Hot-air drying is an effective method to enhance the levels of gamma-aminobutyric acid (GABA) in edible tubers/tuberous roots. However, consumers prefer fresh food to processed food. Therefore, this study aims to develop an effective method to increase the GABA levels in the tubers of Chinese yam (CY tubers) and the tubers/tuberous roots of other plants while preserving its original appearance. Among nitrogen treatment (treatment under a nitrogen atmosphere), carbon dioxide (CO) treatment (treatment under a CO atmosphere), vacuum treatment, and water immersion, CO treatment was the most effective GABA-level-increasing method for CY tubers, with water immersion being more effective than nitrogen treatment and vacuum treatment. The GABA level in CY tubers treated with CO for 72 h reached 1.25 ± 0.08 mg/g. CO treatment and water immersion were also effective GABA-level-increasing methods for CY bulbils, potatoes, and lotus tubers, but they were less effective for carrots.

Yam holds the top position in food crop production, and yam is highly prized by Ivorians. However, storage deterioration poses economic challenges for wholesalers and producers. This study assesses yam quality in warehouse storage, considering its geographical origin. To achieve this, yams from the Bondoukou, Bouna, and Kouassi-Kouassikro regions were kept at a warehouse in Abidjan, allowing an assessment of alterations, cooking properties, and organoleptic characteristics over a 3-month storage period. yam tubers were placed on boards at the warehouse's temperature (27.98 °C) and relative humidity (85.61 %). Temperature and humidity levels were recorded three times per week and four times daily at 08:00, 12:00, 16:00, and 20:00. Physical, cooking, and sensory characteristics were checked at harvest and during each month. The results showed that the main damage observed during storage at the warehouse was rotting and dehydration of the tubers. Rot rates were 47.53 % for yams grown in Bondoukou, 51.96 % for those grown in Bouna and 60.65 % for those grown in Kouassi-Kouassikro. Dehydrated tubers rates were 17.88 %, 25.04 % and 29.20 % for yams from Bondoukou, Bouna and Kouassi-Kouassikro, respectively. The browning indices of yams decrease (P < 0.05) during storage, with a much more marked effect for yams grown in Bouna (23.43-18.56) and Bondoukou (24.73-18.11), in contrast to those grown in Kouassi-Kouassikro (26.09-22.96). Hardness also dropped for yams grown in Bouna, Bondoukou and Kouassi-Kouassikro (38.94-25.19 N, 39.39-26.52 N and 35.59-26.66 N respectively). Sensory analysis showed that yams from Bouna stored for three months were rated highest in taste (score = 4). The storage quality of yams was influenced by the cultivation region. Organic production of yams benefits the environment and human health, while increasing shelf life.

Diosgenin is an important steroidal precursor renowned for its diverse medicinal uses. It is predominantly sourced from Dioscorea species, particularly Dioscorea zingiberensis. Dioscorea zingiberensis has an ability to accumulate 2-16% diosgenin in its rhizomes. In this study, a diverse population of 180 D. zingiberensis accessions was used to evaluate the genomic regions associated with diosgenin biosynthesis by the genome wide association study approach (GWAS).

Yam is a significant staple food and starch source, particularly in tropical and subtropical regions, holding the fourth position among the world's top ten tuber crops. Yam tubers are rich in essential nutrients and a diverse range of beneficial plant compounds, which contribute to their multifaceted beneficial functions. Furthermore, the abundant starch and resistant starch (RS) content in yam can fulfil the market demand for RS. The inherent and modified properties of yam starch and RS make them versatile ingredients for a wide range of food products, with the potential to become one of the most cost-effective raw materials in the food industry. In recent years, research on yam RS has experienced progressive expansion. This article provides a comprehensive summary of the latest research findings on yam starch and its RS, elucidating the feasibility of commercial RS production and the technology's impact on the physical and chemical properties of starch. Yam has emerged as a promising reservoir of tuber starch for sustainable RS production, with thermal, chemical, enzymatic and combination treatments proving to be effective manufacturing procedures for RS. The adaptability of yam RS allows for a wide range of food applications.

Amylose, a prebiotic found in yams is known to be beneficial for the gut microflora and is particularly advantageous for diabetic patients' diet. However, the genetic machinery underlying amylose production remains elusive. A comprehensive characterization of the genetic basis of amylose content in yam tubers is a prerequisite for accelerating the genetic engineering of yams with respect to amylose content variation.

This study investigated the impact of ultrasound treatment on dioscorin, the primary storage protein found in yam tubers. Three key factors, namely ultrasound power, duration, and frequency, were focused on. The research revealed that ultrasound-induced cavitation effects disrupted non-covalent bonds, resulting in a reduction in α-helix and β-sheet contents, decreased thermal stability, and a decrease in the apparent hydrodynamic diameter (Dh) of dioscorin. Additionally, previously hidden amino acid groups within the molecule became exposed on its surface, resulting in increased surface hydrophobicity (Ho) and zeta-potential. Under specific ultrasound conditions (200 W, 25 kHz, 30 min), Dh decreased while Ho increased, facilitating the adsorption of dioscorin molecules onto the oil-water interface. Molecular dynamics (MD) simulations showed that at lower frequencies and pressures, the structural flexibility of dioscorin's main chain atoms increased, leading to more significant fluctuations between amino acid residues. This transformation improved dioscorin's emulsifying properties and its oil-water interface affinity.

Wencheng waxy yam is famous for its glutinous and resilient taste, similar to waxy rice, but there is currently a lack of systematic research on the quality of this featured product, and little is known about its pesticide residues. We carried out a 2 year investigation of Wencheng waxy yam at seven sites from 2021 to 2022 to determine the oxidase content and phytochemical characteristics, namely, amylose, amylopectin, protein, reducing sugar, and mineral contents, such as K, Fe, and Zn, including the status of pesticide residues. The results showed that the oxidase content was affected by rainfall, and adequate water reduced the production of oxidase, including polyphenol oxidase, peroxidase, and superoxide dismutase, during the late growth stage of waxy yam, which was beneficial for reducing browning in yam processing. Radar map analysis showed that, with comprehensive evaluation, standardized production sites 1 and 2 had a relatively higher quality than 3-7 with small farmers. The results of pesticide multiresidue testing showed that no pesticides were detected in 64.29% of the samples, and the detected residues in the samples were very low, making the consumption of yam safe for consumers. These findings could be beneficial for the exploitation of the health benefits of waxy yam tubers and the innovation of yam-based functional products.

Dioscorea polystachya (Chinese yam) is a kind of medicine and food homologous crop, the tubers as its main production organ, with high potassium, low fiber, high protein and rich nutrition characteristics. In 2022, at the Chinese herbal medicine planting experimental site in Anguo, Baoding City, Hebei Province, China, we found the symptoms of Chinese yam decay during the storage, with an incidence of 15%~25%. The diseased part of Chinese yam tuber rots expands from the outside to the inside and sags, with a brown or dark brown discoloration, and the surface covered with a thick grayish green mold. The diseased tissue was first rinsed with clean water to remove dirts from the surface. Thereafter, 3 to 4 mm Chinese yam pieces were picked from rotting edge with a sterilized forceps, sterilized with 75% alcohol for 30 s followed by 0.1% mercuric chloride solution for 1min, and then rinsed three times with sterile water. The sterilized pieces were cultured on potato dextrose agar (PDA). One isolated fungus was obtained, and conidia were observed after incubation for 5 days at 26°C. Pure cultures were isolated by single-spore isolation. Conidia were single spore, round or oval, colorless. Conidiophores produce several rounds of symmetric or asymmetric small stems after multiple branches, which were shaped like brooms. The length and width of 100 conidia were measured, and size ranged from 3 to 4×3 to 4 μm. On the basis of morphological characteristics, the isolate was identified as Penicillium spp. (Uy et al. 2022). To further assess the identity of isolated species, the genomic DNA of the fungal isolate (SYRF1) was extracted by CTAB protocol. The ribosomal DNA internal transcribed spacer (ITS) region and the ribosomal large subunit (LSU) were amplified and sequenced with primers ITS1/4, LR5/LROR respectively (White et al. 1990, Xu et al. 2010). The obtained ITS-rDNA region and LSU sequences (GenBank accession OQ707937 and OQ704185) of the isolate were more than 99% identity to the corresponding sequences of Penicillium cellarum in GenBank (KM249068 and MG714818). Phylogenetic results based on a maximum-likelihood analysis revealed that SYRF1 was grouped with P. cellarum. To determine the pathogenicity of the isolated fungi, tests were carried out by aseptic inoculation of fresh and healthy tubers. Before the experiment, the healthy tubers were washed, surface disinfected and dried. The tubers were then wounded with sterile inoculation needles, and the conidium-bearing hyphal discs (5 mm) were inoculated on the surface of the wounded tubers and covered with wet sterile cotton. Three tubers were inoculated repeatedly each time as the experimental group. Inoculate sterile PDA with three tubers as the control group. Each tuber was inoculated with four mycelium disks, and the pathogenicity test was repeated four times. The inoculated tubers were incubated at 26°C for 14 days with sterile PDA as control. After ten days, the inoculated points showed symptoms similar to those of the initial infection, whereas controls remained symptomless. The reisolated fungus matched SYRF1 based on morphological and sequence analyses, thereby fulfilling Koch's postulates. To the best of our knowledge, this is the first report of Penicillium cellarum as causative agent of postharvest rot of Chinese yam tubers in China. This finding will help inform the prevention and management of postharvest diseases of Chinese yam tubers.

Assessment of the key preferred quality traits in pounded yam, a popularly consumed yam food product in West Africa, is often done through sensory evaluation. Such assessment is time-consuming and results may be biased. Therefore, there is a need to develop objective, high-throughput methods to predict the quality of consumer-preferred traits in pounded yam. This study focused on how key quality traits in pounded yam proposed to yam breeders were determined, measured by biophysical and biochemical methods, in order to shorten the breeding selection cycle through adoption of these methods by breeders.

Wounds on Chinese yam (Dioscorea opposita ) tubers can ocurr during harvest and handling, and rapid suberisation of the wound is required to prevent pathogenic infection and desiccation. However, little is known about the causal relationship among suberin deposition, relevant gene expressions and endogenous phytohormones levels in response to wounding. In this study, the effect of wounding on phytohormones levels and the expression profiles of specific genes involved in wound-induced suberisation were determined. Wounding rapidly increased the expression levels of genes, including PAL , C4H , 4CL , POD , KCSs , FARs , CYP86A1 , CYP86B1 , GPATs , ABCGs and GELPs , which likely involved in the biosynthesis, transport and polymerisation of suberin monomers, ultimately leading to suberin deposition. Wounding induced phenolics biosynthesis and being polymerised into suberin poly(phenolics) (SPP) in advance of suberin poly(aliphatics) (SPA) accumulation. Specifically, rapid expression of genes (e.g. PAL , C4H , 4CL , POD ) associated with the biosynthesis and polymerisation of phenolics, in consistent with SPP accumulation 3days after wounding, followed by the massive accumulation of SPA and relevant gene expressions (e.g. KCSs , FARs , CYP86A1 /B1 , GPATs , ABCGs , GELPs ). Additionally, wound-induced abscisic acid (ABA) and jasmonic acid (JA) consistently correlated with suberin deposition and relevant gene expressions indicating that they might play a central role in regulating wound suberisation in yam tubers.