Table 4. Effect of pretreatment on the TPC, TFC, percentage variation, and true retention in pak choi

Samples	Total polyphenol contents (TPC)			Total flavonoid contents (TFC)
Samples	mg GAE/100 g¹⁾	Percentage variation (%)	True retention (%)	mg QE/100 g²⁾	Percentage variation (%)	True retention (%)
S-CON³⁾	40.83±5.88	-	100.00±0.00	50.43±5.15^b4)5)	-	100.00±0.00
S-WB	35.69±1.20	−12.59±2.95^b	79.53±2.68^b	57.10±4.59^b	13.22±9.11^b	127.22±10.23^b
S-NB	43.61±1.46	6.80±3.58^a	96.54±3.24^a	70.43±1.43^a	39.66±2.83^a	155.91±3.16^a
S-CB	38.06±2.29	−6.80±5.62^b	78.57±4.74^b	34.71±7.42^c	−31.16±14.72^c	71.67±15.33^c
F-value	3.25^NS6)	16.79^**	22.92^**	25.25^***	37.40^***	47.22^***
L-CON	209.58±1.91^a	-	100	176.94±22.94^a	-	100
L-WB	193.33±2.73^b	−7.75±1.30^a	95.40±1.35^a	170.85±16.58^a	−3.44±9.37^a	84.31±8.18^a
L-NB	155.28±3.78^d	−25.91±1.80^b	77.69±1.89^b	117.13±15.08^b	−33.80±8.52^b	49.59±6.38^b
L-CB	146.25±6.93^c	−30.22±3.31^b	61.92±2.94^c	80.75±8.20^c	−54.36±4.64^c	40.40±4.10^b
F-value	149.27^***	16.79^**	180.194^***	22.99^***	32.45^**	38.74^***

GAE, galic acid equivalent.
QE, quercetin equivalent.
CON, non-treatment; WB, blanching with water; NB, blanching with 2% NaCl; CB, blanching with 2% citric acid. Stems and leaves were blanched during 2 min and 30 sec with each treatment method, respectively.
Values are mean±SD (n=5).
Means with different letter (^a-d) within a row are significantly different by Duncan’s multiple range test (p<0.05) **p<0.01 ***p<0.001.
NS, not significant.