ABSTRACT
Curcumin is a natural polyphenol that is widely used in food and medicine. Here, we investigated the effects of curcumin on the antioxidant accumulation and enzymatic browning of soybean sprouts after storage at 4 °C for 2 weeks. Curcumin drastically reduced the water loss, browning index, and peroxide accumulation, increased the activities of superoxide dismutase, catalase, and peroxidase, decreased the activities of phenylalanine ammonia-lyase and polyphenol oxidase, elevated the contents of ascorbic acid, reduced glutathione, nonprotein thiol, phenolics and isoflavones, and enhanced the total antioxidant capacity of soybean sprouts during storage. These curcumin-induced changes were partly but dramatically attenuated by inhibition of NADPH oxidase (NOX). Curcumin induced NOX activity and H2O2 burst in soybean sprouts during the first 24 h after treatment. The curcumin-induced antioxidants and -inhibited enzymatic browning are closely associated with NOX-dependent H2O2 signaling. The findings provide a new method for improving soybean sprout quality during storage.
ABSTRACT
Fertilizer application is typically used to increase the availability of essential elements. In this study, an improved method for essential element supplementation based on seed germination was established. Solutions of essential elements (Fe2+, Zn2+, Cu2+, Mn2+, SeO32+, or I- or their combination) were applied to germinating soybean seeds, and the contents of the essential elements in the soybean sprouts were analyzed by atomic absorption spectroscopy. Compared with the control (seeds treated with water), the contents of iron, zinc, copper, manganese, selenium, and iodine in soybean sprouts produced by germinating seeds treated with solutions containing 10 mM essential elements were approximately 10-2000 times higher. Moreover, treatment with essential element solution increased the total antioxidant capacity and content of total thiols in the soybean sprouts. This rapid and simple technique can be used to improve nutrition for humans and livestock in regions deficient in essential elements.
ABSTRACT
Omethoate (OM) is a highly toxic organophophate insecticide, which is resistant to biodegradation in the environment and is widely used for pest control in agriculture. The effect of OM on maize seed germination was evaluated under salt stress. Salt (800mM) greatly reduced germination of maize seed and this could be reversed by OM. Additionally, H2O2 treatment further improved the effect of OM on seed germination. Higher H2O2 content was measured in OM treated seed compared to those with salt stress alone. Dimethylthiourea (DTMU), a specific scavenger of reactive oxygen species (ROS), inhibited the effect of OM on seed germination, as did IMZ (imidazole), an inhibitor of NADPH oxidase. Abscisic acid (ABA) inhibited the effect of OM on seed germination, whereas fluridone, a specific inhibitor of ABA biosynthesis, enhanced the effect of OM. Taken together, these findings suggest a role of ROS and ABA in the promotion of maize seed germination by OM under salt stress.