Beetroot pulp and residue improve the shelf life of Greek yogurt when added as syrup

Abstract

The physicochemical parameters of the pulp, the raw and steamed beetroot residue and the Greek yogurt after adding the beetroot as syrup were evaluated. The parameters pH, titratable acidity, antioxidant activity, mineral content and color were analyzed for both the yogurt and the raw and steamed beetroot during 28 days of storage, and acceptability only for the yogurt. Comparing fresh and steamed beetroot (p<0.05), the steamed beetroot pulp showed higher values of Mg (2.73 mg/100g), Na (74.76 mg/100g) and phenolic compounds (101 mg/mL). Similar results were observed for the residues, with Mg (2.42 mg/100g), Na (100.71 mg/100g) and phenolic compounds (117.77 mg/mL); the beetroot pulp syrup showed higher (p<0.05) average levels of Mg (8.62 mg/100g) and Na (80.95 mg/100g). Yogurt with 5% pulp syrup showed increased oxidation values over the 28 days. However, the yogurt with 15% waste syrup showed high levels of magnesium, sodium and potassium. In the acceptability test, the yogurts with 5% pulp syrup and 15% residue syrup showed the better scores. The aerial parts (residue) of beetroot, which are commonly rejected because they are hard and consumers are unwilling to use them, have shown to be a valuable source of phenolic compounds. Producing syrups from plant parts that are not commonly edible improves acceptability and visual appearance, and yogurt can be used as a base for adding these syrups.