Rocío Fernández-Vázquez

Summary: This study was aimed to analyse the impact of the debittering process (DP) in the overall sensory properties of orange juice (OJ) (Citrus sinensis L. Var. Salustiana). The fresh industrial squeezed orange juice (FOJ) and the corresponding OJ after the DP (DOJ) were taken. No significant differences were found in acidity, pH and total soluble solids. Colour was evaluated by image analysis (DigiEye System). Hue and lightness were lower (more reddish and darker) after debittering (P < 0.001). Odour profile (limonene, α‐pinene, ethyl butanoate, octanal, linalool, citral and terpineol) decreased significantly (from 16% to 61% on average) as well as total phenolic compounds measured by Folin–Ciocalteu (P < 0.05). The influence of the debittering on the perceived colour, smell and taste was evaluated by paired comparison tests. The naïve panellists found significant differences not only in taste but also in colour and aroma between FOJ and DOJ; however, preference was not clear.

This study was aimed at assessing the differences between industrially processed and hand-squeezed orange juices (OJs) in relation to their color, particle size, carotenoid content, and carotenoid bioaccessibility. Specifically, industrial samples of fresh squeezed OJs after the finishing steps (FISO) and the same OJs after pasteurization (PISO), as well as hand-squeezed OJs (HSO) were studied. The results showed that the HSO and PISO were different (p < 0.05) in terms of color (darker and more reddish vs brighter, more yellowish and colorful), particle size (volume and surface area mean diameter), and total carotenoid content (29 ± 5 and 22 ± 3 mg/L, respectively). On the other hand, the industrial extraction of OJs reduced the particle size distribution, and accordingly, the relative bioaccessibility of bioactive carotenoids increased (p < 0.01). Independently of the type of OJ, the bioaccessibility of carotenoids in decreasing order was the following: α-carotene > β-cryptoxanthin > β-carotene > zeaxanthin > lutein.

This study was aimed at (1) finding out correlations between the instrumental and the sensory evaluation of color attributes (lightness, chroma and hue) in orange juices (OJs) and (2) evaluating consumer preferences on OJs color. Fresh hand squeezed OJs from five varieties of oranges were evaluated by image analysis (DigiEye System, VeriVide Ltd., Leicester, UK) and spectroradiometer. Eighteen trained panelists classified the OJs in increasing order of hue (yellowish–reddish), chroma (dull–vivid) and lightness (clear–dark) and scored the colorimetric parameters on a continuous scale of 10 cm, anchored at the ends. Hue and lightness were well correlated with the instrumental measurement but not chroma. One hundred eleven consumers were asked to order the five OJs according to their color liking. A significant preference (P < 0.05) was observed for the OJs with intermediate hue and lightness values (Valencia Midnight). Consumers' segmentation was also explored by cluster analyses.PRACTICAL APPLICATIONS: For the first time, the correlations between instrumental color parameters obtained with DigiEye and the sensory evaluation of color in orange juice (OJ) has been explored. These correlations have demonstrated that trained panelists can effectively evaluate orange juice hue and lightness. Small chroma differences (<2.96 CIELAB units) are not well appreciated by a trained panel and therefore would not be relevant for the industry.Consumers' preference for OJ color suggests that the preferred hues are the most orangish against other more reddish or yellowish ones. However, there are different segments of the population that show preference for more reddish hues.