Sorghum grain as human food in Africa: relevance of content of starch and amylase activities
Dicko, M.H. ; Gruppen, H. ; Traore, A.S. ; Voragen, A.G.J. ; Berkel, W.J.H. van - \ 2006
African journal of biotechnology 5 (2006)5. - ISSN 1684-5315 - p. 384 - 395.
bicolor l moench - beta-amylase - alpha-amylase - kernel characteristics - protein digestibility - functional ingredient - chemical-composition - partial-purification - cultivated sorghum - fermented sorghum
Sorghum is a staple food grain in many semi-arid and tropic areas of the world, notably in Sub-Saharan Africa because of its good adaptation to hard environments and its good yield of production. Among important biochemical components for sorghum processing are levels of starch (amylose and amylopectin) and starch depolymerizing enzymes. Current research focus on identifying varieties meeting specific agricultural and food requirements from the great biodiversity of sorghums to insure food security. Results show that some sorghums are rich sources of micronutrients (minerals and vitamins) and macronutrients (carbohydrates, proteins and fat). Sorghum has a resistant starch, which makes it interesting for obese and diabetic people. In addition, sorghum may be an alternative food for people who are allergic to gluten. Malts of some sorghum varieties display a-amylase and ß-amylase activities comparable to those of barley, making them useful for various agro-industrial foods. The feature of sorghum as a food in developing as well as in developed countries is discussed. A particular emphasis is made on the impact of starch and starch degrading enzymes in the use of sorghum for some African foods, e.g. ¿tô¿, thin porridges for infants, granulated foods ¿couscous¿, local beer ¿dolo¿, as well agro-industrial foods such as lager beer and bread.
In vivo expression of a Cicer arietinum B-galactosidase in potato tubers leads to a reduction of the Galactan side-chains in cell wall pectin
Martin, I. ; Dopico, B. ; Munoz, F.J. ; Esteban, R. ; Oomen, R.J.F.J. ; Driouich, A. ; Vincken, J.P. ; Visser, R.G.F. ; Labrador, E. - \ 2005
Plant and Cell Physiology 46 (2005)10. - ISSN 0032-0781 - p. 1613 - 1622.
rhamnogalacturonan-i - infrared microspectroscopy - partial-purification - natural substrate - architecture - epicotyls - growth - elongation - autolysis - plants
We report the generation of Solanum tuberosum transformants expressing Cicer arietinum ßIII-Gal. ßIII-Gal is a ß-galactosidase able to degrade cell wall pectins during cell wall loosening that occurs prior to cell elongation. cDNA corresponding to the gene encoding this protein was identified among several chickpea ß-galactosidase cDNAs, and named CanBGal-3. CanBGal-3 cDNA was expressed in potato under the control of the granule-bound starch synthase promoter. Three ßIII-Gal transformants with varying levels of expression were chosen for further analysis. The transgenic plants displayed no significant altered phenotype compared to the wild type. However, ß-galactanase and ß-galactosidase activities were increased in the transgenic tuber cell walls and this affected the potato tuber pectins. A reduction in the galactosyl content of up to 50% compared to the wild type was observed in the most extreme transformant, indicating a reduction of 1,4-ß-galactan side-chains, as revealed by analysis with LM5 specific antibodies. Our results confirm the notion that the pectin-degrading activity of chickpea ßIII-Gal reported in vitro also occurs in vivo and in other plants, and confirm the involvement of ßIII-Gal in the cell wall autolysis process. An increase in the homogalacturonan content of transgenic tuber cell walls was also observed by Fourier transform infrared spectroscopy (FTIR) analysis.
Properties of purified gut trypsin from Helicoverpa zea, adapted to to proteinase inhibitors.
Volpicella, M. ; Ceci, L.R. ; America, T. ; Gallarani, R. ; Bode, W. ; Jongsma, M.A. ; Beekwilder, J. - \ 2003
European Journal of Biochemistry 270 (2003). - ISSN 0014-2956 - p. 10 - 19.
partial-purification - protease inhibitors - phage display - manduca-sexta - resistance - insects - plants - larvae - midgut - expression
Pest insects such as Helicoverpa spp. frequently feed on plants expressing protease inhibitors. Apparently, their digestive system can adapt to the presence of protease inhibitors. To study this, a trypsin enzyme was purified from the gut of insects that were raised on an inhibitor-containing diet. The amino-acid sequence of this enzyme was analysed by tandem MS, which allowed assignment of 66 f the mature protein amino acid sequence. This trypsin, called HzTrypsin-S, corresponded to a known cDNA sequence from Helicoverpa. The amino acid sequence is closely related (76 dentical) to that of a trypsin, HzTrypsin-C, which was purified and identified in a similar way from insects raised on a diet without additional inhibitor. The digestive properties of HzTrypsin-S and HzTrypsin-C were compared. Both trypsins appeared to be equally efficient in degrading protein. Four typical plant inhibitors were tested in enzymatic measurements. HzTrypsin-S could not be inhibited by > 1000-fold molar excess of any of these. The same inhibitors inhibited HzTrypsin-C with apparent equilibrium dissociation constants ranging from 1 nm to 30 nm. Thus, HzTrypsin-S seems to allow the insect to overcome different defensive proteinase inhibitors in plants.