Traditional vegetables in the Southern Africa are African nightshade (Solanum retroflexum Dun) and non-headed Chinese cabbage (known as pak choi). Both of these types of vegetables contain healthy benefits (such as phenolic compounds, with antioxidant properties) and higher levels of calcium and iron than raw spinach.
On the other hand, as any other leafy vegetables, they have antinutrients such as tannins, oxalates, and phytates that prevent us from receiving and absorbing the healthy nutrients of vegetables. Tannins form complexes with proteins and make them unavailable for absorption. Oxalates bind with calcium and prevent them from being absorbed; moreover, oxalates that are stored in the kidney, cause “kidney stones.” Phytates impair absorption of iron and zinc, and to a lesser extent calcium. Luckily, we can increase the benefits of the healthy nutrients and reduce the damaging effect of the antinutrients by different cooking techniques.
A recent study tested different cooking techniques such as boiling, steaming, stir frying, and microwave to see their influence on healthy aspects (phenolic compounds, antioxidant property), antinutritients and sensory properties (taste, visual perception, smell).
Based on the results, stir-frying came out as the best cooking technique to maintain optimal health benefits of the tested vegetables, followed by steaming. An additional bonus from stir-frying was an observed antidiabetic activity as it seems to prevent the adsorption of glucose in the intestine.
Boiling and microwaving turned to be better in reducing antinutrients.
As for the taste and visual perception, the stir-fried Chinese cabbage and nightshade leaves received the preference followed by steamed, microwaved and boiled vegetables.
Curious? HERE is the source