Using maltodextrin and state diagrams to improve thermal transitions in tilapia fillet (Oreochromis spp.)

Background: Tilapia (Oreochromis spp.) in the form of frozen fillets is one of the fishes with the highest commercial production levels worldwide. However, protein denaturation, membrane rupture, and lipid oxidation are commonly observed in fillets when stored at standard commercial freezing temperatures for long periods. This study proposes, for the first time, the use of maltodextrin and state diagrams to define processing strategies and suitable storage temperatures for fresh and dehydrated tilapia fillets. Differential scanning calorimetry (DSC) was used to study the effect of maltodextrin weight fractions ( $W_{\mathrm{MD}}$ ) of 0, 0.4, and 0.8 on the thermal transitions of tilapia fillets as a function of solid mass fractions ( $W_s$ ).

Results: The glass transition temperature curve ( $T_g\mathrm{vs}.W_s$ ) and characteristic parameters of maximal freeze concentration ( $T_g^{\text{'}}$ , $T_m^{\text{'}}$ , $W_s^{\text{'}}$ ) of tilapia increased significantly with the addition of maltodextrin. Using developed state diagrams, freezing and storage temperatures of -22 °C, -15 °C, and -10 °C (P < 0.05) for long-term preservation were defined for tilapia fillets produced with $W_{\mathrm{MD}}$ of 0, 0.4, and 0.8.

Conclusion: Maltodextrin is an excellent alternative as a cryoprotectant and drying aid to increase the thermal parameters of tilapia fillets by achieving frozen storage temperatures above the standard commercial freezing temperature of -18 °C. © 2023 Society of Chemical Industry.