Lemon juice is the extraction of the juice from a lemon. Lemon trees are native to Asia, where they have been cultivated for their sour fruit in ancient times. They were brought to Ancient Rome sometime around the first year AD. The sour taste of lemon juice is from its high citric acid content; for this reason, lemon juice was historically used as a preservative! Lemons have also been used as an effective cleaning source due to their high essential oil content (but that is more about the oil in the rind than in the juice).
Lemon juice does a lot more than add some pizzazz to dishes; it also has some great nutrition. Specifically, fresh lemon juice is very high in vitamin C. It’s important to note that the vitamin C content disintegrates upon exposure to air, so using lemons fresh is totally essential!
I encourage you to get fresh lemons at your local grocery store. But, to help with the juicing, you could pick up a hand juicer or automated juicer on Amazon!