【Regional Product Advanced Utilization Demonstration Field Project】Aosa Project
Joint Faculty of Veterinary Medicine, Assistant Professor KUMAGAI Momochika
Southern Kyushu and Nansei Islands Innovation Center, Specially Appointed Specialist SETOGUCHI Shinji
Background and objectives of activities
In Moroura, Nagashima Town, cultivation of green laver (Aosa) is conducted. The harvest period is from January to April, but a decline in Aosa quality has been observed as seawater temperatures rise. Therefore, clearly identifying quality differences across harvest periods would enable the consolidation of high-quality Aosa for sale as premium-grade products, potentially leading to the branding of Nagashima Town's Aosa. Therefore, we will analyze the taste components of aosa seaweed based on harvest timing to obtain data that can serve as an indicator for quality differentiation. Furthermore, since the impact of the marine environment is suggested as a factor contributing to the decline in cultivated aosa quality, we aim to clarify the influence of the cultivation environment on aosa quality and link this to the development of high-quality aosa cultivation methods.
Summary of Activities
In fiscal year 2024, amino acid analysis, sensory evaluation, and analysis of volatile aroma compounds were conducted on aosa harvested at different times (March and April) to compare their flavors. The results showed that the March-harvested aosa had higher amino acid concentrations overall compared to the April harvest, with particularly high levels of glutamic acid and aspartic acid, which are umami components. Furthermore, a simple sensory test involving a taste test of aosa with added hot water, conducted by five panelists, revealed that the March-harvested aosa had a noticeably higher aroma and stronger umami flavor. Additionally, GC-MS analysis using solid-phase microextraction suggested that the March-harvested aosa contained a greater total amount of volatile components compared to the April-harvested aosa.
Expected Benefits
By clearly identifying quality differences in aosa seaweed based on harvest timing through both compositional and sensory evaluations, we aim to commercialize high-quality aosa and advance the branding of Nagashima Town's aosa. Furthermore, elucidating the impact of marine environments on the quality of cultivated aosa is expected to lead to the development of cultivation methods for even higher-quality aosa.