Srimad-Bhagavatam: Canto 3 - Chapter 1 - Verse 42
Sanskrit:
कषायो मधुरस्तिक्त: कट्वम्ल इति नैकधा ।भौतिकानां विकारेण रस एको विभिद्यते ॥ ४२ ॥
ITRANS:
kaṣāyo madhuras tiktaḥkaṭv amla iti naikadhābhautikānāṁ vikāreṇarasa eko vibhidyate
Translation:
Although originally one, taste becomes manifold as astringent, sweet, bitter, pungent, sour and salty due to contact with other substances.