Accumulation of multiple-repeat starch-binding domains (SBD2–SBD5) does not reduce amylose content of potato starch granules

Planta ◽  
2006 ◽  
Vol 225 (4) ◽  
pp. 919-933 ◽  
Author(s):  
Farhad Nazarian Firouzabadi ◽  
Jean-Paul Vincken ◽  
Qin Ji ◽  
Luc C. J. M. Suurs ◽  
Alain Buléon ◽  
...  
Author(s):  
Pierre Désiré Mbougueng ◽  
Tenin Dzudie ◽  
Joel Scher ◽  
Tchiégang Clergé

In this study, starches were extracted from two cultivars of local Irish potatos (Solanum tuberosum,) and tree cultivars of local Cassava (Manihot esculanta). These starches and a commercial Irish potato starch (IPS), where characterized with respect to their physico-chemical and functional properties. Significant differences (P<0.05) were observed among starches as far as their proximate composition were concerned. The commercial starch showed the highest phosphorus content. The amylose content was observed to be significantly lower (P<0.05) in the cassava starches than in the local Irish potato starches. The highest (P<0.05) gelatinisation parameters were those of 2425 starch cultivar. Potato starch granules exhibited the largest granule size at 10, 50 and 90% diameter compared to those of cassava starches. Potato starches had wider particle size distribution compared to cassava starches. There were apparent differences, between species (Cassava and potatoes) with respect to granule morphology and size. No significant colour difference (P>0.05) was observed between the Sipiera starch cultivars and the Irish potatoes commercial starch.


Author(s):  
Jean-Claude Jésior ◽  
Roger Vuong ◽  
Henri Chanzy

Starch is arranged in a crystalline manner within its storage granules and should thus give sharp X-ray diagrams. Unfortunately most of the common starch granules have sizes between 1 and 100μm, making them too small for an X-ray study on individual grains. There is only one instance where an oriented X-ray diagram could be obtained on one sector of an individual giant starch granule. Despite their small size, starch granules are still too thick to be studied by electron diffraction with a transmission electron microscope. The only reported study on starch ultrastructure using electron diffraction on frozen hydrated material was made on small fragments. The present study has been realized on thin sectioned granules previously litnerized to improve the signal to noise ratio.Potato starch was hydrolyzed for 10 days in 2.2N HCl at 35°C, dialyzed against water until neutrality and embedded in Nanoplast. Sectioning was achieved with a commercially available low-angle “35°” diamond knife (Diatome) after a very carefull trimming and a pre-sectioning with a classical “45°” diamond knife. Sections obtained at a final sectioning angle of 42.2° (compared with the usual 55-60°) and at a nominal thickness of 900Å were collected on a Formvar-carbon coated grid. The exact location of the starch granules in their sections was recorded by optical microscopy on a Zeiss Universal polarizing microscope (Fig. 1a). After rehydration at a relative humidity of 95% for 24 hours they were mounted on a Philips cryoholder and quench frozen in liquid nitrogen before being inserted under frozen conditions in a Philips EM 400T electron microscope equipped with a Gatan anticontaminator and a Lhesa image intensifier.


2021 ◽  
Author(s):  
amandine pruvost ◽  
stanislas helle ◽  
nicolas szydlowski ◽  
Christian ROLANDO

In the present work, we developed a miniaturized method for determining amylopectin chain length distribution (CLD) by fluorescence-assisted capillary electrophoresis (FACE). The method relies on single granule entrapping into capillaries followed by direct starch gelatinization and amylopectin debranching on carbograph-based solid phase extraction (SPE) cartridges. Sample desalting on HypersepTM tips following APTS-labelling and the use of nanovials allowed for the fluorescence analysis of weakly diluted samples. Consequently, method sensitivity was improved by 500-fold which is compatible with the analysis of single potato starch granules. The method was implemented to determine CLD profiles of single starch granules ranging from 50 to 100 µm in diameter. In these experiments, the relative proportion of starch glucans of up to 30 degrees of polymerization (DP) could be quantified.


2018 ◽  
Author(s):  
Wenzhi Zhou ◽  
Shanshan Zhao ◽  
Shutao He ◽  
Qiuxiang Ma ◽  
Xinlu Lu ◽  
...  

AbstractHigh amylose starch, a desired raw material in the starch industry, can be produced by plants deficient in the function of branching enzymes (BEs). Here we report the production of transgenic cassava plants with starches containing up to 50% amylose due to the constitutive expression of hair-pin dsRNAs targeting the BE1 or BE2 genes. A significant decrease in BE transcripts was confirmed in these transgenic plants by quantitative real-time RT-PCR. The absence of BE1 protein in the BE1-RNAi plant lines (BE1i) and a dramatically lower level of BE2 protein in the BE2-RNAi plant lines (BE2i) were further confirmed by Western blot assays. All transgenic plant lines were grown up in the field, but with reduced biomass production of the above-ground parts and storage roots compared to wild type (WT). Considerably high amylose content in the storage roots of BE2i plant lines was achieved, though not in BE1i plant lines. Storage starch granules of BE1i and BE2i plants had similar morphology as WT, however, the size of BE1i starch granules were bigger than that of WT. Comparisons of amylograms and thermograms of all three sources of storage starches revealed dramatic changes to the pasting properties and a higher melting temperature for BE2i starches. Glucan chain length distribution analysis showed a slight increase in chains of DP>36 in BE1i lines and a dramatic increase in glucan chains between DP 10-20 and DP>40 in BE2i lines, compared to that of WT starch. Furthermore, BE2i starches displayed a B-type X-ray diffraction pattern instead of the A-type pattern found in BE1i and WT starches. Therefore, cassava BE1 and BE2 function differently in storage root starch biosynthesis; silencing of cassava BE1 or BE2 caused various changes to starch physico-chemical properties and amylopectin structure. We also report that remarkably high amylose content in cassava starch has been first obtained in transgenic cassava by silencing of BE2 expression, thus showing a high potential for future industrial utilization.


2008 ◽  
Vol 55 (2) ◽  
pp. 89-93 ◽  
Author(s):  
Kaoru Kinoshita ◽  
Azusa Ito ◽  
Makoto Hattori ◽  
Tadashi Yoshida ◽  
Koji Takahashi

2021 ◽  
Author(s):  
Ishita Chakraborty ◽  
Indira Govindaraju ◽  
Sintu Rongpipi ◽  
Krishna Kishore Mahato ◽  
Nirmal Mazumder

AbstractStarchy food items such as rice and potato with high carbohydrate content raise blood sugar. Hence, consuming low glycaemic foods is one tool to keep diabetes under control. In this study, potato and brown rice (Njavara rice) starches were subjected to hydrothermal treatments: heat moisture treatment (HMT) and annealing (ANN) to develop starch-based food products fit for consumption by diabetic patients. The effects of hydrothermal treatments on physicochemical properties and in-vitro enzymatic digestion of starch were determined. It was observed that hydrothermal treatments decreased the swelling power (SP)% and increased the water solubility (WS)% of the native starches. Native potato starch (PSN) showed a high SP of 80.33%, while annealed potato starch (PANN) and heat moisture treated potato starch (PHMT) showed SP reduced to 65.33% and 51.66%, respectively. Similarly, the SP % reduced from 64.33% in native brown rice (BRN) to 44.66% in annealed brown rice (BRANN) and 38.33% in heat moisture treated brown rice (BRHMT). WS % increased from 32.86% in PSN to 36.66% in PANN and 40.66% in PHMT. In BRN, the WS % increased from 14.0% to 14.66% in BRANN and 18.33% in BRHMT. Amylose content increased from 13.23% and 14.56% in PSN and BRN to 16.14% in PANN 17.99% in PHMT, 17.33% in BRANN, and 18.98% in BRHMT. The PSN crystallinity index reduced from 33.49 to 30.50% in PANN and 32.60% in PHMT. At 12 h of enzymatic digestion, it was found that the degree of hydrolysis (DoH) of PHMT (31.66%) and PANN (36.82%) reduced when compared to PSN (41.09%). Similarly, BRHMT exhibited the lowest DoH at 12 h compared to BRANN (29.24%) and BRN (35.48%). This study highlights the importance of hydrothermal treatments on starch in developing low glycaemic index commercial starch-based food products.


2011 ◽  
Vol 287-290 ◽  
pp. 2648-2651
Author(s):  
Wen Yu Wang ◽  
Xin Jin ◽  
Shuan Qing Hou ◽  
Yu Feng Zhang ◽  
Xiao Xu Sha

The effect of acid modification using 1mol/L HCl on viscosity, thermal properties and mechanical properties of potato starch pastes and starch film were investigated. After acid modification, the surface of starch granules did not show more roughness and viscosity of starch pastes become lower. The results of DSC indicated that acid should act on amorphous region of starch firstly and would act on the crystallization region with the longer treatment time. In the very close viscosity scope, the mechanical properties of starch films were increased obviously after acid modification.


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