Currently attention is paid to a possible use of microwave (MW) heating for the drying of cereal grain, rice or pulses. Heat from the kernel surface is transferred by conduction to the inner endosperm if the usual convention drying of grain with hot air is used. This method of drying is time consuming with low economic effectiveness since heat conductivity of wheat kernel is rather low, similarly to insulating materials. MW heating allows drying grains to a permitted limit moisture without deteriorating effects on its composition or properties (CAMPANA et al. 1986). MACARTHUR and D'APPOLONIA (1982) studied the influence of MW heating and grain moisture on wheat conditioning prior to milling and optimisation of semolina yield as well. Some deteriorating changes can occur as a result of high doses of MW treatment. MATERIALS AND METHODSTechnique of microwave treatment: Parameters of a MW oven Whirlpool MT 243/UKM 347 (Norrköpping, Sweden) were as follows: frequency 2450 MHz, pulsed variable MW rated values of power output -90, 160, 350, 500, 750, 850 and 1000 W, inner space volume 25.4 l, without sample rotation during measurement. Before the samples are treated, pre-heating of the oven has to be done to achieve a heating process standard. For this purpose a volume 2 l of water was heated in the oven, using a maximum power output for 5 min. The absorbed power according to BSEN 60705 test (International Standard BSEN 60705 -Methods for measuring the performance of microwave ovens for household and similar purposes) was determined every day as well. Load of water for this test is 350 ± 5 g, initial water temperature 10 ± 2°C. The mean value of absorbed power (n = 22) corresponding to the rated power output 350 W was 298.42 W; standard deviation 8.5 and coefficient of variation (relative standard deviation) 2.85% (SKULINOVÁ et al. 2002).A special polyethylene container with bottom dimensions 100 × 150 mm was used for MW treatment. Weight of single sample was 200 g, height of sample layer in the container was 20 mm. The container with sample was put in the middle of the oven, MW power output was set and the sample let heat until the desired end temperature of heated sample was reached. Then the power output of the oven was switched out and the sample was left in the oven for 1 min more to homogenise the temperature in The effect of microwave (MW) heating on the changes in wet gluten content, Gluten Index, Falling Number and amylographic characteristics was studied in sprouted wheat grain. Different moistures of wheat in two ranges of 10-11% and 15-17% and two end temperatures of MW heated samples (60 and 80°C) were applied to wheat samples. Falling Number and Gluten Index increased with increasing absorbed energy during MW heating, whereas gluten content decreased. Amylographic maximum increased due to α-amylase inactivation progressively with increasing absorbed energy as well. The greatest relative changes occurred when the end temperature of MW heated samples 80°C and moisture 15% were used. An improvement effect on...

FT-IR spectra of isolated high molecule fractions were measured and used for identification of food hydrocolloids in confectionery jellies and food supplements. The simple comparison of spectra of standards and samples proved that this technique is useful for the monitoring of food hydrocolloids in particular food products.

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Grain legumes are important sources of energy and proteins, used in many parts of the world, for both animal and human nutrition. Grain legumes are an important and economic source of significant amounts of proteins, carbohydrates, vitamins and some minerals. The consumption of grain legumes in human diet is limited due to the presence of certain antinutritional factors (α-galactooligosaccharides, phytic acid, condensed tannins, polyphenols, protease inhibitors, α-amylase inhibitors and lectins) (ALONSO et al. 1998). α-galactooligosaccharides (raffinose family oligosaccharides RFO -raffinose, stachyose, verbascose etc.) are characterised by the presence of α(1-6) links between galactose residues and these linkages are not hydrolysed by the intestinal mucosal enzymes (FRIAS et al. 1994). Most researchers ascribe flatulence to the action of anaerobic intestinal microflora on these oligosaccharides that cannot be degraded by mammalian digestive enzymes (VIDAL-VALVERDE et al. 1993). Beneficial effects associated with the consumption of legumes are related to the slow rate of starch digestion and the high content of resistant starch in legumes (TRUSWEL 1992). WÜRSCH et al. (1986) showed that the rigid plant cell walls (dietary fibre) in legumes inhibit swelling and dispersion of starch during processing but the digestibility of starch can be affected by many other factors, such as starch granule structure and the proportion of amylose and amylopectin (BORNET 1993).A wide range of processing techniques such as germination, dehulling, cooking, roasting, autoclaving, fermentation and extrusion have been used and tested to increase the utilization of legumes.The aim of this paper is to evaluate germination, microwave (MW) treatment and hot-air drying effects on changes in soluble carbohydrates and proteins in germinated pea during these processes. It is possible to use germination of grain legumes as the most effective way of decreasing a high content of α-galactooligosaccharides which undesirably affect the nutritive value and acceptability of legumes. Content of α-galactooligosaccharides was reduced to 38% (Gotik cultivar) and to 45% (Grana cultivar) of the original value after 2 days of germination. The aim of further processing was to dry germinated pea to final moisture content 12-14%. Very interesting results were obtained when microwave heating was used as a preliminary treatment before hot air drying. Microwave treatment reduces the time of drying. The contents of soluble carbohydrates (sucrose, raffinose, stachyose and verbascose), proteins and trypsin inhibitor activity were determined as criteria of microwave heating effects on the chemical composition of germinated pea. Germinated pea was used for the preparation of pea soups and these pea dishes were sensory evaluated.Keywords: germination; microwave; drying; pea; α-galactooligosaccharides 24 Vol. 20, Czech J. Food Sci. MATERIAL AND METHODS Plant MaterialSamples of pea (Pisum sativum ssp. sativum L.) -cultivars Grana and Gotik, year of harvest 2000, localit...

The effect of microwave treatment on wet rice was studied. Power output used was 90, 160, 350 or 500 W; final heating temperatures were 40, 60 and 80°C; initial moisture content of rice was 11, 21 or 30%. Temperature of treated sample during microwave heating was measured by means of NoEMI fiber-optic temperature system. Temperature of rice gelatinization, expressed as alkali spreading values and total starch content, was used to evaluate the influence of microwave heating on physicochemical properties of rice. Drying time reduction and the stability of total starch content during microwave treatment of rice makes it possible to recommend the combination of microwave and conventional rice drying for further use.