Potential of vacuum impregnation in pumpkin dessert production for the purpose of calcium impregnation

In this thesis, two processing techniques, immersion at atmospheric pressure and vacuum impregnation under 100 mbar pressure, were applied to pumpkin slices for different periods (30, 60 and 90 minutes). Prior to processing, pumpkin parts were sliced into brick shapes 40×40×10mm in size. Calcium oxide (0.15%, w/v) and vitamin D3 (0.1%, w/v) in distilled water were used as impregnation solution. Vacuum impregnation process was applied to fresh pumpkins to rapidly impregnate calcium oxide in the impregnation solution. Treated samples were cooked in the same way for 85 minutes to obtain pumpkin dessert. Calcium oxide in the impregnation solution was used to increase the hardness of pumpkin dessert and vacuum application to shorten the processing time compared to the traditional method. Samples were analyzed before and after cooking. As a result of the analysis, the highest mass transfer was determined in samples that were vacuum impregnated for 90 minutes. In these samples, the highest impregnated calcium and vitamin D3 contents before cooking were 75.55±5.24 and 6015.84±1165.57µg/g, respectively, while the total calcium content was 76.13±2.30µg/g after cooking. As the time increased in both processes, mass transfer rate also increased, but it was observed that vacuum impregnation process was more effective than immersion process in terms of calcium and vitamin D3 transition into pumpkin tissues. In the analyses of SEM images, calcium oxide particles were observed in the vacuum impregnated pumpkin slice images, unlike the images of the unprocessed and immersed pumpkin slice samples. In texture analyses, the samples of pumpkin dessert/jam that were applied vacuum impregnation were harder than the samples that had been immersed, and the hardest sample (18.92 N) was the one that was vacuum impregnated for 90 minutes. Similarly, the sensory hardness values of the pumpkin dessert/jam samples indicated that samples that were applied vacuum impregnation for 90 minutes were harder. In terms of sensory analyses, calcium oxide did not result in any undesired taste in pumpkin desserts/jams. In conclusion, it has been shown that the vacuum impregnation technique can be used in shortening the production time of pumpkin dessert/jam and it has been determined that this method can have an important potential for industrial applications.