Food Colorants as a Context-Based Approach for High School Chemistry: From Natural Sources to Marketing Practices

Abstract

This study presents an inquiry-driven teaching approach that draws on students’ everyday experiences with colored foods and beverages. The activity synergistically integrates areas of organic and analytical chemistry to develop students’ experimental and problem-solving skills while supporting their informed decision-making in everyday life. Student engagement was fostered through guiding questions framing two central dilemmas – colorful versus uncolored foods and natural versus artificial colorants – providing an authentic context to address issues related to food safety, current legislation, and environmental sustainability. Within this framework, students carried out inquiry-based learning starting with a simple and rapid test using raw wool as a direct qualitative sensor for natural and artificial dyes. Subsequent analysis of commercial food labels further supported students in making evidence-based assessments and validating preliminary assumptions. Additional techniques, including distillation and UV–Vis spectrophotometry, were introduced to help students uncover misconceptions about color-composition relationships and resolve experimental uncertainties, consistent with a constructivist learning perspective. Finally, the feasibility of coloring foods with natural pigments was tested, highlighting a common but often overlooked industrial practice. Following the experimental work and in line with active citizenship goals, students shared the outcomes of their educational research through public outreach events involving the local community.