<![CDATA[Pangasius hypophthalmus is one of the economically superior freshwater fish commodities in Riau Province, Indonesia, which is characterized by high protein content but experiences rapid quality decline during storage at room temperature due to proteolytic enzyme activity and microbial spoilage. This study aims to determine the effect of lime (Citrus hystrix) peel concentration and storage time on catfish protein quality and to develop contextual biotechnology learning posters for grade XII high school students based on the research results. This study used a quantitative experimental approach using a factorial Completely Randomized Design (RAL) with two factors: lime peel concentration (0 g, 200 g, 300 g, and 400 g) and storage time (3, 5, and 7 days) at room temperature (25–30°C), resulting in 36 experimental units. The parameters analyzed included protein content using the Kjeldahl method, pH value, Total Plate Count (TPC), organoleptic characteristics (color, aroma, texture and taste) and hedonic. Data were analyzed using Analysis of Variance (ANOVA) followed by the Duncan's Multiple Range (DMRT) test. The poster development adopted the ADDIE model and was validated by media experts, material experts, and biology teachers. The results showed that lime peel concentration significantly affected catfish protein quality. The 300 g treatment showed the highest protein content (20.96–21.88%), the lowest microbial growth, and superior organoleptic characteristics during the storage period. In contrast, the control treatment showed the most significant protein degradation and microbial proliferation. The developed biotechnology learning poster achieved very high validity scores from the media and relevant experts, demonstrating its suitability as an innovative and contextual educational resource.]]>
