Effect of phosphoric acid treatment on physicochemical,functional, and structural properties of starch extracted from yam (Dioscorea rotundata)

This work was designed to elucidate selected physicochemical, functional, and structural properties of native and modified yam (Dioscorea rotundata) starch. The isolated starch was chemically modified using 5, 10, 15, 20, and 25% phosphoric acid solution at 50°C for 1 h, and yield, swelling power, gelation, water holding capacity, paste clarity, blue value, and amylose and amylopectin content of the native and modified yam starch were determined. Structural changes in the native and starch modified with 25% phosphoric acid were evaluated using Fourier transform infrared spectroscopy and optical microscopy. The result showed that the yield, swelling power, water holding capacity, paste clarity, blue value and amylose and amylopectin content of native yam starch was 33.38% (217 g), 3.84 g/g, 1.0 v/g, 10%, 0.52 and 25.96, respectively, whereas gelation study of the native and modified starch indicated that native starch was viscous and modified starch firm. However, yield, swelling power, water holding capacity, paste clarity, blue value, and amylose content of modified yam starch reduced in a dose dependent manner with phosphoric acid. The reduction in the values of the various functional properties could be associated with the effect of phosphoric acid on the starch granular structure. The result of Fourier transform infrared spectroscopy and optical microscopy revealed that the yam starch was modified by phosphoric acid with changes in functional groups spectra such as –OH stretch (3177 cm^?1), H₂O absorbed (1644 cm^?1) (amorphous region), C-H stretch (2923 cm^?1), CH₂O (1253 cm^?1), and C-O-C (1078 cm^?1) when compared to native starch. The morphology of native and modified yam starch granules ranged from oval to eliptical. However, modified starch granules were rough in surface. In conclusion, the characterized physicochemical and functional properties and structure exhibited by native and modified yam starch indicated that, yam could be a cheap and valuable source of starch for industrial application.     

Steady and dynamic shear rheology of starches from different oat cultivars in relation to their physicochemical and structural properties

Starches isolated from eight oat cultivars were tested for their physicochemical, structural, and rheological properties. The isolated starches had low levels of ash and nitrogen contents with amylose ranging from 21.8 to 32.3 g/100 g. The amount of water released from starch gels decreased significantly (p < 0.05) with increase in freeze thaw cycle. The scanning electron micrographs revealed the presence of polygonal to irregularly shaped starch granules. All the starches exhibited A-type X-Ray diffraction pattern typically characteristic of cereal starches. The rheological properties of pastes were well described by the Herschel-Bulkley model at a shear rate of 0–100 s^?1 (R² > 0.99). The starch pastes behaved like a pseudoplastic fluid and exhibited shear thinning fluid characteristics with values of flow behaviour index considerably less than 1. Both the storage and loss moduli of the pastes increased sharply initially and then dropped after reaching the gelatinization peak. The magnitude of the dynamic rheological parameters varied significantly (p < 0.05) between the cultivars. All the starch pastes were highly elastic than viscous as evidenced by the lower tan δ values. Structure property relationships were established between starches using principal component analysis.     

Tenderization of Beef with Pineapple Juice Monitored by Fourier Transform Infrared Spectroscopy and Chemometric Analysis

For nondestructive monitoring of meat tenderizing processes, factor analysis, and evolving factor analysis (EFA) were applied to successively collected attenuated total reflectance-infrared spectra of beef after treatment with pineapple juice. Absorption around 1600 to 1500 cm^?1 and 1400 cm^?1 regions increased with time. After subtracting the starting spectrum from each of the succeeding spectra, factor analysis and EFA were applied to the resulting data matrix. Factor scores showed a time dependent change, but a clear difference between treated and reference beef was observed in factor 1. Eigenvalues calculated from EFA showed the existence of two vigorous digestion periods during tenderization, which supported the results from biochemical analysis.     

Structure,functionality, and digestibility of acetylated hulless barley starch

Hulless barley starch was extracted and further acetylated using acetic anhydride at different level (3.75, 7.5, 11.25 g/100 g) in this study. The structure changes and functional properties of acetylated hulless barley starches comparing to the native starch were evaluated and analyzed. The shape of granules remained unaltered with cracks formed after modification. Small- (1 μm) and large-sized (20 μm) were observed in four kinds of starches while granule particle sizes distribution changed dramatically. Four hulless barley starches presented A-type x-ray diffraction pattern, with relative crystallinity of 25.6, 27.1, 26.2, and 24.8% for native and acetylated starches. The infrared ratio of 1045/1024 and 1025/995 cm^?1, indicated the difference in long-range order of crystallinities and short-range order of double helices. Results observed in swelling power, gelatinization parameters, pasting viscosities, and in vitro digestibility indicated acetylated hulless barley starch’s potential as a functional food additive and a healthy ingredient.     

Comparative NMR relaxometry of gels of amylomaltase-modified starch and gelatin

With the aim of generating gelatin-like starch gel functionality, starches extracted from normal potato, high amylose potato, maize, waxy maize, wheat and pea and oxidized potato starch were modified with amylomaltase (AM) (4-α-glucanotransferase; E.C. 2.4.1.25) from Thermus thermophilus. Gel characteristics after storage for 1 and 10 days at 20 °C of 12.0% gels were assessed by monitoring proton relaxation for the resulting 51 enzyme-modified starches and two gelatins using low-field ¹H nuclear magnetic resonance (LF NMR) relaxometry. Discrete and distributed exponential analysis of the Carr–Purcell–Meiboom–Gill (CPMG) LF NMR relaxation data revealed that the pastes and gels contained one water component and that the spin–spin relaxation time constants (T₂) and distributions differed with respect to starch type and enzyme modification. Typically, AM modification resulted in starches with decreased T₂ relaxation time and a more narrow T₂ distribution indicating a more homogeneous water population. In contrast, treatment with a branching enzyme (BE) (EC 2.4.1.18) combined with AM increased T₂ relaxation time and a broadened T₂ distribution. As evaluated by the principal component analysis (PCA), long chains of amylopectin generated hard gels and decreased T₂ relaxation time at both day 1 and day 10. Especially at day 10, T₂ relaxation time could be predicted from the amylopectin chain length (CL) distribution. Reconstructed amylopectin CL distribution required to emulate gelatin LF NMR data suggest the importance of combined fractions of long (DP 60–80) and short (DP 10–25) amylopectin chains.     

Molecular Mobilities of Instant Starch Gels Determined by Oxygen-17 and Carbon-13 Nuclear Magnetic Resonance

The molecular mobility of both the water component and the starch component of three instant starches was determined by proton decoupled oxygen-17 (¹⁷O) and proton decoupled carbon-13 (¹³C) Nuclear Magnetic Resonance (NMR) spectroscopy. The effect of starch concentration and various storage conditions were studied. The molecular mobility of the water associated with each of the instant starches over all concentrations studied as measured by ¹⁷O NMR transverse relaxation rates was not much slower than that of free or bulk water. The effect of storage conditions on the molecular mobility and conformation of the starches, as monitored by proton decoupled ¹⁷O and ¹³C NMR, was in most cases small, despite the observed differences in retrogradation among the starches.     

Classification of cassava starch films by physicochemical properties and water vapor permeability quantification by FTIR and PLS

ABSTRACT:  Cassava starches are widely used in the production of biodegradable films, but their resistance to humidity migration is very low. In this work, commercial cassava starch films were studied and classified according to their physicochemical properties. A nondestructive method for water vapor permeability determination, which combines with infrared spectroscopy and multivariate calibration, is also presented. The following commercial cassava starches were studied: pregelatinized (amidomax 3550), carboxymethylated starch (CMA) of low and high viscosities, and esterified starches. To make the films, 2 different starch concentrations were evaluated, consisting of water suspensions with 3% and 5% starch. The filmogenic solutions were dried and characterized for their thickness, grammage, water vapor permeability, water activity, tensile strength (deformation force), water solubility, and puncture strength (deformation). The minimum thicknesses were 0.5 to 0.6 mm in pregelatinized starch films. The results were treated by means of the following chemometric methods: principal component analysis (PCA) and partial least squares (PLS) regression. PCA analysis on the physicochemical properties of the films showed that the differences in concentration of the dried material (3% and 5% starch) and also in the type of starch modification were mainly related to the following properties: permeability, solubility, and thickness. IR spectra collected in the region of 4000 to 600 cm⁻¹ were used to build a PLS model with good predictive power for water vapor permeability determination, with mean relative errors of 10.0% for cross-validation and 7.8% for the prediction set.     

Multi‐scale structural and digestion properties of wheat starches with different amylose contents

The physicochemical and digestion properties of three wheat starches with different amylose contents were studied. Scanning electron microscopy (SEM) showed they displayed a spherical disc‐like form, a lenticular shape and an irregular morphology, respectively. Compared with waxy and normal wheat starches, high‐amylose wheat starch (HAWS) was characterised by the presence of lower molecular weight amylose fraction, and its granules demonstrated the highest resistance to the cooking. The changes in the IR ratio 1022/999–1047/1022 cm^?1 following the gel storage suggested the molecules of HAWS are more readily to re‐associate and re‐organise into a more organised status than other two starches. The determination of glucose release showed that HAWS had the lowest digestion kinetics (P < 0.001), and this difference in the digestion properties between HAWS and the other two starches might imply that starch molecular structure, in particular amylose structure is another key factor for manipulating starch digestion property rather than amylose content alone.     

Influence of some chemical modifications on the characteristics of potato starch powders

The aim of this study was to determine the effect of chemical modification on selected physicochemical properties of potato starch powder. Esterification with acetic anhydride and adipic anhydride (E 1422 starch) caused the most pronounced changes in physicochemical parameters compared with native potato starch powder. In native and E 1422 starches, mean granule diameter changed from 23.1 to 25.4 μm, shape factor from 1.47 to 1.33, specific surface from 0.2115 to 0.1695 m² g⁻¹, porosity from 41.31% to 45.29%, water absorption increased up to 50%, and flow behavior changed from easy to cohesive. A microscopic analysis confirmed also the differences in the surface morphology showing the most rough surface of E 1422 starch. Despite broad variations in the diameter of individual starch granules, it was found that differently sized ridges and valleys on granule surface reflect porosity and water sorption values of the examined starches.     

Study on the physicochemical properties and in vitro digestibility of starch from yam with different drying methods

Four methods were applied to dry yam slices, and then, starches were isolated from dried yam slices. Starch isolated from fresh yam was as the study control, and physicochemical properties and in vitro digestibility of starches were studied. The results showed that the amylose content ranged from 12.62% to 28.25%, water‐binding capacity (WBC) from 111.67% to 262.88%, paste clarity from 2.1% to 6.23%, resistant starch (RS) from 66.60% to 88.49% and crystallinity from 11.27% to 25.52%. Compared with the control starch, hot air‐drying at 60 °C significantly decreased amylose content, paste clarity, RS and crystallinity, while increasing the WBC. Low levels of rapidly digestible starch and glucose and high RS levels were found in the starch from freeze‐drying yam. Digestibility of the starches was significantly correlated with amylose content, WBC, paste clarity and swelling power. The starch samples were divided into three groups by principal component analysis (PCA).     

Functional properties and retrogradation behaviour of native and chemically modified starch of mucuna bean (Mucuna pruriens)

Mucuna bean (Mucuna pruriens) starch was isolated and subjected to chemical modification by oxidation and acetylation. The proximate analysis of the non‐starch components of the native starch on a dry weight basis was 92 g kg^?1 moisture, 5 g kg^?1 ash, 2 g kg^?1 fat, 7 g kg^?1 crude fibre and 19 g kg^?1 protein. Chemical modification reduced the values for all the non‐starch components except the moisture level. For all the samples, swelling power and solubility increased as the temperature increased in the range 50–90 °C. The swelling power of mucuna native starch (MNS) and mucuna acetylated starch (MAS) increased with increasing acidity and alkalinity, while that of mucuna oxidised starch (MOS) only increased with increasing pH in the acidic range. The maximal solubility of all the starches was observed at pH 12. All the starch samples absorbed more oil than water. The lowest gelation concentration followed the trend MAS < MNS < MOS. Chemical modification reduced the gelatinisation temperature (Tp), while peak viscosity (Pv), hot paste viscosity (Hv) and cold paste viscosity (Cv) decreased after oxidation but increased following acetylation. The setback tendency of the native starch was reduced significantly after chemical modification. However, the breakdown value of MNS, 65 BU (Brabender units), was lower than that of MOS (78 BU) but higher than that of MAS (40 BU). Differential scanning calorimetry studies of gelatinisation and retrogradation revealed that chemical modification reduced the onset temperature (T_o), peak temperature (T_p) and conclusion temperature (T_c). Oxidation and acetylation reduced the gelatinisation and retrogradation enthalpies of the native starch. The enthalpy of retrogradation of the starches increased as the length of storage increased. Copyright © 2003 Society of Chemical Industry     

Investigations of Native and Resistant Starches and Their Mixtures Using Near-Infrared Spectroscopy

Resistant starches (RS) play important roles in our nutrition; therefore, the investigation of these starches is notably important. In our study, two native starches (maize and wheat) and two resistant starches (Hi-maize™260, high amylose maize starch as RS2 and Fibersym™70, phosphorylated wheat starch as RS4) were investigated as is and in their physical mixtures (samples containing 20%, 40%, 60% and 80% RS) using near-infrared (NIR) spectroscopy. The aim of our study was to examine the spectra of resistant starches and to differentiate the resistant starch components in different ratios by NIR spectroscopy. The differences of samples were presented in two characteristic absorption bands for carbohydrate: carbohydrate II (2,080–2,130 nm) and carbohydrate III (2,275–2,290 nm) regions. Additionally, principal component analysis (PCA) for all samples was carried out. It was shown that the increasing amount of amylose can be sensitively followed up in carbohydrate II region. The phosphorylated RS4 is not so characteristic probably due to the reduced mobility of amorphous chains; however, the RS4 addition can be observed. Additionally, it was proven that the carbohydrate III region is sensitive for the changes of amylose–amylopectin ratio as well. The wheat-based RS4 addition causes linear changes in maize-based mixtures; thus the botanical origin is determining in this region. The global PCA analysis justified that the RS2 addition can be sensitively followed up independent on the medium; however, the increasing amount of RS4 cannot be detected in the PCA plot. The loading spectra of PC1 component attribute great significance to the carbohydrate III region.     

Effect of peeling and unpeeling on yield,chemical structure,morphology and pasting properties of starch extracted from three diverse potato cultivars of Pakistan

The current study investigates the comparison and quality characteristics of starches isolated from potatoes using different processing methods from three commercial varieties: Lady Rosetta, Asterix and Challenger, for the first time in Pakistan. The analysis of variance revealed that starch yield significantly (P < 0.05) depended on total solids, peeling (12.7%, 12.0% and 12.0%) and unpeeling (15.0%, 14.0% and 14.0%) of potatoes compared to potato varieties for Lady Rosetta, Challenger and Asterix, respectively. Moreover, pasting properties, protein content, redness and yellowness were increased in those starches isolated without peeling while carbohydrates and lightness were increased in peeled potato starches. Furthermore, Fourier-transform infrared spectroscopy analysis revealed that protein (1200–1400 cm⁻¹) was present in starch extracted without peeling. Besides, scanning electron microscopy analysis revealed oval-shaped starch granules with no impurities in peeled potato starch. The findings suggest the suitability of peeling process for obtaining a high-quality pure starch.     

Raman spectroscopic study of the effects of microbial transglutaminase on heat-induced gelation of pork myofibrillar proteins and its relationship with textural characteristics

The effects of microbial transglutaminase (MTG) on heat-induced gelation of pork myofibrillar proteins (PMP) structural changes, textural properties were studied by Raman spectroscopy and texture profile analysis (TPA), respectively. And the relationships between the structural changes and textural characteristics were estimated by principal component analysis (PCA). Changes in the Raman spectra were interpreted as the occurrence of secondary structural changes in myofibrillar proteins with MTG added. Modifications in the amide I (1600-1700 cm^− 1) regions indicated a significant (p < 0.05) decrease in ??-helix content, accompanied by a significant (p < 0.05) increase in ??-sheets, ??-turns and random coil content due to the addition of the enzyme. Obvious texture property changes were also determined by TPA. All these changes showed a strong, irreversible heat-induced gel formed due to the addition of MTG. The application of a dimensionality reducing technique such as PCA proved to be useful to determine the most influential properties of heat-induced gel. Significant (p < 0.05) correlations were found between these structural changes and the textural characteristics (hardness) in PMP system with the addition of MTG by PCA. The hardness was related positively to fraction of ??-sheet, ??-turns and random coil, and negatively to normalized intensity of 760 cm^− 1 and fraction of ??-helix. The samples are closely grouped in a cluster defined by level of MTG.     

Functional Properties of Modified Black Gram (Phaseolus mungo L.) Starch

Black gram (Phaseolus mungo L.) starch was modified by heat and moisture treatments, acetylation, oxidation, cross-linking, and adding free fatty acids (palmitic, stearic, and linoleic). Heat and low moisture treatment, acetylation, oxidation, and cross-linking lowered the starch gelatinization temperature by 1–6°C, while adding fatty acids and the high moisture-heat treatment raised it by 1–4°C. All modifications caused an increase in least gelation concentration of starch. High moisture-heat treatment increased both water and oil absorption of starch. At 95°C, heat-moisture treated, acetylated, and oxidized starches were more soluble, while fatty acid treated and cross-linked starches were less soluble compared to raw starch. The modified starches had greater swelling capacity and solubility at pH 2.0 and 10.0. Heat-moisture treated and chemically modified starches had lower swelling capacity (at 95°C) than that of isolated starch, whereas addition of fatty acids increased it.     

Characterization of Phosphate Monoester Resistant Starch

The properties and structures of corn, wheat, and potato native starches and their phosphate monoester resistant starches were tested and compared. The results indicated that the resistant starch content, light transmittance, and freeze-thaw stability of the phosphate monoester resistant starch increased after modification. The native starches exhibited much higher peak viscosities compared with resistant starch (RS) and phosphate monoester resistant starches. The phosphate monoester resistant starch from corn and wheat starch exhibited a higher peak and final viscosity and lower gelatinization temperatures compared with the resistant starch, while the peak and final viscosity of the potato phosphate monoester resistant starch samples were lower than that of potato resistant starch. In the FT-IR graph, a new peak at 1244 cm^?1 (P=O bond) was observed for all kinds of phosphate monoester resistant starch.     

Gel texture and chain structure of amylomaltase-modified starches compared to gelatin

Amylomaltase (AM) (4-α-d-glucanotransferase; E.C. 2.4.1.25) from Thermus thermophilus was used to modify starches from various botanical sources including potato, high amylose potato (HAP), maize, waxy maize, wheat and pea, as well as a chemical oxidized potato starch (Gelamyl 120). Amylopectin chain length distribution, textural properties of gels and molecular weight of 51 enzyme and 7 non-enzyme-modified starches (parent samples) were analyzed. Textural data were compared with the textural properties of gelatin gels. Modifying starch with AM caused broadening of the amylopectin chain length distribution, creating a unimodal distribution. The increase in longer chains was supposedly a combined effect of amylose to amylopectin chain transfer and transfer of cluster units within the amylopectin molecules.Exploratory principal component analysis (PCA) data analysis revealed that the data were composed of two components explaining 94.2% of the total variation. Parent starches formed a cluster separated from that of the AM-modified starches.Extended AM treatments reduced the apparent molecular weight and the gel texture without changing the amylopectin chain length distribution. However, the gel texture was typically increased as compared to the parent starch. AM-modified HAP gels were about twice as hard as gelatin gels at identical concentration, whereas gels of pea starch were comparable to gelatin gels. Modifying Gelamyl 120 and waxy maize with AM did not change the textural properties. Branching enzyme (BE) (1,4-α-d-glucan branching enzyme; EC 2.4.1.18) from Rhodothermus obamensis was used in just one modification and in combination with AM. The combined AM/BE modification of pea starch resulted in starches with shorter amylopectin chains and pastes unable to form gel network even at concentration as high as 12.0% (w/w). The PCA model of all gel texture data gave suggestive evidence for starch structural features being important for generating a gelatin-like texture.     

The effect of ball milling treatment on structure and porosity of maize starch granule

Maize starch was mechanically treated by a planetary ball mill at 500 rpm for 1, 2 and 3 h. The effect of ball-milling treatment on structure and porosity of maize starch granule was studied. The SEM and TEM analyses indicated that starch granule surfaces were significantly changed and cavities in the central region of distorted granules were observed in the company with disappearance of alternate growth rings. The FT-IR analysis showed that ball milling treatment significantly increased the intensity of band 3382 cm⁻¹ and decreased the ratio of 1047/1018 cm⁻¹ and 995/1018 cm⁻¹ corresponding to the crystalline/amorphous part of starch structure. Special surface area (S_BET), cumulative volume (V_BJH), average diameter pores (D_BJH), span and median diameter (D_{v, 0.5}) increased rapidly and then decreased gradually. The XRD patterns, FT-IR and ¹³C CP/MAS NMR spectra showed that the crystallinity of starches and content of double helices of starch chains were decreased, respectively.

Industrial relevance

Ball milling is one kind of physical modified method in polymer industry. It can be used in a variety of applications, including nanomatrix composites, dispersed alloy materials, metallic refinery, ore treatment, waste disposal, and synthesis of organic materials. Starch is a natural carbohydrate polymer, it contributes greatly to the textural properties of many foods and is widely used in food and industrial applications as a thickener, colloidal stabilizer, gelling agent, bulking agent and water retention agent. However, limitations such as low solubility, high viscosity, shear resistance, thermal resistance, thermal decomposition and high tendency toward retrogradation limit its use in some food and non-food systems.After ball milling treatment, the reactivity of starch is increased. Furthermore, milled starches exhibit the adsorptive capacity which can offer new opportunity for starch application, for example as sorbent in food or pharmaceutical.     

EFFECT OF SUGARS ON THE THERMAL AND RETROGRADATION PROPERTIES OF OAT STARCHES

The thermal and retrogradation properties of oat starches from two cultivars (NO 753-2 and AC Stewart) were characterized in the presence of glucose, fructose and sucrose at a concentration of 36% w/v. In both oat starches, amylose leaching (AML) and swelling factor (SF) decreased in the presence of sugars (sucrose > glucose > fructose). These decreases were more pronounced in AC Stewart starch. The decrease in AML showed that sugars interact with amylose chains within the amorphous regions of the starch granule. The gelatinization transition temperature and the enthalpy of gelatinization increased in the presence of sugars (sucrose > glucose > fructose). The above increase was also more pronounced in AC Stewart starch. The decrease in SF and the increase in gelatinization parameters indicated that these changes were influenced by the interplay of factors such as starch-sugar interaction, changes in water structure in the presence of sugars, and the antiplastizing properties of sugars relative to water. The retrogradation enthalpy and the X-ray diffraction intensities of NO 753-2 and AC Stewart starch gels (stored at 4C) increased in the presence of sugars (glucose > fructose > sucrose). These changes were more pronounced in NO 753-2 starch. The results showed that interaction (during storage) between leached amylopectin and sugar molecules was the main causative factor influencing oat starch retrogradation.