Chemical Composition and Bioactivity of Pomace from Selected Fruits

Figures & data

Table 1. Physical and chemical characteristics of selected fruit pomace.

	Sweet lemon	Blue grapes	Pineapple	Orange
Physical characteristics
Color^z	2.5 Y 8/3 Pale yellow	10 R 2.5/2 Very dusky red	2.5 Y 8/4 Pale yellow	10 YR 8/6 Pale orange
Yield as g/100g of fruit	13.00	6.33	11.04	9.67
Yield as dry powder (g/100g)	18.46	31.36	21.73	15.28
Water absorption capacity (ml/100g)	637.5 ± 3.53	295.0 ± 7.07	483.50 ± 4.94	518.50 ± 2.12
Bulk density (g)	60.34 ± 2.18	67.21± 0.77	60.00 ± 0.00	68.21 ± 2.19
Chemical parameters
Moisture^y (g)	80.39 ± 0.26	85.45 ± 0.45	84.06 ± 0.34	83.26 ± 0.10
Moisture (g)	7.02 ± 0.02	7.67 ± 0.15	7.22 ± 0.32	7.46 ± 0.15
Protein (g)	6.76 ± 0.00b (7.27)	3.30 ± 0.43c (3.57)	3.96 ± 0.00c (4.26)	7.82 ± 0.15a (8.45)
Ether extractives (g)	1.03 ± 0.03a (2.16)	1.65 ± 0.04b (1.78)	1.34 ± 0.00c (1.44)	1.94 ± 0.20ab (2.09)
Insoluble fiber (g)	22.46 ± 2.02c (24.15)	26.00 ± 0.00b (28.15)	28.13 ± 0.23ab (30.31)	29.46 ± 0.41a (31.83)
Soluble fiber (g)	18.33 ± 2.24a (19.71)	11.80 ± 0.69b (12.78)	0.40 ± 0.00c (0.43)	13.06 ± 0.37b (14.11)
Ash (g)	3.86 ± 0.16a (4.15)	1.60 ± 0.06c (1.73)	1.12 ± 0.03d (1.20)	2.46 ± 0.09b (2.65)
Iron (mg)	5.73 ± 0.46a (6.16)	4.89 ± 0.28a (5.29)	5.44 ± 0.25a (5.86)	2.18 ± 0.10b (2.35)
Calcium (mg)	541 ± 7.85a (581)	84 ± 0.92c (91)	61 ± 2.15d (66)	281 ± 5.00b (303)
Phosphorus (mg)	36 ± 0.00d (38)	149 ± 1.15a (161)	46 ± 3.05c (50)	117 ± 2.66b (127)
Ascorbic acid (mg)	17.28 ± 0.41 (18.58)	12.67 ± 0.45 (13.72)	19.95 ± 0.07 (21.50)	27.50 ± 0.19 (29.71)
Total carotenes (µg)	546 ± 1.36 (587)	ND	328 ± 0.63 (354)	703 ± 0.39 (760)
Tannins (mg)	729 ± 17.03 (784)	2208 ± 12.00 (2391)	364 ± 2.59 (392)	1882 ± 12.43 (2034)
Total oxalates (mg)	0.04 ± 0.00c (0.05)	0.06 ± 0.00b (0.07)	0.03 ± 0.00d (0.04)	0.11 ± 0.00a (0.12)
Water soluble oxalates (mg)	0.02 ± 0.00c (0.02)	0.05 ± 0.00b (0.05)	0.02 ± 0.00c (0.02)	0.05 ± 0.00a (0.06)
Phytic acid (mg)	53.71 ± 0.61b (57.76)	46.44 ± 0.51c (50.29)	44.96 ± 2.22c (48.45)	68.39 ± 2.66a (73.90)

^zMunsell color charts (2000).

^yFresh weight, figures in parenthesis indicate values on dry weight basis. Different superscripts in a column indicate significant differences among samples.

Table 2. Extract yield, polyphenols, flavonoids, and total antioxidant activity of fruit pomace in different extracts.

	Sweet lemon	Blue grapes	Pineapple	Orange
Extract yield (mg/100g sample)
Methanol	16.69 ± 0.04	45.88 ± 0.22	43.50 ± 0.50	35.03 ± 0.03
Ethanol	14.11 ± 0.11	41.43 ± 0.45	33.40 ± 0.44	26.71 ± 0.34
Aqueous	25.13 ± 0.91	42.73 ± 0.29	24.30 ± 0.82	34.40 ± 0.39
Polyphenols (mg TAE/100g sample)
Methanol	305 ± 16.43	772 ± 16.39	130 ± 10.95	955 ± 4.50
	(328.02)^z	(836.13)	(140.11)	(1032.34)
Ethanol	190 ± 10.95	546 ± 5.46	160 ± 4.10	392 ± 9.46
	(204.34)	(592.07)	(172.45)	(423.60)
Aqueous	255 ± 5.47	566 ± 9.00	200 ± 0.00	490 ± 0.54
	(274.25)	(613.73)	(215.56)	(530.04)
Flavonoids (mg QE/100g of sample)
Methanol	0.89 ± 0.02	1.45 ± 0.00	0.18 ± 0.01	1.25 ± 0.01
	(0.95)	(1.57)	(0.19)	(1.35)
Ethanol	0.25 ± 0.00	1.15 ± 0.01	0.11 ± 0.00	0.27 ± 0.01
	(0.26)	(1.24)	(0.12)	(0.29)
Aqueous	0.18 ± 0.00	0.63 ± 0.01	0.08 ± 0.00	0.25 ± 0.01
	(0.19)	(0.68)	(0.09)	(0.26)
Total antioxidant activity (µmoles of ascorbic acid/100g of sample)
Methanol	55,260 ± 441.61	110,457 ± 355.33	108,505 ± 149.31	83,681 ± 211.83
Ethanol	37,233 ± 379.13	148,627 ± 574.46	97,233 ± 263.91	65,426 ± 410.73
Aqueous	105,293 ± 1067.53	127,614 ± 182.75	169,574 ± 355.33	118,712 ± 193.09

^zFigures in parenthesis indicate values on dry weight basis.

Table 3. Correlation coefficients between antioxidant components and antioxidant activity of fruit pomace (R value).

Extracts	Total carotene/anthocyanin	Tannins	Polyphenols	Flavonoids
Total antioxidant activity
Methanol	0.54	0.25	0.07	–0.08
Ethanol	0.85	0.49	0.19	0.25
Aqueous	–0.06	–0.42	–0.47	–0.71
Free radical scavenging activity
Methanol	0.99	0.75	0.44	0.65
Ethanol	0.99	0.75	0.43	0.64
Aqueous	0.98	0.57	0.19	0.52
Reducing power
Methanol	0.82	0.75	0.50	0.86
Ethanol	0.95	0.87	0.60	0.77
Aqueous	0.99	0.69	0.34	0.66

Figure 1. Free radical scavenging activity of fruit pomace by DPPH method in different extracts. Concentration: Sweet lemon, pineapple, orange: A–5, B–10, C–15, and D–20 mg. Blue grapes: A–1, B–2, C–3, and D–4 mg.

Figure 2. Reducing power of fruit pomace in different extracts.

Figure 3. Extent of bile acid binding by fruit pomace.

Figure 4. Alpha-amylase inhibitory activity of fruit pomace.