1 (Stat-Soft,

Tulsa, Selleckchem Rapamycin USA). Experimental data were fitted to the second-order polynomial model presented in Equation (1), and regression coefficients (β’s) were obtained. equation(1) Y=β0+β1X1+β2X2+β11X12+β22X22+β12X1X2where Y represents the dependent variable (estimated response) and β0, β1, β2, β11, β22 and β12 represent the equation coefficients. Analysis of variance (ANOVA) was performed for each response variable using the full models, and the p-values indicated whether the terms were significant. Terms that were not significant were removed from the final model. The significance of the regression was also evaluated using ANOVA. To verify the adequacy of the models, the experimental data were compared to the values predicted by the regression models. The average error between the experimentally observed values and values predicted by the model were calculated using Equation (2) equation(2) E(%)=100n∑i=1n|yexp−ypred|yexpwhere E is the average error, n is the number of experimental data points, yexp is the experimental value and ypred is the value predicted by the model. Conventional heating treatments were performed in a glass cell, and the cell content was heated by heat exchange with hot water in the jacket. The glass cell used was similar to the one

employed for ohmic heating but had a 5.5 cm diameter. The time/temperature conditions were the same for both processes, and the product was cooled in the same manner. BMS-354825 in vivo Temperature was monitored using type T thermocouples which were inserted in the center of the cell. For the evaluation of conventional heating on anthocyanin degradation, only the central level of the design was analyzed; therefore, only blueberry pulp containing next 10 g/100 g solids content was used. The anthocyanins were extracted from a 2 g sample with 20 mL of acidified methanol (0.01 mL/100 mL HCl) by homogenizing for 1 h in a shaker (Marconi, Piracicaba, Brazil). After extraction, the sample was centrifuged for 20 min at 4 °C and 4757×g, and the supernatant was collected. To prevent degradation of the pigments, samples were flushed with nitrogen before storage, and during procedures, the samples were protected from light and high

temperatures. Acid hydrolysis was performed according to the methodology of Rodriguez-Saona and Wrolstad (2001) with the modifications proposed by Lima, Pinheiro, Nascimento, Gomes, and Guerra (2006). The methanolic extract, prepared as previously described, was used to hydrolyze the anthocyanins to aglycones by adding 3 mL of extract to 10 mL of a 2 mol L−1 HCl solution. The flask containing the mixture was flushed with nitrogen and immersed in boiling water for 1 h. After hydrolysis, the samples were cooled in an ice bath in the dark for 10 min prior to use. The hydrolyzed extract was passed through a sorbent C18 solid phase extraction (SPE) cartridge (Waters, Milford, USA). Anthocyanidins were adsorbed onto the cartridge, and water-soluble compounds were washed off.