Effect of various concentrations of pectin on the color and anthocyanins stability of black barberry (Berberis cratagina) in the fruit pastille model system

Introduction: Gummy candies are included in many confectionery products, such as jellies, pastilles and etc. The texture of gummy candies is achieved by using various gelling agents, such as gelatin, starch and pectin. Color is the most important quality attribute of gummy candies because it is appreciated for its intrinsic aesthetic value and also allows us to estimate food quality. Synthetic dyes have commonly been applied for food coloring purposes because of their stability against light, oxygen and heat. However, some of these synthetics have been related to toxic effects and it has been reported that their consumption affects children's behaviors. Therefore, synthetic dyes are being increasingly replaced by natural pigments. The principal groups of natural food colorants are anthocyanins, betacyanins, carotenoids, curcuminoids, and chlorophylls. Among these pigments, anthocyanins have gained growing interest because they are widely distributed pigments in nature and represent a wide range of color from red and orange to purple and blue. Berberis b .L (barberry) is the largest genus in the family Berberidaceae and contain about 450–500 species of deciduous or evergreen shrubs. Iran is the largest producer of barberry (B.vulgaris) in the world. Besides, other species in different parts of Iran, especially North Khorasan province, grow wildly. B.cratagina is one of the wild barberries which is known as black barberry among Iranian people. B. cratagina contains large amounts of anthocyanin that can be used as an alternative to synthetic colorants. However, its successful application mainly depends on the stabilization of its anthocyanins. Studies have been shown that some hydrocolloids especially pectin can enhance the stability of anthocyanins. So, the aim of this study was to evaluate the effect of different concentrations of high methyl esterified apple pectin on the degradation kinetics of monomeric anthocyanin and visual color parameters (L, a*, b* and TCD) of black barberry in a fruit pastille model system. Material and Methods: The fruit pastille prepared according to Demars & Zeigler (2001) recipe. Six g gelatin was mixed with pectin (the amount of pectin was varied between 0.5, 1, 1.5 and 2 g) and 20 g water in a beaker. The mixture was heated and deairated in a water bath. Additionally, 30 g of sucrose, 25 g of glucose syrup (80°Brix) and 10 g of water were combined, the mixture was heated at 115°C(2 min), resulting in a total soluble solids content of 80°Brix and added to the gelatin solution. Subsequently, after cooling to 80°C the Berberis juice (10 g ) was added to the mixture Finally, the gel solution was poured into a plastic molds, stored at 4°C for 24h and dried at 25°C until aw=0.6. For shelf life experiments, samples were stored under dark (20±0.5°C) condition for a period of 30days. Samples were drawn at regular intervals of 6 days to quantify total anthocyanin and for color analyses. Total anthocyanin content of samples was determined by the pH differential method and color analysis was performed using computer vision. Linear regression analysis was applied using Slide write software version7.0 to obtain the kinetics parameters. All experiments were repeated at least three times and results were expressed as mean ± SD. Significant differences (α=0.05) of physicochemical properties and kinetic parameters throughout storage were determined using the Duncan's test for differences between independent samples. Data evaluation was performed using the SPSS software version16Result and Discussion: There was a significant difference (P