Table 2.
(Poly)phenol content of purple sweet potato flesh.
| Origin | Sample Extraction | Analytical Method | Phytochemical | Amount of Phytochemical | Ref. |
|---|---|---|---|---|---|
| USA | Methanol (80%) | Folin-Ciocalteu | TPC | ~0.2 to 0.7 mg CA/g FW | [9] |
| pH-differential | TCA | ~0.1 to 0.4 mg TCA/g FW | |||
| Korea | 0.2% HCl in methanol | UHPLC-(ESI)-Qtof, UPLC-Ion trap, and HPLC -DAD | Peo-3-O-glc | 6544 to 26,483 mg/kg DW | [22] |
| Cya -3-O-glc | 943 to 3962 mg/kg DW | ||||
| Pg-3-O-glc | 1242 to 2181 mg/kg DW | ||||
| 0.2% HCl in methanol | UHPLC-(ESI)-QqQ | Phenolic acids: caffeic acid, ferulic acid, chlorogenic acid, p-coumaric acid, cis-ferulic acid, trans-ferulic acid, caffeoylquinic acid, and dicaffeoylquinic acids. | Phenolic acids (mg/Kg DW): Caffeic acid: 44 to 70, cis-ferulic acid; 2 to 7, trans-ferulic acid: 1 to 7, chlorogenic acid: 6714 to 13268, p-coumaric acid: 1, caffeoylquinic acid: 5150 to 5862, dicaffeoylquinic acids 19 to 24. | [22] | |
| Flavonoids: quercetin 3-O-galactoside, and quercetin-3-O-glc, quercetin diglc. | Flavonoids (mg/kg DW): Quercetin 3-O-galactoside:1, quercetin-3-O-glc: 1 to 7, quercetin diglc: 6 to 30. | ||||
| 0.2% HCl in methanol | Folin–Ciocalteu | TPC | 1.80 to 7.37 mg GA/100 g DW | [22] | |
| Japan | Ethanol (80%) | Folin–Ciocalteu | TPC | 0.2 to 1.2 µmol CA/mL. | [28] |
| Reverse-phase HPLC | Peo and Cya | NS | |||
| China | Water, 3.5% citric acid, and 79 U/mL cellulose | HPLC- MS/MS | Cya-based anthocyanins and peo-based anthocyanins | 13.7 mg total anthocyanins /100 g | [29] |
| USA | 7% acetic acid in methanol (80%) | Folin–Ciocalteu | TPC | 408.1 mg CA/100 g FW (raw) | [30] |
| 401.6 mg CA/100 g FW (puree) | |||||
| 7% acetic acid in methanol (80%) | pH-differential | Total monomeric anthocyanin | 101.5 mg cya-3-glc/100 g FW (raw) 80.2 mg cya-3-glc/100 g FW (puree) | [30] | |
| China | Methanol (85%) with 0.5% formic acid | LC−PDA−APCI−MS | Total monomeric anthocyanins: cya 3-soph-5-glc, cya 3-(6′′-p-caffeoylsoph)-5-glc, peo 3-soph-5-glc, cya 3-(6′′-p-feruloylsoph)-5-glc, peo 3-(6′′-p-feruloylsoph)-5-glc | 305.0 mg anthocyanins/100 g DW | [31] |
| Hydroxycinnamic acid derivatives: caffeoyl-hexoside, 5-O-caffeoylquinic acid, caffeic acid, feruloylquinic acid, 3,4-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid | 854.4 mg hydroxycinnamic acids/100 g DW | ||||
| Korea | Methanol (50%) with 1.2 M HCl at 80 °C | HPLC system | Flavonoids: quercetin, myricetin, kaempferol, luteolin. | Flavonoids: 579.5 µg/g DW (Quercetin: 388.9, myricetin: 152, kaempferol: 23.4, luteolin: 15.2) | [27] |
| Anthocyanins: Cya, Peo. | Anthocyanins: 727.4 µg/g DW (Cya: 408.4, and Peo: 319.1) | ||||
| Phenolic acids: ferulic, p-coumaric, p-hydroxybenzoic, sinapic, syringic, and vanillic acids. | Phenolic acids: 744.3 µg/g DW (p-hydroxybenzoic acid: 238.6, vanillic acid: 147.4, syringic acid: 3.9, p-coumaric: 18.1, ferulic acid: 322.3, sinapic acid: 14.1) | ||||
| India | Different extraction solvents: methanol/trifluoroacetic acid (TFA) (99.5:0.5), ethanol/TFA (99.5:0.5), methanol/TFA/water (80:19.5:0.5), and ethanol/TFA/water (80:19.5:0.5) | HR-ESI–MS | TAC | 43.4 mg peonidin-3-O-glc equivalent /100 g of FW | [32] |
| Japan | Methanol/acetic acid (19:1, v/v), methanol/water (1:1, v/v), and tert-butyl methyl ether/methanol (7:2, v/v) | HPLC-DAD, HPLC-ESI-MSn | Cya 3-soph-5-glc (Cya-3-(6′′-caffeoylsoph)-5-glc, cya-3-(6′′-caffeoylsoph)-5-glc, cya-3-(6′′-caffeoyl-6′′′-feruloylsoph)-5-glc, cya-3-feruloylsoph-5-glc) | NS | [33] |
| Peo3-soph-5-glc (Peo-3-(6′′-caffeoylsoph)-5-glc, peo-3-feruloylsoph-5-glc, peo-3-(6′′,6′′′-dicaffeoylsoph)-5-glc, peo-3-(6′′-caffeoyl-6′′′-feruloylsoph)-5-glc, peo-3-(6′′-caffeoyl-6′′′-p-hydroxybenzoylsoph)-5-glc, peo-3-p-hydroxybenzoylsoph-5-glc) | |||||
| China | Ethanol with 1% formic acid | UPLC-PDA, UPLC-QTOF-MS, UPLC-MS/MS analyses | TAC | 90.5 to 1018 mg/100 g DW | [31] |
| Monoacylated anthocyanin | 0.0 to 44.8 mg/100 g DW | ||||
| Diacylated anthocyanin | 79.9 to 982.9 mg/100 g DW | ||||
| Acylated-based anthocyanin | 90.5 to 1018.7 mg/100 g DW | ||||
| Cya-based anthocyanin | 25.7 to 326.6 mg/100 g DW | ||||
| Peo-based anthocyanin | 0.0 to 761.7 mg/100 g DW | ||||
| Korea | Methanol with 0.2% HCl | HPLC-TOF/MS, HPLC/MS/MS, and UV/vis spectroscopy | TAC | 383.2 to 1190.2 mg/100 gDW | [22] |
| Non-acylated anthocyanin | 17.5 to 35.8 mg/100 gDW | ||||
| Monoacylated anthocyanin | 158.2 to 323.4 mg/100 gDW | ||||
| Diacylated-based anthocyanin | 199.6 to 845.1 mg/100 gDW | ||||
| Cya-based anthocyanin | 98.2 to 815.1 mg/100 gDW | ||||
| Peo-based anthocyanin | 281.5 to 740.8 mg/100 gDW | ||||
| Pg-based anthocyanin | 1.2 to 217.0 mg/100 gDW | ||||
| Korea | 5% formic acid in water | LC-DAD-ESI/MS | TAC | Raw: 1342 mg/100 g DW | [34] |
| Steamed 751 mg/100 g DW | |||||
| Roasted 1086 mg/100 g DW | |||||
| USA | 5% formic acid water | HPLC/MS-MS | TAC | Raw: 1390 mg/100 g DW | [35] |
| Baked: 1303 mg/100 g DW | |||||
| Steamed: 1284 mg/100 g DW | |||||
| Microwaved: 1275 mg/100 g DW | |||||
| Pressured cook: 1165 mg/100 g DW | |||||
| Fried: 1217 mg/100 g DW | |||||
| Total Cya content (Cya 3-p-hydroxybenzoyl soph -5-glc, cya 3-(6″-caffeoyl soph)-5-glc, cya 3-(6″ -feruloyl soph)-5-glc, cya 3-(6″,6″′-dicaffeoyl soph)-5-glc, cya 3-caffeoyl-p-hydroxybenzoyl soph -5-glc, cya 3-(6″-caffeoyl-6″′-feruloyl soph)-5-glc) | Raw: 930 mg/100 g DW | ||||
| Baked: 943 mg/100 g DW | |||||
| Steamed: 1060 mg/100 g DW | |||||
| Microwaved: 1038 mg/100 g DW | |||||
| Pressured cook: 943 mg/100 g DW | |||||
| Fried: 937 mg/100 g DW | |||||
| Total peo content (Peo 3-p-hydroxybenzoyl soph-5-glc, peo 3-(6″-feruloyl soph)-5-glc, peo 3-caffeoyl soph -5-glc, peo 3-caffeoyl-p-hydroxybenzoyl soph -5-glc, peo 3-(6″-caffeoyl-6″′-feruloyl soph)-5-glc) | Raw: 460 mg/100 g DW | ||||
| Baked: 360 mg/100 g DW | |||||
| Steamed: 224 mg/100 g DW | |||||
| Microwaved: 237 mg/100 g DW | |||||
| Pressured cook: 222 mg/100 g DW | |||||
| Fried: 280 mg /100 g DW | |||||
| China | Methanol:Water (7:3, v/v) | HPLC-MS | 5-caffeoylquinic acid, 3,5-dicaffeoylquinic acid, 4,5-dicaffeoylquinic acid | NS | [36] |
CA: chlorogenic acid; Cya: cyanidin; DE: dry extract; DW: dry weight; ESI: electrospray ionization; FW: Fresh weight; Glc: glucoside; HPLC: high-performance liquid chromatography; MS: mass spectrometry; NS: non-specified; PDA: photodiode array detection; Peo: peodinin Pg: Pelargonidin; QTOF: quadrupole-time-of-flight; Soph: sophoroside; UPLC: ultra-performance liquid chromatography; TPC: Total phenolic content; TFC: Total flavonoid content; TAC: Total anthocyanin content.