Savoy cabbage and unusual seasonings such as juniper. Signs of desirable quality include cabbage that is heavy for its size with leaves that are unblemished and have a bright, fresh look. Peak season for most cabbages in the Northern Hemisphere runs from November through April. Fresh whole cabbage will keep in the refrigerator for one to six weeks depending on type and variety. Hard green, white or red cabbages will keep the longest while the looser Savoy and Chinese varieties such as napa and bok choy need to be consumed more quickly. It is necessary to keep the outer leaves intact without
Vegetable oils as alternative energy Vegetable oils as alternative energy Vegetable oils are increasingly used as a substitute for fossil fuels. Vegetable oils are the basis of biodiesel, which can be used like conventional diesel. Some vegetable oil blends are used in unmodified vehicles, but straight vegetable oil needs specially prepared vehicles which have a method of heating the oil to reduce its viscosity and surface tension. Another alternative is vegetable oil refining. The availability of biodiesel around the world is increasing, although still tiny compared to conventional fossil fuel sources. There is significant research in algaculture methods to make biofuel from algae. Concerns have