  vitamin  C  (1.04  –  79.70  %),  carotenoids  (47.91  - 66.28%) oxalates  (5.51  –  33.33  %)  and  phytates  (43.83–  78.16 %).The  average  reduction  of polyphenols  content  at  15  min  of  blanching  was  13.84  –  38.23  %.  Contrary  to  these  reductions,  a significant  increase  (0.4  –  29.94  %)  of  fibres  content  was  observed  in  the  studied  blanched  leafy vegetables.  Furthermore  after  15  min  of  blanching  time the  residual  contents  of  minerals  were: calcium  (228.62  –  402.39  mg/100g),  magnesium  (92.19  –  270.82  mg/100g),  potassium  (1255.24  – 2215.65 mg/100g), iron (17.24 – 43.48 mg/100g) and zinc (10.91 – 32.30 mg/100g). All these results
suggest  that the  recommended  time  of  domestic  blanching must  be  less than  15  min for  the  studied leafy  vegetables  in  order  to  contribute  efficiently  to  the  nutritional requirement  and  to  the  food security of Ivorian population.