Model food development for tuna (Thunnus Obesus) in radio frequency and microwave tempering using grass carp mince

Abstract

Low-cost model foods were necessary for developing radio frequency (RF) and microwave (MW) thawing and tempering process for tuna to reduce experimental cost. In this study, grass carp mince with vegetable oil (1.0–8.0% wt), methylcellulose (MC, 1.0–8.0% wt) and NaCl (0.25–4.0% wt) were investigated for their effect on dielectric properties and tempering temperature distribution to simulate tuna. The dielectric properties of the model foods and tuna were both measured over 1–2500 MHz and −40 to +40 °C. The temperature distributions of tuna and the developed model foods after RF (27.12 MHz) and microwave (2450 MHz) tempering from −55 °C were both determined for comparison. Results showed that the dielectric properties of the model food of grass carp mince with 4.0% oil and 4.0% methylcellulose were the closest to that of tuna. Furthermore, the temperature distribution of grass carp mince with 4% Oil, 4% Methylcellulose and 1.0% salt addition matched the respective temperature distribution of tuna mince in both RF and MW tempering. The results laid a foundation for low-cost model food development for tuna in the tempering/thawing industry. In industrial radio frequency and microwave thawing/tempering process development, using model food could largely save the economic cost. For the model food selection, low-cost fish usually has a similar composition as the precious fish species than other model food base. Thus, developing easy preparing model food based on low-cost fish mince is necessary and practical. Results in this study could be utilized in assisting frozen precious fish tempering/thawing process development in radio frequency and microwave, and also provide a new perspective for the model food base and additives.