bitterleaf debittering
process / process-bitterleaf-debittering
ビターリーフの脱苦味処理
Traditional debittering of bitterleaf. Boiling, soaking with several changes of water, or kneading and washing in cold or warm water lowers the leaves’ bitterness to the desired level.
On this page (6 sections)
Reading the bitterness
Debittering bitterleaf is a preparation step in Nigerian home cooking that lowers the bitterness of Vernonia amygdalina leaves to the desired level. A 2011 review states that boiling or soaking with several changes of water can ease the bitterness, and also describes kneading and washing freshly harvested leaves in cold or warm water until their bitterness reaches the desired level.
This process also appears in interview research. A 2008 survey of traditional food systems in 8 communities across 4 states recorded bitterleaf as 「苦く、使う前に洗うのが通例」 (in translation: "bitter and customarily washed before use"). Neither source, however, quantifies how many times the leaves are washed or how much bitterness remains afterward.
A study also examined washing as a preparation step chemically. Comparing several prepared forms of V. amygdalina leaves, it found that powder made from the 「洗浄形」 (in translation: "washed form"), subjected to the customary process of repeated grinding and washing with water to remove bitterness, had a total phenolic content of 0.445 mg/g gallic acid equivalents by the Folin–Ciocalteu method, lower than the aqueous extract’s 24.08 mg/g. The authors conclude that washing reduces total phenolic content. These figures do not measure bitterness itself, however, and the comparison is between differently prepared forms: washed-form powder and an aqueous extract.
Sources for this overview
Antioxidative and Chemopreventive Properties of Vernonia amygdalina and Garcinia biflavonoid
Checked for this overview: Confirmed descriptions of bitterness reduction by boiling, soaking with water changes, and kneading and washing.
Igbo Traditional Food System: Documentation, Uses and Research Needs
Checked for this overview: Confirmed the record that washing is customary in the 8-community survey and its limitations.
Checked for this overview: Comparison of total phenolic content in the washed form and aqueous extract.
Follow the connections
bitterleaf debittering →is documented in→ Igbo traditional food system
Hypotheses and recipe candidates for this entry are on the Japanese page.
Structured claims — open a section to read each claim's confidence, evidence and limits
How processing and cooking change it (3)
Scope: Nigerian home cooking and soup preparation
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process-bitterleaf-debittering —reduces→ "The bitterness of Vernonia amygdalina leaves. Lowered to a desired level by boiling, soaking with several changes of water, or macerating (rubbing while washing) in cold or hot water"Scope: a traditional food-system survey table covering 8 communities across 4 states
Note: Bitter leaf is recorded as "bitter, usually washed before use". The endpoint of washing is not given.
Show data
process-bitterleaf-debittering —is_documented_in→ culture-igboScope: Layer: Food. Total phenolic content measured by the Folin–Ciocalteu method in several prepared forms of V. amygdalina leaves (washed-form powder, unwashed-form powder, juice, and aqueous extract).
Show data
process-bitterleaf-debittering —reduces→ "Powder from the washed form of Vernonia amygdalina leaves (subjected to the customary grinding and washing process intended to remove bitterness) had a total phenolic content of 0.445 mg gallic acid equivalents/g, lower than that of the aqueous extract used for comparison (24.08 mg gallic acid equivalents/g). The authors conclude that washing reduces total phenolic content."