Charak Samhita
अधस्तु पक्वमामं वा प्रवृत्तं ग्रहणीगदः। उच्यते सर्वमेवान्नं प्रायो ह्यस्य विदह्यते॥५२॥
॥ Grahani gada(diseases of grahani)॥ When partially digested and partially undigested bio substances moves downward in gastrointestinal tract it produces a disorder known as grahanigada. In this particular stage the entire food material remains in the state of vidagdha state (partially transformed/sour).
english translation
adhastu pakvamAmaM vA pravRttaM grahaNIgadaH। ucyate sarvamevAnnaM prAyo hyasya vidahyate॥52॥
hk transliteration by Sanscript