Tomas Essén

Fiedler & Lundgren AB · Product Development

The effects on drying rate and texture of treating two plant tissues with calcium, before drying in air with microwave assistance, were studied in this work. The two tissues, potato and apple cubes, which have different structures and composition, were pretreated by immersion in CaCl2 solutions at 20 or at 70 °C before microwave-assisted air dehydr...

Water activity and moisture content are the most valuable characteristics for assessing the stability of dried foods. The aim of this work was to evaluate if a desorption isotherm model could be used to describe the relationship between the water activity and moisture content in the product during osmotic dehydration. This model can lead to a bette...

The objective of this study was to examine how the drying kinetics and physical properties of apples are affected by pre-treatment with 95% ethanol or freezing at –18 °C before microwave-assisted air dehydration at 50, 60 and 70 °C. Microwave heating was used to obtain these temperatures in the centre of the apple cubes. After dehydration the shrin...

The effect of microwave-assisted air-drying with or without osmotic pre-treatment on apple cubes was evaluated. Osmotic pre-treatment in sucrose solution was followed by microwave-assisted air-dehydration at different temperatures (50, 60 and 70°C). The products were compared to the samples that did not undergo any pre-treatment. A puncture test an...

Golden delicious apple cubes were heated with microwave energy of high intensity (20 W/g), as a pre-treatment before air-dehydration at 40°C, 60°C and 80°C. After the microwave treatment extending for 0.75 up to 5 min, the cubes were finish-dried with only forced air at 2 m/s. Dehydrated and rehydrated samples were analysed with a puncture test usi...

Thesis (Ph. D.)--Chalmers University of Technology, 2000.

The relative permittivity ε′, and relative loss factor, ε″, of apple, chervil, mushroom, parsley, and strawberry were measured at 2800 MHz, with a cylindrical TM012 perturbation cavity. The measurements were made over a range of moistures and temperatures. The results show that the relative loss factor has a maximum value at an intermediate moistur...

Microwave-assisted hot-air dehydration of apple and mushroom was performed with low-power microwave energy. The purpose of the investigation was to compare hot-air drying and microwave-assisted hot-air drying. The air velocity, the microwave output power and the air temperature were the variables in the experiments. The microwave energy was supplie...

The consumer demand for healthy convenience meals with ‘near fresh’ properties challenges researchers and industry to develop new or improved conservation procedures for food products. However, this recent food trend towards fresh image on one ride and convenience on the other side often conflict. In most cases the fresh quality is negatively affec...