This work was aimed at investigating, for the first time, a sustainable process for the purification of biologically active compounds from goji berry (Lycium barbarum) fruit extracts. It was based on a 'green' aqueous extraction of fruits, a clarification step of the extract with microfiltration (MF) and ultrafiltration (UF) membranes and a fractionation/concentration step of the clarified extract through the use of tight UF membranes. The aqueous extraction was studied in order to obtain the maximum yield of biologically active compounds. At this purpose, different parameters such as the extraction time, temperature and solid/liquid ratio, were optimized. Three different commercial membranes with molecular weight cut-off (MWCO) from 0.5 to 3.5 kDa (GE, GH and GK from GE Osmonics) were tested in the fractionation step. The performance of selected membranes, was evaluated in terms of productivity and selectivity towards target compounds. To fulfil the final aim to purify polyphenols from carbohydrates the membrane process was also studied in a diafiltration mode. Fouling index and cleaning efficiency were analysed in order to determine process feasibility at industrial scale. Experimental results indicated that the GH membrane with a MWCO of 2.5 kDa exhibited the best separation efficiency of polyphenols from carbohydrates. For this membrane, an improved purification of polyphenols from carbohydrates by increasing the diafiltration volume, D (-), was observed: at a D (-) of 5 the removal of carbohydrates in the UF retentate was higher than 90% in comparison with the clarified extract; on the other hand, the loss of polyphenols in the permeate was lower than 20%. The investigated work allowed to obtain two distinct natural aqueous extracts from goji berries: a concentrated extract enriched in polyphenols with high antioxidant activity of interest for pharmaceutical, cosmetic or nutraceutical applications and a purified extract enriched in carbohydrates useful in the food industry.
A membrane-based purification of bioactive compounds from goji berry (Lycium barbarum) fruit extracts
CConidi;ACassano;
2020
Abstract
This work was aimed at investigating, for the first time, a sustainable process for the purification of biologically active compounds from goji berry (Lycium barbarum) fruit extracts. It was based on a 'green' aqueous extraction of fruits, a clarification step of the extract with microfiltration (MF) and ultrafiltration (UF) membranes and a fractionation/concentration step of the clarified extract through the use of tight UF membranes. The aqueous extraction was studied in order to obtain the maximum yield of biologically active compounds. At this purpose, different parameters such as the extraction time, temperature and solid/liquid ratio, were optimized. Three different commercial membranes with molecular weight cut-off (MWCO) from 0.5 to 3.5 kDa (GE, GH and GK from GE Osmonics) were tested in the fractionation step. The performance of selected membranes, was evaluated in terms of productivity and selectivity towards target compounds. To fulfil the final aim to purify polyphenols from carbohydrates the membrane process was also studied in a diafiltration mode. Fouling index and cleaning efficiency were analysed in order to determine process feasibility at industrial scale. Experimental results indicated that the GH membrane with a MWCO of 2.5 kDa exhibited the best separation efficiency of polyphenols from carbohydrates. For this membrane, an improved purification of polyphenols from carbohydrates by increasing the diafiltration volume, D (-), was observed: at a D (-) of 5 the removal of carbohydrates in the UF retentate was higher than 90% in comparison with the clarified extract; on the other hand, the loss of polyphenols in the permeate was lower than 20%. The investigated work allowed to obtain two distinct natural aqueous extracts from goji berries: a concentrated extract enriched in polyphenols with high antioxidant activity of interest for pharmaceutical, cosmetic or nutraceutical applications and a purified extract enriched in carbohydrates useful in the food industry.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
