Quantitative divergence between refractometric total soluble solids (°Brix) and label-declared values in commercial fruit beverages: implications for screening

Authors

  • Agim Rysha University “Haxhi Zeka”, Faculty of Agribusiness, Department of Food Technology, UÇK Street, 30000 Pejë, Kosovo, Tel.: +38344121271 , University "Haxhi Zeka" image/svg+xml Author
  • Leonita Mulaj University “Haxhi Zeka”, Faculty of Agribusiness, Department of Food Technology, UÇK Street, 30000 Pejë, Kosovo, Tel.: +38349841160 , University "Haxhi Zeka" image/svg+xml Author

DOI:

https://doi.org/10.5219/scifood.105

Keywords:

fruit juice, sugar content, °Brix, refractometry

Abstract

Refractometric determination of total soluble solids (°Brix) is widely used as a rapid analytical tool in fruit beverage quality control. However, °Brix represents the cumulative concentration of all soluble constituents, rather than sugars alone, and therefore is not directly comparable to label-declared sugar or carbohydrate values. This study aimed to quantify the magnitude, direction, and variability of divergence between refractometrically determined °Brix values and label-declared sugar or carbohydrate values in commercial non-carbonated fruit beverages and to evaluate the analytical behavior of °Brix as a screening indicator across different beverage categories. Thirty commercially available fruit beverages (local and imported) were sampled from retail markets in Peja, Kosovo. Total soluble solids were measured using a calibrated digital refractometer, and declared nutritional values were extracted from product labels. Measured soluble solids ranged from 2.7 to 13.2 g/100 mL, while declared sugar or carbohydrate values ranged from 5.9 to 13.3 g/100 mL. The mean measured °Brix value was 9.47 ± 2.83 g/100 mL, compared with 8.72 ± 2.09 g/100 mL for declared values. The mean bias (°Brix − label value) was +0.75 ± 2.31 g/100 mL, with with wide dispersion (−6.3 to +4.4 g/100 mL). A moderate positive correlation was observed (r = 0.608). Bland–Altman analysis demonstrated substantial and formulation-dependent divergence rather than analytical agreement between the variables. Because °Brix and label-declared sugar or carbohydrate values represent non-equivalent analytical constructs, the results should be interpreted as exploratory screening data rather than method-comparison outcomes. Refractometric °Brix measurement is useful as a rapid compositional screening tool but cannot independently assess labelling accuracy without complementary chemical analyses.

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Published

2026-04-22

Issue

Vol. 20 (2026): Scifood

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Copyright (c) 2026 Agim Rysha, Leonita Mulaj (Author)

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How to Cite

Quantitative divergence between refractometric total soluble solids (°Brix) and label-declared values in commercial fruit beverages: implications for screening. (2026). Scifood, 20(1), 351-360. https://doi.org/10.5219/scifood.105

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