In the storage time range from 3 to 28 d, the retention rate of PC and microcapsules showed a decreasing trend, and microcapsules were more resistant to storage than single PC; there was a significant difference between them ( p < 0.05), such as when the storage time was extended to 28 d.
The retention of PC in both single PC and microcapsules showed a trend of increasing and then decreasing with increasing concentration of sodium bisulfite solution in the range of 0.1–0.5 mg/mL ( Figure 7 D) ( p < 0.05).
In the range of 0.2–0.3 mg/mL of citric acid solution, both proanthocyanidin retention showed an increasing trend, presumably because the presence of citric acid caused the hydrolysis of PC into anthocyanins, which had a certain degree of color-enhancing effect on PC [ 34 ], but it also destroyed the original structure of PC as a result, so the citric acid solution was detrimental to microcapsules and PC.