Production of orange powder rich in bioactive components by different drying methods

In this study, the effect of the drying process on the quality properties of the powder products obtained from the orange powder (Citrus sinensis L.) in both foam form and puree form with refractance window and hot air drying systems was investigated. For this purpose, puree and foam forms which were dried in refractance window and hot air drying systems were stored at 4 and 25ºC temperatures for 90 days. Some physical (color, water activity, bulk density, compressed density, flowability, particle size, solubility) and chemical (moisture, ascorbic acid, total phenolic agent, total carotenoid agent, antioxidant activity, phenolic agent composition, volatile component composition, amount of HMF) were performed at the 0 th, 15 th, 30 th, 60 th and 90 th days of storage. In the optimization study in determining the rate of use of the foaming agent for the foam form of the orange puree, the carboxymethyl cellulose, whey protein and soy protein isolate were used as the foaming agent. For the ratio of foaming agents, the lower and upper limits commonly used for the foam drying method have been determined and the optimization has been carried out according to the Box-Behnken experimental design with the maximum foam stability and foam capacity. In this study, optimum ratios for Carboxymethylcellulose, whey protein powder, soy protein powder were determined as 1.5% - 3% and 1.5%, respectively. In the optimization of the drying of the orange purees, the most suitable intervals were selected as 2-4 mm values as a result of preliminary trials for the paving thickness in the refractance window drying system. For the temperature parameters, 60-90 ºC intervals were selected which were applied in similar drying studies. The optimization was performed according to the Central-Composite experimental design using the response surface method. Optimum processing conditions were determined by optimizing these variables to be the highest amount of ascorbic acid. As a result of this study, optimum points were determined as 90 ºC temperature and 2 mm paving thickness. In order to optimize the drying of the orange purees on hot air drying system, thickness 2-4 mm, temperature 60-90ºC, air velocity 1-3 m/ s intervals were selected. The optimization was performed using the Box-Behnken experimental design using the response surface method. Optimum processing conditions were determined by optimizing these variables to be the highest amount of ascorbic acid. As a result of the optimization, optimum points were found as 90ºC, 2 mm thickness and 3m/sec air velocity. The physical and chemical properties of the samples, which were stored in two different temperature environments after the drying processes carried out at optimum points, were carried out in the determined intervals. As a result of the research, it was determined that the moisture content of the samples varied between 3.47-2.16% during storage and the products produced in the refractance window drying system had lower moisture content. It was observed that the lowest water activity values belong to the samples produced in the refractance window drying system in parallel with the moisture content and the water activity values of all products varied between 0.3506-0.2066. When the color results were examined, it was found that the products obtained by foam drying method in the refractance window drying system gave the best results in terms of L, a, b, Hue angle and Chroma values. It was determined that the highest amount of ascorbic acid, antioxidant activity, total phenolic substance, total carotenoid substance and lowest HMF content belong to products obtained by foam drying method in refractance window drying system. It was stated that the highest HMF content belongs to orange powders dried in hot air drying system. A decrease in the analyzed components of all products occurred during storage, while an increase in the HMF content of the products was observed. It was determined that the products with the highest volatile component content were obtained by foam drying method in hot air drying system, and the products produced in the refractance window drying system had the lowest volatile component content. When the results of the research are evaluated together, it is understood that the foam drying method reduces the drying time and affects the product quality positively. In order to obtain orange powder, it has been determined that the foam drying method is a preferable approach in the refractance window drying system.