Questions & Answers about O macarrão está delicioso.
Portuguese often uses estar for a temporary/current state and ser for a more permanent/defining characteristic.
So O macarrão está delicioso means the pasta (this serving/this dish right now) tastes delicious.
Using é (O macarrão é delicioso) can sound more like a general statement: pasta as a category is delicious, or this dish is “inherently” delicious.
The accent marks the stressed syllable and the vowel quality: es-TÁ.
It also distinguishes it from esta (no accent), which is a form of este/esta meaning this (feminine): esta cadeira = this chair.
Brazilian Portuguese commonly uses the definite article before singular nouns in everyday speech: O macarrão, A pizza, O café.
You can omit it in some contexts (headlines, recipes, or certain regional/style choices), but Macarrão está delicioso sounds unnatural for most everyday conversation.
If you want “some pasta,” you might say Um macarrão (less common) or more naturally Um prato de macarrão.