Evaluation of Anthocyanin Profile and Color in Sweet Cherry Wine: Effect of Sinapic Acid and Grape Tannins during Aging

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.

Assessment of Enzymatic Browning and Evaluation of Antibrowning Methods on Dates

Dates’ color is known to play a crucial role in determining the value and quality of the fruit. The color changes from the natural accepted golden color to unfavorable dark brown color during storage. In this study, the effect of different color preservation methods (modified atmosphere packaging, cold storage (4°C), sulfur dioxide gas (SO2), and blanching) and its relation to darkening due to action of the browning enzymes and melanin production were investigated. Polyphenol oxidase was shown to be active in all treatments except the samples treated with SO2 gas and steam blanching for ten minutes. Likewise, peroxidase activity showed a similar trend in all samples, but a decrease in activity was observed in sulfated samples and total inactivation in steam blanching for ten minutes. Moreover, sulfated samples have shown improvement in color compared to all other treatments, whereas the steamed samples showed the highest color deterioration. Concurrently, melanin content increased in all samples over the period of storage except in the sulfated samples. FTIR analyses of dates’ melanin have revealed similar structural feature to the reference melanin; however, some differences were noticed in the regions 2850–2950 cm-1 and 1690–1705 cm-1 which indicated major structural difference between the two melanin samples. More work is suggested to reveal structural and functional properties of dates’ melanin.

Antimicrobial and Antioxidant Activities of Deer Blood Hydrolysate on Fresh Beef during Refrigerated Storage

The aim of this work was to determine the inhibitory effect of deer blood hydrolysates addition on lipid oxidation, color deterioration and microbial contamination of ground beef during during 9 days of refrigerated storage. The pH value, total plate count, thiobarbituric acid-reactive substances value (TBARS), total volatile basic nitrogen (TVB-N) and color were also determined. The results showed that the treatments added hydrolysates had significant inhibitory effects on lipid oxidation and kept the red color of ground beef in 9 days, when compared with controls (P < 0.05). Furthermore, the inhibitory effect enhanced as the adding level of the hydrolysates increased (P < 0.05). These results suggest that deer blood hydrolysates are good source of natural antioxidants.

Influence of the heat treatment on the color of ground pepper (Capsicum annuum)

Red pepper (Capsicum annuum L.) is one of the most important vegetables in the world. The main ground pepper quality attributes are extractable color, surface color, qualitative and quantitative carotenoid content. In this work, the influence of heat treatment on ground pepper quality was investigated. Microbiological status was examined in non-sterilized and sterilized ground pepper. Color changes were assessed by measuring the extractable color (ASTA) and surface color, using a photocolorimeter. The obtained results showed that at the end of experiment, non-sterilized samples had higher color values in comparison to the sterilized ones. Also, color deterioration was heightened at room temperature.