Acorns

Acorns

　　Acorns are the fruit of oak trees and are commonly found in the mountainous regions of eastern Hubei. They resemble silkworm cocoons, hence they are also called "chestnut cocoons." Acorns have a hard, reddish-brown outer shell, and their inner kernels resemble peanut kernels, containing abundant starch. In his time of poverty, Du Fu often relied on them for sustenance.

　　Acorns are edible. However, some acorns naturally contain high levels of tannic acid, making them bitter, astringent, and potentially irritating if consumed raw. This is especially true for dark-colored acorns from red oaks. Light-colored acorns from white oaks contain lower levels of tannic acid, are naturally sweeter, and may be eaten either raw or after being processed or cooked. The basic cooking technique involves boiling mature acorns for several hours, often changing the water multiple times. During this process, the tannic acid is leached out. After boiling, acorns can be eaten directly; they can also be roasted, baked, or ground into flour. Acorn flour develops a slightly nutty flavor if the acorns are lightly roasted before grinding. Rich in oils, acorn flour can easily go rancid or spoil and must be stored carefully. Acorns are sometimes also prepared as a coffee substitute.

　　Acorns are calorie-dense, providing 510 kcal per 100 grams. Their composition is 6% water, 54% carbohydrates, 8% protein, and 32% fat, primarily monounsaturated. Acorns are also rich in calcium, phosphorus, potassium, and niacin.