Cherries are rich in bioactive phenolic compounds and are often fermented into cherry wines. The degradation of anthocyanins during storage will cause color deterioration. The study aimed to utilize sinapic acid and grape tannins in cherry wine to maintain a high fraction in the colored forms of anthocyanins, in order to maximize the color intensity, the latter being associated with good product quality. The effects on the anthocyanin profile and on color parameters of copigments, utilizing spectral measurement combined with UPLC-MS quantitative analysis, have been evaluated in sweet cherry wines. The copigmentation effect of sinapic acid and grape tannin was accompanied by the bathochromic shift and the hyperchromic effect, which lead to an increase in color intensity (lower L*, higher a* and b*). During the aging process, sinapic and grape tannin increased the content of pyranoanthocyanins in cherry wine, especially the addition of sinapic acid makes the cherry wine generate 10-syringyl-pyranocyanidin-3-rutinoside. These results demonstrate that sinapic acid is suitable for adding before alcohol fermentation, while grape tannins can be added before aging.

Oxygen exposure is unavoidable and the impact of its management during the post-fermentation stage (PFS) on dry red wine is poorly investigated. This study was dedicated to the variation of acetaldehyde, color and phenolics of Cabernet Sauvignon dry red wine during five discontinuous oxidation cycles of four levels of controlled oxygen supply, which were carried out to simulate probable oxidation during the PFS. Free SO₂ disappeared after the first, second and third oxidation cycles in wines with high, medium and low levels of oxygen exposure severally, but subsequent oxygen exposure below or equal to 2 mg O₂/L per cycle had little effect while 3–3.9 mg O₂/L per cycle dramatically facilitated acetaldehyde accumulation, which was accompanied by an enormous variation in color and pigments, especially when total oxygen consumption was above 10 mg/L. The utilization of clustered heatmap and partial least square regression demonstrated the feasibility of characterization of wine oxidation degree using the chemical parameters measured by UV-spectrophotometry. Oxygen exposure during the PFS should be emphatically controlled, and chemical indexes determined by the UV–spectrophotometric method can be used for a scientific and effective description of wine oxidation degree.

Acetaldehyde is a key carbonyl by-product during red wine alcoholic fermentation; it is reactive and takes part in certain reactions involving anthocyanin. The aim of this study was to investigate the influence of SO₂ and condensed tannin on the acetaldehyde accumulation of Saccharomyces cerevisiae (S. cerevisiae) during alcoholic fermentation and the ripple effect on wine anthocyanin. In this study, six sets of Cabernet Sauvignon alcoholic fermentation with two different sulfur levels (HS and LS) were carried out by adding exogenous condensed tannins before fermentation (T0) in the acetaldehyde rise period (TA) of S. cerevisiae and at the end of fermentation (TE), separately. The acetaldehyde evolution was identified during fermentation and anthocyanin was analyzed comparatively. The results showed that HS treatment slowed down the degradation of acetaldehyde, while tannins accelerated the degradation of acetaldehyde during alcoholic fermentation, especially TA wines. Furthermore, TA wines possessed a unique anthocyanin profile after fermentation regardless of SO₂ level compared with other wines. These results suggest that acetaldehyde-mediated anthocyanin polymerization most likely occurs timely at the acetaldehyde production phase of S. cerevisiae during alcoholic fermentation, and managing tannin addition time during production could be used to regulate the anthocyanin profile.