Selective extraction of intracellular components from the microalga Chlorella vulgaris by combined pulsed electric field–temperature treatment

The synergistic effect of temperature (25–65 C) and total specific energy input (0.55–1.11 kWh kgDW 1 ) by pulsed electric field (PEF) on the release of intracellular components from the microalgae Chlorella vulgaris was studied. The combination of PEF with temperatures from 25 to 55 C resulted in a conductivity increase of 75% as a result of cell membrane permeabilization. In this range of temperatures, 25–39% carbohydrates and 3–5% proteins release occurred and only for carbohydrate release a synergistic effect was observed at 55 C. Above 55 C spontaneous cell lysis occurred without PEF. Combined PEF–temperature treatment does not sufficiently disintegrate the algal cells to release both carbohydrates and proteins at yields comparable to the benchmark bead milling (40–45% protein, 48–58% carbohydrates)

The influence of post-harvest UV-C and pulsed light treatments on quality and antioxidant properties of tomato fruits during storage

In this work, immature green tomatoes were exposed to different doses of either PL or UV-C irradiation (1-8 J/cm2) and thenstoredat 20±2°C forupto21days. Theeffectsof light treatments on the physical-chemical properties and antioxidant compounds of tomato fruits, were evaluated during storage and compared with those of untreated samples. Results indicated that, at the energy doses investigated, pH and °Brix of all samples were not affected by light treatments and storage period. The skin colour of untreated and treated fruits turned from green to red during storage and no appreciable influence of the light treatments was detected. However, the content of lycopene, total carotenoid, phenolic compounds and antioxidant activity of light treated samples increased during storage up to, respectively, 6.2, 2.5, 1.3, and 1.5-fold, when compared with the untreated samples. These results demonstrated that PL and UV-C irradiation have the potential to enhance the accumulation of health-beneficial food compounds in tomatoes without significant changes of the physical properties of the product during storage

Effect of temperature and energy input on PEF processing of the green microalgae Chlorella vulgaris

Microalgae are a promising source for proteins, lipids and carbohydrates for the cosmetic, nutraceutical, chemical, food/feed and biofuel industry. Biorefinery comprises the downstream processing of all products produced by microal-gae after cultivation. However severe conditions can affect the properties of some components. To preventthis, focus needs to be put on biorefinery techniques which are mild and effective. Among the cell disruption techniques, in the last 5 years PEF has been claimed to be promising for opening the cell and improving the extraction of intracellular compo-nents/organelles. In this study the microalgaeChlorella vulgaris was treated in a lab-scale continuous flow PEF unit.Biomass concentration was set at 25 g/L and PEF treated at 20 kV/cm.The effects of inlet temperature (25-65ºC) and energy input (50-100 kJ/kg) on the release of proteins, sugars, antioxidants and pigments in the aqueous phase was investigated. With respect to the con-trol experiments carried out without electrical pulses, up to 2 g/L of carbohydrates and 1 g/L of protein were released in the aqueous phase when PEF was carried out at both the highest temperature and highest energy input