Influences of Extraction Methods on Physicochemical and Functional Characteristics of Three New Bulbil Starches from Dioscorea opposita Thunb. cv. Tiegun

Purification and characterization of two non-starch polysaccharides from bulbils of Dioscorea opposita Thunb. 'Tiegun' and their antioxidant and hypoglycemic activity

BACKGROUND

Dioscorea opposita Thunb. cv. 'Tiegun' has substantial agricultural and economic value. Its underground tubers are used widely in food and traditional medicine but the bulbils - small globular structures in the leaf axils - are frequently overlooked and discarded. This wastes biological resources and reduces overall plant productivity.

RESULTS

To address this, subcritical water extraction was applied to extract substances from the bulbils, followed by separation and purification. As a result, two non-starch polysaccharide components, DBP1 and DBP2, were obtained, with extraction rates of 2.25% and 0.85% respectively. Subsequent research on their properties and activity showed that DBP1 (21.9 kDa) was a neutral polysaccharide mainly made of Gal and Glc, and DBP2 (109.8 kDa) was an acidic polysaccharide composed of GalA and Gal. Due to the higher yield of DBP1, its structure was studied in greater depth. Methylation experiments indicated that its main chain consisted of 1,4-Galp and 1,4,6-Glcp glycosidic bonds with branch points, consistent with nuclear magnetic resonance (NMR) results. Scanning electron microscopy revealed that DBP1 and DBP2 had distinct filamentous structures yet similar spherical morphologies. Fourier transform infrared spectroscopy and thermal analysis were used to study their functional groups and thermal stability. In activity tests, DBP1 and DBP2 both showed antioxidant activity and could inhibit α-glucosidase and α-amylase, demonstrating hypoglycemic activity.

CONCLUSION

In conclusion, DBP1 and DBP2, two non-starch polysaccharides, showed good antioxidant and hypoglycemic effects. They can be used as raw materials for functional foods and drugs and merit further development. Maximizing bulbil utilization promotes green, sustainable agriculture and prevents resource waste. © 2025 Society of Chemical Industry.

Effects of isolation methods on physicochemical properties of defatted starch from the acorn (Quercus brantii)

This study explores the innovative combined effects of alkaline isolation with ultrasound pretreatment on the physicochemical properties of acorn (Quercus brantii) starch. The optimal pH for maximizing the yield of alkaline-isolated acorn starch (AAS) was determined, followed by comparison with alkaline-isolated defatted acorn starch (ADAS), ultrasound-pretreated acorn starch (UAS), and ultrasound-pretreated defatted acorn starch (UDAS). The results demonstrated substantial improvements in yield and purity, with the highest yield (68.97 ± 0.16 %) achieved at pH 9. ADAS showed high purity, with protein and fat contents of 1.82 ± 0.07 % and 0.025 ± 0.02 %, respectively. UDAS exhibited superior swelling power, solubility, and turbidity, indicating enhanced functional properties. Scanning Electron Microscopy (SEM) revealed variations in granule sizes across treatments, from 12.42 μm (ADAS) to 10.72 μm (UDAS). X-ray diffraction analysis showed C-type patterns with crystallinity ranging from 31.25 % (ADAS) to 26 % (UAS). Thermal analysis demonstrated UDAS had the highest peak viscosity and lowest thermal parameters. Texture analysis indicated that AAS formed a softer gel, while ADAS displayed greater hardness and gumminess. These findings highlight the effectiveness of combining alkaline isolation with ultrasound pretreatment to improve acorn starch quality for sustainable applications in food and biotechnology.

Customizing Starch Properties: A Review of Starch Modifications and Their Applications

Starch has been a convenient, economically important polymer with substantial applications in the food and processing industry. However, native starches present restricted applications, which hinder their industrial usage. Therefore, modification of starch is carried out to augment the positive characteristics and eliminate the limitations of the native starches. Modifications of starch can result in generating novel polymers with numerous functional and value-added properties that suit the needs of the industry. Here, we summarize the possible starch modifications in planta and outside the plant system (physical, chemical, and enzymatic) and their corresponding applications. In addition, this review will highlight the implications of each starch property adjustment.

Widely Targeted Metabolomics Reveals the Effects of Soil on the Metabolites in Dioscorea opposita Thunb

Chinese yam (Dioscorea opposita Thunb. cv. Tiegun), a type of homologous medicinal plant, mainly grows in sandy soil (SCY) and loessial soil (LCY). However, the effects of the soil on the metabolites in SCY and LCY remain unclear. Herein, this study aims to comprehensively elucidate the metabolites in SCY and LCY. A UPLC-MS/MS-based, widely targeted metabolomics approach was adapted to compare the chemical composition of SCY and LCY. A total of 988 metabolites were detected, including 443 primary metabolites, 510 secondary metabolites, and 35 other compounds. Notably, 177 differential metabolites (classified into 12 categories) were identified between SCY and LCY; among them, 85.9% (152 differential metabolites) were upregulated in LCY. LCY significantly increased the contents of primary metabolites such as 38 lipids and 6 nucleotides and derivatives, as well as some secondary metabolites such as 36 flavonoids, 28 phenolic acids, 13 alkaloids, and 6 tannins. The results indicate that loessial soil can improve the nutritional and medicinal value of D. opposita.

Effects of Different Extraction Methods on the Gelatinization and Retrogradation Properties of Highland Barley Starch

The purpose of this study was to compare the gelatinization and retrogradation properties of highland barley starch (HBS) using different extraction methods. We obtained HBS by three methods, including alkali extraction (A-HBS), ultrasound extraction (U-HBS) and enzyme extraction (E-HBS). An investigation was carried out using a rapid viscosity analyzer (RVA), texture profile analysis (TPA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Fourier-transform infrared spectrometry (FTIR). It is shown that the different extraction methods did not change the crystalline type of HBS. E-HBS had the lowest damaged starch content and highest relative crystallinity value (p < 0.05). Meanwhile, A-HBS had the highest peak viscosity, indicating the best water absorption (p < 0.05). Moreover, E-HBS had not only higher G′ and G″ values, but also the highest gel hardness value, reflecting its strong gel structure (p < 0.05). These results confirmed that E-HBS provided better pasting stability and rheological properties, while U-HBS provides benefits of reducing starch retrogradation.

Structure and Bioactivities of a Novel Polysaccharide Extracted From Dendrobium huoshanense by Subcritical Water

In this study, the polysaccharide was extracted by subcritical water from Dendrobium huoshanense. A novel polysaccharide (DHPs-1) was obtained through several purification steps and its structure and bioactivity were investigated. Structural analysis indicated that the weight-average molecular weight of DHPs-1 was 5.0 × 10⁴ Da and it was mainly composed of glucose (65.04%), mannose (14.23%), galactose (8.17%), galacturonic acid (6.41%), rhamnose (2.34%), and xylose (1.25%). 1,4-Glcp, and 1,4,6-Galp were existed in the backbone of DHPs-1. The residues of 1,3,4-Galp, 1,4-Manp, 1,4-Galp, and 1,3,4,6-Galp could be in the backbone or the side chains with the non-reducing terminal of α-Manp. Bioactivity tests indicated that DHPs-1 had immunomodulatory activity in that it significantly enhanced transcript levels of cytokines [Tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6), Interleukin-1β (IL-1β), and Interleukin-10 (IL-10)]. DPPH and hydroxyl radical scavenging tests showed that it had good antioxidant activity. These results reveal that DHPs-1 could be developed as a safe immunomodulatory agent and antioxidant for pharmacological or functional food applications.

Isolation and characterization of starch from purple yam (Dioscorea trifida)

As a starchy raw material, purple yam presents pigments and mucilaginous material, what can difficult the extraction of pure starch. The extracted starches of Dioscorea trifida by aqueous and alkaline ways were investigated for purity, thermal, physicochemical, technological and functional properties. The starch obtained by alkaline extraction presented higher water absorption capacity and pasting temperature when compared to that obtained by the aqueous extraction method. The starch obtained by the aqueous extraction showed higher oil absorption capacity and less water loss in the freezing-thawing cycles. For both processes, the starches exhibited B-type X-ray diffraction pattern. Thermal analysis showed that both starches pass easily through transition phenomena as observed by T₀ and enthalpy values. The thermal effects presented similar behavior for both extraction methods. Although the extraction method induced changes in the properties of the starches, these changes did not compromise the functionality of the extracted starch and the purple yam starch was left unmodified. Starch can be used in preparations that require higher resistance to high temperatures as well as exposure to longer preparation times.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-021-05066-9.