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Calculation of Retention Factors for Flavonoids in Cooked Broccoli
Author(s) -
Wu Xianli,
Zhao Yang,
Bhagwat Seema,
Haytowitz David B,
Harnly James M,
Pehrsson Pamela R,
Chen Pei
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1176.8
Subject(s) - aglycone , chemistry , steaming , kaempferol , glycoside , food science , flavonoid , quercetin , retention time , chromatography , biochemistry , organic chemistry , antioxidant
Thermal processes such as cooking have a large influence on flavonoids in foods, which further impact the accuracy of developing food flavonoid database and the estimation of their dietary intake. The objective of this study was to determine how common cooking methods alter complex flavonoids in broccoli, and to compare the effects of different cooking and calculating methods for estimating retention factors. Fresh broccoli samples were purchased from local grocery chains and were cooked by three common ways (boiling, steaming and microwaving). Flavonoids were analyzed by HPLC‐MS/MS. Eight major kaempferol (Km) tri‐ or tetra‐glycosides and one quercetin tri‐glycoside were identified and quantified in raw and cooked broccoli. Retention factors were calculated on individual flavonoids based on the dry weight; they ranged widely from 33.9% to 237.2%, depending on the chemical structure and cooking method. Contents of certain Km glycosides elevated after cooking, probably due to the increased release from cells or from binding with other components. In addition, different calculation methods to generate an overall retention factor for multiple flavonoids with the same aglycone were compared. Among the three methods, namely “retention factor by aglycone”, “retention factor by weight” and “retention factor by average”, the “retention factor by aglycone” was shown to be an appropriate method. The retention factors by aglycone for Km glycosides in broccoli was calculated as 83.9% for boiling, 131.6% for steaming and 136.1% for microwaving. Support or Funding Information NIH Agreement 58‐1235‐3‐126 and USDA