Cadmium (Cd) is one of the most injurious heavy metals, affecting plant growth and development. Melatonin (N-acetyl-5-methoxytryptamine) was discovered in plants in 1995, and it is since known to act as a multifunctional molecule to alleviate abiotic and biotic stresses, especially Cd stress. Endogenously triggered or exogenously applied melatonin re-establishes the redox homeostasis by the improvement of the antioxidant defense system. It can also affect the Cd transportation and sequestration by regulating the transcripts of genes related to the major metal transport system, as well as the increase in glutathione (GSH) and phytochelatins (PCs). Melatonin activates several downstream signals, such as nitric oxide (NO), hydrogen peroxide (H2O2), and salicylic acid (SA), which are required for plant Cd tolerance. Similar to the physiological functions of NO, hydrogen sulfide (H2S) is also involved in the abiotic stress-related processes in plants. Moreover, exogenous melatonin induces H2S generation in plants under salinity or heat stress. However, the involvement of H2S action in melatonin-induced Cd tolerance is still largely unknown. In this review, we summarize the progresses in various physiological and molecular mechanisms regulated by melatonin in plants under Cd stress. The complex interactions between melatonin and H2S in acquisition of Cd stress tolerance are also discussed.

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DNJ, an inhibitor of α-glucosidase, is used to suppress the elevation of postprandial hyperglycemia. In this study, we focus on screening an appropriate microorganism for performing fermentation to improve DNJ content in mulberry leaf. Results showed that Ganoderma lucidum was selected from 8 species and shown to be the most effective in improvement of DNJ production from mulberry leaves through fermentation. Based on single factor and three factor influence level tests by following the Plackett-Burman design, the optimum extraction yield was analyzed by response surface methodology (RSM). The extracted DNJ was determined by reverse-phase high performance liquid chromatograph equipped with fluorescence detector (HPLC-FD). The results of RSM showed that the optimal condition for mulberry fermentation was defined as pH 6.97, potassium nitrate content 0.81% and inoculums volume 2 mL. The extraction efficiency reached to 0.548% in maximum which is 2.74 fold of those in mulberry leaf.

The fresh Chinese hickory nuts (Carya cathayensis sarg.) were exposed to airborne ultrasound‐assisted convective drying and microwave‐assisted convective drying, as well as their combination. We investigated the effect of different drying schemes on process kinetics and quality characteristics. The global model of drying kinetics based on coupled ordinary differential equations was used to describe the moisture and material temperature profiles during drying. Application of ultrasound and microwave in convective drying reduced drying time in the range of 14.0–56.6%, but the maximum savings was found for simultaneous exposure of convection, ultrasound, and microwave with the range of 73.6–84.2%. The globally mathematical model was successfully used to simulate the real drying kinetics processes. The quality properties about the content of heat‐sensitive bioactive substances such as phenolic, flavonoid, proanthocyanidin, individual phenolic compounds, as well as antioxidant capacity in convective drying assisted with microwave (100 W) and ultrasound (200 W; CU2M1) are found to be significantly higher than the other groups. The results allow stating ultrasound increase drying efficiency, as expected by reducing the drying time there is less damage to the product. Practical Application In this work, we designed an experimental scale hybrid dryer that equipped with hot‐air convective drying, ultrasound generator and microwave drying system to dehydrate Chinese hickory nut and the effect of different drying schemes on the drying kinetics and product characteristics were investigated. This is an innovative technology of microwave and ultrasound hybrid drying to produce dried hickory products. Application of ultrasound and microwave in convective drying reduced drying time in the range of 14–56.6%, but the shortest drying time was observed for simultaneous action of convection, ultrasound, and microwave. The results of qualitative analysis showed a product improvement due to ultrasound as compared to convective drying and microwave‐convective drying.

In this work, red quinoa was successively subjected to α‐amylase steaming, complex enzyme Viscozyme (R) L hydrolysis, and lactic acid bacteria (LAB) fermentation. The total phenolic compound content (TPC), flavonoid content (TFC), and antioxidant capacities of the solvent‐extractable (free) and bound fractions and the individual phenolic compounds released were determined. Compared to steaming with α‐amylase, enzymatic hydrolysis and fermentation of quinoa resulted in approximately 82.6, 26.9, 36.3, and 45.2% increases in the TPC (the sum of free and bound fractions), TFC, DPPH, and ORAC values, respectively. HPLC‐QqQ‐MS/MS analysis showed that enzymolysis and fermentation increased the content of protocatechuic acid, catechin, procyanidin B2, and quercetin by 126.3, 101.9, 524, and 296.3%, respectively. Moreover, a major proportion of individual phenolic compounds existed as bound form. The results indicated that complex enzymatic hydrolysis and LAB fermentation were practical and useful to release promising polyphenols. This research provides a basis for the processing of quinoa beverages rich in phenolic compounds. Practical Application In this work, liquefying with α‐amylase, hydrolyzing with cellulolytic enzyme mixture, and fermenting with Lactic acid bacteria (LAB), successively, were exploited to process quinoa. This is an innovative method of quinoa processing to produce beverage products. Complex enzymatic hydrolysis and fermentation with LAB can significantly enhance phenolic compound, especially protocatechuic acid, catechin, procyanidin B2, and quercetin. In additional, LAB fermentation is very beneficial to improve the antioxidant activity of quinoa. We also found that a major proportion of phenolic compounds existed as bound forms in quinoa.