Pulverulent compositions of a complex between an acid and a metal and method of preparation thereof

A spray-dried particle, comprising:

• a spray-dried homogeneous sphere or a fraction of a spray-dried homogeneous sphere, being formed of a complex or a salt, between an acid or a corresponding anion and at least one metal or a corresponding metal cation,
• said acid or corresponding anion being selected from the group consisting of 2-hydroxy-4-methyl-thiobutanoic acid (HMTBA), methionine, aspartic acid, alginic acids, pectinic acids, corresponding anions, 2-hydroxy-4-methyl-thiobutanoate, methioninate, aspartate, alginates and pectinates,
• said metal or metal cation being divalent or trivalent,
• said spray-dried particle having an amorphous fraction a mass of which represents at least 50% of a total mass of said spray-dried particle,
• said spray-dried particle being substantially devoid of uncomplexed acid or anion and of uncomplexed metal or metal cation.