Table 1.
Composition of pectin-rich agro-industrial residues hydrolysates depending on their pre-treatment and hydrolysis
| Feedstock | Pre-treatment | Hydrolysis | Sugar composition after hydrolysis (g/100 g matter) | Reference |
|---|---|---|---|---|
| Sugar beet pulp | Steam explosion at 152 °C to 175.5 °C and 4 to 8 bar pressure | (Soluble fraction) Acid hydrolysis: 72%H2SO4 for 1 h at 30 °C and 150 rpm | Glucose 26 | Hamley-Bennett et al. (2016) |
| Arabinose 24 | ||||
| Xylose 1.6 | ||||
| Rhamnose 2.4 | ||||
| Galactose 6 | ||||
| Galacturonic acid 14 | ||||
| (insoluble fraction) Enzyme hydrolysis: 0.5 mg cellulase/g glucan 50 °C with shaking for 24 h | Glucose 10 | |||
| Arabinose 0.4 | ||||
| Xylose 0.3 | ||||
| Rhamnose 0.1 | ||||
| Galactose 0.1 | ||||
| Galacturonic acid <0.1 | ||||
| Not used | Enzyme hydrolysis: Viscozyme and Ultraflo Max (Novozymes) treatment | Total of reducing sugars 6.6 | Berlowska et al. (2017) | |
| Apple pomace | 15 g/L sulphuric acid for 16 min at 91 °C with laccase 100 units/L at 30 °C for 12 h at 90 rpm | Enzyme hydrolysis: Viscozyme and Celluclast (0.5 μL/mL, 0.038 mg/mL) together with Novozyme188 (0.05 μL/mL, 0.0024 mg/mL) | Galacturonic acid 33 | Gama et al. (2015) |
| Glucose 21 | ||||
| Arabinose 17 | ||||
| Galactose 5 | ||||
| Not used | Acid hydrolysis 1.5 g sulphuric acid/100 mL, 91 °C reaction temperature during 16 min | 18.2 g of glucose and fructose/100 g dry matter | Parmar and Rupasinghe (2012) | |
| Not used |
Acid hydrolysis 72% sulphuric acid for 45 min at room temperature and diluted with distilled water to 4% sulphuric acid, followed by autoclaving for 1 h at 121 °C |
Galacturonic acid (not quantified) | Choi et al. (2015) | |
| Glucose 25 | ||||
| Fructose 24 | ||||
| Arabinose 6 | ||||
| Sucrose 9 | ||||
| Galactose 4 | ||||
| Xylose 6 | ||||
| Rhamnose 2 | ||||
| Not used | Acid hydrolysis 2 M Trifluoroacetic acid for 2 h at 100 °C with constant shaking | Rhamnose 0.5 | Wikiera et al. (2015) | |
| Arabinose 8 | ||||
| Glucose 12 | ||||
| Galactose 4 | ||||
| Xylose 4 | ||||
| Mannose 0.7 | ||||
| Acid hydrolysis 0.2 M Trifluoroacetic acid for 72 h at 80 °C with constant shaking | Enzyme hydrolysis: Viscozyme (25 μL) incubated at 50 °C during 24 h with constant shaking | Rhamnose 0.4 | ||
| Arabinose 7 | ||||
| Glucose 11 | ||||
| Galactose 4 | ||||
| Xylose 4 | ||||
| Mannose 0.3 | ||||
| Citrus peel | 80% v/v ethanol for 20 min, filtered on a sintered glass, and dried at 40 °C for 72 h | Acid hydrolysis: 0.05 M hydrochloric acid at 85 °C | Galacturonic acid 15 | Yapo et al. (2007a) |
| Arabinose 4 | ||||
| Galactose 1 | ||||
| Glucose 1 | ||||
| Rhamnose 0.5 | ||||
| Not used | Acid hydrolysis 72% sulphuric acid for 45 min at room temperature and diluted with distilled water to 4% sulphuric acid, followed by autoclaving for 1 h at 121 °C | Orange peel | Choi et al. (2015) | |
| Galacturonic acid (not quantified) | ||||
| Glucose 36 | ||||
| Fructose 12 | ||||
| Arabinose 6 | ||||
| Sucrose 5.6 | ||||
| Galactose 3 | ||||
| Xylose 2 | ||||
| Rhamnose 2 | ||||
| Lemon peel | ||||
| Galacturonic acid (not quantified) | ||||
| Glucose 27 | ||||
| Fructose 3 | ||||
| Arabinose 5 | ||||
| Sucrose 0 | ||||
| Galactose 5 | ||||
| Xylose 3 | ||||
| Rhamnose 2 | ||||
| Steam explosion at 150 °C for 10 min and 15 kg/cm pressure | Pectinase, xylanase (5 mg/g dry matter) and β-glucosidase (2 mg/g dry matter) cocktail at 45 °C for 24 h | Galacturonic acid (not quantified) | Choi et al. (2013) | |
| Glucose 45 | ||||
| Fructose 18 | ||||
| Arabinose 3 | ||||
| Galactose 2 |