Microwave treatment and drying of germinated pea

Abstract

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...

Chemical and biochemical changes during microwave treatment of wheat

“…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).…”

“…Location of a temperature sensor was 2 mm below the sample surface. A detailed scheme of the temperature sensor position was demonstrated in our previous paper (SKULINOVÁ et al 2002).…”

“…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.…”

Germination Response of MR 219 Rice Variety to Different Exposure Times and Periods of 2450 MHz Microwave Frequency

“…For instance, the parallel examination on maize has already revealed the positive impact of microwaves at 945 MHz on germination, growth rate, and absorbance efficiency of photosynthetic pigments [ 23 ]. Skulinová et al [ 24 ] have highlighted the impact of the microwave treatment on the biochemical composition of germinated pea ( Pisum sativum L.). The content of soluble carbohydrates, proteins, and trypsin inhibitor activity was reviewed as criteria of the microwave heating effects in Skulinová's survey [ 24 ].…”

Dynamics of Some Hydrolytic Enzymes During the Sprouts Production from Lentil Seeds (Lens Culinaris)

“…heat treatment significantly improves the protein quality in pulses by destruction or inactivation of the heat labile anti-nutritional factors (28,30). On the other hand α-D-galactosidic bonds of these oligosaccharides are resistant to cooking and other small scale processing steps, but are hydrolyzable by endogenous α-galactosidases on germination or soaking (1,8,18,23,24,25). Germination is one of the most effective ways of preparing grain legumes for consumption.…”