Answer:
I don't see any word in bold, however, I will tell you the part of speech of each word of the sentence you have provided and according to its context.
Explanation:
So we have nouns, which are: things. As you can see, we have three things in this sentence: Orange juice, its concentrate --although concentrate could be a verb too but in this context is referring to the extract of the juice-- we also have the freezer as an object. Verbs are actions we do, for instance: I Jump, you jump, we jump, etc... in this sentence we have two: Can and be, although can is modal which means are not like regular verbs as what they do is to add meaning to the main verb by expressing possibility.
We also have an adjective which is a words that describes a thing or person, in this context it is being described with a possibility (the modal verb) the juice as "stored". We have a preposition of place: where is the juice? In the freezer; and, the definite article the, which is used to indicate the reader the identitity of the noun.
