Asian palm civet
Kopi luwak is brewed from coffee beans that transversed the gastrointestinal tract of an Asian palm civet, and were thus subjected to a combination of acidic, enzymatic and fermentation treatment. During digestion, digestive enzymes and gastric juices permeate through the endocarp of coffee cherries and break down storage proteins, yielding shorter peptides. This alters the composition of amino acids and impacts the aroma of the coffee. In the roasting process, the proteins undergo a non-enzymatic Maillard reaction.