Sorbic acid in plant-based yogurt alternatives marketed in Campinas, Brazil: comparison with a reference limit

The growing consumption of plant-based foods, including plant-based yogurt alternatives, underscores the importance of monitoring food additives used in these products. Sorbic acid and its salts, particularly potassium sorbate, are preservatives that inhibit mold and yeast growth, thereby extending shelf life, especially in fruit-containing formulations. This study aimed to determine sorbic acid concentrations in 18 samples of plant-based yogurt alternatives marketed in Campinas, São Paulo, Brazil. Samples formulations were based primarily on coconut, isolated soy protein, and pea protein, with fruit ingredients including strawberry, apricot, banana, papaya, apple, and red berries. Sorbic acid was quantified by high-performance liquid chromatography (HPLC) using a method previously validated for a dairy matrix. Samples were homogenized, weighed, and extracted with water under agitation. The extracts were clarified using potassium ferrocyanide and zinc acetate solutions, followed by filtration through filter paper and a 0.45 µm PVDF membrane. Chromatographic analysis was performed using a C18 column and a diode-array detector (261 nm), with an isocratic mobile phase consisting of 1% acetic acid and acetonitrile (78:22, v/v). A reference limit of 300 mg/kg, expressed as sorbic acid, was adopted, based on Brazilian Ministry of Agriculture Normative Instruction No. 46/2007, which established this limit for fermented milks containing fruit preparations. In this category, sorbates were permitted only through carry-over from fruit preparations, rather than through direct addition to the final product. Sorbic acid was detected in 15 of the 18 samples (83%). Ten samples contained concentrations ranging from 172.7 to 245.3 mg/kg, below the reference limit, whereas five exceeded it, with concentrations ranging from 327.6 to 1,120.1 mg/kg. The highest concentration was approximately 3.7 times the reference limit. In the five samples above the limit, the labels declared potassium sorbate directly in the formulation, without a declared fruit preparation, and two were plain products; samples with the preservative in the fruit preparation were all below the limit. As plant-based yogurt alternatives do not fall within the identity standard for fermented milks, which applies to products derived from milk, this limit was used solely as a comparative reference. Therefore, concentrations exceeding this value indicate a deviation from the reference but do not necessarily constitute a regulatory violation.The frequent detection of sorbic acid, including five samples above the reference limit, highlights the need for continued monitoring and for specific regulatory provisions addressing this product category.

Acknowledgments: CNPq (master’s scholarship, M.C.T. Salomão); Capes (cod 001).