STABILITY OF THE VOLATILE PROFILE OF MIXED FRUIT AND VEGETABLES REFRESHMENT

Industrial mixed juices are usually consumed within the first few days after opening, following the manufacturer's instructions. Thus, it becomes relevant to evaluate the chemical stability of these processed beverages, through the analysis of the profile of volatile compounds (VC's). Thus, the objective of this work was to identify possible changes in the profile of volatile compounds in a mixed soft drink formulation (pineapple, cabbage, lemon and ginger) without the addition of food additives, during a storage period of 15 days after opening the product. Samples were analyzed under the following conditions: Day 0 (after processing); Day 3, Day 5, Day 10 and Day 15 (refrigerated at 4°C). The stability was evaluated through the percentage of degradation of the main compounds. The extraction of volatile compounds from the soft drink was performed by exposing the SPME polyacrylate fiber (PA, film thickness 85 μm) in headspace mode in vials containing about 20 mL of the sample, kept under constant agitation, heated in block of aluminum at 65 °C for 20 minutes to reach equilibrium. After extraction, the fiber was introduced into the chromatographic system for desorption of the analytes. For this, a Gas Chromatograph coupled to Mass Spectrometer -quadrupole analyzer was used, with a DB-5MS column (30 m x 0.25 mm x and 0.25 μm), operated in the MS Full Scan acquisition mode (35-400 m/z). The mass spectra obtained were compared with data from the NIST Library (National Institute of Standards and Technology). The volatile profile was evaluated at peak intensity, observing the percentage area of each compound. A total of 90 CV's were detected, among these 16 main compounds, such as d-limonene (83.98%), citral (81.37%) and (-)-zingiberene (37.29%). A remarkable reduction was observed during the stability study, from 90 to 60 compounds in 15 days. Possible causes of this reduction: oxidation of some constituents, temperature and presence of oxygen during opening of the product. However, some compounds such as cis-3-hexenal, α-pinene, caprylic acid, citral, β-atlantol and α-sesquiphelandrene were stable in the range of 3 to 5 days, with percentage levels of degradation lower than 27%. The results obtained indicate reliability in the stability of the CV's of the mixed soft drink, if consumed between 3 to 5 days after opening, kept under domestic refrigeration.