Effect of Different Cooking Methods on Natural Antioxidants in Pumpkin (Cucurbita moschata) Products

Abstract

The present study aimed to investigate the effects of various cooking methods on antioxidant content and radical scavenging activity of pumpkin. Three heat treatments were applied, namely,blanching, and stir frying for cubes(1.5×1.5×1.5 cm) and roasting for slices (0.5mm) to produce soup, juice and roasted pumpkin. The results indicated that carotenoids content ranged between 11,07 IU/100g (soup) and 892 IU/100g (juice).Roasted product exhibited significantly (P≤0.05) the least flavoniod content (12.09g/kg), while soup possessed significantly (P≤0.05) the highest content(17.96 g/Kg). Lycopene content (0.15 mg/100g) was found to be significantly(P≤0.05)the least (in soup produced from cubes blanched for 4 mins). In contrast, the counterpart raw juice had significantly (P≤0.05) the highest lycopene content (0.70mg /100g). Total polyphenols content of stir fried product was significantly (P≤0.05) the least(406.25 g/kg), while roasted product exhibited significantly (P≤0.05) the highest polyphenols content (670.18g/kg). It was obvious that raw juice possessed significantly (P≤0.05) the highest DPPH (63.79%), on contrary to roasted product being significantly (P≤0.05) the least antioxidant activity as assessed by DPPH method (30.31 %).The H2O2 scavenging (2.85 %) was found to be significantly (P≤0.05) the highest ( in soup produced from cubes blanched for 4 min) .While, the raw juice has significantly(P≤0.05)the least H2O2 scavenging (0.32%).So, It is necessary to apply the most proper cooking conditions (temperature and cooking time) to avoid any degradation of the bioactive compounds present in pumpkin. The results revealed the superiority of blanching process since it maintained the bioactive compoundsin pumpkin without any deteriorative effects.