Green onions enhance flavor and offer nutritional value. To save preparation time, many people pre-chop a large quantity and freeze them for later use.

Nutritionist Lao Gu from Taiwan, China, explained that green onions belong to the Allium genus, which is related to garlic, onions, and chives. These vegetables are rich in organosulfur compounds. Meta-analysis studies indicate that increased consumption of Allium vegetables may reduce the risk of certain cardiovascular diseases and cancers. However, individuals should maintain a balanced diet and not consider green onions a standalone "miracle cure".

Delving into the mechanism of aroma, Lao Gu shared that when green onions are chopped, cells break, activating enzymes that immediately produce pungent sulfur compounds – this is the characteristic "onion aroma".

However, after undergoing freezing, some of these volatile sulfur compounds gradually decrease. Simultaneously, the levels of certain aldehydes, such as hexanal, increase, shifting the aroma from a "fresh flavor" to a bland or even cooked vegetable smell. Additionally, ice crystals damage cells, allowing aroma molecules to escape more easily, preventing frozen green onions from retaining the pungency of freshly chopped ones.

Dry green onions stored in the freezer will not clump, retain their green color, but lose their characteristic aroma. *Aboluowang*

From a culinary perspective, Lao Gu suggests that frozen chopped green onions are acceptable for stir-fries or soups. However, when used as a final garnish for dishes like tofu, noodles, or braised pork rice, diners will distinctly notice the absence of a fresh aroma.

Nutritionally, freezing primarily affects flavor and does not equate to significant nutrient loss. Components like fiber and minerals in green onions are largely preserved. The main difference lies in the taste experience.

"Frozen chopped green onions will indeed be much less aromatic, so it's best not to put green onions in the freezer", Lao Gu emphasized.

My Y (According to Yahoo TW)