The present study was undertaken to assess the effect of high pressure treatments and conventional thermal processing on antioxidant activity, levels of key antioxidant groups (polyphenols, ascorbic acid and anthocyanins) and the colour of strawberry and blackberry purees. Bioactive compounds (cyanidin-3-glycoside, pelargonidin-3-glucoside, ascorbic acid) and antioxidant activity were measured in strawberry and blackberry purees subjected to high pressure treatment (400, 500, 600 MPa/15 min/10–30 °C) and thermal treatments (70 °C/2 min). Samples were assessed immediately after processing. Different pressure treatments did not cause any significant change in ascorbic acid (p > 0.05). In contrast, following thermal processing (P70 ≥ 2 min) ascorbic acid degradation was 21% (p   0.05), whereas conventional thermal treatments significantly reduced the levels (p  Industrial relevance This research paper provides scientific evidence of the potential benefits of high pressure processing in comparison to thermal treatments in retaining important bioactive compounds. Antioxidant activity (ARP), ascorbic acid, and anthocyanins after exposure to high pressure treatments (400–600 MPa) were well retained. Our results also show that redness and colour intensity of strawberry and blackberry purees were better preserved by high pressure processing than conventional thermal treatment. From a nutritional perspective, high pressure processing is an attractive food preservation technology and offers opportunities for horticultural and food processing industries to meet the growing demand from consumers for healthier food products. Therefore high pressure processed foods could be sold at a premium than their thermally processed counterparts as they will have retained their fresh-like properties.

Impact of high pressure processing on total antioxidant activity, phenolic, ascorbic acid, anthocyanin content and colour of strawberry and blackberry purées.

Current applications and new opportunities for the use of pulsed electric fields in food science and industry

Carotenoids from microalgae: A review of recent developments.

Antioxidant activity of Citrus fruits

Understanding the influence of processing operations such as drying/dehydration, canning, extrusion, high hydrostatic pressure, pulsed electric field, and ohmic heating on the phytochemicals of fruits, vegetables, and grains is important in retaining the health benefiting properties of these antioxidative compounds in processed food products. Most of the previous investigations in the literature on the antioxidants of fruits, vegetables, and grains have shown that food-processing operations reduced the antioxidants of the processed foods, which is also the usual consumer perception. However, in the last decade some articles in the literature reported that the evaluation of nutritional quality of processed fruits and vegetables not only depend on the quantity of vitamin C but should include analyses of other antioxidant phytochemicals and antioxidant activity. Thermal processing increased the total antioxidant activity of tomato and sweet corn. Most importantly, analysis also depends on the condition, type, and mechanism of antioxidant assays used. This review aims to provide concise information on the influence of various thermal and nonthermal food-processing operations on the stability and kinetics of health beneficial phenolic antioxidants of fruits, vegetables, and grains.

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Effect of Processing on Phenolic Antioxidants of Fruits, Vegetables, and Grains—A Review

Bioactive compounds (vitamin C, carotenoids, and flavanones) and DPPH• radical scavenging capacity (RSC) were measured in orange juice (OJ) subjected to different technologies. High pressure (HP) (400 MPa/40 °C/1 min), pulsed electric fields (PEF) (35 kVcm-1/750 μs), low pasteurization (LPT) (70 °C/30 s), high pasteurization (HPT) (90 °C/1 min), HPT plus freezing (HPT+F) (−38 °C/15 min), and freezing (F) were studied. Among the treatments assayed, even though the losses in total vitamin C were <9%, treatments with the higher temperatures tended to show the higher decrease in the content of both forms of vitamin C. HP treatment led to an increased (P < 0.05) carotenoid release (53.88%) and vitamin A value (38.74%). PEF treatment did not modify individual or total carotenoids content. Traditional thermal treatments did not exert any effect on total carotenoid content or vitamin A value. With regard to individual carotenoid extraction, HPT and HPT+F led to different releases of carotenoids. With respect to f...

Impact of High Pressure and Pulsed Electric Fields on Bioactive Compounds and Antioxidant Activity of Orange Juice in Comparison with Traditional Thermal Processing

Influence of ripening and astringency on carotenoid content of high-pressure treated persimmon fruit (Diospyros kaki L.)

Onions have antioxidant properties and they are an important source of bioactive compounds such as phenols. The aim of this work was to study the effect of high hydrostatic pressure (HHP) (100–600 MPa/1–3 min/25 °C) on the microstructure and antioxidant properties of onions (cv. Doux) and its relationship with changes in the extractability of potential health-related compounds. Cryo scanning electron microscopy was used to study the microstructure. Vitamin C, total phenolic content and antioxidant activity (DPPH˙, ABTS˙+, FRAP) were also analyzed. Tonoplast, plasmalemma and cell walls were affected by the HHP treatment and it favored the diffusion of the cellular content to the intercellular spaces. Vitamin C did not show significant changes, whereas the extracted phenolic content and antioxidant activity increased at pressures of 300 or 600 MPa. Therefore, it could be concluded that HHP produced changes in membrane permeability and disruption of cell walls favoring the release of phenolic compounds from tissue and, in consequence, improving their extractability.

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Lucía Plaza

Papers

Impact of High Pressure and Pulsed Electric Fields on Bioactive Compounds and Antioxidant Activity of Orange Juice in Comparison with Traditional Thermal Processing

Influence of ripening and astringency on carotenoid content of high-pressure treated persimmon fruit (Diospyros kaki L.)

Changes in the structure and antioxidant properties of onions by high pressure treatment

Nutritional characterization of tomato juices.

Nutritional and health aspects of fresh-cut vegetables