Table 1.
Methods employed in the extraction and purification of proteins from fruit residues.
| Residue | Extracting Media | Extraction Conditions | Protein Purification Conditions | Refs. |
|---|---|---|---|---|
| SOLID–LIQUID CONVENTIONAL EXTRACTION | ||||
| Tomato seeds | NaCl (1.5%, pH 11.5) | DGS: extracting medium at ratio 1:10 (w/v); stirring (room temperature and 1 h) | Centrifugation and precipitation at pH 4.0 | [21,43] |
| Tomato seeds | NaOH aq. (pH 7.5–1.5) | 1 g of DGS and 82 mL water; stirring (50 °C and 50 h) | Centrifugation and filtration | [37,41] |
| Tomato seeds | NaOH aq. (pH 7.5) | DGS: extracting medium at ratio 1:82.81 (30 °C and 50 h) | Centrifugation and precipitation at pH 3.9 | [42] |
| Watermelon seeds | Alkali (0.8%) | DGS: extracting medium at ratio 1:30 (40 °C and 30 min) | Precipitation at pH 4.5 | [52] |
| Watermelon seeds | NaOH aq. (pH 12.0) | DGS: extracting medium at ratio 1:10 (w/v); stirring (1 h); 2 additional extractions after centrifugation | Precipitation at pH 4.0 | [48,50] |
| Jujube seeds | (I) Water; (II) 50 mM Tris-HCl (pH 7.5); (III) 0.6 M NaCl (0.1% HCl); and (IV) acetic acid (5%) | (I and II) 1.5 g ground seeds and 20 mL solvent; stirring (4 °C and 2 h); (III) Idem at ground seeds:solvent 1:3 (w/v); and (IV) 5 g and 20 mL solvent. Shaking overnight (80 rpm) | (I, II, and III) Precipitation with (NH₄)₂SO₄ and dialysis (24 h, 4 °C); (IV) filtration and precipitation with acetone | [45] |
| Chinese cherry seeds | NaOH aq. (pH 10.0) | DGS: extracting medium at 1:20 (w/v); stirring (40 °C and 40 min) | Filtration and precipitation at pH 3.84 | [55] |
| African breadfruit seeds | NaOH aq. (pH 9.0) | DGS: extracting medium at ratio 1:10 (w/v); stirring (30 min at room temperature) | Precipitation at pH 4.5 | [56] |
| Pumpkin (Cucurbita pepo) seeds | NaOH aq. (pH 10.0) | DGS | Precipitation at pH 5.0 | [57,61] |
| Pumpkin (Cucurbita pepo) oil cake | NaOH aq. (pH 10.0) | DGS | Filtration and precipitation at pH 5.0 | [58,62] |
| Pumpkin (Cucurbita pepo) oil cake | NaOH aq. (pH 10.0) | Defatted oil cake: extracting media at ratio 1:10 (w/v) | Precipitation at pH 5.0 | [59] |
| Pumpkin (Cucurbita pepo) oil cake | NaOH aq. (pH 11.0) | DGS: extracting medium at 1:30 (w/v); stirring (50 °C and 1.5 h) | Precipitation at pH 5.3 | [60] |
| Pumpkin (Cucurbita moschata), watermelon, and bottle gourd seeds | Tris HCl (pH 8.0) | 200 mg of DGS and 50 mL buffer (1 h) | Centrifugation and precipitation with acetone | [32] |
| Bottle gourd seeds | 50 mM phosphate buffer (10 mM EDTA, 100 mM KCl, 1 mM DTT, and 1% SDS) | Sample: extracting medium at ratio 1:3 (w/v) (3 times) | Filtration and precipitation with chilled ethanol | [30] |
| Wax gourd seed | 20 mM phosphate buffer (pH 6.5, 5.0 mM EDTA, and 10 mM DTT) (buffer I) and phosphate (2.0 mM EDTA, 1 mM DTT, urea 4 M, and 2% Triton X 100) (buffer II) | 500 g of DGS and buffer I, 3 h; centrifugation and 2nd extraction under same conditions; centrifugation and 3rd extraction with buffer II and centrifugation | Dialysis, centrifugation, and filtration | [44] |
| Jujube seeds | Tris-HCl (pH 7.5) | 1.5 g of ground seeds and 50 mM buffer (2 h) | Centrifugation, precipitation with (NH₄)₂SO₄ (4 °C), centrifugation, and dialysis | [46] |
| Milled rapeseed | 50 mM Tris-HCl (pH 8.5, 750 mM NaCl, 5 mM EDTA, and 0.3% Na₂O₅S₂) | 0.1 g/L (room temperature, 1 h) | Centrifugation | [23] |
| Pumpkin (Cucurbita moschata) seeds | Osborne method: (1) water; (2) Tris-HCl (5% NaCl); (3) isopropanol (55%); and (4) acetic acid (0.2 N) | 150 mg of DGS and 10 mL extracting medium (60 min). Next extractions at extracting medium:sample ratio 7:1 | (I, II, and III) Centrifugation and precipitation with acetone | [20] |
| Muskmelon seeds | Osborne method: (1) water; (2) NaCl (5%); (3) NaOH (0.1 M); and (4) ethanol (70%) | 100 g of DGS and 500 mL extracting medium (60 min) | (I) Centrifugation; (II) centrifugation and dialysis; (III) precipitation at pH 4.0; and (IV) evaporation at 40 °C | [47] |
| Bottle gourd seeds | Osborne method: (1) water; (2) Tris-HCl (100 mM, pH 8.1, 0.5 M NaCl); (3) isopropanol (55%); and (4) acetic acid (0.2 N) | 8 g of DGS and 60 mL extracting medium (60 min). Next extractions at extracting medium:sample ratio 7:1 | (I, II, III, and IV) Centrifugation and precipitation with acetone | [31] |
| Watermelon seeds | Osborne method | - | - | [49] |
| ULTRASOUND-ASSISTED EXTRACTION | ||||
| Pomegranate peel | 100 mM Tris-HCl (pH 7.5, 0.5%, SDS, and 0.25% DTT) | 150 mg milled peel and 5 mL buffer using HIFU (30%, 1 min) | Evaporation and precipitation with cold acetone | [3] |
| Peach, plum, apricot, cherry, and olive seeds | 100 mM Tris-HCl (pH 7.5, 0.5% SDS, and 0.5% DTT) | 30 mg DGS and 5 mL buffer using HIFU (30%, 1 min) | Precipitation with cold acetone | [11,13] |
| Plum seeds | 100 mM Tris-HCl (pH 7.5, 1% SDS, and 0.25% DTT) | 30 mg DGS and 5 mL buffer using HIFU (30%, 1 min) | Precipitation with cold acetone and filtration | [14,35] |
| Olive and peach seeds | 100 mM Tris-HCl (pH 7.5, 0.5% SDS, and 0.5% DTT) | 30 mg DGS and 5 mL buffer using HIFU (30%, 5 min) | Precipitation with cold acetone | [16] |
| Olive seeds | 125 mM Tris-HCl (pH 7.5, 1% SDS, and 0.1% DTT) | 30 mg milled seeds and 5 mL buffer using HIFU (30%, 5 min) | Precipitation with cold acetone | [17] |
| Plum and peach seeds | 50 mM Tris-HCl (pH 7.4) and 15 mM NaCl (buffer I)50 mM Tris-HCl (pH 7.4) and 15 mM NaCl and 1% SDS and 25 mM DTT (buffer II) | 200 mg DGS and 10 mL of buffer I or II (10 min) and shaking (overnight) | Evaporation and precipitation with cold acetone | [29] |
| Cherry seeds | 100 mM Tris-HCl (pH 7.5, 1% SDS, and 0.5% DTT) | 30 mg DGS and 5 mL buffer using HIFU (30%, 5 min) | Precipitation with cold acetone | [33] |
| PRESSURIZED LIQUID EXTRACTION | ||||
| Pomegranate peel | Ethanol (70% (v/v)) | 2 g ground dried peels and 8 g sand (1500 psi; 120 °C; static extraction time, 3 min; extraction time, 12 min; static cycles, 1) | Evaporation and precipitation with cold ethanol | [25] |
| EXTRACTION USING DEEP EUTECTIC SOLVENTS | ||||
| Pomegranate peel | Choline chloride:AA:H₂O in 1:1:10 molar ratio | 150 mg dried peels and 5 mL extracting medium (HIFU, 11 min, and 30%) | Evaporation and precipitation with cold ethanol | [25] |
| ULTRASOUND–MICROWAVE SYNERGISTIC EXTRACTION | ||||
| Pumpkin (Cucurbita moschata) seeds | PEG 200-choline chloride at 3:1 molar ratio | Microwave-assisted extraction (6 min, 120 W); ultrasound-assisted extraction (30 min, 240 W); water bath extraction (43 °C and 60 min); ultrasound–microwave synergistic extraction (28%, 28 g /L, 140 W, 43 °C and 4 min) | Isoelectric point precipitation; ethanol precipitation; centrifugation; centrifugation, isoelectric point precipitation, and ethanol precipitation | [64] |
| EXTRACTION USING PULSED ELECTRIC FIELD (PEF) AND HIGH VOLTAGE ELECTRICAL DISCHARGE (HVED) | ||||
| Olive seeds | Water | Sample: extracting medium at ratio 10 (w/w); pretreatment with HVED, PEF, and ultrasound; extraction (2 min and 150 rpm) | - | [34] |
| Rapeseed press-cake | Water | Sample: extracting medium at ratio 20 (v/w); HVED (240 kJ/kg) | - | [24] |
| Mango peels | I and II) Water; III) water (pH 11.0); IV) water and water (pH 11.0) | 300 g of sample at ratio 1/10 (w/v); (I) PEF (13.3 kV/cm, 0.5 Hz); (II) HVED (40 kV/cm, 0.5 Hz); (III) aqueous extraction (20–60 °C and pH = 2.5, 6.0, 11.0); (IV) PEF; and (I) and aqueous extraction (50 °C, pH 6.0, and 3 h) | - | [26] |
| Papaya peels | (I and II) Water; (III) water (pH 11.0); (IV) water and water (pH 11.0) | 300 g sample at ratio 1:10 (w/v); (I) PEF (13.3 kV/cm, 0,5 Hz); (II) HVED (40 kV/cm, 0.5 Hz); (III) aqueous extraction (20–60 °C, pH = 2.5, 6.0, 11.0); (IV) PEF; and (I) aqueous extraction (50 °C, pH 7.0, and 3 h) | - | [54] |
| METHODS USING NANOMATERIALS | ||||
| Plum seeds | 100 mM Tris–HCl buffer (pH 7.5, 1% SDS, and 0.25% DTT) | 30 mg DGS and 5 mL buffer using HIFU (30%, 1 min) | 3G carboxylate-terminated dendrimers at pH 1.8 (30 min) | [74] |
| Plum seeds | 100 mM Tris–HCl buffer (pH 7.5, 1% SDS, and 0.25% DTT) | 30 mg DGS and 5 mL buffer using HIFU (30%, 1 min) | 2G dimethylamino-terminated dendrimers at pH 7.5 (30 min) | [75] |
| Plum seeds | - | 3G single wall carbon nanotubes functionalized with sulphonate-terminated carbosilane dendrimers at pH 7.5 with shaking (1 h) | Ultrafiltration | [76] |
| Peach seeds | - | 2G gold nanoparticles coated with carbosilane dendrimers with carboxylate groups at pH 2.5 with shaking (2 h) | Ultrafiltration | [77] |
Note: DGS: defatted ground seeds; Tris: tris(hydroxymethyl)aminomethane; DTT: dithiothreitol; SDS: sodium dodecyl sulfate; HIFU: high-intensity focused ultrasound.