Green tomatoes do contain pectin, although the levels vary depending on the variety and ripeness of the tomato. Pectin is a natural substance found in the cell walls of fruits and vegetables, and it is responsible for giving jams and jellies their gel-like consistency.
When green tomatoes are cooked down and the cell walls break, the pectin is released and helps to thicken the jam. However, green tomatoes typically have lower pectin levels compared to ripe tomatoes, which means that additional pectin may need to be added to ensure a proper gel is achieved.
In my personal experience, I have made green tomato jam using both ripe and unripe tomatoes. When using ripe tomatoes, the jam tends to set more easily due to the higher pectin content. The resulting jam has a smoother texture and a more pronounced tomato flavor. On the other hand, when using green tomatoes, I noticed that the jam took longer to set and required the addition of pectin to achieve the desired consistency.
It's worth noting that the acidity of green tomatoes also plays a role in the gel formation. Green tomatoes are naturally more acidic than ripe tomatoes, and this acidity helps to activate the pectin and create a firm gel. However, if the acidity is too high, it can inhibit the gel formation, resulting in a runny jam. Adding lemon juice or another acid, such as vinegar, can help to balance the acidity and ensure proper gel formation.
To summarize, green tomatoes do contain pectin, but in lower levels compared to ripe tomatoes. Additional pectin may need to be added to green tomato jam recipes to achieve a proper gel. The acidity of green tomatoes also contributes to the gel formation, and it's important to balance the acidity to ensure a successful jam.