Effects of potato extract on betalains, antioxidant activity, and sensory preference in buttermilk through fermentation with Lactobacillus acidophilus and Streptococcus salivarius

Abstract

Utilizing flavorings in drinks enhances aroma, preserves natural properties, and poses challenges in production costs and crop demands. Mitigating these challenges is possible by employing waste products like potato skins. This investigation aims to explore the potential of dried mint-flavored stirred Buttermilk enriched with harvested potato water extract (HPE) for improved functionality and acceptability. To achieve this objective, the betalains, antioxidant, and antimicrobial activities were examined at pH 4.5 and 5.5, along with the phenolic and flavonoid content. Following that, HPE was incorporated at different concentrations of 3 % (T1), 5 % (T2), and 7 % (T3) to assess the stability of betalains, the physicochemical properties, the nutritional value, and the lactic acid bacteria (LAB) content during storage (for 0, 7, 14, and 21 days at 5 °C).In comparison to the control group (0 % HPE), the inclusion of HPE remarkably (p < 0.05) reduced the pH, increased total acidity, total LAB, vitamin C, antioxidant activity, and sensory preference. Total LAB increased from 5.25 – 5.79 CFU/mL and reached its peak at 7 %HPE addition, ranging between 5.76 – 6.28 CFU/mL. Vitamin C content increased from 4.78 mg/100 g to 5.27 mg/100 g, and after 21 days, it declined to the level of the control group, ranging between 3.14 mg/100 g. HPE at 5 % concentration resulted in a more stable vitamin C content during the 21-day storage period. HPE exhibited significant quantities of betalains (478.42 mg/L), phenolics (156.44 mg/g), and flavonoids (51.23 mg/g), showcasing elevated levels of Caffeic acid and p-coumaric acid. The stability of betalains at pH 4.5 was superior to that at pH 5.5 following a 21-day storage period (332.21 and 253.22 mg/L, respectively). The application of HPE led to the development of a functional drink boasting elevated phenolic content (90.02 ± 2.05 mg/g) and flavonoids (65.21 ± 1.33 mg/g) in the presence of 7 %HPE, as compared to the control (78.91 ± 2.55 and 59.32 ± 1.46 mg/g, respectively). The drinks demonstrated notable DPPH inhibitory activity (69.31 ± 1.1) in comparison to the control (85.52 ± 1.33 µL/mL). In conclusion, the addition of HPE can enhance the stability of sensory properties in buttermilk and improve its acceptability.