J Food Bioact

Journal of Food Bioactives, ISSN 2637-8752 print, 2637-8779 online

Journal website www.isnff-jfb.com

Original Research

Volume 11, September 2020, pages 75-83

Phenolic antioxidants of bael fruit herbal tea and effects on postprandial glycemia and plasma antioxidant status in healthy adults

Figure 1. Mean plasma glucose concentration of healthy adults after consuming bael fruit herbal tea and the control.

**Table 1.** Phenolic compounds identified in bael fruit extracts
Compound	[M-H]⁻ (m/z)	Other product ions (m/z)	Contents (µg/100 g)
Data represent mean values for each sample ± standard deviations (n = 3). Means followed by the same letter within a column are not significantly different (p > 0.05). Quantified as equivalent of protocatechuic acid. *Quantified as equivalent of catechin. nd: not detected.
Ellagic acid	301	283	0.04 ± 0.003^c
Protocatechuic acid derivative*	337	153, 109	25.63 ± 0.86^b
Resveratrol derivative**	433	227	497.8 ± 17.2^a

Table 1. Phenolic compounds identified in bael fruit extracts

Compound

[M-H]⁻ (m/z)

Other product ions (m/z)

Contents (µg/100 g)

Data represent mean values for each sample ± standard deviations (n = 3). Means followed by the same letter within a column are not significantly different (p > 0.05). *Quantified as equivalent of protocatechuic acid. **Quantified as equivalent of catechin. nd: not detected.

Ellagic acid

301

283

0.04 ± 0.003^c

Protocatechuic acid derivative*

337

153, 109

25.63 ± 0.86^b

Resveratrol derivative**

433

227

497.8 ± 17.2^a

**Table 2.** Phenolic contents and antioxidant activitieof aqueous bael fruit extract
Method	Results
*Abbreviations are: GAE, gallic acid equivalents, CE, catechin equivalents; TE, trolox equivalents; AAE, ascorbic acid equivalents; EDTA, ethylenediaminetetraacetic acid; Eq, equivalents. Data represent mean values (three determinations) for each sample ± standard deviations.
Total phenolic content (µmol GAE/g)	108.3 ± 1.4
Total flavanoid content (µmol CE/g)	73.0 ± 2.4
Trolox equivalent antioxidant capacity (µmol TE/g)	429.9 ± 0.01
DPPH radical scavenging ability (µmol TE/g)	27.4 ± 4.3
Reducing power (µmol AAE/g)	122.1 ± 4.2
Ferrous ion chelating ability (µmol EDTA eq/g)	0.09 ± 0.01

Table 2. Phenolic contents and antioxidant activitieof aqueous bael fruit extract

Method

Results

*Abbreviations are: GAE, gallic acid equivalents, CE, catechin equivalents; TE, trolox equivalents; AAE, ascorbic acid equivalents; EDTA, ethylenediaminetetraacetic acid; Eq, equivalents. Data represent mean values (three determinations) for each sample ± standard deviations.

Total phenolic content (µmol GAE/g)

108.3 ± 1.4

Total flavanoid content (µmol CE/g)

73.0 ± 2.4

Trolox equivalent antioxidant capacity (µmol TE/g)

429.9 ± 0.01

DPPH radical scavenging ability (µmol TE/g)

27.4 ± 4.3

Reducing power (µmol AAE/g)

122.1 ± 4.2

Ferrous ion chelating ability (µmol EDTA eq/g)

0.09 ± 0.01

**Table 3.** Mean scores for sensory attributes and Friedman test ranks for different preparations of bael fruit tea
	780	892	531
All values are mean (n = 50) ± SD; Values in each row having the same letter are not significantly different (p > 0.05).
Mean scores
Color	5.1 ± 1.5^a	6.0 ± 1.1^a	4.5 ± 1.2^b
Taste preference	5.3 ± 1.0^a	4.3 ± 1.3^b	3.5 ± 1.0^c
After taste	5.4 ± 0.8^a	5.3 ± 1.1^a	3.5 ± 0.9^b
Overall acceptance	5.4 ± 1.1^a	4.6 ± 0.9^b	3.7 ± 0.8^c
Willingness to drink regularly	5.1 ± 1.1^a	4.2 ± 1.0^b	3.6 ± 1.1^c
Friedman test ranks
Mean rank	2.41	1.98	1.61

Table 3. Mean scores for sensory attributes and Friedman test ranks for different preparations of bael fruit tea

780

892

531

All values are mean (n = 50) ± SD; Values in each row having the same letter are not significantly different (p > 0.05).

Mean scores

Color

5.1 ± 1.5^a

6.0 ± 1.1^a

4.5 ± 1.2^b

Taste preference

5.3 ± 1.0^a

4.3 ± 1.3^b

3.5 ± 1.0^c

After taste

5.4 ± 0.8^a

5.3 ± 1.1^a

3.5 ± 0.9^b

Overall acceptance

5.4 ± 1.1^a

4.6 ± 0.9^b

3.7 ± 0.8^c

Willingness to drink regularly

5.1 ± 1.1^a

4.2 ± 1.0^b

3.6 ± 1.1^c

Friedman test ranks

Mean rank

2.41

1.98

1.61

**Table 4.** Difference of postprandial plasma glucose response of healthy adults for bael fruit tea compared to the control
	0 min	30 min	45 min	60 min	90 min	120 min
SEM, Standard error of mean
Mean difference	−7.89	15.9	10.5	6.9	10.5	1.54
SEM	5.58	16.4	13.7	16.3	11.9	5.99

Table 4. Difference of postprandial plasma glucose response of healthy adults for bael fruit tea compared to the control

0 min

30 min

45 min

60 min

90 min

120 min

SEM, Standard error of mean

Mean difference

−7.89

15.9

10.5

6.9

10.5

1.54

SEM

5.58

16.4

13.7

16.3

11.9

5.99

**Table 5.** Plasma antioxidant capacity (µmol trolox equiv/L) of healthy adults at baseline and 120 min after ingestion of herbal teas
	Baseline	End (120 min after ingestion)	Difference between baseline and end	Percentage change (%) compared to baseline at the end
All values are mean (n = 15) ± SEM; Values in each column with the same letter are not significantly different (p > 0.05); Values in each row having the same letter are not significantly different (p > 0.05). * Percentage increment of plasma antioxidant capacity of bael fruit tea compared to the respective baseline is significant (p > 0.05).
Control	206.9 ± 44.1^a	196.1 ± 43.5^a	−10.8	–
Bael fruit tea	229.1 ± 27.1^a	397.2 ± 39.4^b	168.1	74.6*

Table 5. Plasma antioxidant capacity (µmol trolox equiv/L) of healthy adults at baseline and 120 min after ingestion of herbal teas

Baseline

End (120 min after ingestion)

Difference between baseline and end

Percentage change (%) compared to baseline at the end

All values are mean (n = 15) ± SEM; Values in each column with the same letter are not significantly different (p > 0.05); Values in each row having the same letter are not significantly different (p > 0.05). * Percentage increment of plasma antioxidant capacity of bael fruit tea compared to the respective baseline is significant (p > 0.05).

Control

206.9 ± 44.1^a

196.1 ± 43.5^a

−10.8

–

Bael fruit tea

229.1 ± 27.1^a

397.2 ± 39.4^b

168.1

74.6*