Effects of different heating methods on the contents of nucleotides and related compounds in minced Pacific white shrimp and Antarctic krill

- Heating methods can control the ATP degradation in minced shrimps.
- High content of the flavor nucleotide was obtained by combined heating.
- The K value is not suitable for assessing the freshness of Antarctic krill.

The effect of heating methods (microwave and water bath, and combined microwave and water bath heating) on 6 nucleotides and related compounds (NRCs) in minced Pacific white shrimp and Antarctic krill was investigated at 25, 40, 55, 65, 75, 85, and 95 °C. In Pacific white shrimp, the main changes of NRCs were in adenosine monophosphate (AMP) and inosine monophosphate (IMP). High temperature (85 and 95 °C) can inhibit the ATP degradation by water bath heating. In Antarctic krill, the main change of NRCs was in inosine (HxR) that decreased in microwave heating treatment at 95 °C. The different methods were compared in terms of IMP content and flavor/bitter ratio, which are related to flavor of aquatic products. The best heating method was pre-heating at 75 °C in water bath followed by microwave heating at 95 °C (IMP content and relatively flavor/bitter ratio were 4.34 μmol/g and 3.00, respectively) for pacific white shrimp and pre-heating at 65 °C in microwave followed by water bath heating at 95 °C (IMP content and relatively flavor/bitter ratio were 0.18 μmol/g and 0.06, respectively) for Antarctic krill, respectively. Chemical analysis, microbiological analysis and sensory evaluation showed that the K value is not suitable for assessing the freshness of Antarctic krill.