Total phenolics in germinated beans were extracted according
to our pervious publication (Xu & Chang, 2007). Briefly, 0.5 g of
dry beans or germinated bean with sprouts were extracted twice
with 5 mL of acetone/water/acetic acid (70:29.5:0.5, v/v/v) in dark.
The extracts were combined for determination. TPC content was
determined using gallic acid as an external standard. The extracts
were mixed with distilled water, Folin–Ciocalteu reagent and 7%
Na2CO3. After standing for 2 h at room temperature, the absorbance
was measured at 765 nm by an UV–visible spectrophotometer
(TI-1901, Beijing Purkinje General Instrument Co., Ltd, Beijing,
China) with extraction solution as blank. A calibration curve of gallic
acid was used to calculate the TPC with a unit of milligrams of
gallic acid equivalents per gram of freeze-dried beans or germinated
bean with sprouts (mg GAE/g).