Extraction of carotenoids from pumpkin peel and pulp: Comparison between innovative green extraction technologies (ultrasonic and microwave-assisted extractions using corn oil)

Natural pigments improve aesthetic value as well as antioxidant potential of a foodproduct. This study was designed to determine the effects of green extraction techniques oncarotenoids, polyphenols and antioxidant activities of pulp and peel of two varieties of pumpkin (Cucurbita maxima). Innovative green extractions (IGE; Ultrasound and Microwave-AssistedExtractions) synergised with corn oil (used as green solvent) were compared with conventionalextraction (CE; hexane/isopropyl alcohol; 60:40, v/v). Results showed total carotenoids to be almostdouble on employing IGE (PM2-UAE-peel = 38.03 ± 4.21; PM4-UAE-peel = 33.78 ± 1.76 µg/g) whencompared to conventional extraction (PM2-CE-peel = 19.21 ± 4.39; PM4-CE-peel = 16.21 ± 2.52 µg/g).Polyphenolic contents ranged between 510.69 ± 5.50 and 588.68 ± 7.26 mg GAE/100 g of extract inIGE, compared with conventional extracts (269.50 ± 2.17 to 318.46 ± 6.60 mg GAE/100 g) and percentinhibition of 2,2-Diphenyl-1-picrylhydrazyl (DPPH) ranging between 88.32 ± 1.51 and 93.53 ± 0.30%in IGE when compared with conventional extraction (50.61 ± 1.44 to 57.79 ± 2.09%). Further, oxidative stability of carotenoids extracts from IGE (protection factor = 1.59 ± 0.01 to 1.81 ± 0.05) werefound to be significantly higher (p < 0.05) than conventional extracts. Based on results, this study supports the use of innovative green extraction techniques to obtain bioactive pigments like carotenoids.It is anticipated that results generated will find potential applications in food, pharmaceutical andcosmetic industries