Is the percentage of oxalic acid increases as guava ripeness?

Yes, the percentage of oxalic acid tends to increase as guava ripens. During the ripening process, the fruit undergoes various biochemical changes, including an increase in organic acids like oxalic acid. This change can affect the fruit's taste and nutritional profile. Ultimately, while ripening enhances sweetness, it can also lead to higher levels of certain acids, including oxalic acid.