Effect of active carbon produced from pomegranate peel on the color properties of pear juice

Recently, interest in environmental conditions and pollution reduction methods has led to the importance of research on the production of non-fossil-based activated carbon. Activated carbon is produced from carbon-based raw materials and has many different uses owing to its large surface area, high porosity and various surface functional groups. In the food industry, activated carbon application is used in the elimination of undesirable tastes and odors, color improvement and bleaching processes. Within the scope of the study, active carbons were produced from pomegranate peel, which is a food industry waste, by physical activation at 500°C, 700°C and 900°C for 75 min. with the KN, KN-SB, SN and SN-SB methods. In order to characterize the produced activated carbons, the moisture content, volatile matter content, ash content, fixed carbon ratio, yield and surface area of the samples were determined. Two activated carbons (900 KN-SB and 900 SN-SB) were selected based on their surface areas and their effects on the color and some quality properties of pear juice were examined. Activated carbons with very low surface area (<100 m2/g) were produced by directly using dry pomegranate peels. Rehydrating pomegranate peels by soaking in water only made a difference in activated carbons produced at 900°C, causing the BET surface area to increase and change between 204.2-233.3 m2/g. Applying water vapor to dry and soaked pomegranates during activated carbon production caused the surface area of samples at 700°C and 900°C to increase. The BET surface areas of activated carbons produced by applying water vapor at 700°C were found to be between 359.8-518.8 m2/g. The BET surface areas of activated carbons produced by applying water vapor at 900°C varied between 650.3-952.3 m2/g. The water-soluble dry matter contents of pear juices did not change after treatment with activated carbon. Although the pH values of the samples increased compared to the control sample, the pear juice maintained its acidic structure. The increase in the concentration of activated carbon caused the titratable acidity value of the pear juice to decrease. It was determined that the produced activated carbons improved the color by lightening the brown color of the pear juice and also increased the clarity of the pear juice.