Optimization of Extraction Conditions for the Antioxidant Potential of Different Pumpkin Varieties (Cucurbita maxima)

Abstract

Antioxidants are a wide group of chemical compounds characterized by high bioactivity. They affect human health by inhibiting the activity of reactive oxygen species. Thus, they limit their harmful effect and reduce the risk of many diseases, including cardiovascular diseases, cancers, and neurodegenerative diseases. Antioxidants are also widely used in the food industry. They prevent the occurrence of unfavourable changes in food products during storage. They inhibit fat oxidation and limit the loss of colour. For this reason, they are often added to meat products. Many diet components exhibit an antioxidative activity. A high antioxidative capacity is attributed to fruit, vegetables, spices, herbs, tea, and red wine. So far, the antioxidative properties of various plant materials have been tested. However, the antioxidative activity of some products has not been thoroughly investigated yet. To date, there have been only a few studies on the antioxidative activity of the pumpkin, including pumpkin seeds, flowers, and leaves, but not the pulp. The main focus of our experiment was to optimize the extraction so as to increase the antioxidative activity of the pumpkin pulp. Variable extraction conditions were used for this purpose, i.e., the type and concentration of the solvent, as well as the time and temperature of the process. In addition, the experiment involved a comparative analysis of the antioxidative potential of 14 pumpkin cultivars of the Cucurbita maxima species. The study showed considerable diversification of the antioxidative activity of different pumpkin cultivars.Sustainability 2020, 12, 1305 2 of 21 (neutralize) reactive oxygen species (ROS), including hydroperoxide radicals, superoxide anion radicals, singlet oxygen, hydrogen peroxide, and hydroxyl radicals [1,2]. The following compounds are usually listed as strong antioxidants: Carotenoids (e.g.

Antioxidants and Health-Beneficial Nutrients in Fruits of Eighteen Cucurbita Cultivars: Analysis of Diversity and Dietary Implications

“…The presented research work on fruits of 18 Cucurbita cultivars enabled to compare their antioxidant properties and confirmed the great diversity found for different objects. This observation is similar to that reported by other authors for many other examined cultivars [64,65,67]. Such variability should not be considered surprising, taking into account that pumpkin is one of the first domesticated plants and has been grown worldwide for several hundred years thus giving farmers enough time to obtain and introduce cultivars with unique characteristics.…”

“…Taking into account the content of phenolic compounds ( Table 2), it is thus justified that both carotenoids and phenolics contributed to the resultant exceptional activity. It should be noted here that in the complementary study [67] 'Hokkaido' also ranked high among the other tested C. maxima cultivars in terms of antioxidative/antiradical activity. The fruits of 'Indomatrone' accumulated the highest amounts of total phenols and, expectedly, they revealed the highest antioxidant capacities as measured by FRAP and CUPRAC assays.…”

“…This conclusion gave reasons to launch direct measurements of antioxidant (CUPRAC, FRAP) and antiradical (DPPH) capacities of pumpkin flesh extracts. For the case of Cucurbitaceae, it is a novel approach, first applied in our pilot work [66], and follows that of the most recent study of Kulczyński et al [67]. Similarly to our strategy, these authors have employed several independent methods to evaluate antioxidant potential of 14 C. maxima cultivars.…”

Calcium-Enriched Pumpkin Affects Serum Leptin Levels and Fat Content in a Rat Model of Postmenopausal Osteoporosis

“…Increased reactive oxygen species also leads to cell dysfunction, altered signaling and transport between cells, and decreased energy metabolism, which can lead to weight gain [ 17 ]. Pumpkin has high antioxidant potential, which was studied in our previous research [ 18 ]. Antioxidants can reverse the negative effects of estrogen deficiency by decreasing oxidative stress, which destroys bone tissue and increases body weight.…”

Polyphenol Extraction by Different Techniques for Valorisation of Non-Compliant Portuguese Sweet Cherries towards a Novel Antioxidant Extract

“…Nevertheless, ABTS applies to both hydrophilic and lipophilic antioxidant systems, whereas DPPH applies to hydrophobic systems [54]. ORAC method has been reported by different authors as a more relevant antioxidant procedure because it engages a biological radical (peroxyl) source and is a very high sensitivity method, which is mainly used to measure the activity of hydrophilic antioxidants compounds [23,55].…”