The Influence of Hydroponic Potato Plant Cultivation on Selected Properties of Starch Isolated from Its Tubers.

Starch is a natural polysaccharide for which the technological quality depends on the genetic basis of the plant and the environmental conditions of the cultivation. Growing plants under cover without soil has many advantages for controlling the above-mentioned conditions. The present research focuses on determining the effect of under cover hydroponic potato cultivation on the physicochemical properties of accumulated potato starch (PS). The plants were grown in the hydroponic system, with (greenhouse, GH) and without recirculation nutrient solution (foil tunnel, FT). The reference sample was PS isolated from plants grown in a tunnel in containers filled with mineral soil (SO). The influence of the cultivation method on the elemental composition of the starch molecules was noted. The cultivation method also influenced the protein and amylose content of the PS. Considering the chromatic parameters, PS-GH and PS-FT were brighter and whiter, with a tinge of blue, than PS-SO. PS-SO was also characterized by the largest average diameters of granules, while PS-GH had the lowest crystallinity. PS-SO showed a better resistance to the combined action of elevated temperature and shear force. There was a slight variation in the gelatinization temperature values. Additionally, significant differences for enthalpy and the retrogradation ratio were observed. The cultivation method did not influence the glass transition and melting.

Amylose/cellulose nanofiber composites for all-natural, fully biodegradable and flexible bioplastics.

Thermoplastic, polysaccharide-based plastics are environmentally friendly. However, typical shortcomings include lack of water resistance and poor mechanical properties. Nanocomposite manufacturing using pure, highly linear, polysaccharides can overcome such limitations. Cast nanocomposites were fabricated with plant engineered pure amylose (AM), produced in bulk quantity in transgenic barley grain, and cellulose nanofibers (CNF), extracted from agrowaste sugar beet pulp. Morphology, crystallinity, chemical heterogeneity, mechanics, dynamic mechanical, gas and water permeability, and contact angle of the films were investigated. Blending CNF into the AM matrix significantly enhanced the crystallinity, mechanical properties and permeability, whereas glycerol increased elongation at break, mainly by plasticizing the AM. There was significant phase separation between AM and CNF. Dynamic plasticizing and anti-plasticizing effects of both CNF and glycerol were demonstrated by NMR demonstrating high molecular order, but also non-crystalline, and evenly distributed 20 nm-sized glycerol domains. This study demonstrates a new lead in functional polysaccharide-based bioplastic systems.

Autoclaving and extrusion improve the functional properties and chemical composition of black bean carbohydrate extracts.

Common beans (Phaseolus vulgaris L.) are rich in starch with a high content of amylose, which is associated with the production of retrograded and pregelatinized starch through thermal treatments. The purpose of this study was to evaluate the composition, morphology, thermal, functional, and physicochemical properties of carbohydrate extracts (CE) obtained from autoclaved (100 and 121 °C) and extruded (90, 105, and 120 °C) black beans. After evaluation of the functional properties, the CE from autoclaved beans at 100 °C for 30 min and 121 °C for 15 min 2×, and extruded beans at 120 °C and 10 rpm, were selected to continue the remaining analysis. Autoclaving treatments at 100 °C for 30 min and 121 °C for 15 min 2× showed a reduction of resistant starch by 14.4% and 26.6%, respectively, compared to dehulled raw bean CE. Meanwhile, extrusion showed a reduction in resistant starch of 54.2%. Autoclaving and extrusion treatments also decreased the dietary fiber content. Extrusion reduced almost entirely the content of α-galactooligosaccharides, in comparison to dehulled raw bean CE. The results showed differences in color and granule morphology. The onset, peak, and conclusion temperatures, transition temperature range, and enthalpy of autoclaved and extruded bean CE were lower than dehulled raw bean CE. The CE from autoclaved and extruded beans contain retrograded and pregelatinized starch, which could be incorporated in food products as a thickening agent for puddings, sauces, creams, or dairy products. PRACTICAL APPLICATION: Thermally treated black bean carbohydrate extracts are rich in starch, fiber, and protein. Because these extracts are already cooked, they can be added to products that do not require a thermal process such as puddings, sauces, creams, or dairy products, acting as a thickening agent.

Effects of high temperature during two growth stages on caryopsis development and physicochemical properties of starch in rice.

Global warming may affect the development of rice at different growth stages, thereby decreasing rice yield and deteriorating grain quality. The difference in rice responses to high temperature during primordial differentiation (PD) and pollen filling (PF) stages has been rarely studied. In this paper, two temperature treatments (40 °C and 30 °C) at the two stages (PD and PF) were imposed to four rice groups under the controlled temperature chambers. Compared with rice under normal temperature, high temperature-stressed rice showed accelerated growth rate, smaller caryopsis and decreased yield. Moreover, high temperature affected the starch physicochemical properties, resulting in lower apparent amylose content and higher order degree, gelatinization temperatures, and thereby increased peak, trough and final viscosities in starch. High temperature during PD stage inhibited cell development and starch deposition, thus leading to small starch granule and low retrogradation. However, temperature-stressed rice during PF stage showed increased starch accumulation and larger granule size. Therefore, effects of high temperature during the two stages on caryopsis development and starch properties were partly similar but also notably different. These results enriched and deepened the study of high temperature-stressed rice and served as an important reference for the processing and utilization of rice starch in food industry.

Characterization of amylose and amylopectin fractions separated from potato, banana, corn, and cassava starches.

Analytical techniques such HPSEC, DSC, and TGA have been employed for amylose determination in starch samples, though spectrophotometry by iodine binding is most commonly used. The vast majority of these techniques require an analytical curve, using amylose and amylopectin standards with physicochemical properties similar to those found in the original starch. The current study aimed to obtain the amylose and amylopectin fractions from potato, banana, corn, and cassava starches, characterize them, and evaluate their behavior via thermogravimetric curves. Blue amylose iodine complex and HPSEC-DRI methods have obtained high purity amylose and amylopectin fractions. All molecular weights of the obtained amylose and amylopectin fractions were similar to those presented in other reports. Different results were obtained by deconvolution of the amylopectin polymodal distribution. All amyloses presented as semi-crystalline V-type polymorphs, while all amylopectin fractions were amorphous. The Tg of all Vamyloses presented were directly proportional to their respective crystalline index. TGA evaluations have shown that selective precipitation of amylose with 1-butanol strongly changes its thermal behavior. Therefore, the separation procedure used was an ineffective pathway for obtaining standards for thermal studies.

Composition, Granular Structure, and Pasting Properties of Native Starch Extracted from Plectranthus edulis (Oromo dinich) Tubers.

Chemical composition, granular morphology and pasting properties of native starch extracted from tubers of Plectranthus edulis were analyzed. Starch was extracted from tubers of 6 accessions collected from 4 different areas in Ethiopia. Particle size analysis (PSA) and cryo-scanning electron microscope (cryo-SEM) imaging were used to examine the granular morphology and visualize the starch paste, respectively. Pasting properties, water absorption, and gelation capacity were compared. A wide range was found for the amylose (14.2% to 23.9%), calcium (216 to 599), potassium (131 to 878), and phosphorus (1337 to 2090) contents (parts per million per dry matter). PSA showed a bimodal distribution containing small spherical (14.6 µm) and large ellipse-shaped (190.4 µm) granules. Major differences were found for the pasting with peak viscosities differing from 3184 to 7312 mPa⋅s. Starch from accessions Chencha and Inuka showed a difference in packing density as clearly seen through cryo-SEM image at 75% of the peak viscosity (PV), and the granular integrity was mainly responsible for the significant difference in their PV and breakdown. Principal component analysis revealed 2 distinct groups: native starch extracted from accessions at the Wolayta zone (Inuka, Lofua, and Chenqoua) and other accessions (Jarmet, Arjo white, and Chencha). The study revealed the potential of P. edulis starch for its application in food industries. However, the inherent variation due to environmental conditions on physicochemical properties of the starch needs further investigation. PRACTICAL APPLICATION: Plectranthus edulis is cultivated in considerable amounts throughout Ethiopia, which makes it a valuable starch source. Due to its low tendency to retrograde, it could be applied in food industry as an equivalent for the current starch sources. Moreover, the low amylose content makes it preferable for an application in refrigerated foods as this unique quality trait prevents syneresis in end products during storage. Based on the significantly higher pasting temperature of the studied P. edulis starch extracts, it can form an alternative for potato starch, which is less suitable for its use in pasteurized foods.

In vitro digestibility and changes in physicochemical and structural properties of common buckwheat starch affected by high hydrostatic pressure.

High hydrostatic pressure (HHP), a non-thermal processing technology, was applied at 120, 240, 360, 480, and 600MPa to assess its effect on the in vitro digestibility, physicochemical, and structural properties of common buckwheat starch (CBS). HHP treatment resulted in CBS granules with more rough surfaces. With the increasing pressure level, amylose content, pasting temperature, and thermal stability substantially increased and relative crystallinity, hardness, swelling power, and viscosity decreased. At 120-480MPa, HHP did not affect the 'A'-type crystalline pattern of CBS. However, at 600MPa, HHP contributed to a similar 'B'-type pattern. Compared with native starch, HHP-modified CBS samples had lower in vitro hydrolysis, reduced content of rapidly digestible starch, and increased levels of slowly digestible starch and resistant starch. These results revealed that the in vitro digestibility, physicochemical, and structural properties of CBS are effectively modified by HHP.

Structural and thermodynamic properties of starches extracted from GBSS and GWD suppressed potato lines.

A combined DSC-SAXS approach was employed to study the effects of amylose and phosphate esters on the assembly structures of amylopectin in B-type polymorphic potato tuber starches. Amylose and phosphate levels in the starches were specifically engineered by antisense suppression of the granule bound starch synthase (GBSS) and the glucan water dikinase (GWD), respectively. Joint analysis of the SAXS and DSC data for the engineered starches revealed that the sizes of amylopectin clusters, thickness of crystalline lamellae and the polymorphous structure type remained unchanged. However, differences were found in the structural organization of amylopectin clusters reflected in localization of amylose within these supramolecular structures. Additionally, data for annealed starches shows that investigated potato starches possess different types of amylopectin defects. The relationship between structure of investigated potato starches and their thermodynamic properties was recognized.

[The study on the extraction and the antivirus activity of amylose extracted from Grateloupia filicina].

OBJECTIVE: To determine the activity of anti-Herpes simplex II virus (HSV-2) of amylose extracted from Grateloupia filicina. METHODS: Grateloupia filicina amylose was extracted by five kinds of abstraction methods and its suppression on Herpes simplex II virus was observed on cell level in three aspects: the drug activity of protecting cell, the drug influence of HSV-2 proliferation and the drug synthesis action of HSV-2. RESULTS: Grateloupia filicina had prominence anti-Herpes simplex II virus activity, IC50 of amylose extracted by water distilling and ethanol sedimentation was 5.80 microg/ml. CONCLUSION: It suggest that the antivirus activity happen in the stage of HSV-2 binding, adsorption and ingression with Vero cell.

[Screening of glucosidase inhibitors from various fractions of Mulberry leaves].

OBJECTIVE: To search for glucosidase inhibitors of various fractions extracted from mulberry leaves. METHOD: The constituents of mulberry leaves water fraction were prepared by the process of boiling, condensing, precipitating, exchanging with resins and rinsing. In vitro glucosidase inhibitory activities were examined by photometric bioassay derived from rats. To investigate in vivo effect of lowering blood glucose, the mouse blood glucose level was assayed by glucose tolerance experiments. RESULT: The glucosidase inhibitory activities were found in all the constituents of alkaloids, flavones and amyloses, the alkaloid constituent being the strongest. CONCLUSION: The effect of reducing blood glucose of mulberry leaves is related to the inhibitory activities against glucosidase of different constituents.

Molecular fractionation of starch by density-gradient ultracentrifugation.

Amylose and amylopectin in corn and potato starches were fractionated by centrifugation at 124,000g for 3-72 h at 40 degrees C in a gradient media, Nycodenz, based on their sedimentation rate differences. The fractions were collected from a centrifuge tube, and then analyzed by the phenol-sulfuric acid method and iodine-binding test. Amylopectin, a large and highly branched starch molecule, migrated faster than amylose and quickly reached its isopycnic point with a buoyant density of about 1.25 g/mL, exhibiting a sharp and stable carbohydrate peak. Amylose, which is a relatively small and linear molecule, however, migrated slowly in a broad density range and continued moving to higher density regions, eventually overlapping with amylopectin peak as the centrifugation continued. This could indicate that the buoyant density of amylose is similar to that of amylopectin. Under centrifugal conditions of 3 h and 124,000g, amylose and amylopectin molecules were clearly separated, and the presence of intermediate starch molecules (11.5 and 7.7% for corn and potato starch, respectively) was also observed between amylose and amylopectin fractions. The amylose content of corn and potato starches was 22.6 and 21.1%, respectively, based on the total carbohydrate analysis after the ultracentrifugation for 3 h. In alkaline gradients (pH 11 or 12.5), the sedimentation rate of starch molecules and the buoyant density of amylopectin were reduced, possibly due to the structural changes induced by alkali.

Linear beta-mannose-containing polysaccharide, beta-xylan, and amylose from the cultured photobiont Trebouxia sp. of the ascolichen Ramalina celastri.

The cultured photobiont Trebouxia sp. of Ramalina celastri was successively extracted at 100 degrees C with hot water, 2% aqueous KOH, and 10% aqueous KOH to give polysaccharide-containing fractions A (2.9%), B (3.9%), and C (0.9% yield) respectively. The intact biont contained 3.8% amylose, which was present in each fraction, and was identified by a blue color formed with iodine solution. In fraction A, and following retrogradation from aqueous solution, it was characterized by (13)C-NMR spectroscopy. Fraction B was treated with alpha-amylase to give a water-soluble fraction consisting mainly of beta-mannose-containing polysaccharides (1.5% yield), whose main component had dn/dc 0.162 and M(r) 17 kDa. Fraction C was subjected to freeze-thawing and the precipitate was treated with alpha-amylase to give a resistant, linear, low molecular mass (1-->4)-linked beta-xylan. The beta-D-mannopyranan preparation contained mainly of 3-O- (28%), 4-O- (11%), and 6-O-substituted Manp units (35%), with 3-O-substituted Rhap units (11%). A controlled Smith degradation provided a beta-mannan with nonreducing end- (8%), 3-O- (85%) and 6-O-substituted units, showing (1-->3)- and (1-->6)-linked structures in the original polysaccharide. These could be present as block-type structures.

A simple preparative method for the isolation of amylose and amylopectin from potato starch.

The defatted starch was dispersed in NaOH (1 M) and neutralized with HCl (1 M). The amylose 1-butanol complex is adsorbed on defatted cellulose powder in the solvent system containing acetate buffer (pH 4.8,0.1 M) + urea (2 M) + 1-butanol (8.5%, v/v). The complex adsorbed on cellulose powder is separated by centrifugation (2418 g). The sediment is washed with the solvent system-I to obtain the intermediate fraction. The adsorbed amylose is eluted with urea (2 M) in acetate buffer (pH 4.8, 0.1 M). The amylose, intermediate fraction and amylopectin were precipitated with ethanol, washed free of urea and air dried. They were characterized by determining their blue value and beta -amylolysis limit.