Among the available food preservation methods, freezing has the potential of preserving food even for years. If effectively utilized, frozen preservation can ensure stable food supply, cost reduction, environmental conservation, among other benefits. Freezing is highly suitable for preserving meat, fish, and processed food but not plants and vegetables because plant cells are highly susceptible to cold temperatures induced by freezing conditions. Nevertheless, further utilization of frozen preservation has been greatly affected by divergent consumer opinions regarding the taste of frozen foods compared to unfrozen foods.
Freezing preservation of fishery food consumed in raw as sushi or sashimi is one of the foods that have been negatively affected by consumer prejudice that “frozen fish tastes worse than non-frozen fish”. Henceforth, freezing has never been a popular method for preserving sashimi. This negative consumer belief was established in the early 19th century, a time when the quality of frozen-preserved fish was not satisfactory. However, the belief seems to persist despite the remarkable improvement of frozen fish quality thanks to advanced technology. If not urgently addressed, the belief has great potential of affecting the entire market of freeze-preserved fish. This can further lead to an unstable food supply besides negatively affecting the economy.
In a recent paper published in the International Journal of Refrigeration, researchers at Tokyo University of Marine Science and Technology Professor Manabu Watanabe and Dr. Toru Suzuki, in collaboration with Dr. Kiyoyuki Ichimaida, Dr. Tsukiko Hattori, and Dr. Reiko Ueda from Hattori Nutrition College, conducted a sensory evaluation of sashimi made of pacific saury to investigate whether freezing degrades the consumer preference of frozen-thawed fish to non-frozen fish. Also, the influence of the term ‘frozen’ on consumer preference was evaluated. In their approach, the authors conducted a pair of tests to compare frozen and non-frozen samples. The test was executed twice, where the first test was carried out without disclosing the information about the identity of the sample (whether frozen or non-frozen) while the second test was carried out after disclosing the identity of the sample.
Results showed that without disclosing the identity of the sample, the average score of the preference i.e., frozen or non-frozen was almost the same. However, when the information about the sample identity was disclosed, the averages score of the frozen-thawed saury drastically dropped, suggesting that the term ‘frozen’ had a significant influence on the panelists’ decisions. The drastic drop could be attributed to the possibility of the panelists perceiving some quality difference between the frozen-thawed and non-frozen saury meat. Also, it could be related to the degradation of the scores of key quality characterization descriptors such as smooth mouthfeel, taste and flavor. However, it was worth noting that the degradation due to disclosing the information was high in female panelists than their male counterparts.
In summary, the study presented an investigation of consumer preference for frozen-thawed fish in comparison to non-frozen fish based on sensory evaluation. Results showed a drastic degradation in the average score when the information about the identity of the fish was disclosed, suggesting the influence of the term ‘frozen’ on consumer preference. In a statement to Advances in Engineering, Professor Manabu Watanabe stated that the results would help further investigations aimed at improving the quality of frozen-thawed fish parallel to that of non-frozen fish.
Watanabe, M., Suzuki, T., Ichimaida, K., Hattori, T., & Ueda, R. (2020). Do consumers actually sense that sashimi made from frozen-thawed fish tastes worse than non-frozen one?. International Journal of Refrigeration, 111, 94-102.