The effects of field strength and multiple thermal treatments on electrical conductivity of strawberry products were investigated. Electrical conductivity increased with temperature for all the products and conditions tested following linear relations. Electrical conductivity was found to depend on the strawberry-based product. An increase of electrical conductivity with field strength was obvious for two strawberry pulps and strawberry filling but not for strawberry topping or strawberry-apple sauce. Thermal treatments caused visible changes (a decrease) in electrical conductivity values of both strawberry pulps tested, but the use of a conventional or ohmic pre-treatment induces a different behavior of the pulps' conductivity values. Ascorbic acid degradation followed first order kinetics for both conventional and ohmic heating treatments and the kinetic constants obtained were in the range of the values reported in the literature for other food systems. The presence of an electric field does not affect ascorbic acid degradation. ᮊ Industrial relevance: Due to the ability of the ohmic heating technologies to achieve rapid and reasonably uniform heating of electrically conductive materials its impact on food quality is of interest. This study shows interesting relationships between heat treatment and electrical conductivity of strawberry pulps and also suggested the product dependency for optimum ohmic heating applications.

This work deals with the determination of the inactivation kinetics of several enzymes, most of them used as time-temperature integrators in the food industry. The tested enzymes were polyphenoloxidase, lipoxygenase, pectinase, alkaline phosphatase, and ␤ ␤ ␤ ␤ ␤-galactosidase, and the inactivation assays were performed under conventional and ohmic heating conditions. The thermal history of the samples (conventional and ohmically processed) was made equal to determine if there was an additional inactivation caused by the presence of an electric field, thus eliminating temperature as a variable. All the enzymes followed 1st-order inactivation kinetics for both conventional and ohmic heating treatments. The presence of an electric field does not cause an enhanced inactivation to alkaline phosphatase, pectinase, and ␤ ␤ ␤ ␤ ␤-galactosidase. However, lipoxygenase and polyphenoloxidase kinetics were significantly affected by the electric field, reducing the time needed for inactivation. The results of the present work can be used industrially to determine processing effectiveness when ohmic heating technology is applied.

The effects of field strength, soluble solids (from 14 to 59.5 °Brix) and particle size (using two size distributions) on electrical conductivity were investigated. Electrical conductivity increased with temperature for all the products and conditions tested following linear or quadratic relations. Electrical conductivity was found to vary greatly between strawberry‐based products. an increase of electrical conductivity with field strength was obvious for fresh strawberries and strawberry jelly but not for strawberry pulp, probably due to the presence of texturizing agents. This parameter decreases with the increase of solids and sugar content. For some of the formulations tested (solid content over 20% w/w and over 40 °Brix) a different design of ohmic heater may be necessary because of the low values of electrical conductivity.

Selva and Camarosa strawberry varieties were characterized chemically and physically. The importance of keeping the stem until processing, the influence of different transport periods under refrigerated conditions, the effects of freezing and exposure to air of damaged surfaces were evaluated. During freezing, losses of ascorbic acid, sucrose, fructose and glucose were reported for both varieties. However, keeping the stem intact minimizes the losses of ascorbic acid in frozen fruits. The exposure to air of cut surfaces affects ascorbic acid content of fresh fruits, with the highest losses reported in Camarosa. Selva showed properties important for commercial use, as compared to Camarosa, with regard to a higher resistance to thawing and higher contents of total phenolics, total protein, and ascorbic acid.

<abstract> <p>Polydimethylsiloxane (PDMS) has been a promising material for microfluidic, particularly in lab-on-chip. Due to the panoply of good physical, mechanical and chemical properties, namely, viscosity, modulus of elasticity, colour, thermal conductivity, thermal coefficient of expansion, its application has been increasingly requested in quite different areas. Despite such characteristics, there are also some drawbacks associated, and to overcome them, several strategies have been developed to modify PDMS. Given the great variety of relevant conducted research in this field, the present work aims to gather the most relevant information, the advantages and disadvantages of some of the techniques used, and also identify potential gaps and challenges in it. To this end, a systematic literature review was conducted by collecting data from four different databases, Science Direct, American Chemical Society, Scopus, and Springer. Two authors independently screened the references, extracted the key information, and assessed the quality of the included studies. After the analysis of the collected data, 25 studies were selected that addressed the various mechanical properties of PDMS and how to modify them in order to suit a particular application.</p> </abstract>