Special planning of the “Health from Food” series | Why do we “pick walnuts during White Dew and pick persimmons during Frost Descent”?

There are many folk proverbs related to the 24 solar terms, such as "Pick walnuts in Bailu and pick persimmons in Shuangjiang", which means that during the Bailu season, walnuts are in season; during the Shuangjiang season, persimmons are at their best ripening period and need to be picked in time. So why do we "pick walnuts in Bailu and pick persimmons in Shuangjiang"?

White Dew Walnuts

Bailu is the fifteenth solar term of the twenty-four solar terms and the third solar term in autumn. It is an important season that reflects the temperature changes in nature and is also the time when walnuts mature. As the proverb "Bailu Bailu, walnuts burst their bellies", when walnuts grow to Bailu, their skin turns from green to yellow, and the top of the skin of some walnuts will crack. The walnut kernels are full and fragrant, and it is the right time to harvest. Walnuts were originally called walnuts, also known as longevity seeds and longevity fruits. Walnuts have the effects of strengthening the stomach, replenishing blood, nourishing the spirit, moistening dryness and reducing phlegm. During the Bailu season, the climate is mostly dry, with little precipitation, a large temperature difference between day and night, and low air humidity. Therefore, during the Bailu season, we should pay attention to strengthening the spleen and moistening dryness, promoting lung function and reducing phlegm, nourishing yin and replenishing qi, and it is advisable to eat warm and nourishing things, such as walnuts, so this is the reason for hitting walnuts during Bailu.

Picking persimmons during frost season

Frost is the eighteenth solar term of the twenty-four solar terms and the last solar term of autumn. As the saying goes, "Pick persimmons in Frost, pick soft dates in Beginning of Winter, don't pick persimmons in Frost, hard persimmons turn into soft persimmons". Before and after Frost is the season when persimmons are ripe. After being hit by frost, the nutrients of persimmons are precipitated and converted into sugar content. They taste sweet, less astringent, and have higher nutritional value, which is deeply loved by people. During the Frost season, the weather will turn from cool to cold, the temperature difference between day and night will change greatly, and autumn dryness will be obvious. You should pay attention to keeping warm, preventing autumn dryness, strengthening the spleen and stomach, and eating a balanced diet. You can eat more persimmons, autumn pears, duck meat, etc. Therefore, picking persimmons during Frost has become a custom in many regions.

As the seasons change, the diet also changes. Whether it is walnuts harvested in the White Dew season or persimmons picked in the Frost Descent season, there is a certain reason. The Yellow Emperor's Classic of Internal Medicine records that "eat according to the season". Therefore, in autumn, we should moisturize, nourish yin and drink more water, eat less spicy food and more sour food, and go to bed and get up early to relieve autumn fatigue.

Author: Huang Mingyue, Henan University of Science and Technology

Review expert: Wang Yao, associate professor of the School of Food and Bioengineering, Henan University of Science and Technology