We present a novel solution to prepare bioactive, biomineralized calcium phosphate (mCP) loaded biopolymer composites scaffold material with porous structure. We investigated two types of polymers as matrices, one natural, such as cellulose acetate (CA) and one synthetic such as polycaprolactone (PCL). Owing to the intrinsic biodegradable nature of these polymers, they can be innovatively utilized as resorbable fillers or bone grafts in bone tissue engineering or even in drug-releasing systems. The biomineralized calcium phosphate particles were prepared via wet chemical precipitation and addition of organic biominerals like magnesium gluconate and zinc gluconate to boost the bioactivity of the pure CP phase. We compared the morphological and chemical characteristic of the two types of composites and the effect of the biomineralization on the particle structure of pure CP. The obtained CP was mainly nanocrystalline apatite, and the organic trace element addition strongly affected the morphology by reducing the size of the particles. SEM elemental mapping proved the perfect incorporation of the mCP particles into both CA and PCL polymer matrices forming composites. The short-term immersion test revealed that the decomposition rate of both composites is slow, but moderate and gradual ionic dissolution takes place according to the ICP-AES measurements.