Recently, the food additive industry has been looking to use bioproducts as a source of food colorants. Therefore, this study aimed to assess the stability of anthocyanins from residues of the grape when were applied as a food colorant in kefir and carbonated water. The degradation of anthocyanins incorporated in food matrices followed the first-order kinetic behavior during storage, in exposure to light or the dark. For stability assessment of anthocyanins in kefir, the anthocyanins retention was 67% during storage and the half-life time (t 1/2 ) was approximately 27 days. The highest stability in the carbonated water samples was shown in anthocyanin malvidin-3-glucoside when they were stored in the dark; the t 1/2 was almost four times longer than in light exposure. The light had adverse effects on the color of carbonated water while the colored kefir showed physical properties similar to kefir without additives. Practical ApplicationsThe incorporation of synthetic additives to provide coloration in beverages causes harmful effects on human health. Food industries produce a significant amount of waste that causes serious environmental problems and economic losses if they are not utilized efficiently. This study shows a new way to approach the residues of food processing as natural sources of bioactive compounds that could be used as a colorant in food and beverages. The anthocyanins from skin grape applied in food matrices present better thermal stability and higher half-life time when were stored in the dark. Therefore, it can be used as a natural additive in beverages or dairy products. In addition to their ability to provide color, the anthocyanins offer beneficial effects on human health due to their antioxidant activity. The results indicate that the anthocyanins from grape byproducts have potential use as a substitute of synthetic colorants in processed food.

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A. de O. Rios, and V. Manfroi. 2020. Characterization of feijoa fermented beverage. Int. J. Agric. Nat. Resour. This study aimed to prepare a feijoa wine and to assess its physicochemical parameters, bioactive compounds, and antioxidant activity. Feijoa were harvested at physiological maturation, and their pulp was fermented in a BOD device at 16 ± 2 °C for 15 days. After the fermentation process, the beverage was characterized for its physicochemical parameters, total phenolic compounds and total flavonoids by spectrophotometry, carotenoids by HPLC, and antioxidant activity by the FRAP, DPPH, and ABTS methods. These same analyses were performed on the pulp in natura for comparative and evaluation purposes of the process. The feijoa fermentation process had a high yield (82%), and the physicochemical characteristics were in accordance with this class of beverage. The beverage had high antioxidant activity, while six carotenoids were identified in the fruit in natura, with (all)-trans-lutein and β-cryptoxanthin being the major carotenoids, in addition to a phenolic content of 176.22 mg GAE 100 g-1 and a total flavonoid content of 0.11 mEq quercetin 100 g-1. The wine had a lower bioactive compound content but a higher antioxidant activity than the pulp. Feijoa wine is a viable technological product in addition to exhibiting antioxidant activity.