Here's an entry from my Malay dictionary suggesting that the Malay equivalent of 'ripe' (and also 'ripen') is masak:Er ... no; masak means 'cook', and the Malay for 'ripe' is matang.
This seems to be a simple error; and note that, in the illustrative sentence, mematangkan (with matang as its root) is used for 'ripen', confirming that matang is the correct equivalent for 'ripe(n)'.
There is a tendency for many people to believe that a dictionary is the ultimate authority, so if something is printed in one, it must be correct. But this example illustrates that dictionaries have errors, just like all other books. You shouldn't believe that something is necessarily true simply because it is printed.
Just one further observation about this: matang can mean 'ripe' or 'mature'; so we can say that the Malay word has a broader meaning than 'ripe'. In linguistic terms, we can say that matang is a superordinate term while the two English words 'ripe' and 'mature' are its hyponyms. If you are translating from Malay into English, you need to be careful which English word to choose.