The nutritional value of goji berries is abundant, making it a versatile food with both medicinal and dietary uses. There are various ways to consume goji berries and they have a wide range of applications. However, the effects of goji berries can vary depending on the quality. Here, we will teach you how to distinguish the quality of goji berries.
1. Distinguishing by color
1. Distinguishing by color
Fresh goji berries have different colors depending on their origin, but the color is soft and glossy, with plump flesh. Dyed goji berries are usually old stock from previous years, and they have poor flesh quality, lack glossiness, but have a bright and attractive appearance. Therefore, when buying goji berries, do not be deceived by the color. It is recommended to choose goji berries from the first harvest of the summer. Especially for dyed goji berries, the whole berry is red, including the small white spot at the stem end, while normal goji berries have a yellow or white color at the tip of the berry, and the dyed goji berries have a red color at the tip. It is recommended to put a dozen goji berries into water when purchasing. If they do not discolor, it means they are sulfur fumigated goji berries because sulfur is not soluble in water. If red color appears, it means colorants have been used. The normal color is orange-yellow (pale yellow) with a small amount of floating flocculent material.
2. Distinguishing by shape
Goji berries from Ningxia, China, have small white spots at the tips, which are absent in goji berries from other regions. When placed in water, goji berries from Ningxia will float, whether used for making tea or soup. Goji berries from Qinghai and Inner Mongolia are oval, but goji berries from Ningxia will float when soaked in water, while goji berries from Qinghai and Inner Mongolia will sink. Goji berries from Xinjiang, on the other hand, are round and easy to distinguish.
3. Distinguishing by smell
For goji berries that have been fumigated with sulfur, simply hold a handful and cover it with both hands for a while, then smell it. If you can smell a pungent odor, it means it has been fumigated with sulfur.
4. Distinguishing by taste
Goji berries from Ningxia are sweet, but they leave a slight bitterness in the throat after eating. Goji berries from Inner Mongolia, Xinjiang, and other regions are overly sweet and can be slightly greasy. Goji berries soaked in alum will have a bitter taste of alum when chewed, while goji berries treated with sulfur will have a sour, astringent, and bitter taste.
Medicinal identification
1. Identification by characteristics
Goji berries (Lycium barbarum) are the dried mature fruit of the goji plant. They are oval or spindle-shaped, slightly flattened, 1.5-2 cm long, and 4-8 mm in diameter. The surface is bright red to dark red with irregular wrinkles and a slight gloss. One end has a white stem mark. The flesh is soft and moist, with many yellow seeds, flattened and kidney-shaped. It has no odor but tastes sweet, with a red-yellow color when chewed. The best goji berries are large, fleshy, with few seeds, red in color, and soft in texture. They are mainly produced in Ningxia, with Zhongning in Ningxia being the best, so they are called Zhongning goji berries or Ningxia goji berries.
Goji berries (Lycium chinense) are also known as "Jinxiue" or "Duzi". They are the dried mature fruit of the goji plant. They are oval or cylindrical, slightly pointed at both ends, 1-1.5 cm long, and 3-5 mm in diameter. The surface is bright red or dark red with irregular wrinkles and no gloss. The flesh is soft and slightly moist, with many seeds, similar in shape to the previous type. It has no odor but tastes sweet. The best ones are large, fleshy, with few seeds, red in color, and soft in texture. Small, thin, grayish-red ones are of lower quality. They are mainly produced in Hebei, but also in Henan, Shaanxi, Sichuan, Shanxi, Jiangsu, and other regions. In addition to the above varieties, there are also "Ganzhouzi" produced in Gansu, which are the fruits of Lycium turcomanicum Turcz. and Lycium potaninii Pojark., and "Guchengzi" produced in Xinjiang, which are the fruits of Lycium dasy stemum Pojark. These are also used as goji berries in their local areas. The dried fruits are elongated or ovoid, 6-9 mm long, and 2-4 mm in diameter. The surface is dark red with irregular wrinkles and no gloss. The flesh is slightly soft, with many seeds. It has no odor but tastes sweet and sour.
2. Microscopic identification
Cross-section of the fruit peel: The outer fruit peel has 1 layer of cells, with slightly thickened, non-lignified or slightly lignified walls, and a horny layer on the outer surface, with irregular fine tooth-like edges. The middle fruit peel has about 10 layers of cells, with the outermost layer of cells slightly elongated, and the cells below it are round, elongated, or rectangular, gradually increasing in size towards the inside, with some cells smaller on the innermost side and slightly thickened walls. The cells contain numerous orange-red pigment particles, some of which contain calcium oxalate sand crystals. The vascular bundle is double-flanged, mostly scattered, with small ducts. The inner fruit peel has 1 layer of cells, with thickened cell walls all around, and lignification.
Powder characteristics: Yellow-orange or dark red. ① Seed coat stone cells: Irregular polygonal or elongated polygonal on the surface, with deep wavy or slightly wavy walls, with a diameter of 37-117 μm, up to 196 μm in length, and a wall thickness of 5-27 μm. The cross-section is square or flattened square, with thickened side walls and inner walls slightly curved, and the outer walls are mucified. ② Outer fruit peel cells: Polygonal or elongated polygonal on the surface, with fine wavy or straight walls, and fine parallel keratin stripes on the outer flat surface. ③ Middle fruit peel thin-walled cells: Polygonal, with orange-red or reddish-brown pigment particles in the cell cavity, some containing calcium oxalate sand crystals. There are also endosperm cells containing lipid droplets and starch granules.
3. Physical and chemical identification
Thin-layer chromatography:
Sample solution: Take 1g of crushed goji berries, add 5ml of chloroform, soak for 24 hours, filter, and concentrate the filtrate to 1ml as the test solution.
Reference solution: Take Sudan Yellow chloroform solution as the reference.
Development: Spot 2μl of each sample on a silica gel G-cmC plate and develop it with petroleum ether-acetic ether-methanol (9:1:0.5) for 10cm.
Visualization: Under natural light, Ningxia goji berries show 11 yellow spots, one of which corresponds to the reference solution. Under UV light, the original spot shows blue and yellow fluorescent spots.
