Method of treating green coffee beans under ph regulation
A method of treating green coffee beans is provided that can prevent contamination by acetic-acid producing bacteria when implementing a fermentation treatment on green coffee beans using microorganisms and that can impart new and favorable flavor and aroma to a coffee drink. This object can be achieved by a method of treating green coffee beans comprising a fermenting step for performing fermentation by bringing a nutritive substance and a fermenting microorganism into contact with one another and then supplying the fermented components thus formed to green-coffee beans, wherein, in the fermenting step, the nutritive substance and the fermenting microorganism are brought into contact with one another in a pH range for inhibiting the growth of acetic-acid producing microorganisms.
1 . A method of treating green coffee beans, comprising:
a fermenting step for performing fermentation by bringing a nutritive substance and a fermenting microorganism into contact with one another and then supplying the fermented components thus formed to green coffee beans, wherein
in the fermenting step, the nutritive substance and the fermenting microorganism are brought into contact with one another in a pH range for inhibiting the growth of acetic-acid producing microorganisms.
2 . The method of treating green coffee beans according to claim 1 , wherein the green coffee beans are in at least one state from among a state of isolation from coffee cherry or a state of being inside the coffee cherry.
3 . The method of treating green coffee beans according to claim 1 , wherein the pH is pH 2.4 to 4.7.
4 . The method of treating green coffee beans according to claim 1 , comprising a pH-regulating step for using a pH-regulating agent and regulating the pH to within the aforementioned range.
5 . The method of treating green coffee beans according to claim 4 , wherein the pH-regulating agent is at least one from among lactic acid and phosphoric acid.
6 . The method of treating green coffee beans according to claim 1 , wherein the fermenting microorganism is of at least one type selected from among the group composed of yeast, lactic acid bacteria, and Deuteromycota.
7 . The method of treating green coffee beans according to claim 6 , wherein the yeast is a wine-fermenting yeast.
8 . The method of treating green coffee beans according to claim 6 , wherein the Deuteromycota belongs to the genus Geotrichum.
9 . The method of treating green coffee beans according to claim 8 , wherein the Deuteromycota belonging to the genus Geotrichum is Geotrichum sp. SAM2421 (international deposit number FERM BP-10300), a variant thereof, or a transformant thereof.
10 . The method of treating green coffee beans according to claim 1 , wherein the nutritive substance is fruit juice or coffee pulp.
11 . Green coffee beans obtained using the method of treating green coffee beans according to claim 1 .
12 . Roasted coffee beans resulting from roasting the green coffee beans according to claim 11 .
13 . A coffee drink obtained using the roasted coffee beans according to claim 12 as a raw material.