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

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.