Comparison of Free and Bound Benzoic Acid Naturally Occurring in Vaccinium and Prunus Fruits by Ultrasound‐Assisted and Conventional Extraction Methods

Abstract

ABSTRACT Benzoic acid (BA, E210) is a common food preservative and naturally occurring plant metabolite. It exists in plant tissues as free (f‐BA) and bound (b‐BA) forms. This makes accurate quantification challenging, as traditional extraction methods may underestimate total BA content. In this study, 26 berries and plum samples of 7 Vaccinium and Prunus taxa were analyzed by conventional shaking extraction (CSE, f‐BA) and ultrasound‐assisted extraction (UAE, total releasable f‐BA + b‐BA). Benzoic acid concentrations ranged from 4.1 to 581.8 mg/kg across taxa, with wild‐harvested V. macrocarpon reaching the highest levels and V. oxycoccos approximately 15‐fold lower. UAE increased measured BA over CSE in every sample (16%–41%), with a consistent gain of ∼20% in V. macrocarpon and Prunus spp. regardless of concentration, but a more variable and higher gain (up to 41%) in V. myrtillus , suggesting species‐dependent differences in BA binding within the cell wall. This shows the extraction method strongly affects measured BA content, relevant for EU food additive compliance. The results support UAE as a more reliable, though not absolute, estimate of total BA (t‐BA) in fruit products. These findings highlight the need for harmonized extraction protocols for compliance testing and further validation of UAE in other fruit and food matrices.

The authors' abstract, as published at the source. Food Safety and Health, 2026 · DOI ↗