Direct contact ultrasound assisted freezing of chicken breast samples

Summary

Nowadays, rapid freezing is sought to favor the formation of small ice crystals. Several studies have shown that
the application of ultrasounds (US) accelerates the processes of energy and mass transfer when they are applied
through immersion systems. However, there are hardly any studies on its application in direct systems without
the use of a liquid medium for its transmission. Therefore, the objective of this work was to evaluate the potential
of the application of US for improving the freezing process of chicken breast samples. First, the application of
intermittent US treatments at different net sonication times of 7, 17, 37, 50 and 67% during the freezing of
distilled water samples in a conventional freezer was evaluated. It was observed that net sonication times of 37,
50 and 67% reduced the phase change period by 30.0, 21.4, 27.0%, respectively. The effective freezing time was
also reduced by 12.4 and 12.8% by applying net sonication times of 37 and 50%. Considering these results, an
intermittent US treatment with a net sonication time of 37% was chosen for chicken breast freezing in an airforced
cooling tunnel at ambient temperatures from −13 to −22 °C. The length of all the freezing phases was
reduced upon application of US, leading to an overall process time reduction of approx. 11%. On the other hand,
no significant differences were found either in the Water Holding Capacity (WHC) or Cooking Loss (CL) values
between control and US assisted frozen chicken breast samples. Furthermore, in vitro experiments showed that
US-assisted freezing did not influence protein digestibility of chicken meat samples.
This study demonstrates the potential of the application of US by direct contact to favor energy transfer
processes during freezing of water and chicken breasts samples. However, its effect on the quality of the frozen
products should be further studied.

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DOI : doi.org/10.1016/j.ultsonch.202...
NVA : hdl.handle.net/11250/2738797