Dynamics of Polyphenolic Compounds During Wet Processing of Peanuts

The study analyzed changes in phenolic compounds and the total polyphenol content during peanut sauce cooking, comparing samples prepared with peanuts with and without kernel coating. The peanut sauce formulation consisted of 3.3% w/v peanut powder mixed with water, which was boiled for 2 h at around 100°C. Methanol extracts were used to assess the polyphenol content. Identification and quantification of phenolic compounds were performed using high‐performance liquid chromatography (HPLC). Nine polyphenols were identified, including several phenolic acids (4‐hydroxybenzoic acid, vanillic acid, p ‐coumaric acid, and trans ‐ferulic acid), flavonoids (daidzein, quercetin, genistein, and kaempferol), and one stilbene (resveratrol). The concentrations of 4‐hydroxybenzoic acid, p ‐coumaric acid, resveratrol, daidzein, and genistein in the noncoated peanuts significantly increased from 0 to 60 min (from 70 to 120 μ g/g, 20 to 30 μ g/g, 5 to 10 μ g/g, 30 to 60 μ g/g, and 30 to 50 μ g/g, respectively), followed by degradation at extended cooking up to 120 min. In conclusion, the removal of the coating resulted in a more pronounced maxima and degradation of these compounds during the cooking process. The results can be understood by applying a consecutive model describing the release of bound polyphenols and the degradation of free polyphenols during the cooking process.