Investigations into the influences of processing operations, fruit quality, and geographical origin on key parameters for authentication of Citrus juices and juice concentrates

Volatile commodity prices continue to drive food fraud risks, especially with Citrus juices. Common fraudulent practices include blending juices from undeclared, foreign Citrus species, bypassing proper manufacturing practices, and misrepresenting origins. Ensuring authenticity of Citrus juices is crucial to uphold consumer trust and fair trade. This study delves into distinguishing food fraud from deviations in good manufacturing practices - a complex task given the specificities of Citrus juice production.
Employing advanced techniques like ¹H-NMR spectroscopy and HPLC-MS, the research analysed thousands of global samples, revealing how species, processing methods, and geographic origin impact key quality markers. Findings contributed to establishing critical threshold levels, such as phlorin limits in the AIJN Code of Practice, assisting in identifying unauthorised processing methods and additive use. The work further identified specific markers for distinguishing between Citrus species, including detailed analyses for lemon and lime juices, which often face challenges of deliberate mixing.
Through a combination of quantitative ¹H-NMR and HPLC, the study enables comprehensive chemical profiling, detecting authenticity markers with high precision and differentiating species-specific profiles. Ultimately, this thesis provides robust methodologies to assess Citrus juice authenticity, advancing the industry's ability to separate genuine food fraud from manufacturing variations and safeguard product integrity.