Granular Potato Starch Research Articles

Specific Modification of Granular Potato Starch by Means of Partial Debranching Using Pullulanase

AbstractNative potato starch (PS‐N) is enzymatically modified in the granular state using pullulanase (PUL) for the purpose of a specific partial molecular degradation of the polymers. The PUL compound is added to the aqueous starch suspension (40%, w/w) and processed. The process parameters are varied systematically (enzyme dosage [ENZ] 4/20 mL; pH of the suspension [pH 4.7/7.3]; hydrolysis temperature [TEMP] 40/50 °C, and hydrolysis duration [TIME] 20/120 min) and a new‐developed heat‐induced enzyme inactivation approach (storage of the partially dewatered moist starch for 120 min at 100 °C) is intended to terminate the hydrolysis. Morphological (LM, SEM, and CLSM) and thermal characterization (DSC) of the starch products indicate a partial damage of the granules and a partial loss of the semicrystalline structure owing to the heat treatment, which is confirmed by XRD. The molecular properties (SEC‐MALS‐DRI) are mainly controlled by the factors ENZ, pH, and TEMP, but the intended degradation of the amylopectin (AP) by cleavage of the α‐1,6‐linkages (debranching) is accompanied by a molecular degradation of the amylose (AM) fraction. However, both specificity of the hydrolysis and achievable gel strength are remarkably improved compared to acid‐thinned products.

Effect of hydrothermal treatment on physicochemical properties of amorphous granular potato starch (AGPS)

Using restructuring technology, A- or B-type crystalline granular potato starch was produced from amorphous granular potato starch (AGPS). AGPS was prepared using ethanol-heat processing, and hydrothermal treatments were performed with different moisture contents (18, 29, 200% d.b.) and temperatures (4, 25, 40, 60, 80 °C) for 3 weeks. AGPS showed no endothermic peak in a DSC thermogram, while hydrothermally treated AGPS (HAGPS) revealed endothermic peaks. In X-ray diffraction, AGPS displayed an amorphous pattern, and HAGPS displayed A- or B-type crystalline patterns depending on treatment temperature and moisture content. Neither AGPS nor HAGPS had typical RVA pasting curves, and their viscosities gradually increased. Raman spectroscopy and FT-IR confirmed that ordered structure and crystalline regions increased in HAGPS. Resistant starch (RS) and slowly digestible starch (SDS) contents of HAGPS increased but rapidly digestible starch (RDS) content decreased compared to AGPS. These results elucidated that hydrothermal treatment could change the physicochemical properties of AGPS and produce an identical material, such as granular potato starch with A-type and B-type crystalline granular potato starch.

Enzymatic Modification of Granular Potato Starch Using Isoamylase—Investigation of Morphological, Physicochemical, Molecular, and Techno‐Functional Properties

AbstractGranular potato starch is modified using the debranching enzyme isoamylase. The modification is performed in aqueous suspension (40% w/w) at 35 °C by grading the volume (100, 250, and 400 µL/50 g of starch, 200 U · mL−1) of enzyme solution added. The starch products obtained are comprehensively investigated in terms of morphological (scanning electron microscopy), structural (X‐ray diffraction), thermal (differential scanning calorimetry), techno‐functional (solubility, hot paste viscosity, gel strength), and molecular properties (size exclusion chromatography‐multi angle laser light scattering‐differential refractive index detection). The granular integrity is basically preserved after modification and a molecular degradation predominantly of the amylopectin by debranching is proved. However, a slight reduction of the weight average molar mass of the amylose fraction is found too. In addition, the intended partial molecular degradation of the starch polysaccharides, the effect of the preparation procedure including washing with ethanol and grinding impacts several starch characteristics conspicuously.

The supporting effect of ultrasound on the acid hydrolysis of granular potato starch

The modification of starch owing to acid-thinning (AT) is intensified by a concomitant ultrasound (US) treatment, but the specific effect of the US on molecular changes, and the respective contribution of the single impacts are still unknown. The present study investigates the supporting effect of the US via examination and comparison of the single modifications [general conditions: starch slurry (40 % w/w), 40 °C, stirring; US: gradation of amplitude (50 and 100 %), cycle (0.50 and 0.75) and sonication time (20 and 60 min); AT: 0.36 M HCl, reaction time of 4 h] with the corresponding US assisted AT modified starches (US-AT) in terms of granular, molecular and functional properties. The US induced essentially a molecular degradation (debranching) of the amylopectin (AP), whereas chain cleavage within the amylose (AM) wasn’t excluded completely. Altogether, the US was estimated to be a separate and assisting modification rather than an AT accelerating component.

Enzymatic Modification of Granular Potato Starch ‐ Effect of Debranching on Morphological, Molecular, and Functional Properties

The debranching enzyme pullulanase (PUL) is used in order to conduct a partial conversion of a regular granular potato starch (PS) improving the techno‐functional properties when used as a gelling agent. The starch is hydrolyzed systematically by grading the amount of a technical enzyme solution added (1, 2, 3, 4, 5, 10, 20, and 40 mL PUL solution) resulting 400 g of a 20% (w/w) suspension. Morphological characteristics of the granules (scanning electron microscopy, SEM), swelling behavior (differential scanning calorimetry, DSC), polymer solubility, hot paste viscosity, gel strength, and molecular properties of the starch samples (size exclusion chromatography‐multi angle laser light scattering‐differential refractive index detection, SEC‐MALS‐DRI) as well as the respective separated amylose (AM) and amylopectin (AP; size exclusion chromatography‐conventional standard calibration‐differential refractive index detection, SEC‐cal‐DRI) branch chains fractions are comprehensively analyzed. The granule surface is visibly affected, but the granular structure is largely intact. The DSC gelatinization characteristics are impacted manifold, and the solubility, in particular when disintegrated using pressure cooking, increases. The hot paste viscosity decreases, while the ability to form mechanically stable gel structures increases due to modification. The weight‐average molar mass (Mw) decreases from 38.2 × 106 (native) to 2.3 × 106 g mol−1 (40 mL PUL solution), in particular due to cleavage of α‐1,6‐linkages within the AP. Surprisingly, the detailed analysis reveals a concomitant and remarkable degradation of the AM‐fraction. The partial hydrolysis of granular starch by means of a debranching enzyme is shown to be basically a very specific, fast, and serious alternative to e.g., the acid‐tinning process.

Partial Hydrolysis of Granular Potato Starch Using α-Amylase - Effect on Physicochemical, Molecular, and Functional Properties

Potato starch (PS) is enzymatically modified using α‐amylase and comprehensively characterized. Modified PS is prepared by adding different amounts of α‐amylase (0.04, 0.08, 0.16, and 0.33 mL of an enzyme solution (LpHera, Novozymes A/S) to 400 g of a 40% w/v aqueous starch suspension and reacting for 15 min at 40 °C. Morphological characteristics (SEM), pasting (viscosity profile, thermal behavior‐DSC) and molecular properties (SEC‐MALS‐DRI), carbohydrates solubility, hot paste shear viscosity, and gel strength are analyzed. The morphological characteristics are significantly affected by the α‐amylase. The surface of the granules shows small cracks and holes. In regard to the characteristic pasting parameters, there are significantly decreased values after hydrolysis. However, the DSC gelatinization properties are slightly impacted by the modification. The solubility of the starch polymers is increased by the increase of both the enzyme dosage and the disintegration temperature applied (95 and 145 °C). Moreover, the molecular composition of the solubilized starch is impacted, too. The investigation of molecular dispersed solutions demonstrates the strong degradation of both amylose (AM) and amylopectin (AP). An increasing enzyme concentration led to a systematically decreased Mw in the samples. The degradation within the amorphous areas is presumed to be faster, similar to acid hydrolysis in native granular starch. However, gelation properties of the enzymatically modified starches are not perceptible. The gradual depolymerization effected the reduction of the hot paste viscosity accordingly.

An antioxidant rich novel β-amylase from peanuts (Arachis hypogaea): Its purification, biochemical characterization and potential applications

β-Amylase from un-germinated seeds of peanut (Arachis hypogaea) was purified to apparent electrophoretic homogeneity with final purification fold of 205 and specific activity of 361μmol/min/mg protein. The enzyme was purified employing simple purification techniques for biochemical characterization. The purified enzyme was identified as β-amylase with Mr of 31kDa. The enzyme displayed its optimum catalytic activity at pH5.0 and 60°C with activation energy of 4.5kcal/mol and Q10 1.2. The enzyme displayed Km and Vmax values, for soluble potato starch of 1.28mg/mL and 363.63μmol/min/mg, respectively. Thermal inactivation of β-amylase at 65°C resulted into first-order kinetics with rate constant 0.0126min−1 and t½ 55min. The enzyme was observed to act on native granular potato starch, which could minimize the high cost occurring from solubilization of starch in industries. Enzyme fractions scavenge 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical, indicating its antioxidative nature. In addition, the purified β-amylase was successfully utilized for the improvement of antioxidant potential of wheat. These findings suggest that β-amylase from peanuts have potential application in food and pharmaceutical industries.

Preparation and characterization of amorphous granular potato starches (AGPS) and cross-linked amorphous granular potato starches (CLAGPS)

Amorphous granular potato starch (AGPS) was prepared through heat treatment of native potato starch (NPS) at 94°C with 53% EtOH, while cross-linked amorphous granular potato starch (CLAGPS) was prepared through cross-linking of NPS with sodium trimetaphosphate/sodium tripolyphosphate (STMP/STPP, 99:1) and heat treatment. Light and polarized microscopy showed that both AGPS and CLAGPS maintained their granule shapes but lost birefringence. DSC and XRD of both AGPS and CLAGPS also revealed complete gelatinization. On the other hand, CLAGPS exhibited no RVA pasting viscosity and AGPS had a higher final viscosity than NPS or CLAGPS. AGPS had a higher RS content than gelatinized potato starch, while that of CLAGPS did not increase, despite the cross-linking modification. Thus, AGPS and CLAGPS had distinct physicochemical properties from each other and from NPS, suggesting their potential applicability to the food, textile, and paper industries.

Characterization of acid hydrolysis of granular potato starch under induced electric field

Compared to traditional heating methods by static immersion or stirring, induced electric field (IEF) treatment can significantly increase hydrolysis rate of potato starch. The aim of this study was to examine the characterization of acid hydrolysis of granular potato starch under IEF. Potato starch was hydrolyzed using 0.15 mol/L HCl combined with IEF (IEF-HCl) at an excitation voltage of 75 V from 4 h to 120 h. The changes in granular, crystal, and molecular structure of starch granules during IEF-HCl hydrolysis were investigated. Scanning electron microscope analysis showed the outer surface of potato starch was firstly attacked by free ions and then the inner structures was completely disrupted and broken into pieces. X-ray diffraction studies indicated that the crystallinity decreased from 38.92% to 34.9% after 4-h hydrolysis, and then gradually increased to 41.88% as hydrolysis time increased to 96 h, but decreased thereafter. The weight-average molecular weight dramatically decreased from 104.7 × 106 Da to 9.291 × 106 Da in the first 24 h and then decreased gradually. These results suggested that there were three steps in the catalytic process of IEF-HCl hydrolysis. Initially, hydrogen ions destroyed the external crystalline shell of granules. Next, hydrogen ions attacked the loose amorphous region and dense crystalline part within starch granules simultaneously. Finally, the remaining crystalline region was hydrolyzed slowly.

Continuous-flow electro-assisted acid hydrolysis of granular potato starch via inductive methodology

The induced electric field assisted hydrochloric acid (IEF-HCl) hydrolysis of potato starch was investigated in a fluidic system. The impact of various reaction parameters on the hydrolysis rate, including reactor number (1-4), salt type (KCl, MgCl2, FeCl3), salt concentration (3-12%), temperature (40-55°C), and hydrolysis time (0-60h), were comprehensively assessed. Under optimal conditions, the maximum reducing sugar content in the hydrolysates was 10.59g/L. X-ray diffraction suggested that the crystallinity of IEF-HCl-modified starches increased with the intensification of hydrolysis but was lower than that of native starch. Scanning electron microscopy indicated that the surface and interior regions of starch granules were disrupted by the hydrolysis. The solubility of IEF-HCl-modified starches increased compared to native starch while their swelling power decreased, contributing to a decline in paste viscosity. These results suggest that IEF is a notable potential electrotechnology to conventional hydrolysis under mild conditions without any electrode touching the subject.

에탄올을 활용한 무정형입자감자녹말(Amorphous Granular Potato Starch) 제조방법 최적화

Recently, amorphous granular starch (AGS) or non-crystalline granular starch (NGS) is of great interest because it has specific physicochemical properties compared to native starches. Various approaches have been taken to prepare gelatinized starch while still maintaining its granular shape. The granular cold-water soluble starch (GCWS) can be prepared by alcoholic-alkaline treatment or by using liquid ammonia and ethanol. However, these starches exhibit significant deformation and shrinking, and chemical treatments may raise safety issues for their potential food applications. Therefore, in this study, the optimization of preparation method for amorphous granular potato starch (AGPS) was investigated using ethanol and heat treatments. Response surface methodology (RSM) and central composite design (CCD) were used to find the optimum conditions for AGPS preparation based on granule integrity and birefringence. Optimum conditions were 53.3% ethanol and 93.87°C heat treatment for 15 min. Prepared AGPS maintained its granular structure and lost birefringence, crystallinity, and DSC amylopectin melting peak, suggesting that proper AGPS could be made using optimized conditions.

Enzymatic degradation of granular potato starch by Microbacterium aurum strain B8.A

Microbacterium aurum strain B8.A was isolated from the sludge of a potato starch-processing factory on the basis of its ability to use granular starch as carbon- and energy source. Extracellular enzymes hydrolyzing granular starch were detected in the growth medium of M. aurum B8.A, while the type strain M. aurum DSMZ 8600 produced very little amylase activity, and hence was unable to degrade granular starch. The strain B8.A extracellular enzyme fraction degraded wheat, tapioca and potato starch at 37 °C, well below the gelatinization temperature of these starches. Starch granules of potato were hydrolyzed more slowly than of wheat and tapioca, probably due to structural differences and/or surface area effects. Partial hydrolysis of starch granules by extracellular enzymes of strain B8.A resulted in large holes of irregular sizes in case of wheat and tapioca and many smaller pores of relatively homogeneous size in case of potato. The strain B8.A extracellular amylolytic system produced mainly maltotriose and maltose from both granular and soluble starch substrates; also, larger maltooligosaccharides were formed after growth of strain B8.A in rich medium. Zymogram analysis confirmed that a different set of amylolytic enzymes was present depending on the growth conditions of M. aurum B8.A. Some of these enzymes could be partly purified by binding to starch granules.

Synthesis and characterisation of starch cuprate

The cupration of granular potato starch with ammonium tetrachlorocuprate(II) was performed by a 20min lasting microwave-assisted process and by 40min convectional heating. In both cases the degree of esterification (DE) did not exceed 6.4×10−3. A higher dose of cuprate had a positive effect on DE, regardless of whether the microwave irradiation or the convectional heating was applied, and on the thermal stability of the starch cuprate produced in the microwave-assisted way. As a result of cupration, the hydroxyl ligand of the starch d-glucose units was replaced by the chloride ligand of the tetrachlorocuprate(II) anion. In the starch cuprate formed in the microwave-assisted process, the cuprate anion additionally coordinated water molecules. The cupration reduced starch crystallinity, as indicated by X-ray diffractometry and differential scanning calorimetry.

Synthesis of Carboxymethyl Starch with High Degree of Substitution by a Modified Dry Process

Granular carboxymethyl starch (CMS) with high degree of substitution (DS) was synthesized using a modified dry process. The carboxymethylation reaction was carried out with granular potato starch, solid NaOH and sodium monochloroacetate (SMCA). The effects of reaction temperature, reaction time, molar ratio of NaOH and SMCA to starch on the degree of substitution (DS) and the reaction efficiency (RE) of CMS were investigated. High DS up to 0.78 was obtained for reaction at 323 K for 6 h with molar ratio of NaOH and SMCA to starch being 2:2:1. CMS was characterized by Fourier transform infrared spectrophotometer and scanning electron microscopy.

Microwave-assisted preparation of potato starch silicated with silicic acid

Abstract Application of microwave irradiation for the silication of granular potato starch with silicic acid, and the properties of silicated starch were investigated. Potato starch was esterified on 20 min microwave irradiation of starch with silicic acid, applying the power of 450 or 800 W and, for comparison, on 120 min convectional heating of the reagent blend at 100 °C. The degree of esterification and the reaction efficiency did not depend on the silication mode, but they increased with increasing power of the microwave irradiation. The degree of esterification increased with the reagent ratio. The esterification provided either monoesters or crosslinked esters of retained granularity, insignificantly disrupted crystallinity, and high hydrophobicity. An increased dose of silicic acid in the reaction mixtures provided thermally more stable crosslinked esters.

Graft Polymerization of Vinyl Acetate onto Potato Starch Dissolved in an Alkaline Solution

AbstractGraft polymerization of vinyl acetate (VAc) onto gelatinized and dissolved granular potato starch has been carried out using an initiation system of ceric ammonium nitrate (CAN)/nitric acid (HNO3) at 50°C. The granular starch was dissolved in an aqueous alkaline solution (0.25 M NaOH) for 24 h before graft reaction. The effects of reaction variables, such as the concentrations of acid, monomer, and initiator, on the grafting parameters of prepared starch/VAc copolymers have been investigated in both grafting methods for comparison. Although the scanning electron microscopy (SEM) images showed a rather similar homogeneous structure for dissolved and gelatinized starch, a higher grafting level, especially at lower monomer concentrations, was obtained for the copolymers prepared using the dissolved starch. A larger number of reactive sites uniformly created on the starch molecules led to greater accessibility of the monomer and improved considerably the grafting efficiency in the grafting conditions using the dissolved starch. The effects of the grafting methods on the microstructure, morphology, and thermal stability of the resulting copolymers have been studied by Fourier‐transform infrared (FTIR) spectroscopy, scanning electron microscopy, and thermogravimetric analysis (TGA), respectively. The TGA results showed that the grafting of VAc onto dissolved starch led to the formation of more thermally stable graft copolymers.

Mediator facilitated, laccase catalysed oxidation of granular potato starch and the physico-chemical characterisation of the oxidized products

The primary hydroxyl groups in potato starch were selectively oxidized to the corresponding aldehyde and carboxylic acid functionalities by mediators like TEMPO, using laccase from fungi as catalytic oxidant and oxygen as the primary oxidant. Oxidized starch products with degree of substitution (DS CHO ranging from 0.16 to 16.4/100AGU and DS COOH from 0.01 to 3.71 carboxyl groups/100AGU) were obtained with mediator facilitated enzymatic oxidation. Maximum conversion of the primary alcohol group was obtained at a pH of 5, with TEMPO as mediator, under oxygen bubbling and two step administration of Trametes versicolor laccase (200 + 200 nkat/g of starch). The oxidized products were characterised by IR spectroscopy, XRD and thermal studies. In the oxidized samples, the larger starch granules exhibited cracks and fractures in comparison to the smaller granules which were relatively unaffected, as observed from the microstructural studies.

Microwave-assisted boration of potato starch

Granular potato starch was successfully borated with boric acid and sodium tetraborate decahydrate (borax) in a microwave-assisted solid state reaction. Products of starch boration reached (dependently on the conditions of the process) the maximal value of the degree of esterification (DE) equal to 0.27 when boric acid was applied, and 0.18 when borax was used. DTA, TG, DTG and FT-IR methods revealed that boration of starch provided boron esters or borate complexes. High-pressure size exclusion chromatography (HPSEC), DSC and X-ray diffraction showed that although the boration of starch caused changes in its macrostructure, the thermal stability of borated starch was enhanced even by 20 °C when compared with native product, with larger stability exhibited by complexes than by esters. The thermal stability of the borated starch increased with an increase in DE. After modification, granularity of starch was retained, as was indicated by the scanning electron microscopy.

Surface effects in the acetylation of granular potato starch

The occurrence of surface effects in the acetylation of granular potato starch with acetic anhydride to degrees of substitution 0.04–0.2 was studied by two different approaches. The first approach involved the fractionation of granular starch acetates into five different size classes and analysis of their acetate content. Alternatively, two narrow size fractions of potato starch acetate granules were surface-peeled by chemical gelatinization in 5 M CaCl 2, and the remaining cores were analyzed for acetyl content at different peeling levels. It was established that true surface peeling occurs in this medium and that the ester linkages are stable under the conditions applied. Both approaches led to the conclusion that the acetylation of potato starch granules is accompanied by a pronounced surface effect. The surface peeling method allows determination of the extent of substitution as a function of the radial position in the starch granule.

Esterification of starch with sodium selenite and selenate

Granular potato starch was esterified with selenous and selenic acid sodium salts in the microwave assisted solid state reaction. Degree of esterification (DE) in both cases did not exceed 3.01 × 10 −2. Reaction with selenite provided higher DE. DE increased with the applied power of the microwave oven but increased amount of admixed selenium reagents had no positive effect upon DE. The thermal stability of products was higher than that of native starch. The esterification retained granularity of starch but the crystallinity of granules partly ceased as indicated by scanning electron microscopy (SEM) and X-ray diffractometry, respectively.