High Hydrostatic Pressure vs. Thermal Pasteurization: The Effect on the Bioactive Compound Profile of a Citrus Maqui Beverage

Abstract

The effects of high hydrostatic pressure (HHP) compared to thermal pasteurization (TP) were studied in healthy citrus-maqui beverages. The impact of the processing technologies on the microbiological and phytochemical profile was assessed by applying two HHP treatments at 450 and 600 MPa for 180 s and TP at 85 °C for 15 s. The shelf life under refrigeration (4 °C) and room temperature (20 °C) was monitored for 90 days. All treatments ensured microbiological stability at both storage temperatures. Aside from that, the physicochemical parameters were not significantly different after processing or throughout the storage period. Regarding color parameters, an increase in the reddish coloration was observed during storage for those beverages treated by HHP. In general, phenolic compounds were little affected by the processing technique, even when treatment under HHP was more stable than by TP during storage. On the other hand, vitamin C showed great degradation after processing under any condition. It can be concluded that HHP is an effective alternative to thermal treatments, achieving effective microbial inactivation and extending the shelf life of the juices by contributing to a better preservation of color and bioactive compounds.

Influence of Sweeteners (Sucrose, Sucralose, and Stevia) on Bioactive Compounds in a Model System Study for Citrus–Maqui Beverages

“…It must be mentioned that this is the most unstable bioactive compound of the beverage, as, in general, it presents a 100% loss after less than one month of storage, which is in good agreement with previous studies [ 14 , 39 , 40 ]. Therefore, in the present work, it was observed that, on day 27, the degradation of vitamin C was complete in the citrus–maqui control and citrus juice ( Figure 5 A,B), but not when ascorbic acid was studied as a model solution (reaching only 40% loss), as described in Figure 5 C.…”

“…In this sense, sucrose was the least effective in maintaining the concentration of vitamin C in citrus–maqui beverages, as up to 80% total loss (final concentration of 4.60 mg/100 mL) occurred on day 9 when stevia and sucralose still preserved almost 50% (final concentration of 10.82 and 11.31 mg/100 mL) of vitamin C ( Figure 5 A). These results could be explained by taking into account that sucrose was one of the sweeteners with the highest protective effect on anthocyanins, enabling a major interaction between these compounds, triggering a higher percentage of the breakdown of vitamin C. These results are in full agreement with those previously obtained by Salar et al [ 13 , 14 ] for this citrus–maqui beverage, processed under industrial conditions.…”

“…The bioactive compound degradations, in the citrus–maqui control during storage ( Figure 1 ), were in concordance with those previously obtained for the citrus–maqui beverage [ 13 , 14 ], resulting in a 10% loss of total flavanones (final concentration of 8.36 mg/100 mL; characteristic of citrus juices), 35% loss of total anthocyanins (final concentration of 10.66 mg/100 mL; characteristic of maqui berry), and 100% loss of vitamin C (also from citrus juice although for this the total loss was observed at day 27 relative (18 days later than the citrus–maqui control)).…”

“…In this frame, citrus–maqui control beverages presented a faster degradation (100% loss at day 9) in comparison with citrus controls (100% loss at day 27) or ascorbic acid model solutions (46% total loss during 27 days of storage; final concentration of 12.43 mg/100 mL) ( Figure 1 C). Because of the lower degradation in the vitamin C control relative to the citrus and citrus–maqui controls, it could be speculated that the degradation of ascorbic and dehydroascorbic acids is due, regardless of extrinsic factors, to endogenous enzymes with oxidase activity in the matrix of the citrus juice [ 26 ], such as polyphenol oxidase, peroxidase, and especially ascorbate oxidase, which catalyze ascorbic acid oxidation [ 14 , 27 , 28 ]. Last, but not least, the faster degradation of vitamin C, present in citrus–maqui beverages seems to be not only due to extrinsic factors, or to the presence of endogenous enzymes, but also to the presence of the anthocyanins characteristic of the maqui fruit.…”

“…Despite this, the influence of the diverse added sweeteners was observed when different processing and storage conditions were applied [ 13 , 14 , 15 ]. The differences observed between sweeteners in terms of bioactive compounds’ stability, bioavailability, and bioactivity were proposed to be due to specific interactions between the different phytochemicals with each other, in addition to the role of the added sweetener [ 13 , 16 , 17 ].…”