Basic Introduction to Hui'an Olive Fruit
The Olive fruit, also known as the ox gall fruit, is named “yugan” due to its characteristic of tasting bitter before turning sweet. Hui'an yugan, also known as oil gall and yuganzi, is a specialty of Quanzhou City, Fujian Province, primarily produced in villages such as Lantian Village and Guanxi Village in Zishan Town, Hui'an County, Fujian Province. Hui'an yugan received national agricultural product geographical indication protection registration in 2019. The protected area includes 123 administrative villages (communities) across six towns in Hui'an County, Quanzhou City, Fujian Province: Zishan Town, Huangtang Town, Wanchuan Town, Luocheng Town, Luoyang Town, and Tuzhai Town. The geographical coordinates are from 118°39′02″ to 118°52′19″ east longitude and from 24°56′34″ to 25°07′51″ north latitude.
In southern Fujian, people refer to candied haws on a stick as “yuganzi.” The sweetness of the sugar perfectly balances out the sourness of the yugan, making it an unforgettable childhood delicacy for generations of southerners. The main terrain in the production area of Hui'an yugan is low mountains and hills, with soil mainly consisting of brick-red red soil and yellow soil, which is slightly acidic and very suitable for the growth and cultivation of yugan. The climate is characterized by a subtropical maritime monsoon climate, without extreme heat or cold, abundant sunlight, and concentrated rainfall. The average annual temperature is 20°C, which meets the climatic requirements of yugan, which prefers mild winters and no scorching summers. Sufficient sunlight ensures robust growth of branches and leaves, good flower bud differentiation, high yield, excellent coloring, and high vitamin C content, resulting in large and sweet Hui'an yugan. There are more than 32 varieties of yugan cultivated over 30,000 mu, producing over 60,000 tons of fresh fruit annually, with an additional 5,000 mu of wild yugan. The produced yugan has been recognized as a “famous, special, superior, and rare fruit,” and was granted national agricultural product geographical indication protection on September 4, 2019.
Nutritional Value
It is rich in vitamins C, E, B, various trace elements, and minerals. It also contains 14 amino acids required by the human body, superoxide dismutase (SOD), and abundant organic selenium, especially vitamin C, with 500-1841 milligrams per 100 grams of fresh yugan fruit, four times higher than kiwifruit, known as the king of vitamins, and 25 times higher than citrus fruits.
Product Characteristics
Hui'an yugan has a flat round shape, greenish-white color, rough surface with tiny wart-like protrusions, and a circular scar at the base where the stem used to be. The fruit is hard to the touch. The flesh is yellowish-white, thick, juicy, with few fibers, initially tastes sour, but then leaves a refreshing sweet aftertaste.
The solid-to-acid ratio of Hui'an yugan is 8.07, with starch content reaching 2.29%, 261 mg of vitamin C, 8.68 mg of iron, and 152 mg of potassium per 100g, earning it the title of “king of vitamin C.”
Historical Folklore
The ox gall fruit is revered as a sacred fruit in India. During the Ming Dynasty, Emperor Zhengde tasted the fruit of a yugan tree in Nantian, Hui'an, and bestowed upon it the title of “Emperor's Sweet.” This particular yugan tree is over 630 years old. Although it was split in half by lightning during the Qing Dynasty, it remains lush and continues to bear fruit every year. This tree has been designated as a key cultural relic under state protection, attracting a steady stream of visitors who consider it a national treasure. In southern Fujian folklore, there is a saying: “The sweet aftertaste of yugan makes one feel younger with each bite,” and a folk song that goes, “After eating yugan, one experiences a sweet aftertaste; even the elderly become youthful again.”
Awards and Honors for Hui'an Yugan
July 16, 2019 – Received public notice of registration as a national agricultural product geographical indication by the People's Republic of China;
September 4, 2019 – Approved as a protected national agricultural product geographical indication according to Announcement No. 213 of the Ministry of Agriculture and Rural Affairs of the People's Republic of China;
December 28, 2019 – Registered as a national geographical indication trademark;
April 2021 – Included in the first batch of national list of distinctive, high-quality, and new agricultural products for 2021;
Tasting and Preparation Methods
Eating them raw is best, although they can be quite bitter and astringent, so they are often pickled before consumption, making them easier to eat. They can also be made into vinegar or dried fruit.
Pickling Method: First, wash the fruit thoroughly. Then sprinkle salt over the fruit until it is lightly coated. Next, immerse the fruit in a mixture of rice wine and vinegar, placing them in an opaque container. Ensure the liquid covers the fruit by about 1 centimeter. Allow the fruit to soak for at least one month until they turn brownish-yellow when the container is opened again.