Effect of different grape residues polyphenols impregnation techniques in mango

The objective of this work was to evaluate the effect of the incorporation of grape residue polyphenols in mango using different impregnation methods. Experiments were performed at atmospheric pressure or vacuum, and with or without performing osmotic treatment and ultrasound. The samples were evaluated after the different impregnation techniques in terms of carotenoids, phenolic compounds, ascorbic acid, energy consumption, color, and firmness. The osmotic dehydration assisted impregnation showed positive results in relation to the incorporation of polyphenols in the mango (3.22–3.34 mg GAE/g DM), but negative in relation to carotenoids (27.37–32.71 μg/g DM) and ascorbic acid (11.90–16.22 mg/100 g DM), while the use of ultrasound showed results satisfactory in all evaluated parameters. The combination of ultrasound and osmotic dehydration in the impregnation resulted in samples with higher losses of carotenoids (28.8–29.38 μg/g DM), small incorporation of phenolic compounds (2.21–2.54 mg GAE/g DM) and retention of ascorbic acid (21.34–22.32 mg/100 g DM). Although the total energy expenditure was higher (0.05–0.09 kWh), the vacuum impregnation and ultrasound-assisted vacuum impregnation assays presented the best performance in relation to the retention of carotenoids (33.07–34.53 μg/g DM) and ascorbic acid (28.29–40.97 mg/100 g DM), greater incorporation of polyphenols from the grape residue by mango (6.29–7.74 mg GAE/g DM), greater color change due to the presence of grape residue extract, and softer texture when compared to untreated samples.