Astanga Hrudaya
किट्टं सारश्च तत्पक्वमन्नं सम्भवति द्विधा। तत्राच्छं किट्टमन्नस्य मूत्रं विद्याद्धनं शकृत्॥६१॥
Formation of essence and waste portions of food after its digestion: The digested food (after both phases of digestion) gets divided into two parts viz, kitta (waste) and sara (essence) the fine (liquid) portion of waste product of food becomes mutra (urine) and the solid portion becomes sakrt (faeces)
english translation
kiTTaM sArazca tatpakvamannaM sambhavati dvidhA। tatrAcchaM kiTTamannasya mUtraM vidyAddhanaM zakRt॥61॥
hk transliteration by Sanscript