Effect of HHP and UHPH High-Pressure Techniques on the Extraction and Stability of Grape and Other Fruit Anthocyanins

Abstract

The use of high-pressure technologies is a hot topic in food science because of the potential for a gentle process in which spoilage and pathogenic microorganisms can be eliminated; these technologies also have effects on the extraction, preservation, and modification of some constituents. Whole grapes or bunches can be processed by High Hydrostatic Pressure (HHP), which causes poration of the skin cell walls and rapid diffusion of the anthocyanins into the pulp and seeds in a short treatment time (2–10 min), improving maceration. Grape juice with colloidal skin particles of less than 500 µm processed by Ultra-High Pressure Homogenization (UHPH) is nano-fragmented with high anthocyanin release. Anthocyanins can be rapidly extracted from skins using HHP and cell fragments using UHPH, releasing them and facilitating their diffusion into the liquid quickly. HHP and UHPH techniques are gentle and protective of sensitive molecules such as phenols, terpenes, and vitamins. Both techniques are non-thermal technologies with mild temperatures and residence times. Moreover, UHPH produces an intense inactivation of oxidative enzymes (PPOs), thus preserving the antioxidant activity of grape juices. Both technologies can be applied to juices or concentrates; in addition, HHP can be applied to grapes or bunches. This review provides detailed information on the main features of these novel techniques, their current status in anthocyanin extraction, and their effects on stability and process sustainability.

Continuous-Flow High-Pressure Homogenization of Blueberry Juice Enhances Anthocyanin and Ascorbic Acid Stability during Cold Storage

“…In particular, CFHPH at 300 MPa provides optimal conditions for the inactivation of PPOs, stability of anthocyanins, and subsequently better antioxidant activity. 63 Overall, our results show that pressure treatment of 300 MPa at an inlet temperature of 4 °C across all flow rates successfully reduced PPO activity in blueberry juice at a level of inactivation comparable to that achieved by HTST treatment. 64 3.4.…”

“…Therefore, the pressure and temperature maintained in the CFHPH positively impact anthocyanins in blueberry juice by effectively releasing bound anthocyanins and reducing PPO activity. , Cold storage at 4 °C showed no detrimental effect but an increment in PPO activity with storage period, as shown in Figure . In particular, CFHPH at 300 MPa provides optimal conditions for the inactivation of PPOs, stability of anthocyanins, and subsequently better antioxidant activity . Overall, our results show that pressure treatment of 300 MPa at an inlet temperature of 4 °C across all flow rates successfully reduced PPO activity in blueberry juice at a level of inactivation comparable to that achieved by HTST treatment …”

“…Based on the impact on anthocyanin and its stability over 45 days of storage, CFHPH treatment at 300 MPa at 4 °C inlet temperature was the optimal condition for stabilizing juice quality during storage as compared to the traditional method of pasteurization. Overall, the PCA biplot suggests that CFHPH is the optimal method for stabilizing essential compounds like anthocyanin and ascorbic acid during cold storage which is not possible through thermal treatment. , …”

“…Overall, the PCA biplot suggests that CFHPH is the optimal method for stabilizing essential compounds like anthocyanin and ascorbic acid during cold storage which is not possible through thermal treatment. 45,63 Therefore, the juice industry could greatly benefit from adopting CFHPH due to its ability to surpass HTST processing in preserving blueberry juice's nutrients and health-promoting molecules (HPMs) during market-simulated storage. CFHPH's preservation qualities meet the industry's objective to provide nutrient-rich juices that meet the evolving preferences of consumers.…”