What is the color of unripe blueberries

Immature blueberries usually appear blue-green or light red, and gradually turn into deep blue or purple black as they mature. The color change of blueberries is related to the accumulation of anthocyanins, with chlorophyll dominating during immaturity and anthocyanin content significantly increasing after maturity. The blueberry peel in the blue-green stage contains a large amount of chlorophyll, and the fruit is sour, hard, and has a lower sugar content. The seeds inside the fruit have not fully matured, and antioxidant substances such as anthocyanins and polyphenolic compounds have not reached their peak. Blueberries at this stage are not suitable for fresh consumption, but can be used to make jam or baked goods. Heating and processing can reduce the astringency caused by tannins. During the light red transition period, blueberries begin to synthesize small amounts of anthocyanins, and red purple spots appear on the skin. At this point, the acidity of the fruit slightly decreases, but the sweetness is still not obvious, and the texture of the flesh is still relatively hard. Some early maturing varieties may be harvested in advance for long-distance transportation at this stage, but there is a certain gap in nutritional value compared to fully ripe fruits. If blueberries are found to have an uneven red green color pattern, they usually need to be left to mature naturally for a few more days. During the ripening process of blueberries, direct sunlight or high temperature environments should be avoided. Storing them in a ventilated area at room temperature can promote uniform coloring. When purchasing, the freshness can be judged by the completeness of the fruit powder, and the surface white frost is a natural wax layer that has a protective effect. Patients with diabetes can choose immature blueberries with slightly sour taste, whose glycemic index is relatively low, but those with weak gastrointestinal function should be careful to eat immature fruits.