Table 1.

Content of phenolic compounds in some fruit by-products.

Fruit by-Product	TPC	Phenolic Compounds	References
Pomegranate peel	139.4 *	Punicalagin A, punicalagin B, catechin, gallic acid, ellagic acid	[30,31,32]
	420.6 ***
Pomegranate pomace	134.8 **	Gallic acid, catechin, ellagic acid, rosmarinic acid, hesperidin, p-coumaric acid, chlorogenic acid	[33,34]
Rowanberry pomace	167.4 ****	Cyanidin, Chlorogenic acid, quercetin, kaempferol	[35,36]
Apple pomace	13.8 *	Hydroxycinnamic acids, Hydroxycinnamates, phloretin glycosides, quercetin glycosides, catechins, procyanidins	[37,38]
Apple peel	34.3 *	Gallic acid, caffeic acid, vanillic acid, catechin, epicatechin gallate, chlorogenic acids, phloridzin, rutin	[38,39]
Banana peel	29.2 *	Epicatechin, rutin, hydroxybenzoic acid, myricetin, ferulic acid, chlorogenic acid, gallic acid	[40]
Date by-products	4.4 *	Quercetin, luteolin, apigenin, chrysoeriol, kaempferol, isorhamnetin, malonyl derivatives	[41,42]
Elderberry pomace	4.7 *	Cyanidin, rutin, oleanolic acid, ursolic acid, linoleic acid	[43,44]
Grape juice by-product	23.4 *	Benzoic and hydroxycinnamic derivatives, catechins, flavanols, anthocyanins, tannins, proanthocyanidins	[45,46]
Grape pomace	142.1 *	Phenolic acids (ferulic, p-coumaric, caffeic, gallic, vanillic, p-hydroxybenzoic), flavanols (proanthocyanidins), flavonols (kaempferol, quercetin, myricetin), stilbenes (resveratrol, piceid, astringin), anthocyanins	[47,48]
Grape seed	74.0 *	Gallic acid, caftaric acid, catechin, epicatechin, epicatechin gallate, procyanidins, resveratrol	[48,49,50]
Mango kernel	72.1 *	Gallates, gallotannins, gallic acid, ellagic acid and its derivatives	[48,51]
Orange by-product	4.21 *	Caffeic acid, Ferulic acid, p-Coumaric acid, Eriocitrin, Narirutin, Hesperidin, Neohesperidin	[52,53]
Orange peel	65.7 *	Caffeic acid, p-coumaric acid, naringin, kaempferol, neohesperidin, rutin	[54]
Orange pulp	22.3 *	Flavonone (Eriocitrin, Narirutin, Hesperidin, Didymin…), Flavone (Quercitrin, Nobiletin…), Kaemperol, Benzoic acids, Cinnamic acids, Chlorogenic acid,	[55]
Lemon peel	49.8 *	Caffeic acid, Coumaric acid, Ferulic acid, Sinapic acid	[56,57]
Passion fruit by-products	3.84 *	p-coumaric acid, Epicatechin	[52,58]
Guava by-product	19.9 *	Resveratrol, coumarin	[23]
Cherry by-product	91.3 *	Flavonoids, anthocyanidins, stilbenes, resveratrol, quercetin, gallic acid	[59]

* mg gallic acid eq./g extract DW; ** mg gallic acid eq./g liquid extract; *** mg tannic acid eq./g extract DW; **** mg catechin eq./g extract DW.