Physicochemical Properties and Nutritional Relevance of Rice Beverages Available on the Market

Abstract

Recently, more consumers have reached for plant-based milk substitutes, mainly for health, dietary, and flavour reasons. This study aimed to evaluate the physicochemical and bioactive properties and sensory profile of 10 selected rice drinks available on the EU market. Assessment of the physicochemical characteristics included measurement of soluble solids, pH, osmolality, foaming properties and colour parameters. Analysis of bioactive compounds involved the determination of polyphenolic compounds and antioxidant activity. Based on the manufacturer’s data, the composition and nutritional value of the above-mentioned beverages were also analysed in this study. The tested beverages were characterised by a low fat content of 0.6–1.3 g/100 mL, derived mainly from added sunflower oil, but are a good source of energy (energy value of 37–55 kcal/100 mL), derived mainly from naturally occurring carbohydrates whose content ranged from 8.0–11.0 g/100 mL. The protein content of all rice drinks was shallow, not exceeding 0.5 g/100 mL. Of the ten rice drinks analysed, in only two were vitamins B12 and D added (0.38 μg/100 mL and 0.75 μg/100 mL, respectively) and in only three was calcium (120 mg/100 mL) added. In evaluating the physicochemical characteristics, the drinks showed a pH close to neutral (mean 6.85 ± 0.01). The average soluble solids content was about 11%, which was determined by the carbohydrate content. The osmolality of the beverages averaged 324.73 ± 70.17 mOsm/kg H2O, with four beverages classifiable as hypertonic ones (osmolality > 330 mOsm/kg H2O), three as isotonic ones (with osmolality between 270–330 mOsm/kg H2O), and three as hypotonic beverages (osmolality 2O). Only two rice drinks evaluated in this study showed foaming properties. The high whiteness index (81.79 ± 2.55) indicated high white colour saturation of the tested beverages. The rice drinks were characterised by a relatively diverse sensory quality regarding aroma and flavour notes. The overall sensory quality was rated highest for the beverages with the highest sugar content. The tested beverages were characterised by a low content of total polyphenols (average 1.40 ± 0.62 mg GAE/100 mL) and relatively high antioxidant activity (average 418.33 ± 59.65 µM TEAC/100 mL). Based on the research conducted and the analysis of the manufacturer’s data, it can be concluded that the rice drinks studied in this paper can be included in the daily diet, providing a rehydrating beverage that shows free radical-neutralizing properties and provides carbohydrates. At the same time, it should be highlighted that the studied drinks have a low nutritional value and cannot be recommended as milk substitutes due to low protein levels and lack of milk-specific vitamins and minerals.

Keywords

• vegetable drinks
• rice
• physicochemical properties
• nutritional value