Mapping Ca, Fe, K, and Zn in Biofortified Gilthead Seabream and Common Carp Fish Through X‐Ray Fluorescence Spectrometry

ABSTRACT Globally, there is a growing demand for healthy and sustainable food products, where seafood can play a relevant role, because it is widely recognized as a healthy food item and is an important source of essential nutrients. Still, one third of the world population suffers from food insecurity and different forms of malnutrition. Hence, developing tailor‐made fortified farmed fish is a promising solution to overcome nutritional deficiencies and increase consumer confidence in these products. The aim of this study is to evaluate differences in nutritional elements distribution in biofortified and non‐biofortified fillets from gilthead seabream and common carp, using micro‐X‐ray fluorescence (μ‐XRF). This technique is a fast and nondestructive multielement mapping method with simple operation and sample preparation procedures. Results showed that calcium was mainly accumulated in the skin layer, which includes the scales and spines (skeleton), whereas iron, potassium, and zinc were uniformly distributed in the fish muscle. Compared with the control, biofortified gilthead seabream fillets showed a higher concentration of iron in the inner area of the skin layer (dermis) and muscle tissue, whereas biofortified common carp fillets showed a higher concentration of iron in muscle tissue and zinc in the abdominal cavity tissue of the sample. This study demonstrates that micro‐X‐ray is a suitable technique to assess the elemental distribution with micrometer resolution in fish fillets.