Processing of vitamin C-fortified sugarcane juice: the combined effect of high hydrostatic pressure and heat treatment

Abstract

Sugarcane juice is a highly energetic beverage but is poor in vitamin C. This study evaluates the impact of heat treatment (HT) and high hydrostatic pressure (HHP) on vitamin C-fortified cane juice using camu-camu (Myrciaria dubia) as a natural source. The fruit pulp was added to the juice until attaining the pH of 4.0. The drink was then split into three parts, subjected to: 1) HT (72, 82 and 92 °C/15 s), 2) HHP (400, 500 and 600 MPa/25 °C/2 min), and 3) HT followed by HHP (72 °C/15 s + 400 MPa/25 °C/2 min, 82 °C/15 s + 500 MPa/25 °C/2 min, 92 °C/15 s + 600 MPa/25 °C/2 min). The evaluation of treatments was conducted by physicochemical assays (pH, soluble solids and titratable acidity), microbiological tests (mesophiles, molds and yeasts, psychrotrophs, lactic acid bacteria and thermotolerant coliforms counts), enzymic tests (polyphenol oxidase and peroxidase activity), sensory evaluation (hedonic scale), color parameters, and vitamin C determination. The pH values of the raw cane juice varied between 5.1 and 5.3. The soluble solids (SS) content of the freshly extracted cane juice ranged from 20.3 to 22.4, and a variation between 4.9 and 5.9 ºBrix was found in camu-camu. The ascorbic acid content shows the great superiority of camu-camu pulp (1158.1–1495.4 mg/100 mL) compared to cane juice (0.3–0.4 mg/100 mL). The addition of camu-camu pulp increased the vitamin C content in cane juice by up to 237-fold. The treatments provoked significant variations (p ≤ 0.05) in the pH, soluble solids content, acidity and vitamin C of the beverage. Regarding the microbial reduction, there was no synergy between HT and HHP; however, the HT was more effective than HHP in terms of enzymic inactivation. The impact of HT and HHP on the samples’ colors widely varied as a function of different parameters (pressure, temperature and holding time) tested. No difference (p > 0.05) in the overall sensory acceptability´product was observed among the treatments.The outcome of this study was a clean label vitamin C-fortified cane juice with low microbial load and high sensory acceptance.

Graphical Abstract