Improved extractability of carotenoids from tomato peels as side benefits of PEF treatment of tomato fruit for more energy-efficient steam-assisted peeling

Abstract The combination of steam blanching (SB) with Pulsed Electric Fields (PEF) treatments of whole tomatoes, in addition to reducing the energy required for tomato peeling, can significantly contribute to the recovery of carotenoids from the peels. In this work, PEF (0.25-0-75 kV/cm, 1 kJ/kg) and SB (1 min at 50–70 °C), as pre-treatment prior to hand peeling, were investigated to assess their ability, separately and in combination, to induce the cell permeabilization of tomato peels, and hence to improve the carotenoids extraction in acetone (4 h at 25 °C). PEF and SB, by inducing significant damages at the cuticular level, caused the increase of the yield in total carotenoids (up to 188% for PEF and 189% for SB) and antioxidant power (up to 372% for PEF and 305% for SB) with respect to the peels from untreated tomatoes. The application of a combined treatment (PEF + SB) significantly increased the carotenoid content and the antioxidant power of the extracts, with a synergistic effect observed already at 60 °C (37.9 mg/100 g fresh weight tomato peels). HPLC analyses revealed that lycopene was the main carotenoid extracted and that neither PEF nor SB caused any selective release or degradation of lycopene. Results obtained from this study demonstrate that the integration of PEF in the processing line of tomato fruits prior to SB contributes to the valorization of tomato processing by-products

An insight into curcumin-based photosensitization as a promising and green food preservation technology

Consumer awareness on the side effects of chemical preservatives has increased the demand for natural preservation technologies. An efficient and sustainable alternative to current conventional preservation techniques should guarantee food safety and retain its quality with minimal side effects. Photosensitization, utilizing light and a natural photosensitizer, has been postulated as a viable and green alternative to the current conventional preservation techniques. The potential of curcumin as a natural photosensitizer is reviewed in this paper as a practical guide to develop a safe and effective decontamination tool for industrial use. The fundamentals of the photosensitization mechanism are discussed, with the main emphasis on the natural photosensitizer, curcumin, and its application to inactivate microorganisms as well as to enhance the shelf life of foods. Photosensitization has shown promising results in inactivating a wide spectrum of microorganisms with no reported microbial resistance due to its particular lethal mode of targeting nucleic acids. Curcumin as a natural photosensitizer has recently been investigated and demonstrated efficacy in decontamination and delaying spoilage. Moreover, studies have shown the beneficial impact of an appropriate encapsulation technique to enhance the cellular uptake of photosensitizers, and therefore, the phototoxicity. Further studies relating to improved delivery of natural photosensitizers with inherent poor solubility should be conducted. Also, detailed studies on various food products are warranted to better understand the impact of encapsulation on curcumin photophysical properties, photo-driven release mechanism, and nutritional and organoleptic properties of treated foods

Encapsulation of food ingredients by single O/W and W/O nanoemulsions

Nanoemulsions are finding applications in diverse products for encapsulating food ingredients, such as nutraceuticals, micronutrients, flavorings, and colorants. In particular, nanoemulsions enable to significantly increase the dispersibility of molecules in phases where they are insoluble, and increase their bioaccessibility and bioavailability, thanks to their submicron size and high surface area, as well as protection and controlled release of a wide range of bioactive compounds. Nanoemulsions exhibit also other unique properties, in comparison with conventional emulsions, such as, for example, the extended stability against gravitational separation, translucency, as well as the nanoconfinement effects on the disperse phase during crystallization. In this chapter, the formulation and fabrication of oil-in-water and water-in-oil nanoemulsions, and their use as delivery systems for food ingredients will be discussed

OXIDATIVE DEHYDROGENATION OF ETHANE OVER A PEROVSKITE-BASED MONOLITHIC REACTOR

The oxidative dehydrogenation (ODH) of ethane has been investigated in a short-contact-time reactor consisting of a LaMnO3-based monolithic catalyst with a honeycomb morphology. Using an ethane/air mixture with a C2H6/O2 ratio=1.5 and a preheat temperature ranging from 250 to 400◦C results in a 55% ethylene yield, a value even higher than those reported in the same experimental conditions over Pt-based catalysts. By investigating the effect of the experimental conditions, we found that the major role of increasing the feed flow rate and decreasing the C2H6/O2 ratio is to raise the degree of adiabaticity of the reactor and, consequently, ethane conversion and temperature. The selectivity to ethylene also seems to increase with increasing temperature, but only up to about 950◦C. At higher temperatures, further degradation of ethylene to C2H2 and CH4 occurs. We also found that, unlike Pt monoliths, the perovskite catalyst is intrinsically active in OD

CATALYST INVESTIGATION FOR APPLICATIONS OF OXIDATIVE DEHYDROGENATION OF ETHANE IN SHORT CONTACT TIME REACTORS

LaMnO3-based catalysts were tested in a head-to-head comparison with Pt in the oxidative dehydrogenation of ethane at short contact times under the same reactor configuration (400 cpsi honeycomb monolith). The comparison, carried out at varying C2H6/O2 feed ratio and flow rate, showed that on LaMnO3-based catalyst ethylene formation is greatly enhanced in comparison with Pt under a wide range of experimental conditions. Accordingly, product distribution unveils a deeper oxidation of ethane on LaMnO3, resulting in a more efficient heat production and the formation of lower amounts of CO