Artisanal sour buttermilk is generated as domestic waste at the household level during the conservation of milk fat in the form of clarified fat using an artisanal method. Around 15-20 kg of artisanal sour buttermilk is generated during the production of 1 kg clarified fat (ghee). Artisanal sour buttermilk has a huge bulk with low total solids (TSs-4%) and high acidity, and it is usually discarded due to the lack of any suitable technique for its preservation. Henceforth, artisanal sour buttermilk was concentrated up to 19.61% TS employing nanofiltration (NF) at 35±2 ºC and subsequently converted to artisanal sour buttermilk powder using spray drying. This powder exhibited excellent wettability (3 s, instant), flowability (angle of repose- 32.10º), water-binding capacity (4.20 g per g of protein), and emulsion stability (80.15%). Furthermore, NF permeate was used as a natural coagulant to prepare heat- and acid-coagulated milk gel from buffalo milk. Buffalo milk heat- and acid-coagulated gel has been criticized for its hard texture and grainy body. Buffalo milk heat- and acid-coagulated gel prepared using NF permeate exhibited significantly (p<0.05) lower hardness and higher yield over cow milk heat and acid-coagulated gel. The developed process enables conversion of artisanal sour buttermilk (by-product) into an easily digestible, low-lactose and high-protein powder. The permeate is able
to develop soft heat- and acid-coagulated milk gel from buffalo milk. This will also curtail environmental pollution and generate extra income for farmers. Thus, an eco-friendly process was developed to increase environmental sustainability.