Chapters authored
An Overview of the Effects of Heat Treatments on the Quality of Organic Wastes as a Nitrogen Fertilizer
Sewage sludge is often heat-dried to eliminate water and pathogens. However, heat-drying can also change the form of nitrogen (N). To improve our understanding of this phenomenon, we examined the heat-induced changes in the rate of N mineralization from soils and organic wastes. Published results revealed that the response to the heating temperature differed between soils and organic wastes. As the heating temperature increased to 200°C, the rate of N mineralization increased in soils but decreased in organic wastes. In organic wastes such as sewage sludge, the content of mineralized N tended to decrease sharply when heating temperatures increased to 150–200°C. Furthermore, our results obtained from heat-drying of sewage sludge at 180°C indicated that the rate of carbon (C) mineralization decreased with increasing heating period after the sludge temperature reached 180°C. The C in sewage sludge heated at 180°C for 120 hours after complete drying contained more humin and aromatic C than that in sludge that was heat-dried at 180°C without the additional heating period. These results suggest that the heat-drying treatment can be divided into the drying and denaturing periods and that the temperature of the sludge, not that of the reactor, affects the quality of the end-product.
Part of the book: Nitrogen in Agriculture
Anthocyanins in Apple Fruit and Their Regulation for Health Benefits
In most industrialized countries, cancer and cardiovascular disease have been linked to lifestyle choices, the most important of which is diet. Antioxidants show protective effects against both of these diseases. Anthocyanins contribute greatly to the antioxidant properties of certain colorful foods, such as apples. Apples are rich in anthocyanins in the peel, followed by the whole fruit and then the flesh. From a nutritional point of view, therefore, regular consumption of apples with peel is recommended to enhance the dietary intake of antioxidant compounds. The anthocyanin concentration of apple peel changes according to internal plant conditions (e.g., fruit maturity and plant hormones), environmental factors (e.g., light, temperature, and nutrients), and the cultivar. The combination of cultivar variation and responsiveness to specific environmental conditions could create opportunities for the production and processing of apples with improved anthocyanins and antioxidant properties.
Part of the book: Flavonoids