Normal Potato Starch Research Articles

Changes in the structure and enzyme binding of starches during in vitro enzymatic hydrolysis using mammalian mucosal enzyme mixtures

Starches are hydrolyzed into monosaccharides by mucosal α-glucosidases in the human small intestine. However, there are few studies assessing the direct digestion of starch by these enzymes. The objective of this study was to investigate the changes in the structure and enzyme binding of starches during in vitro hydrolysis by mammalian mucosal enzymes. Waxy maize (WMS), normal maize (NMS), high-amylose maize (HAMS), waxy potato (WPS), and normal potato (NPS) starches were examined. The order of the digestion rate was different compared with other studies using a mixture of pancreatic α-amylase and amyloglucosidase. NPS was digested more than other starches. WPS was more digestible than WMS. Hydrolyzed starch from NPS, NMS, WPS, WMS, and HAMS after 24 h was 66.4, 64.2, 61.7, 58.7, and 46.2 %, respectively. Notably, a significant change in the morphology, reduced crystallinity, and a decrease in the melting enthalpy of the three starches (NPS, NMS, and WPS) after 24 h of hydrolysis were confirmed by microscopy, X-ray diffraction, and differential scanning calorimetry, respectively. The bound enzyme fraction of NPS, NMS, and WPS increased as hydrolysis progressed. In contrast, HAMS was most resistant to hydrolysis by mucosal α-glucosidases in terms of digestibility, changes in morphology, crystallinity, and thermal properties.

Effects of Heat-Moisture Treatment on the Digestibility and Physicochemical Properties of Waxy and Normal Potato Starches.

Heat-moisture treatment (HMT) is a safe, environmentally friendly starch modification method that reduces the digestibility of starch and changes its physicochemical properties while maintaining its granular state. Normal potato starch (NPS) and waxy potato starch (WPS) were subjected to HMT at different temperatures. Due to erosion by high-temperature water vapor, both starches developed indentations and cracks after HMT. Changes were not evident in the amylose content since the interaction between the starch molecules affected the complexation of amylose and iodine. HMT increased pasting temperature of NPS from 64.37 °C to 91.25 °C and WPS from 68.06 °C to 74.44 °C. The peak viscosity of NPS decreased from 504 BU to 105 BU and WPS decreased from 384 BU to 334 BU. The crystallinity of NPS decreased from 33.0% to 24.6% and WPS decreased from 35.4% to 29.5%. While the enthalpy values of the NPS declined from 15.74 (J/g) to 6.75 (J/g) and WPS declined from 14.68 (J/g) to 8.31 (J/g) at 120 °C. The solubility and swelling power of NPS decreased while that of WPS increased at 95 °C. Due to the lack of amylose in WPS, at the same HMT processing temperature, the reduction in peak viscosity of treated WPS compared to that of native starch was smaller than that of NPS. The resistant starch (RS) content of NPS after HMT at 120 °C was 73.0%. The slowly digestible starch (SDS) content of WPS after HMT at 110 °C was 37.6%.

Chemical Modifications of Normal and Waxy Potato Starches Affect Functional Properties of Aerogels.

Aerogels are of increasing interest because of their exceptionally large surface area, porous structure, and low weight. Despite the significant increase in interest in the subject of starch-based aerogels, the number of detailed studies is rather scarce, which is especially evident in the case of chemically modified derivatives. Therefore, the study aims to evaluate the physicochemical properties of aerogels from chemically modified potato starch preparations (E 1422 and E 1450) obtained both from normal and waxy starches. Aerogels were prepared through the retrogradation of starch pastes followed by the gradual replacement of water with ethyl alcohol. The obtained preparations were characterized in terms of their bulk density, oil-binding capacity, as well as the texture and rheological properties of the formed pastes. Moreover, their usefulness was evaluated in an emulsion system employing rheological and low-field NMR methods. The obtained aerogels were characterized by a lower bulk density of 0.18-0.59 g/cm3 and 5.4-6.6 times higher oil-binding capacity compared to native potato starch. The chemical modification of starch helped to further alter the functional properties of the obtained aerogels, making them more effective oil binders, emulsifiers, and stabilizers (increasing the stability from 55 to 90%), which was especially evident for E 1450 preparation. Amylose content improved the aerogel properties, as waxy preparations were characterized by worse functional properties with the only exception of improved thickening ability. The most beneficial properties for the preparation of emulsions were observed for the aerogel obtained based on E 1450 normal potato starch.

An Insight into Pasting and Rheological Behavior of Potato Starch Pastes and Gels with Whole and Ground Chia Seeds.

With regard to technological innovations, we applied chia (oilseeds) as a stabilizer additive in a normal and waxy potato starch sample to obtain stable starch-based gels during 20 days of storage. The aim of this study was to investigate the 5% w/w normal and waxy potato starch pastes (hot samples) and gels (cold samples) with the addition of 1% w/w whole and ground chia seeds properties as pasting and flow properties of pastes and textural properties of gels. The pasting process using a viscograph showed that normal and waxy potato starch with the addition of chia had a different pasting characteristic. The addition of chia seeds had a greater effect on the properties of normal potato starch than waxy potato starch. From a rheological point of view, starch pastes without chia were less theologically stable as they showed bigger areas of hysteresis loops. Minor changes in the hardness of gels were obtained in normal starch gels with chia seeds during 20 days of storing compared to the samples without chia seeds, whereas in the waxy starch gels, the effect was the opposite.

Thermal and pasting properties and digestibility of blends of potato and rice starches differing in amylose content

In this study, waxy or normal potato starches (WPS or NPS) were blended with waxy, low-amylose or high-amylose rice starch (WRS, LARS or HARS) in different ratios (100:0, 80:20, 60:40, 40:60, 20:80 and 0:100). Pasting profiles of blends were additively between those of the component starches separately except for some mixtures of WRS and potato starches. Twin or even three gelatinization peaks were observed for potato-WRS or potato-HARS blend, while only one peak was observed in potato-LARS blend. Addition of WRS enhanced the nutritional profile of blends containing WPS by decreasing the rapidly digestible starch level. Microscopy revealed that addition of WRS was beneficial for the development of dense and compact structure of gels of blends compared with their counterparts, which may be because few amylose chains leached to inhibit the interaction between swollen potato and rice starch granules. Besides, peak, trough, breakdown and final viscosity as well as gelatinization enthalpy showed significantly negative correlations with amylose leaching. Non-additive behaviours were observed for properties, but more independent behaviour was observed between potato starch and LARS or HARS. Results suggested that properties of blends of potato and rice starches differing in amylose content varied through different extents of amylose leaching.

PREVENTING OF PACKAGING EXUDATION IN FRANKFURTER SAUSAGES BY USING MODIFIED POTATO STARCH

The effect of potato starch modified by pre-gelatinization on frankfurter sausage exudation level was investigated. This liquid exuded from the food product may have a negative impact in sensorial properties of packaged food as well as in its microbial quality for consumers acceptance. Modified potato starch caused a decrease in exudation formation vacuum-sealed packages of frankfurter sausages stored at +4 0C. The juice exuded into the package of the control group was higher than the other groups (P<0.05). Also, some quality characteristics of frankfurter sausages (color, pH, water activity, thiobarbituric acid reactive substance (TBARS), conjugated diene and free fatty acid (FFA) were analyzed during the storage period. Potato starch exhibited a high reducing hydrolysis activity in this study. As a result; it is advisable to use modified potato starch instead of normal potato starch to reduce or delay the exudation level in sausages.

Comparison of physicochemical properties of oca (Oxalis tuberosa), potato, and maize starches

Oca (Oxalis tuberosa) represents a novel source of starch. Starches from the tubers of two commercial oca varieties were studied for various physicochemical properties. One normal potato starch and one normal maize starch were used for comparison. Oca starches showed lower gelatinization temperatures compared to both potato and maize starches. The pasting, flow, and gelation behaviors of oca starches were intermediate between potato and maize starches. Oca starch pastes were more viscous than maize starch paste and more elastic than potato starch paste. The differences in the properties could be largely due to lower amylose content, intermediate contents of phosphate groups (~400 ppm) and granule size (34.6 μm) of oca starches as compared to the other two starches. The internal unit chains of amylopectin such as the amount of fingerprint B-chains and length of B-chains could also partially explain the different physicochemical properties among oca, potato and maize starches.

Swelling kinetics of rice and potato starch suspensions

AbstractGranule size distribution of 8% w/w suspension of normal rice starch (NRS), waxy rice starch (WRS), modified potato starch (MPS), and normal potato starch (NPS) in water when subjected to heating at 60, 65, 70, 75, 80, and 85°C at different hold times (0–60 min) were characterized. The average starch granule diameter was larger at higher temperatures and hold times for NRS, WRS, and MPS indicating swelling, whereas for NPS it decreased indicating breakage. Swelling varied in the order: MPS > NRS > WRS. Earlier proposed pseudo first‐ and second‐order kinetic and Weibull models for swelling were evaluated. Swelling kinetics was also predicted using our previously developed mechanistic model (Desam et. al., 2018a Journal of Food Engineering 222:237–249) whose predictions agreed well with the experimental data of mean granule diameter and granule size distribution with time at different temperatures, and therefore can be employed to describe swelling at different processing conditions.Practical ApplicationsStarches are incorporated in food products for a variety of reasons such as stabilizing, thickening, binding, and gelling. Starch occurs as discrete granules. Upon exposure to water, starch granules swell when heated. This results in thickening of starch suspension (known as pasting) due to an increase in volume fraction of swollen granules. Starch pasting results in an increase in its viscosity. Therefore, the texture of a variety of food products such as sauces, puddings, soups, batter mixes, and so forth are influenced by pasting. The rheology and texture of starch paste obtained by cooking of starch granules are governed by its swelling. It is, therefore, necessary to quantify swelling in order to predict the rheology of starch paste as well as to develop new food formulations. We developed a mechanistic model which predicts the swelling kinetics of rice and potato starch suspensions.

Structure and functional properties of waxy starches

A comprehensive study was conducted to elucidate structural and functional properties of waxy starches. The specific objectives were to examine the relationship between gelatinization/pasting properties and morphology of starch cooks, determine how the retrogradation properties are affected by chain-length distribution, and use a novel sensory approach to assess freeze-thaw stability of starch pastes. Waxy potato starch had a greater degree of granule swelling, higher paste viscosities, and better paste clarity than waxy starches from maize, wheat, rice, and tapioca. Waxy starches typically had greater paste viscosities than their normal counterparts, but the exception was potato starches. Waxy potato starch, which had no amylose, had lower paste viscosity than normal potato starch. Both waxy rice and waxy tapioca starches had less retrogradation tendency, which was closely related to the higher proportion of chains with DP 6–11 and the lower proportion of chains with DP 12–24. The sensory evaluation in this study allowed for an easier assessment of water separation as compared to the conventional centrifuge methods. Waxy maize and waxy potato starches had noticeable water separation from the paste after 1–2 freeze-thaw cycles, whereas both waxy rice and waxy tapioca starches could survive 6 freeze-thaw cycles without apparent syneresis. Waxy wheat, waxy rice and waxy tapioca starches are potential starting materials from which clean-label functional starches may be produced.

CO2 inclusion complexes of Granular V-type crystalline starch: Structure and release kinetics

Granular V-type crystalline starch (V-type starch) was prepared using different starch varieties by alcoholic-alkaline treatment. Carbon dioxide was encapsulated into V-type starch using a solid encapsulation method. The morphological and structural properties of the inclusion complexes (ICs) were characterised using scanning electron microscopy and X-ray diffraction. Fourier-transform infrared spectroscopy and 13C Nuclear Magnetic Resonance proved that CO2 was successfully encapsulated. The encapsulation capacity of V-type starches was determined by head space gas chromatography, and ICs made from normal maize starch achieved the highest CO2 concentration (2.55%, w/w). The controlled release characteristics of ICs were also determined at various temperatures and relative humidity, and ICs made from normal potato starch exhibited slower release characteristics. The release kinetics showed that the release of CO2 from ICs was accelerated by increasing temperature or RH. V-type starch is a renewable, inexpensive material for encapsulation of gasses such as CO2.

Characteristics of granular cold-water-soluble potato starch treated with alcohol and alkali.

The characteristics of cold-water-soluble potato starch (CWSS) produced using alcoholic-alkaline treatment were determined using scanning electron microscopy, rapid visco analysis (RVA), X-ray diffraction, differential scanning calorimetry, storage modulus (G'), loss modulus (G″), and gel images. Scanning electron microscopy revealed a damaged crystalline structure when CWSS was suspended in ethanol. The RVA analysis of native starch showed a peak value of viscosity at high temperatures, whereas the viscosity of CWSS did not show such a peak. The DSC diagram of native starch showed a gelatinization peak temperature; however, no such peak was observed for CWSS. Cold-water solubility tremendously increased in CWSS owing to the loss of crystallinity. The values of G' and G″ in CWSS decreased with increasing temperature; the opposite was observed for normal potato starch. These results indicate that alcoholic-alkaline treatment affects the starch structure and produces totally different physicochemical properties from native starch; this makes CWSS feasible for use in a variety of food materials.

Encapsulation of Ethylene Gas into Granular Cold-Water-Soluble Starch: Structure and Release Kinetics.

Ethylene gas was introduced into granular cold-water-soluble (GCWS) starches using a solid encapsulation method. The morphological and structural properties of the novel inclusion complexes (ICs) were characterized using scanning electron microscopy, X-ray diffractometry, and Raman spectroscopy. The V-type single helix of GCWS starches was formed through controlled gelatinization and ethanol precipitation and was approved to host ethylene gas. The controlled release characteristics of ICs were also investigated at various temperature and relative humidity conditions. Avrami's equation was fitted to understand the release kinetics and showed that the release of ethylene from the ICs was accelerated by increasing temperature or RH and was decelerated by increased degree of amylose polymerization. The IC of Hylon-7 had the highest ethylene concentration (31.8%, w/w) among the five starches, and the IC of normal potato starch showed the best controlled release characteristics. As a renewable and inexpensive material, GCWS starch is a desirable solid encapsulation matrix with potential in agricultural and food applications.

Binary mixtures of two anionic polysaccharides simulating the rheological properties of oxidised starch

Abstract Modifications of starches are carried out to improve their industrial usefulness. However, the consumers prefer natural products. For this reason, various methods of starch properties modification are applied to replace those requiring the use of chemical reagents. The aim of this study was to determine whether it is possible to use binary pastes, containing normal potato starch and xanthan gum, as substitutes of chemically modified starches (with oxidised starch E 1404 pastes as an example). Flow curves with hysteresis loops, apparent viscosity at constant shear rate of 50 s−1 and in-shear structural recovery test with pre-shearing were applied to study the rheological properties of the pastes. It was found that two anionic hydrocolloids, potato starch and xanthan gum, can form binary systems with thickening properties, provided that their proportions are adequately adjusted. Some of the binary pastes under investigation exhibited rheological properties resembling pastes of starch oxidised with hypochlorite (E 1404). The way of tailoring the binary pastes properties is presented.

Thixotropic properties of the normal potato starch – Locust bean gum blends

The aim was to study the rheological, especially thixo- and antithixotropic properties of normal potato starch (NPS) with the addition of locust bean gum (LBG) depending on the pasting temperature, the starch concentration and the amount of LBG. All the pastes under study were rheologically unstable, non-Newtonian, shear thinning fluids. The increase in the LBG content obstructed pasting of the starch granules and increased viscosity of the pastes. In a vast majority of cases obstruction in swelling granules and, hence, higher amount of non-pasted granules evoked thixotropy. In turn, a higher numbers of well swollen granules and, hence pasted granules led to antithixotropy. Apart from the concentration of both polysaccharides and pasting temperature the results depended also on the measuring method applied.

Molecular rearrangement of waxy and normal maize starch granules during in vitro digestion

The objective of the present study is to understand the changes in starch structures during digestion and the structures contributing to slow digestion properties. The molecular, crystalline, and granular structures of native waxy maize, normal maize, high-amylose maize, and normal potato starch granules were monitored using SEC, XRD, DSC, and SEM. The amylose and amylopectin molecules of all four starches were hydrolyzed to smaller dextrins, with some having linear molecular structure. Neither the A- nor B-type crystallinity was resistant to enzyme hydrolysis. Starch crystallites with melting temperature above 120°C appeared in waxy and normal maize starches after digestion, suggesting that the linear dextrins retrograded into thermally stable crystalline structure. These crystallites were also observed for high-amylose maize starch before and after digestion, contributing to its low enzyme digestibility. On the contrary, the enzyme-resistant granular structure of native normal potato starch was responsible for its low susceptibility to enzyme hydrolysis.

Thixotropic properties of normal potato starch depending on the degree of the granules pasting.

The aim of this paper was the study of the rheological instability (thixotropy and/or antithixotropy) of normal potato starch (NPS) pastes depending on their concentration (2-5%) and degree of pasting. Flow curves with hysteresis loops, apparent viscosity at constant shear rate and in-shear structural recovery tests were carried out. Granule size profiles, the pasting characteristic of corresponding starch suspensions and the transmittance of the pastes, the molecular weights and polydispersity of granular starch and its pastes prepared at 80, 95 and 121°C were also studied. The degree of pasting was dependent on the temperature and the concentration and influenced strongly the rheological behavior of the pastes. All pastes belonged to the non-Newtonian liquids thinned by shear and were rheologically unstable to the various extent. Thixotropic properties were connected to the size and the number of the starch granules in the pastes as well as depended on the measuring method used. In the 2 and 3% samples pasted at 80°C the swelling of the granules prevailed their destruction (thixotropy was observed). In the other samples the destruction predominated the swelling (antithixotropy observed).

Amylolysis of native and annealed potato starches following progressive gelatinisation

The extent of α-amylase hydrolysis of normal potato starches, extracted from different varieties grown under the same conditions in the same season, is regulated more by gelatinisation than the composition or structure of the granules. This is evident for native and annealed starches gelatinised and then hydrolysed with α-amylase. With similar gelatinisation peak (Tp) temperatures (62.5–66.1 and 70.2–72.3 °C respectively) and enthalpies (15.1–17.8 and 15.8–19.5 Jg−1 respectively) for the native and annealed starches, increasing the temperature exposure in excess water (to cause progressive gelatinisation) by 10 °C increments creates progressively more hydrolysis reflecting the (similar) gelatinisation transition. Overall, therefore, processing has a greater potential impact on the glycaemic index (GI) of potato starches than any variety specific variations.

Comparison of waxy and normal potato starch remaining granules after chemical surface gelatinization: Pasting behavior and surface morphology

To understand the contribution of granule inner portion to the pasting property of starch, waxy potato starch and two normal potato starches and their acetylated starch samples were subjected to chemical surface gelatinization by 3.8mol/L CaCl2 to obtain remaining granules. Native and acetylated, original and remaining granules of waxy potato starch had similar rapid visco analyzer (RVA) pasting profiles, while those of two normal potato starches behaved obviously different from each other. All remaining granules had lower peak viscosity than the corresponding original granules. Contribution of waxy potato starch granule's inner portion to the peak viscosity was significant more than those of normal potato starches. The shell structure appearing on the remaining granule surface for waxy potato starch was smoother and thinner than that for normal potato starches as observed by scanning electron microscopy, indicating a more regular structure of shell and a more ordered packing of shell for waxy potato starch granules. The blocklet size of waxy potato starch was smaller and more uniform than those of normal potato starches as shown by atomic force microscopy images of original and remaining granules. In general, our results provided the evidence for the spatial structure diversity between waxy and normal potato starch granules: outer layer and inner portion of waxy potato starch granule had similar structure, while outer layer had notably different structure from inner portion for normal potato starch granule.

Nano-structure of heat–moisture treated waxy and normal starches

Surface regions of untreated and heat–moisture treated (HMT) normal rice, waxy rice, normal corn, waxy corn, normal potato, and waxy potato starch granules were examined by atomic force microscopy (AFM). AFM images revealed surface roughness of untreated starch granules and protrusions with a diameter of approximately 15–90nm. After treatment, the smooth surface region on starch granules was observed, especially in normal rice, waxy rice, and normal corn starches. A significant reduction in the size of protrusions on the surface of HMT potato starch granules was also detected. The newly formed structures may act as barriers and retard water penetration into starch granules. The blocklet model of starch granule architecture was also confirmed by the AFM images.

Structure of starch hydrolysates following in vitro oral digestion: Effect of botanical source of starch and hydrothermal treatments

AbstractDigestion of starch in humans occurs progressively in the gut. However, the literature is scant on the structures of the starch digestion products along the gut from the mouth to the small intestines – products that impact glucose homeostasis. This submission focuses on the first step of starch digestion, i.e., impact of human salivary amylase on the structure of hydrolysis products obtained from cooked starches from different botanical sources. Normal corn (NCS), normal wheat (NWS), and normal potato (NPS) starches were cooked at 1:0.7 (T0.7) or 1:2 (T2) starch:water ratios. Cooked starches were subjected to salivary amylase at conditions mimicking oral digestion. Extent of hydrolysis was lower at T0.7 compared to T2, but the amount of carbohydrates in different fractions and the MW profiles within each treatment showed no apparent differences between starches from different botanical sources. However, debranching of the hydrolysates revealed structural differences between the different starches with regards to extent of amylose hydrolysis and the amount and profile of lower MW fractions. Therefore, the structures of hydrolysates that are likely the substrate for subsequent hydrolysis in the gut are different based on cooking condition or botanical source of starch, with potential consequence for glucose homeostasis.