MongoDB: Nested values vs separate collections for search performance - DB schema design

Working with Data
1

Suppose I have a MongoDB where I have separate texts which consist of statements.

I need to be able to search for the texts, which have certain keywords in statements (also multiple texts that have an occurrence of a search term).

I also need to be able to find all the statements in all the texts added by a particular user, which contain a particular search phrase.

My question: do I need to create a separate collection for statements or can I simply add them as nested into the texts collection?

So, option 1 (separate collections):

Texts collection


text: {
    name: 'nabokov',
    id: '1'
}

Statements collection:

statement: {
    text_id: '1',
    id: '24',
    text: 'He opened the window and saw the sky`
}

Option 2 (nested):


text: {
    name: 'nabokov',
    id: '1'
    statements: [
        id: '24',
        text: 'He opened the window and saw the sky`
    ]
}

Which MongoDB storage schema is better if I want to retrieve statements separately based on keyword search and retain the contextual data (e.g. which text they belong to etc.)

My texts would be limited to 16 Mb.