Umeboshi

These potent Japanese sour pickled plums resemble wizened apricots and are eaten as a snack or as part of onigiri (rice balls with nori) for breakfast or lunch. After picking, they are packed in salt and weighted down to press out the liquid. They possess a very high level of citric acid and are purported to have many health benefits, such as warding off colds, stopping ageing and curing hangovers. You can use the mashed paste to make delicious dressings, sauces and glazes for meat. Buy umeboshi plums as a paste in jars or the whole plums. The latter cost a bit more, but are better quality and have a sweeter taste.