The effect of storage conditions on changes of pH, total soluble solids (°Brix), colour, betalains (betacyanins and betaxanthins), and 5-hydroxymethylfurfural was investigated in apple-beetroot juices stored at 2, 7 and 20 °C for 120 days. The results obtained showed that the quality of apple-beetroot juice is significantly influenced by temperature and storage duration. Increasing storage time and temperature induced an apparent rise (P < 0.05) of lightness (L*), yellowness (b*), hue angle, total colour difference (ΔE) and 5-hydroxymethylfurfural. Maximal concentration of 5-hydroxymethylfurfural reached 14.97 ± 0.03 mg/L at 20 °C; however, this concentration is under the allowable maximal level in apple juice (20 mg/L). The increase in total colour difference and 5-hydroxymethylfurfural concentration was associated with a decrease of betacyanins and betaxanthins, confirmed by strong inverse correlations (r from − 0.7991 to − 0.9813). Degradation of both betacyanins and betaxanthins followed the first-order kinetic model and showed positive correlation with redness (a*) and chroma. Higher rate constants (k) for betacyanin degradation (k ≈ 0.0064-0.0285 day −1 ) in comparison with the rate constants for betaxanthin degradation (k ≈ 0.0073-0.0471 day −1 ) demonstrate that betacyanins degraded slightly faster. The changes in all monitored characteristics were significantly greater at 20 °C (P < 0.05) than at 7 and 2 °C, except pH and °Brix. Therefore, apple-beetroot juices should be stored at lower temperatures to maintain their acceptable quality. Keywords Apple-beetroot juice quality • Storage • Colour • Betacyanins and betaxanthins • 5-hydroxymethylfurfural Abbreviations A Absorbance a* Greenness/redness AA Ascorbic acid ANOVA Tukey's HSD Analysis of variance-Tukey's honest significant difference b* Blueness/yellowness BC Betacyanins BX Betaxanthins°B rix Total soluble solids CIE L*a*b* Colour space defined by International Commission for Illumination c t=0 Initial concentration of betacyains/betaxanthins (mg/L)

The positive effects of fruit on human health are mainly attributed to their antioxidant activity. The aim of this work was to observe public awareness about antioxidants consumed in fruit, to analyze their preferences and the frequency of fruit consumption in selected population groups. Preferences were assessed by questionnaire, which was attended by 220 respondents. Information about the presence of antioxidants in fruit showed 85% of respondents. Temperate zone fruit is prefered by 48% of respondents and 52% of respondents prefer fruit of southern zone. Fresh fruit is consumed by 54% of respondents, 18% of respondents prefer fruit juices, compotes are consumed by 12% of respondents, fruit spreads by 11% of respondents, and 5% favour the dried fruit. Fruit is consumed by 31% of respondents once to three times a week, 26% of respondents consumed fruit once a day, 23% occasionally and 20% of respondents more times a day. In terms of sex, higher fruit consumption was recorded at women who consume fruit mostly once a day, while men only once to three times a week. The relationship between place of residence and the possibility to grow their own fruit as well as preference between home and the consumption of fruit by country of origin was confirmed.

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