Changes in water-soluble vitamins, resveratrol and bioactive components of the cranberry nectar stored at different temperatures

In this study, the physical (color) and chemical (Water-soluble dry matter (WSC), pH, titration acidity, ash, total dry matter amount in the nectars during storage of cranberry nectar, total phenolic (TFM), total antioxidant activity (TAE), sugar composition) properties of the cranberry nectar were investigated at different temperatures (4 °C, 22 °C, 30 °C and 40 °C) during 6 months. It was determined that the water-soluble dry matter, ash, and total dry matter values were approximately the same throughout the storage, and the pH values decreased slightly towards the end of the storage. It was found out that the total phenolic and total antioxidant activity of cranberry nectars decreased at high storage temperatures by being affected by the temperature, but there was no regular change in the storage period. The content of water-soluble vitamins and trans-resveratrol was determined by liquid chromatographic (HPLC), while the total phenolic content and total antioxidant activity were determined by spectrophotometric method. The existence of water-soluble vitamins such as ascorbic acid, thiamine, riboflavin, niacin, pantothenic acid and pyridoxine was observed. Among all vitamins, the highest values were found in ascorbic acid and the lowest values were found in niacin and thiamine. While the initial value of trans-resveratrol found in cranberry nectar was 0.9518 mg/L, the lowest value was observed as 0.6478 mg/L at the 40°C in the 6th month. There was a significant decrease in the bioactive and nutritive value of cranberry nectar during storage, and it was determined that the decrease in water-soluble vitamins and trans-resveratrol content during storage fit the first-order kinetic model. It was determined that the physical and chemical changes occurred at a minimum temperature of 4 °C and the maximum changes occurred at a temperature of 40 °C during the entire storage.