Chinese Yam Research Articles

Identification Of Pathogen Causing Wilt Disease Of Chinese Yam (Dioscorea Polystachya Turczaninow) In Hunan

This study aims to identify the pathogen causing wilt disease of Chinese yam (Dioscorea polystachya Turczaninow.) in Hunan Province. Diseased stems were collected from the fields in Loudi City in the Hunan Province. Tissue culture method was used for the isolation of the pathogen causing wilt disease of Chinese yam, and was identified as Fusarium asiaticum based on the morphological characteristics and molecular technology. Out of five fungicides, Difenoconazole· Azoxystrobin 40% SC, Hexaconazole 5% SC, and Difenoconazole 10% WDG, demonstrated inhibitory effects on the pathogen. Among them, hexonazole 5% SC had the lowest EC50 value and was the most sensitive to the pathogen of Chinese yam wilt, so it should be selected first for the control of Chinese yam wilt. Bangladesh J. Bot. 53(3): 857-863, 2024 (September) Special

Targeted and non-targeted metabolic characteristics of 6,7-dihydroxy-2,4- dimethoxyphenanthrene during simulated gastrointestinal digestion

6,7-dihydroxy-2,4-dimethoxyphenanthrene (PC4), isolated and identified from Chinese yam, was one of the important characteristic active ingredients. The present study established simulated gastrointestinal digestion and caco-2 intestinal epithelial models to investigate the digestive and metabolic characteristics of PC4. The results indicated that PC4 was mainly digested and metabolized in the intestine, with a digestion rate of 94 %, producing active characteristic metabolites including 2,6-dimethoxy-4-phenanthrenol (MC1) and 1-methoxyphenanthrene (MC2). Molecular docking indicated that the COX-2 enzyme inhibitory activity of MC1 might be superior to that of the prototype PC4. During 24 h co-incubation of PC4 with caco-2 monolayer epithelial, the signal pathway related to lipid decomposition was up-regulated within 0–12 h, while the diabetes complications AGE-RAGE was inhibited just in 0–6 h period significantly. The research database provided scientific basis for the digestion and metabolism of PC4, and laid theoretical foundation for the scientific development of Chinese yam functional foods.

Chinese yam polysaccharide-loaded aluminium hydroxide nanoparticles used as vaccine adjuvant to induce potent humoral and cellular immune responses

Due to their safety and efficacy, aluminium salts (Alum) are considered the most important adjuvants in human vaccines. However, Alum adjuvants are unable to elicit a cellular immune response, which is vital for the prevention of various chronic infectious diseases and cancers. Herein, we isolated and purified a water-soluble polysaccharide from Chinese yam, named CYP, which was primarily composed of →4)-α-D-Glcp-(1→, →4,6)-α-D-Glcp-(1→, and α-D-Glcp-(1→. Meanwhile, we prepared aluminium hydroxide nanoparticles (Al NPs) with a nanometer-scale size and thin stick-like shape. Being an immunostimulant, the CYP was then loaded onto the Al NPs to obtain a novel adjuvant delivery system (CYP-Al NPs) that enhances the immunostimulatory activity of CYP. Our findings showed that the CYP-Al NPs facilitated macrophages activation and promoted the antigen uptake by macrophages. The in vivo experiment showed that the CYP-Al NPs, as the adjuvant to ovalbumin, promoted the activation of dendritic cells and germinal center B cells in draining lymph nodes, induced a durable and strong antibody response, especially the Th1-type IgG2a antibody response, and improved the cytotoxic T lymphocytes response. These results demonstrated that the CYP-Al NPs could generate robust humoral and cellular responses, and has the great potential to serve as an adjuvant delivery system.

Sulfated Chinese yam polysaccharide exert anti-inflammatory potential via MAPK/NF-κB signaling pathways in a co-culture system and LPS-induced acute inflammatory mice model.

Our previous study has demonstrated that sulfated Chinese yam polysaccharide (SCYP) can improve immunomodulatory activity in Raw 264.7 cells. However, its anti-inflammatory is little known. In this study, the anti-inflammatory effects of SCYP were systematically investigated via the Lipopolysaccharides (LPS)-induced Raw264.7 cell model, Caco-2/Raw264.7 co-culture system, and acute inflammation mice model. The results suggested SCYP promoted the cell proliferation and have no toxicity in Raw264.7 and Caco-2 cells at the concentration of 200µg/mL. Moreover, when treated with SCYP, the production of pro-inflammatory cytokines (interleukin [IL]-1β, IL-6, and tumor necrosis factor-α) reduced significantly in Raw264.7 via the MAPK/NF-κB pathway. In the Caco-2/Raw264.7 co-cultured system, SCYP could regulate inflammation reaction by improving intestinal barrier, which might prevent systemic inflammation. Further, systemic inflammation was alleviated by SCYP in LPS-induced acute inflammation mice through MAPK/NF-κB pathway. PRACTICAL APPLICATION: These results supported that SCYP may be used as an anti-inflammation agent in the functional food field.

Whole Plant Extracts for Neurocognitive Disorders: A Narrative Review of Neuropsychological and Preclinical Studies.

The incidence of neurodegenerative disorders like Alzheimer's or Parkinson's Disease, characterized by a progressive cognitive decline, is rising worldwide. Despite the considerable efforts to unveil the neuropsychological bases of these diseases, there is still an unmet medical need for effective therapies against cognitive deficits. In recent years, increasing laboratory evidence indicates the potential of phytotherapy as an integrative aid to improve cognitive functions. In this review, we describe the data of plant whole extracts or single compounds' efficacy on validated preclinical models and neuropsychological tests, aiming to correlate brain mechanisms underlying rodent behavioral responses to human findings. After a search of the literature, the overview was limited to the following plants: Dioscorea batatas, Ginkgo biloba, Melissa officinalis, Nigella sativa, Olea europaea, Panax ginseng, Punica granatum, and Vitis vinifera. Results showed significant improvements in different cognitive functions, such as learning and memory or visuospatial abilities, in both humans and rodents. However, despite promising laboratory evidence, clinical translation has been dampened by a limited pharmacological characterization of the single bioactive components of the herbal products. Depicting the contribution of the single phytochemicals to the phytocomplex's pharmacological efficacy could enable the comprehension of their potential synergistic activity, leading to phytotherapy inclusion in the existing therapeutic package against cognitive decline.

Shenqi Pill alleviates acetaminophen-induced liver injury: a comprehensive strategy of network pharmacology and spectrum-effect relationship reveals mechanisms and active components

BackgroundAcetaminophen (APAP), commonly used for its antipyretic and analgesic properties, can cause severe liver injury or even acute liver failure when overdosed. However, the options for treating APAP-induced liver toxicity are limited. Shenqi Pill (SQP), a traditional Chinese herbal formula, has shown effectiveness in treating various liver ailments. SQP consists of cinnamon, aconite, rehmannia, cornus, peony bark, Chinese yam, poria, and alisma in a ratio of 1:1:8:4:3:4:3:3. However, the mechanisms and active components of SQP that counteract drug-induced liver injury (DILI) are not well understood. PurposeThis study aimed to explore the protective effects of SQP against APAP-induced liver injury in both laboratory and animal settings. It seeks to identify the active components and potential mechanisms by which SQP targets mitochondria to alleviate liver damage. MethodsA mouse model with APAP-induced liver injury was established to assess SQP's therapeutic impact. This study then analyzed the components of SQP using UPLC-Q-TOF-MS in both in vivo and in vitro environments. Network pharmacology and the GEO database helped predict potential pathways and targets. Potential active components were identified through spectrum-effect relationship analysis and validated their efficacy using Seahorse assays and molecular docking. ResultsTreatment with SQP significantly reduced liver dysfunction, tissue damage, lipid metabolic disruptions, and inflammation caused by APAP in mice. In cellular tests, SQP-treated serum notably enhanced mitochondrial function, maintained membrane potential, decreased ROS levels, and prevented mitochondrial permeability transition pore opening. Biochemically, SQP reversed the suppression of p-AMPK, p-ACC, CPT1, and ACADM expression caused by APAP overdose. This study identified 97 in vitro and 24 in vivo components of SQP, with eight showing significant mitochondrial benefits. Molecular docking studies suggest that fuziline and paeoniflorin could activate AMPK. ConclusionSQP effectively mitigates APAP-induced liver injury by enhancing mitochondrial function via the AMPK-ACC-CPT1-ACADM pathway. Moreover, this study introduces a novel strategy for analyzing the relationship between the chemical and pharmacological properties of drug-containing serum, successfully identifying compounds with mitochondrial activity. Fuziline and paeoniflorin, in particular, emerge as promising mitochondrial protectants and warrant further investigation. This research underpins the development of innovative treatments for DILI using SQP and its components.

The metabolic profiling of Chinese yam fermented by Saccharomyces boulardii and the biological activities of its ethanol extract in vitro

Chinese yam (Dioscorea opposita Thunb.), as one of the medicinal and edible homologous plants, is rich in various nutrients and functional factors. In this study, Chinese yam fermented by Saccharomyces boulardii was performed to investigate its bioactive components and metabolic profile. And then, the main bioactive components and biological activities of fermented Chinese yam ethanol extract (FCYE) were evaluated. Results showed that there were 49 up-regulated metabolites and 52 down-regulated metabolites in fermented Chinese yam compared to unfermented Chinese yam. Besides, corresponding metabolic pathways analysis initially revealed that the distribution of bioactive substances was concentrated on alcohol-soluble small molecular substances. Ulteriorly, the total polyphenol content and the total flavonoid content in FCYE were significantly increased, and the corresponding antioxidant and immunomodulatory activities in vitro were also significantly enhanced. Our study provided a new reference for the comprehensive utilization of Chinese yam and laid a theoretical foundation for the development and application of natural probiotic-fermented products.

Investigating the Discoloration of Leaves of Dioscorea polystachya Using Developed Atomic Absorption Spectrometry Methods for Manganese and Molybdenum.

The Chinese yam (Dioscorea polystachya, DP) is promising for the food and pharmaceutical industries due to its nutritional value and pharmaceutical potential. Its proper cultivation is therefore of interest. An insufficient supply of minerals necessary for plant growth can be manifested by discoloration of the leaves. In our earlier study, magnesium deficiency was excluded as a cause. As a follow-up, this work focused on manganese and molybdenum. To quantify both minerals in leaf extracts of DP, analytical methods based on atomic absorption spectrometry (AAS) using the graphite furnace sub-technique were devised. The development revealed that the quantification of manganese works best without using any of the investigated modifiers. The optimized pyrolysis and atomization temperatures were 1300 °C and 1800 °C, respectively. For the analysis of molybdenum, calcium proved to be advantageous as a modifier. The optimum temperatures were 1900 °C and 2800 °C, respectively. Both methods showed satisfactory linearity for analysis. Thus, they were applied to quantify extracts from normal and discolored leaves of DP concerning the two minerals. It was found that discolored leaves had higher manganese levels and a lower molybdenum content. With these results, a potential explanation for the discoloration could be found.

Diosgenin-rich Yam (rhizome of Dioscorea batatas) extract ameliorates cognitive functions and plasma biomarkers for mild cognitive impairment and mild Alzheimer's disease: A randomized controlled trial

IntroductionIn Alzheimer's disease (AD), neural circuit disconnection primarily causes memory dysfunction, which leads to the hypothesis that repairing neural networks may be an appropriate treatment strategy for AD. We previously found that diosgenin stimulated neurite regeneration and synapse formation in AD model mice, and diosgenin-rich Yam extract enhanced cognitive function in healthy people and normal mice. In this study, we investigated the efficacy and safety of Yam extract in patients with mild cognitive impairment (MCI) and mild AD. MethodsPatients were administered either diosgenin-rich Yam extract or placebo, respectively, for 24 weeks. The primary outcome was cognitive function, which was evaluated using the Mini Mental State Examination Japanese version (MMSE-J), Alzheimer's Disease Assessment Scale-Cognition (ADAS-Cog), and verbal fluency test; the secondary outcomes were plasma biomarker levels [neurofilament light chain (NfL); axonal marker, glial fibrillary acidic protein levels; reactive astrocyte marker, and the Aβ42/40 ratio; marker of brain Aβ]. ResultsDiosgenin-rich Yam extract improved the ADAS-Cog Praxis domain score and plasma NfL (12 to 24 weeks) in all patients. The number of patients with improved/maintained ADAS-Cog total, Praxis or Memory scores was high in the Yam extract group, but not in placebo group. Divided by severity of pathology, diosgenin-rich Yam extract also improved the total and Memory domain in ADAS-Cog, and plasma NfL levels in patients with MCI. In the Yam extract group, improvement of MMSE-J was related to plasma Aβ42/40 increase, and improvement of plasma NfL was related to better MMSE-J. ConclusionTreatment with diosgenin-rich Yam extract for 24 weeks resulted in modest cognitive improvement and a decrease in plasma NfL levels, which may suggest axonal protection in the brain.

First report of basal stem rot caused by three Fusarium species on Chinese yam in China.

The cultivated variety of Chinese yam (Dioscorea polystachya Turcz. cv. Tiegun) is an economically important plant, capable of producing tubers that are used as food and traditional Chinese medicine. The basal stem rot was found on approximately 65% of yam (tuber expansion stage) in a total of 10 ha field in Wuzhi, Wen, and Hua counties, Henan, China (Sep 2021). Dark brown fusiform lesions initially occurred at the stems basal, irregularly extending to join together and leading to loop-stem necrotic indentation. Three diseased samples from Wuzhi county were collected, cut into 5 × 5 mm pieces, surface sterilized in 75% ethanol (30 s) and 1% NaClO (1 min), washed in sterile water 3 times, and placed on PDA in the dark for 3 days at 28℃. A total of 44 isolates forming three groups of Fusarium colonies were obtained using monosporic isolation, of which 19, 8, and 17 isolates were identified as F. oxysporum, F. solani, and F. proliferatum based on colony morphology, respectively. Typical isolates SYJJ6, 9, and 10 for each group were further studied. The SYJJ6 colonies showed gray white abundant fluffy aerial mycelium with rough edges, formation of ellipsoid, unicellular microconidia without septa, 5.6 to 13.4 × 2.4 to 4.7 μm (n = 50), and sickle-shaped, slightly curved macroconidia with 2 to 4 septa, 14.0 to 23.9 × 3.4 to 5.1 μm (n = 50). Isolate SYJJ9 produced flocculent white colonies, grew in a circular pattern with a sharp edge, forming oval or oblong microconidia with zero or one septum, 11.2 to 18.8 × 3.4 to 6.2 μm (n = 50), and slightly curved macroconidia with 2 to 3 septa, 27.6 to 44.0 × 3.9 to 7.4 μm (n = 50). SYJJ10 produced whitish or pinkish white colonies with fluffy aerial mycelium and a red pigmentation, produced renal or oval microconidia with no septa, 5.1 to 11.8 × 1.8 to 4.2 μm (n = 50), and falcate, slightly curved macroconidia with 3 to 4 septa, 16.1 to 30.2 × 3.1 to 5.9 μm (n = 50). Additionally, TUB, EF-1α, and RPB2 genes were amplified with primers BT2a/BT2b, EF1/EF2, and 5f2/-7cr, respectively (Glass and Donaldson 1995; O'Donnell et al. 1998, 2010). BLASTn analysis on SYJJ6 (OR047663, OR047666, OR047669), SYJJ9 (OR047665, OR047667, OR047670), and SYJJ10 (OR047664, OR047668, OR047671) gene sequences were over 99% identical to those of F. oxysporum (100%, MK432917; 100%, MN417196; 99.61%, MN457531), F. solani (100%, MF662662; 100%, MN223440; 99.80%, CP104055), and F. proliferatum (100%, ON557521; 100%, ON458137; 99.90%, LT841266), respectively. Pathogenicity tests of three isolates were separately performed on 60-day-old yam seedlings. The basal stems were wounded using needle, and the wounds were wrapped with cotton balls soaked with conidial suspension (1 mL, 3×106 conidia/mL) or water (control). Each isolate treated three plants and repeated three times. All plants were grown at 28℃ under a 16/8-h light/dark cycle. Typical symptoms emerged on basal stems at 16, 13, and 17 days after inoculation with the conidia of isolates SYJJ6, 9, and 10, while the control basal stems appeared healthy. The re-isolated fungi were identical to the original three isolates. Fusarium species (F. oxysporum, F. commune, F. humuli, etc.)were previously reported to cause wilt or stem rot on different D. polystachya cultivars (Fang et al. 2020; Li et al. 2023; Zhao et al. 2013), or basal stem rot on Panax ginseng (Ma et al. 2020). This is the first report of Chinese yam basal stem rot caused by Fusarium species, which threatens the production of Chinese yam 'Tiegun' and should be further studied.

Effects of cold plasma pretreatment before different drying process on the structural and functional properties of starch in Chinese yam

This article compared the effects of hot air drying (HAD), infrared drying (IRD), and cold plasma (CP) as a pretreatment on the structure, quality, and digestive characteristics of starch extracted from yam. As the most commonly used drying method, HAD was used as a control. SEM and CLSM images showed that all treatments preserve the integrity of the yam starch. CP caused some cracks and breaks in the starch granules. IRD did not destroy the crystal structure of starch molecules, but made the spiral structure tighter and increased short-range orderliness. However, CP led to the depolymerization and dispersion of starch molecular chains, resulting in a decrease in average molecular weight and relative crystallinity. These molecular conformation changes caused by different processes led to differences in solubility, swelling power, pasting parameters, digestion characteristics, and functional characteristics. This study provided an important basis for the reasonable drying preparation and utilization of yam starch.

Effects of multiphase microwave drying on the microstructure of Chinese yam: A study based on X-ray micro-computed tomography technology

To address the issues of long drying time and high equipment costs present in freeze drying and freeze drying-microwave vacuum combined drying techniques, as well as to obtain higher-quality dried products, multiphase microwave drying (MMD) has been proposed. This study investigated the effects of MMD at different transition point moisture content levels (0.36, 0.59, and 0.79 g/g d.b.) on the microstructure and texture of dried Chinese yam. Using freeze drying (FD), microwave freeze drying (MFD), and microwave vacuum drying (MVD) as controls, X-ray micro-computed tomography (micro-CT) visualized and quantified Chinese yam’s structure across drying methods. The results indicated that as the transition point moisture content increased, the porosity and connected pore area and volume decreased, while non-connected pore area and volume increased. Chinese yam samples obtained from MMD scheme I (transition point moisture content of 0.36 g/g d.b.) exhibited a uniform and porous structure with a high total porosity (48.19 ± 0.32%), similar in hardness and shrinkage to freeze-dried yams, preserving microstructural integrity. MMD reduced drying time and maintained the quality of dried Chinese yam compared to FD, MVD, and MFD, highlighting its potential as a cost-effective method for producing premium dried Chinese yam products.

Protection effect of Dioscoreae Rhizoma against ethanol-induced gastric injury in vitro and in vivo: A phytochemical and pharmacological study

Ethnopharmacological relevanceDioscoreae Rhizoma, a kind of Chinese yam, is a medicinal and edible plant used in China for strengthening the spleen and stomach. However, there is a lack of modern pharmacology studies regarding its anti-gastric injury activity. Aim of the studyThis study aimed to investigate the phytochemical composition of Chinese yam aqueous extract (CYW) and evaluate its gastroprotective effects against ethanol-induced gastric injury in vitro and in vivo. Materials and methodsThe active components of CYW were identified using HPLC-QTOF-MS/MS in combination with the GNPS molecular networking and network pharmacology. In vitro studies were performed in the RAW264.7/GES-1 cell coculture system. In vivo study, mice were treated with CYW (0.31, 0.63, and 3.14 g/kg BW, orally) for 14 days, followed by a single oral dose of ethanol (10 mL/kg BW) to induce gastric injury. The biochemical, inflammation and oxidative stress markers were analyzed using commercial kits. Histopathology was used to assess the degree of gastric injury. Gene and protein expressions were studied using RT-qPCR and western blotting, respectively. ResultsCYW significantly restored the levels of SOD, GPx and CAT, and reduced the MDA content. Further analyses showed that CYW significantly alleviated the gastric oxidative stress by inhibiting the inflammation via decreasing p-NF-κB and p-IκB-α expression levels and inhibiting the generation of IL-6, TNF-α, and IL-1β. At the same time, the fraction remarkably upregulated Bcl-2, downregulated Bax and increased growth factor secretion, thereby prevented gastric mucous cell. Besides, The combination of HPLC-QTOF-MS/MS, GNPS molecular networking analysis, and network pharmacology demonstrated that linoleic acid, 3-acetyl-11-keto-beta-boswellic acid, adenosine, aminocaproic acid, tyramine, DL-tryptophan, cycloleucine, lactulose, melibiose, alpha-beta-trehalose, and sucrose would be the main active compounds of CYW against ethanol-induced gastric injury. ConclusionThis study showed that CYW is potentially rich source of anti-oxidant and anti-inflammatory bioactive compounds. It showed efficacy against ethanol-induced gastric injury by inhibiting inflammation, oxidative stress, and apoptosis in the stomach. The results of the current work indicate that Dioscoreae Rhizoma could be utilized as a type of natural resource for production of new medicine and functional foods to prevent and/or ameliorate ethanol-induced gastric injury.

An evaluation on the shrinkage deformation characteristics of Chinese yam during multiphase microwave drying based on digital image processing

The deformation characteristics of Chinese yam during multiphase microwave drying (MMD) was evaluated by image processing, and the effects of MMD on the drying characteristics, physical properties, shrinkage behavior, and microstructure of the samples were also investigated. The drying time was significantly reduced by increasing microwave power density. Compared with Scheme I, the time of Scheme V was shortened by 22.22%. The moisture content at the transition point from sublimation to evaporation drying stages (TPS-E) significantly affected the shrinkage of the samples. In Scheme I, the lowest moisture content at TPS-E of 0.354 g. g−1 was found, and the dried products with the shrinkage ratio and bulk density closest to those of FD. The deformation of Chinese yam mainly appeared in the evaporation drying stage. At this stage, the rate of change in cross-sectional area of dried samples ranged from 9.74% to 26.76% for Schemes II to Scheme V, compared to 2.03% for Scheme I. Similarly, the shrinkage ratio of the dried samples in Schemes II, III, IV, and V increased from 16.82% to 21.12% at TPS-E to 29.23% to 51.28% at the end of drying, respectively. Additionally, the shrinkage caused by the pores collapse of the samples because of the high moisture content at TPS-E (Scheme III, IV, and V) during the evaporation drying stage resulted in increases of bulk density. The present study can provide valuable insights for rational control of shrinkage and deformation of fruits and vegetables in MMD. Industrial relevanceChinese yam is a widely used food and medicinal resource in China due to its rich nutritional and medicinal values. Since the moisture content of Chinese yam can reach as high as 70–80%, drying serves as an effective method to broaden its application. However, shrinkage and deformation of materials during drying are common forms of appearance deterioration that can directly impact consumer acceptability. MMD has proven to be a promising drying technology. Nevertheless, improper drying parameter settings may lead to a deterioration of the appearance quality of MMD products. Therefore, comprehending the information of shrinkage and deformation of Chinese yam during MMD and effectively regulating these processes is essential. Mastering these aspects is critical for enhancing the economic value and consumer acceptance of dried Chinese yam products.

A Frontier Review of Nutraceutical Chinese Yam.

Yams are the edible subterranean rhizomes, or tubers, of plants from the genus Dioscorea. There are approximately 600 species of yam plants in the world, with more than 90 of these growing in East Asia. One particular species, Dioscorea opposita Thunb., is highly praised as "the Chinese yam". This distinction arises from millennia of storied history, both as a nutritional food source and as a principal ingredient in traditional Chinese medicine. Among the many cultivars of Dioscorea opposita Thunb., Huai Shanyao has been widely regarded as the best. This review surveyed the historical background, physiochemical composition, applications as food and medicine, and research prospects for the Chinese yam. Modern science is finally beginning to confirm the remarkable health benefits of this yam plant, long-known to the Chinese people. Chinese yam promises anti-diabetic, anti-oxidative, anti-inflammatory, immunomodulatory, anti-hyperlipidemic, anti-hypertensive, anti-cancer, and combination treatment applications, both as a functional food and as medicine.

Dune soil nitrogen leaching for Chinese-yam cultivation: Impact of microbe-decomposable slow-release fertilizer

Chinese yam production is thriving in Aomori Prefecture, a cold and snowy region in Japan. Recently, there has been an increasing risk of nitrogen leaching in Chinese-yam fields, which consist of sandy soil, due to localized torrential rain. The relationships between the type of fertilizer used for Chinese-yam cultivation, the amount of nitrogen (N) leaching, and the timing of leaching remain unknown. Therefore, this study aimed to fill this knowledge gap by investigating the effects of different fertilizers (fast-acting and/or slow-release fertilizer) and irrigation practices (conventional and/or excessive irrigation) in order to mitigate the detrimental impact of nitrogen leaching on groundwater quality. An enhanced mathematical model and the spatiotemporal dynamics of inorganic nitrogen concentration in soil pore water were evaluated the negative impact of nitrogen leaching on the groundwater environment was evaluated. The results showed that the combined use of slow-release fertilizers could significantly reduce nitrate-nitrogen concentration in soil-water, especially during the harvest season. This study demonstrated that cultivating Chinese yam with a fertilizer application system that includes the use of slow-release fertilizer can diminish the negative impact of nitrogen leaching on the groundwater environment, contributing to our understanding of sustainable agricultural practices in regions facing similar environmental challenges. Therefore, our findings represent an important advancement providing new approaches to maintaining productivity while mitigating the adverse impacts on groundwater environments, as well as offering guidelines for agricultural practices in regions facing similar environmental challenges.

Drag reducing performance and its influencing on natural yam mucilage

Yam mucilage is a novel environmentally friendly drag reducer. This study investigates drag reduction and degradation characteristics of Chinese yam mucilage, using an in-house rotor device. The effects of temperature, aging, and salts on the drag reduction rate (DR) of yam mucilage were also explored. Furthermore, the synergistic drag reduction properties of Chinese yam-polyethylene oxide (PEO) solution were investigated by blending Chinese yam mucilage with PEO. The rotational speed range of the rotor device was set at 200–700 r/min, corresponding to Reynolds numbers (Re) ranging from 30 396 to 106 385. The results demonstrated that the DR of yam mucilage initially increased, and then decreased at low concentrations, with increasing Re. Conversely, the DR of yam mucilage at high concentrations increased with increasing Re, albeit at a gradually slowing rate as concentration increased; however, the shear stability was gradually enhanced. Degradation testing revealed that yam slime exhibited semi-rigid, or rigid polymer characteristics, with notable shear stability. At a concentration of 2000 ppm and Re = 106 385, the maximum DR reached 44.1%. Prolonged heating and standing resulted in the reduced DR of yam mucilage. However, salt ions exerted dual effects on the DR of yam mucilage: Low concentrations of NaCl improved its effectiveness while Na2SO4 and high concentrations of NaCl diminished its efficacy. The addition of a small quantity of PEO was found to significantly enhance the drag reduction efficacy of yam mucilage, but no significant improvement in the shear stability of yam mucilage was observed. Yam mucilage exhibits promising potential as an environmentally friendly drag reducer with remarkable drag reduction capabilities.

Effects of cooking methods on the physical properties and in vitro digestibility of starch isolated from Chinese yam

The objective of this study was to compare the structural and functional attributes of Chinese yam starches obtained via different domestic cooking methods. Cooking changed the crystalline type from the C type to the CB type, and disrupted the short- and long-range molecular order of Chinese yam starch. The average chain length of amylopectin in BOS (boiling starch) was the smallest at 22.78, while RWS had the longest average chain length, reaching 24.24. These alterations in molecular structure resulted in variations in functional properties such as solubility, swelling power (SP), pasting characteristics, and rheological properties. Among these alterations, boiling was the most effective method for increasing the water-binding capacity and SP of starch. Specifically, its water holding capacity was 2.12 times that of RWS. In vitro digestion experiments indicated that BOS has a higher digestion rate (k = 0.0272 min−1) and lower RDS (rapidly digestible starch), which may be related to its amylopectin chain length distribution. This study can guide us to utilize yam starch through suitable cooking methods, which is relevant for the processing and application of Chinese yam starch.

Combined Addition of Citric Acid and Ascorbic Acid Significantly Inhibits Browning in Chinese Yam (Dioscorea polystachya Turczaninow) Processing

Chinese yam (Dioscorea polystachya Turczaninow) is widely cultivated in East Asia, whose edible stem is a common vegetable and herb in traditional Chinese medicine. In fruit and vegetable processing, browning is estimated to be a major reason of waste. Browning lowers the nutrition value and brings undesired characteristics in food processing. To develop a secure and low-cost browning inhibiting protocol in yam processing, different thermal treatment conditions and color protectants were tested for their color-protecting ability. Color difference ΔE was calculated to evaluate the browning with a colorimeter. To ensure that the color-protecting treatment does not influence the quality of yam, texture properties and nutrition compositions were quantified. The optimal treatment is as follows: deactivate yam in water bath of 60°C for 10 min and then incubate in 2 g/L citric acid and 1 g/L ascorbic acid for 1 hour. The treatment led to significant decrease of the color difference, with no obvious changes in the texture properties and nutrition value. To summarize, this research provides an ideal color-protecting solution in yam processing.

Partial substitution of chemical fertilizer by organic fertilizer increases yield, quality and nitrogen utilization of Dioscorea polystachya.

This field experiment aimed to investigate the effects of different ratios of organic and inorganic fertilizers with maintaining equal nitrogen application rates on the yield, quality, and nitrogen uptake efficiency of Dioscorea polystachya (yam). Six treatments were set, including a control without fertilizer (CK), sole application of chemical fertilizer (CF), sole application of organic fertilizer (OM), 25% organic fertilizer + 75% chemical fertilizer (25%OM + 75%CF), 50% organic fertilizer + 50% chemical fertilizer (50%OM + 50%CF), and 75% organic fertilizer + 25% chemical fertilizer (75%OM + 25%CF). The experiment followed a randomized complete block design with three replications. Various yield parameters, morphology, quality indicators, and nitrogen utilization were analyzed to assess the differences among treatments. The results indicated that all fertilizer treatments significantly increased the yield, morphology, quality indicators, and nitrogen utilization efficiency compared to the control. Specifically, 25%OM + 75%CF achieved the highest yield of 31.96 t hm-2, which was not significantly different from CF (30.18 t hm-2). 25%OM + 75%CF exhibited the highest values at 69.23 cm in tuber length and 75.86% in commodity rate, 3.14% and 1.57% higher than CF respectively. Tuber thickness and fresh weight of 25%OM + 75%CF showed no significant differences from CF, while OM and 50%OM+50%CF exhibited varying degrees of reduction compared to CF. Applying fertilizer significantly enhanced total sugar, starch, crude protein, total amino acid, and ash contents of D. polystachya (except ash content between CK and OM). Applying organic fertilizer increased the total sugar, starch, crude protein, total amino acid, and ash contents in varying degrees when compared with CF. The treatment with 25%OM+75%CF exhibited the highest increases of 6.31%, 3.78%, 18.40%, 29.70%, and 10%, respectively. Nitrogen content in different plant parts followed the sequence of tuber > leaves > stems > aerial stem, with the highest nitrogen accumulation observed in 25%OM + 75%CF treatment. Nitrogen harvest index did not show significant differences among treatments, fluctuating between 0.69 and 0.74. The nitrogen apparent utilization efficiency was highest in 25%OM + 75%CF (9.89%), followed by CF (9.09%), both significantly higher than OM (5.32%) and 50%OM + 50%CF (6.69%). The nitrogen agronomic efficiency varied significantly among treatments, with 25%OM + 75%CF (33.93 kg kg-1) being the highest, followed by CF (29.68 kg kg-1), 50%OM + 50%CF (21.82 kg kg-1), and OM (11.85 kg kg-1). Nitrogen partial factor productivity was highest in 25%OM + 75%CF treatment (76.37 kg kg-1), followed by CF (72.11 kg kg-1), both significantly higher than 50%OM + 50%CF (64.25 kg kg-1) and OM (54.29 kg kg-1), with OM exhibiting significantly lower values compared to other treatments. In conclusion, the combined application of organic and inorganic fertilizers can effectively enhance the yield, quality, and nitrogen utilization efficiency of D. polystachya. Particularly, the treatment with 25% organic fertilizer and 75% chemical fertilizer showed the most promising results.