Physicochemical Properties and Antioxidant Activity of Pumpkin Polysaccharide (Cucurbita moschata Duchesne ex Poiret) Modified by Subcritical Water

Abstract

In this paper, subcritical water (SCW) was applied to modify pumpkin (Cucurbita moschata Duchesne ex Poiret) polysaccharides, and the properties and antioxidant activity of pumpkin polysaccharides were investigated. SCW treatments at varying temperature led to changes in the rheological and emulsifying properties of pumpkin polysaccharides. SCW treatments efficiently degraded pumpkin polysaccharides and changed the molecular weight distribution. Decreases in intrinsic viscosity, viscosity-average molecular weight, and apparent viscosity were also observed, while the activation energy and flow behavior indices increased. The temperature of SCW treatment has a great influence on the linear viscoelastic properties and antioxidant activity of pumpkin polysaccharides. Pumpkin polysaccharides solution treated by SCW at 150 °C exhibited the highest emulsifying activity and antioxidant activity, which was probably due to a broader molecular mass distribution and more reducing ends exposed after treatment. Scanning electron microscopy showed that SCW treatment changed the microstructure of pumpkin polysaccharides, resulting in the exposure of bigger surface area. Our results suggest that SCW treatment is an effective approach to modify pumpkin polysaccharides to achieve improved solution properties and antioxidant activity.

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“…In general, W-CCPs, RPP-3, and RPP-4, which have stronger antioxidant activity, also have better α-glucosidase and α-amylase inhibitory activities. According to previous reports, similar results have been observed that extracted or molecularly modified pumpkin polysaccharides have better in vitro antioxidant and hypoglycemic activities (9)(10)(11)(12). The nonpurified pumpkin polysaccharides (WA-CCPs, DPPs), which were extracted by hot water extraction and water extraction and alcohol precipitation, have lower in vitro antioxidant and hypoglycemic activities than the hot water-extracted pumpkin polysaccharide, W-CCPs.…”

“…Pumpkin (Cucurbita moschata) is one of the most popular vegetables in the world, and it contains carotenoids, pectin, dietary fiber, mineral elements, polysaccharides, para-aminobenzoic acid, sterols, proteins, and peptides. At present, researchers have shown that pumpkin polysaccharides can be used as potential hypoglycemic substances and have certain therapeutic effects on diabetes (4)(5)(6)(7)(8), antioxidant activity (4,(9)(10)(11)(12), lowering plasma lipids (8), improving immunity (9), and anti-cancer (13). Currently, studies on in vitro hypoglycemic activity in pumpkin polysaccharides mainly focus on radical-scavenging ability assay, plasma iron reduction ability assay, α-glucosidase and α-amylase inhibition assay, bile acid binding ability assay, and pancreatic islet β-cell damage protective ability assay (4,9,(11)(12)(13).…”

“…At present, researchers have shown that pumpkin polysaccharides can be used as potential hypoglycemic substances and have certain therapeutic effects on diabetes (4)(5)(6)(7)(8), antioxidant activity (4,(9)(10)(11)(12), lowering plasma lipids (8), improving immunity (9), and anti-cancer (13). Currently, studies on in vitro hypoglycemic activity in pumpkin polysaccharides mainly focus on radical-scavenging ability assay, plasma iron reduction ability assay, α-glucosidase and α-amylase inhibition assay, bile acid binding ability assay, and pancreatic islet β-cell damage protective ability assay (4,9,(11)(12)(13). Among these studies, the different extraction methods had different in vitro hypoglycemia activity, which is related to its monosaccharide types and molar ratios of the pumpkin polysaccharides.…”

Ultrasonic treatment of Dendrobium officinale polysaccharide enhances antioxidant and anti‐inflammatory activity in a mouse D‐galactose‐induced aging model

“…Reduction of Mw for such polysaccharides enhanced antioxidant activities, including radical scavenging activity and reducing power. Q. Li's group proposed that reduction of Mw resulted in the exposure of more reducing ends for such polysaccharides (Yu et al., 2021 ). Thus, the high ROS and reactive nitrogen species (RNS) radical scavenging activities we observed for M‐DOP may have been due to decreased Mw and increased exposure of reducing ends.…”

Whey Protein Isolate Nanofibers Prepared by Subcritical Water Stabilized High Internal Phase Pickering Emulsion to Deliver Curcumin

“…The absolute value of WPINs–SW–PE on the zeta potential was greater than that of WPINs–H–PE on the zeta potential. Interestingly, both of them were greater than 30 mV, indicating that WPINs treated with both SW and hydrothermal methods could enhance the stability of PE [ 52 ]. Based on these results, SW treatment may reduce the average particle size and increase the zeta potential of PE, which was attributed to the increase in the surface charge and distribution of WPINs during SW. WPINs–SW–PE will act as a higher and more stable encapsulation rate during the subsequent encapsulation of Cur.…”