Octopus maya is an endemic species of the Yucatan peninsula of great sociocultural and commercial importance, being its capture and trade two of the main economic activities in the region. Even though Octopus vulgaris is the most common octopus’ species worldwide, 74 % of the octopuses captured on the Yucatan peninsula are O. maya. One of the most important aspects for handling octopus is the gelling temperature that is directly related to its cooking temperature since, when cooked at the wrong conditions, their meat becomes tough, compromising the consumer’s acceptance. The cooking temperature of mollusks ranges from 55-60 °C, but there is scarce information about the one of octopuses. Therefore, the object of this work was to determine the gelling temperature of O. maya muscle and study the changes on its structure based on its viscosity and location.
Samples were made by blending three octopuses into a paste, each from different ports of Yucatan (Coloradas CL, Rio Lagartos RL and Cuyo CU). The rheological behavior of the octopus’ paste was characterized using a rheometer (DHR2, TA Instruments; EE.UU.) with a plate-plate geometry (40 mm) and a 1,050 mm gap. The samples were allowed to rest at the rheometer for 5 min/25 °C before the analysis; a vapor trap was attached to the geometry to reduce water evaporation. Temperature ramps were run on the samples over the range 25 - 90 °C (rate= 5 ºC/min; shear rate= 2 s-1).
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The temperature ramps showed that all three samples had a similar temperature at which their viscosity started to raise (Figure 1 Table 1) with no statistically significant difference, as well as the final temperature. The viscosity of the samples varied (CL 2562, RL 729 and CU 491 Pa·s), being the octopus from CL statistically significant different from the others. This could be caused by the location, for the environment feed or for the lack of control on the age of capture of the octopuses. By the change of the samples viscosity, it can be inferred that internal structure modifications, that can be associated to its cooking temperature, take place.
The range of gelling temperatures obtained (51-68.8 °C) were slightly different to the cooking temperature range reported for mollusks (55-60 °C). O. maya needed higher temperatures to reach their maximum viscosity (8.8 °C). This information is of vital importance in heated processes as cooking or making industrial products with octopus.