Effect of Microwave Drying on the Phenolic Content and Color Changes in Different Regions of Persimmon Slices
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
Using persimmons as raw materials, the changes in moisture, color, and phenolic composition and content in six regions (A1, A2, B1, B2, C1, C2) of persimmon slices were investigated under fresh and different microwave drying times (11, 13, 15 min), powers (415, 485, 555 W), and loading capacities (2.15, 2.35, 2.55 kg/m2). The results showed that the contents of water, total phenolics, total flavonoids, total flavanols, and persimmon tannins in the A2 region of fresh persimmon slices were the highest at 81.92%, 125.68, 38.58, 12.77, and 111.29 mg/g, respectively. Microwave drying was found to reduce the overall water and phenolic contents in different regions of persimmon slices, and the color changed from yellow to brownish black. During the microwave drying, changes in the B2 region were the most pronounced, with the lowest water content. Browning first occurred in the B2 region and then spread to other regions. Correlation analysis showed that the contents of total phenolics and persimmon tannins were significantly and positively correlated with brightness (L*) (P<0.05) and significantly and negatively correlated with the total chromatic aberration (ΔE) (P<0.05). Microwave drying can cause the color of persimmon slices to deteriorate, and microwave-dried persimmon slices can no longer have the color of fresh persimmon. The color change is related to the self-oxidation of phenolics, and flavonoids and flavanols are not responsible for the color deterioration of persimmon slices. The results of this study can provide a reference for the drying of persimmon. Further studies should be conducted on the regulation of color changes in persimmon from the perspective of phenolics.
