Quark (dairy product) 6.1). Acidification allowed to continues until the pH reaches around 4.6, at which acidity level the casein proteins in the milk begins to precipitate. In Germany, the curd is continuously stirred to prevent it from getting hard, resulting in a thick, creamy texture. According to German regulations on cheese ("Käseverordnung"), "fresh cheeses" ("Frischkäse") such as quark or cottage cheese must contain at least 73% water in the fat-free component. German quark is usually sold in plastic tubs with most or all of the whey. This type of quark has the firmness of sour cream but is slightly drier, resulting in
Constituent quark surrounded by a cloud of virtual quarks and gluons. This cloud, in the end, underlies the large constituent-quark masses. Definition: Constituent quarks are valence quarks for which the correlations for the description of hadrons by means of gluons and sea-quarks are put into effective quark masses of these valence quarks. The effective quark mass is called constituent quark mass. Hadrons consist of 'glued' constituent quarks. The quantum chromodynamic binding energy of a valence quark in a hadron is the amount of energy required to make the hadron spontaneously emit a meson containing the valence quark. This is the same as