According to yoga scriptures, is intake of raw food recommended over cooked food?
The answer depends on the purpose. Since it is mentioned "Yoga" I assume the end goal is "Union" - with the Self. Short answer therefore is Yes.
To achieve a union with the inner Self, the mind has to be transcended. To transcend the mind, one should have attained Asana Siddhi (the ability to remain in a posture for more than 3 hours without being bodily conscious).
Assuming one has attained Asana Siddhi, the next goal post remains taming the mind (the flow of thoughts). This is where the above question comes into picture. This involves observing the mind as it functions - with sense organs feeding their inputs to the mind, thoughts emerging, transitioning, triggering more thoughts and eventually getting stored as taste (Ruchi).
Now all this observation needs a person who is awake, aware and alert. Food consumed determines how aware and awake a person is. The more fresh the food, the greater is the quotient of awareness. This definitely means the life energies derived from the food increases as we go from left to right in the list below:
Frozen Food | Fried Food | Cooked Food | Semi Cooked / Steamed food | Raw food | Freshly plucked Fruits / Vegetables | Cow milk / Juices | fresh water (from mountains/streams)
The more one consumes the items listed to the right, that much lighter they feel (due to the increase in the Udana Vayu) and that much alert and awake the mind becomes.
So the scope (of this question) of selecting appropriate food comes primarily between the stages of Asana and Pratyahara.