Extraction and functional properties of pigment from pumpkin peels by a novel green deep eutectic alcohol two-phase system

Pumpkin peel pigments contain a variety of natural antioxidants carotenoids including alpha-carotene, 8-carotene, 8-cryptoflavin, and xanthine, etc.. Conventional extraction methods gener-ally have low yields and high energy consumption. To explore a green and efficient extraction process, firstly, different kinds and proportions of deep eutectic solvent (DES) alcohol two -aqueous phase system were prepared, and then ultrasound-assisted cellulase was used to opti-mize the parameters by Box-Behnken design (BBD) on the basis of single factor experiment. The results showed that the extraction solvent was determined as DES (choline chloride: triethylene glycol = 1 : 3) and ethanol = 6 : 4, the yield of the pigments was 2.460% +/- 0.037% at cellulase dosage of 2.10%, solid-liquid ratio of 1 : 40 g/mL, ultrasonic power of 300 W for 40 min. The in-hibition rate of the pigments to alpha-amylase and sucrase was 82.20% +/- 0.90% and 75.63% +/- 1.19%, respectively, at the concentration of 100 mu g/mL. They could significantly pro-long the survival rate of Caenorhabditis elegans under hydrogen peroxide stress (p < 0.05), and the mean lifespans of C. elegans reach 9.047 +/- 0.296 h, which was significantly higher than that of the negative control (2.717 +/- 0.125 h) and the positive control group (5.067 +/- 0.327 h). They also significantly enhanced the activities of T-SOD (>77.17%) and CAT (>112.09%) and reduced the level of MDA (p < 0.05), indicating that the pigments played an important role in al-leviating oxidative stress damage, and with great development value as a recyclable resource.

Automated summary

Pumpkin peel pigments contain natural antioxidants carotenoids and can be extracted efficiently using a deep eutectic solvent (DES) alcohol two-aqueous phase system combined with ultrasound-assisted cellulase. The obtained pigments showed inhibitory effects on alpha-amylase and sucrase, prolonged the survival rate of Caenorhabditis elegans under hydrogen peroxide stress, and increased the activities of T-SOD and CAT enzymes while reducing the level of MDA. These findings indicate the potential of pumpkin peel pigments as a valuable recyclable resource for alleviating oxidative stress damage.