Walkowiak-Tomczak Dorota, Czapski Janusz, Młynarczyk Karolina
Institute of Food Technology of Plant Origin, Poznań University of Life Sciences, Poland.
Acta Sci Pol Technol Aliment. 2016 Jul-Sep;15(3):299-309. doi: 10.17306/J.AFS.2016.3.29.
Elderberries are a source of dietary supplements and bioactive compounds, such as anthocyanins. These dyes are used in food technology. The aim of the study was to assess the changes in colour parameters, anthocyanin contents and sensory attributes in solutions of elderberry juice concentrates during storage in a model system and to determine predictability of sensory attributes of colour in solutions based on regression equations using the response surface methodology.
The experiment was carried out according to the 3-level factorial design for three factors. Independent variables included pH, storage time and temperature. Dependent variables were assumed to be the components and colour parameters in the CIE Lab* system, pigment contents and sensory attributes.
Changes in colour components X, Y, Z and colour parameters L*, a*, b*, C* and h* were most dependent on pH values. Colour lightness L* and tone h* increased with an increase in experimental factors, while the share of the red colour a* and colour saturation C* decreased. The greatest effect on the anthocyanin concentration was recorded for storage time. Sensory attributes deteriorated during storage. The highest correlation coefficients were found between the value of colour tone h* and anthocyanin contents in relation to the assessment of the naturalness and desirability of colour. A high goodness-of-fit of the model to data and high values of R2 for regression equations were obtained for all responses.
The response surface method facilitates optimization of experimental factor values in order to obtain a specific attribute of the product, but not in all cases of the experiment. Within the tested range of factors, it is possible to predict changes in anthocyanin content and the sensory attributes of elderberry juice concentrate solutions as food dye, on the basis of the lack of a fit test. The highest stability of dyes and colour of elderberry solutions was found in the samples at pH 3.0, which confirms the advisability of using an anthocyanin preparation to shape the colour of high-acidity food products, such as fruit fillings, beverages,desserts.
接骨木果是膳食补充剂和生物活性化合物（如花色苷）的来源。这些色素用于食品技术。本研究的目的是评估接骨木果汁浓缩液在模型系统中储存期间颜色参数、花色苷含量和感官属性的变化，并使用响应面法基于回归方程确定溶液颜色感官属性的可预测性。
实验按照三因素的三级析因设计进行。自变量包括pH值、储存时间和温度。因变量假定为CIE Lab*系统中的成分和颜色参数、色素含量和感官属性。
颜色成分X、Y、Z以及颜色参数L*、a*、b*、C和h的变化最依赖于pH值。颜色亮度L和色调h随实验因素的增加而增加，而红色度a和颜色饱和度C的占比下降。储存时间对花色苷浓度的影响最大。储存期间感官属性变差。在颜色自然度和适宜性评估方面，发现色调h*值与花色苷含量之间的相关系数最高。所有响应的模型与数据拟合良好，回归方程的R2值较高。
响应面法有助于优化实验因素值以获得产品的特定属性，但并非在所有实验情况下都适用。在测试的因素范围内，基于失拟检验，可以预测接骨木果汁浓缩液作为食用色素时花色苷含量和感官属性的变化。在pH 3.0的样品中发现接骨木溶液的色素和颜色稳定性最高，这证实了使用花色苷制剂来调配高酸度食品（如水果馅料、饮料、甜点）颜色的可行性。
