Abstract

Nowadays all kind of food additives, and among them acidity regulators, have become necessary components of most food products. Their role is lengthening shelf-life, improving the sensory properties and protecting food products from microbial contaminations. However, despite advantages, there are also some undesirable effects of use of food additives that have raised public concern recently. Therefore, food industry considers the possibility of replacing current food additives with natural equivalents, especially those exhibiting health promoting properties. The purpose of this paper was to verify the possibility of using juices from selected fruits characterized by the high antioxidant potential as natural acidity regulators with improvednutritional properties. The tested fruits included: mirabelle plum, sea buckthorn, lemon and blue-berried honeysuckle. The potentiometric titration was used to compare the efficacy of the juices as acidity regulators with citric acid, a widely used acidity regulator. Beetroot juice served as a model food product. All tested juices showed the ability to lower pH of beetroot juice comparable to citric acid. The closest titration diagram to citric acid was determined for mirabelle plum juice and sea buckthorn juice. The antioxidant activity of obtained mixtures of beetroot juice and a titrant was assessed by spectrophotometric tests ABTS and FC. The first axperiments examined mixtures with a final concentration of titrant equal to 10% [v/v] to compare which of the titrants added in the same amounts ensure the highets antioxidant activity of the mixtures. The second series of tests examined mixtures with final pH of about 3.5 to compare which of the titrants added in the amount needed to achieve the desired pH provides the highest antioxidant activity of the mixtures. The results of spectrophotometric tests demonstrated that all of the tested potential ecidity regulators lead to the products with higher antioxidant activity in comparison to beetroot juice titrated with citric acid.

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