Storage Stability of Novel Functional Drinks Based on Ricotta Cheese Whey and Fruit Juices

To study the storage stability of drinks produced by blending ricotta cheese whey (RCW) with fruit juices, apple-RCW and apple and blueberry mix (50:50)-RCW (juice/RCW ratio: 70/30, 14.5% soluble solids content) were prepared. Color, sugar and organic acid profiles, antioxidant composition, and sensory features were analyzed after 15 to 150 days of storage on an open shelf at room temperature. A browning phenomenon occurred in the apple-RCW-based drink, while no significant color changes occurred in the mix-based drink. Significant degradation of polyphenol compounds (TPC) occurred in both drinks, but more markedly in the mix-based one. Storage strongly influenced the stability of the total monomeric anthocyanins (MAP) due to their sensitivity to temperature and light. Antioxidant capacity was preserved in both drinks, suggesting that the antioxidant capacity of Maillard reaction products and/or polymeric anthocyanins formed during storage compensated for the TPC/MAP loss. Sugar and organic acid profiles changed without influencing the sensory characteristics. Except for the sourness intensity in the apple-based drink, which increased significantly, storage did not negatively influence the sensory parameters, so both RCW-based drinks obtained high acceptance scores at the end of the storage period. Despite the bioactive compound losses, both drinks provided interesting nutritional value at the end of the storage period, particularly the mix-based drink. The overall results showed that both products are stable enough to hypothesize their commercialization.