Development and Physicochemical Characterization of New Resistant Citrate Starch from Different Corn Starches

Resistant starch has drawn broad interest for both potential health benefits and functional properties. In this study, a technology was developed to increase resistant starch content of corn starch using esterification with citric acid at elevated temperature. Waxy corn, normal corn and high‐amylose corn starches were used as model starches. Citric acid (40% of starch dry weight) was reacted with corn starch at different temperatures (120–150°C) for different reaction times (3–9 h). The effect of reaction conditions on resistant starch content in the citrate corn starch was investigated. When conducting the reaction at 140°C for 7 h, the highest resistant starch content was found in waxy corn citrate starch (87.5%) with the highest degree of substitution (DS, 0.16) of all starches. High‐amylose corn starch had 86.4% resistant starch content and 0.14 DS, and normal corn starch had 78.8% resistant starch and 0.12 DS. The physicochemical properties of these citrate starches were characterized using various analytical techniques. In the presence of excess water upon heating, citrate starch made from waxy corn starch had no peak in the DSC thermogram, and small peaks were found for normal corn starch (0.4 J/g) and Hylon VII starch (3.0 J/g) in the thermograms. This indicates that citrate substitution changes granule properties. There are no retrogradation peaks in the thermograms when starch was reheated after 2 weeks storage at 5°C. All the citrate starches showed no peaks in RVA pasting curves, indicating citrate substitution changes the pasting properties of corn starch as well. Moreover, citrate starch from waxy corn is more thermally stable than the other citrate starches.     

Lily Starch—An Underutilized and Non-Conventional Source: Properties and Applications

Lily belongs to the genus Lilium of the family Liliaceae. Starch is the main component of lily bulbs which accounts for 53–69% of their dry weight. Lily starch (LS) has B-type X-ray diffraction characterized by a peak at 5.6°, 17°, 22°, and 24°. The swelling and solubility of the LS are significantly higher than rice and corn starches. The gelatinization temperatures of the LS are much lower than maize but higher than wheat and potato starches. The pasting temperature, peak, breakdown, and setback viscosities of lily starches are falling within the range; 66.1–72.7 °C, 1409–3940 cP, 88–1206 cP, and 445–1952 cP, respectively. The range for initial temperature, gelatinization temperature range, and enthalpy for lily starches is also 56.5–64.0 °C, 3.8–10.3 °C, and 3.9–13.9 J g⁻¹, respectively. This review focuses on the recent advances in the understanding of the composition, structure, and properties of lily starches. Furthermore, the limited modification associated with lily starches is also discussed. There is a bold attempt to compare the properties of lily starch with that of the commercial starches of corn and potato.     

Structures and Physicochemical Properties of Acid‐Thinned Corn,Potato and Rice Starches

The structures and physicochemical properties of acid‐thinned corn, potato, and rice starches were investigated. Corn, potato, and rice starches were hydrolyzed with 0.14 N hydrochloric acid at 50 °C until reaching a target pasting peak of 200—300 Brabender Units (BU) at 10% solids in the Brabender Visco Amylograph. After acid modification the amylose content decreased slightly and all starches retained their native crystallinity pattern. Acid primarily attacked the amorphous regions within the starch granule and both amylose and amylopectin were hydrolyzed simultaneously by acid. Acid modification decreased the longer chain fraction and increased the shorter chain fraction of corn and rice starches but increased the longer chain fraction and decreased the shorter chain fraction of potato starch, as measured by high‐performance size‐exclusion chromatography. Acid‐thinned potato starches produced much firmer gels than did acid‐thinned corn and rice starches, possibly due to potato starch's relatively higher percentage of long branch chains (degree of polymerization 13—24) in amylopectin. The short‐term development of gel structure by acid‐thinned starches was dependent on amylose content, whereas the long‐term gel strength appeared dependend on the long branch chains in amylopectin.     

Characteristics and application of octenyl succinic anhydride modified waxy corn starch in sausage

Native and acid‐hydrolyzed wx corn starches were modified by octenyl succinic anhydride (OSA) in aqueous slurry systems. The characteristics of the modified wx corn starches and their effects on chicken meat sausages were evaluated by means of FT‐IR, rapid visco analyser, SEM, and texture profile analysis. FT‐IR spectroscopy indicated that the ester carbonyl groups in the OSA modified native and acid‐hydrolyzed starches were characterized at 1725 cm⁻¹. The process of OSA modification could achieve starch derivatives, which had higher viscosities, better paste clarity and freeze–thaw stability than the native counterparts. Texture results showed that the hardness, springiness, cohesiveness, and chewiness of the sausage increased as OSA‐H0 was added (p < 0.05). SEM revealed that the sausages with native wx corn starch had larger and uneven pores, while it was comparatively compact for the sausages with OSA starches. The OSA modified wx corn starch offered a great potential to be used in meat products to enhance textural quality.     

Effect of Acid Hydrolysis and Ball Milling on Porous Corn Starch

Porous corn starch from glucoamylase hydrolysis of native corn starch was examined before and after cross-linking, acid hydrolysis and dry ball milling. Cross-linking does not significantly change the crystallinity, water absorption or gelatinisation properties but acid hydrolysis at 60°C increases, proportionately, crystallinity and water absorption capacity and decreases moisture adsorption at humidities less than 80%, in comparison to untreated porous corn starch. Highly crystalline porous starch has a fragile granule structure. Ball milling destroys crystallinity in both normal, porous, and cross-linked or partially hydrolyzed starches. Particle sizes of 1–2m are obtained by milling dry starches for 48 h. Water absorption for milled starches is more than 200% (weight water/weight starch d.b.). Viscosities of these products were significantly reduced at high temperatures. Products formed stable gels in 25–30% dispersions in cold water.     

Microstructural and physicochemical properties of heat-moisture treated waxy and normal starches

Starches from normal rice (21.72% amylose), waxy rice (1.64% amylose), normal corn (25.19% amylose), waxy corn (2.06% amylose), normal potato (28.97% amylose) and waxy potato (3.92% amylose) were heat-treated at 100 °C for 16 h at a moisture content of 25%. The effect of heat-moisture treatment (HMT) on morphology, structure, and physicochemical properties of those starches was investigated. The HMT did not change the size, shape, and surface characteristics of corn and potato starch granules, while surface change/partial gelatinization was found on the granules of rice starches. The X-ray diffraction pattern of normal and waxy potato starches was shifted from B- to C-type by HMT. The crystallinity of the starch samples, except waxy potato starch decreased on HMT. The viscosity profiles changed significantly with HMT. The treated starches, except the waxy potato starch, had higher pasting temperature and lower viscosity. The differences in viscosity values before and after HMT were more pronounced in normal starches than in waxy starches, whereas changes in the pasting temperature showed the reverse (waxy > normal). Shifts of the gelatinization temperature to higher values and gelatinization enthalpy to lower values as well as biphasic endotherms were found in treated starches. HMT increased enzyme digestibility of treated starches (except waxy corn starch); i.e., rapidly and slowly digestible starches increased, but resistant starch decreased. Although there was no absolute consistency on the data obtained from the three pairs of waxy and normal starches, in most cases the effects of HMT on normal starches were more pronounced than the corresponding waxy starches.     

Effect of controlled gelatinization in excess water on digestibility of waxy maize starch

An aqueous dispersion of waxy maize starch (5%, w/w) was controlled gelatinized by heating at various temperatures for 5 min. The treated samples were analysed using in vitro Englyst assay, light microscopy, differential scanning calorimetry, X-ray diffraction, and Fourier-transform infrared spectroscopy. When heated, SDS and RS levels were decreased inversely with RDS. A high SDS content (>40%) was kept prior to the visible morphological and structural changes (before 60 °C). Swelling factor began to increase slightly at 50–60 °C and continued to maximum value at 80 °C. A large decrease in ΔH, crystallinity, and ratio of 1047/1022 cm⁻¹ attributed to partially dissociation of crystalline clusters and double helices occurred at 65–80 °C. These changes showed that controlled gelatinized starch with slow digestion property occurred in the molecular rearrangement process before granule breakdown and SDS mainly consists of amorphous regions and a small portion of less perfect crystallites.     

Effects of pulsed electric fields (PEF) treatment on physicochemical properties of potato starch

Potato starch–water suspensions (8.0%, w/w) were subjected to pulsed electric fields (PEF) treatment at 30 kV·cm^− 1, 40 kV·cm^− 1 and 50 kV·cm^− 1, respectively. The physicochemical properties of PEF-treated potato starch samples were investigated using scanning electron microscopy (SEM), laser scattering technique, X-ray diffractometry (XRD), differential scanning calorimetry (DSC), and the Brabender rheological method, with native potato starch as reference. It has been concluded from SEM analysis that dissociation and damage of PEF-treated potato starch granules appeared. Some granules aggregated with each other and showed gel-like structures. It was revealed from particle size analysis that there was an obvious increase of the granule size after PEF treatment. This has been attributed to the aggregation among granules. It was also demonstrated from other analysis that relative crystallinity, gelatinization temperatures, gelatinization enthalpy, peak viscosity as well as breakdown viscosity of modified samples all decreased with increasing electric field strength.

Industrial relevance

In this study, the effect of PEF treatment (up to 50 kV·cm^− 1) on physicochemical properties of potato starch has been investigated. The results from SEM images showed that dissociation, denaturation and damage of potato starch granules had been induced by the PEF treatments. Some of granule fragments showed gel-like structures, and congregated with each other or with other starch granules. Laser scattering measurements of particle size revealed that an obvious increase of granule size under electric field strength of 50 kV·cm^− 1, which was attributed to the aggregation of the starch granules. The X-ray diffraction pattern showed an obvious loss of crystalline structure after the PEF treatment at 50 kV·cm^− 1, which induced a trend of transformation from crystal to non-crystal in potato starch granules. DSC analysis showed a decrease in gelatinization temperatures (T_o and T_p) and gelatinization enthalpy (ΔH_gel) with increasing electric field strength. Brabender rheological method has been used to show that the peak viscosity and breakdown viscosity decrease with increasing electric field strength of PEF treatment. All the results reveal that the PEF treatment can lead to an intragranular molecular rearrangement of potato starch granules, which induces changes of various physicochemical properties of the treated starch thus may endow it some new characteristics and functions. This phenomena may warrant further more detailed study.     

Tailoring a New Sizing Agent via Structural Modification of Pregelled Starch Molecules Part 1: Carboxymethylation and Grafting

Pregelled starch (PS) was subjected to acid hydrolysis using phosphoric acid to prepare pregelled starches having different molecular sizes. The degraded pregelled starches were carboxymethylated at different reaction times. The carboxymethyl derivatives were grafted with either methacrylamide (MAam) or methacrylonitrile (MAN) as vinyl monomers using ceric ammonium nitrate (CAN) as initiator. Suitability of the new graft derivatives of pregelled starch as sizing agent of cotton yarns was studied. It is shown by the data that the extent of carboxymethylation, expressed as carboxyl content, increases by increasing the extent of hydrolysis and reaction time. Furthermore, the graft yield, expressed as mmol MAam or MAN monomer/100 g graft copolymer (grafted carboxymethylated pregelled starch or grafted carboxymethylated hydrolyzed pregelled starch) increases with increasing extent of carboxymethylation and degree of hydrolysis and follows the order: MAam > MAN. In addition cotton yarns sized with grafted carboxymethylated hydrolyzed pregelled starch – irrespective of the grafting monomer used – have better mechanical properties (tensile strength, elongation at break, and abrasion resistance) than hydrolyzed pregelled starches, carboxymethylated pregelled starch and carboxymethylated hydrolyzed pregelled starches.     

Molecular structure,rheological and thermal characteristics of ozone-oxidized starch

The effects of oxidation by ozone gas on the molecular structure, rheological and thermal properties of starch (corn, sago and tapioca) were investigated. Starch, in dry powder form, was exposed to ozone for 10 min at different ozone generation times (OGTs). Average molecular weight decreased in oxidized corn and sago starches but increased in oxidized tapioca starch. All oxidized starches exhibited non-Newtonian shear-thinning behaviour. Starch viscosity decreased drastically with increasing OGT. Young’s modulus for all oxidized corn and sago starch gels stored for 1 and 7 days at 4 °C increased significantly compared to unmodified starch. No differences were noted in gelatinization temperatures and gelatinization enthalpies of all oxidized starches compared to unmodified starch. Retrogradation enthalpy increased markedly in corn starch after 1 min OGT. These results show that the extent of starch oxidation varies among starches of different botanical origins under similar ozone treatment conditions.     

Physicochemical characterization of mung bean starch

Starch from mung bean (Vigna radiata) was isolated and some of the important characteristics determined. The yield of starch was 31.1% on a whole-seed basis. The shape of the starch granule was oval to round to bean shaped, with granules 7–26 μm in diameter. Scanning electron micrographs revealed the presence of smooth surfaces. The gelatinization temperature range was 58–67–82°C and the enthalpy of gelatinization was 18.5 J/g. The total amylose content was 45.3%, of which 12.1% was complexed by native lipids. The X-ray diffraction pattern was of the ‘C’ type and the X-ray intensities were much stronger than in other legume starches. The starch exhibited a high swelling factor ( 43.6 at 95°C) in water. The viscoamylographic examination of the starch paste (6% w/v) showed the absence of a peak viscosity, a low 95°C viscosity [200 Brabender units (BU)], an increase in consistency ( 140 BU) during the holding cycle at 95°C and a set-back of 220 BU. Native granules were readily hydrolyzed by porcine pancreatic α-amylase (76.4% in 72 h). Retrogradation of mung bean starch (as measured by changes in syneresis, gel strength, enthalpy and X-ray diffraction intensities) appeared to be more severe than in other legume starches.     

酸解对不同链/支比含量玉米淀粉特性的影响

以4种不同链/支比含量的玉米淀粉为原料,酸解处理不同时间,以酸解玉米淀粉的形貌特性、冻融稳定性、膨胀度、溶解度、晶体性质为指标衡量不同酸解时间对玉米淀粉结构性质的影响。结果表明:4种玉米淀粉酸水解程度的顺序为:蜡质玉米普通玉米淀粉G50G80。酸解后,同品种的4种玉米淀粉的析水率随着酸解天数的增加而增加;溶解度增加,膨胀度降低。酸解并未改变淀粉的晶型,随着酸解时间的延长,蜡质玉米淀粉和普通玉米的相对结晶度先增大后保持不变,G50和G80的相对结晶度随着酸解时间的增加而增大。表明酸解对低直链淀粉(蜡质玉米淀粉和普通玉米淀粉)的结构、性能影响最大。     

Structural characteristics and in vitro digestibility of Mango kernel starches (Mangifera indica L.)

Structural characteristics and digestibility of starches isolated from the kernels of two mango cultivars (Chausa and Kuppi) were studied and compared with those of a commercial normal corn starch. Mango kernel starches showed an A-type X-ray diffraction pattern, with relative crystallinities of 35.4% and 38.3%, respectively for Kuppi and Chausa cultivars. The structural characterisation obtained, using high performance size exclusion column chromatography connected to multi-angle laser light scattering and refractive index detectors (HPSEC-MALLS-RI), revealed that the mango kernel starches had lower molecular weight (M_w) and radius of gyration (R_g) of amylopectin and amylose compared to those of corn starch. The M_w of amylopectin for Chausa and Kuppi starches were 179 × 10⁶ and 140 × 10⁶ g/mol, respectively. The amounts of readily digestible starch (RDS) and slowly digestible starch (SDS) were lower for mango kernel starch than those of corn starch. Resistant starch (RS) contents in the mango kernel starches (75.6% and 80.0%, respectively) were substantially higher than those of corn starch (27.3%). The glycemic index (GI) values for mango kernel starches were 48.8 and 50.9 (for Chausa and Kuppi, respectively), whereas that of corn starch was 74.8, indicating that the mango kernel starch granules were highly resistant to digestion with significant contents of RS.     

Mathematical approach for two component modeling of salep–starch mixtures using central composite rotatable design: Part I. Physicochemical and steady shear properties

A 2-factor-5-level central composite rotatable design (CCRD) of response surface methodology (RSM) was used to model linear, interaction and quadratic effects of some processing variables (salep and each starch type, the composition variables) on the response variables; physicochemical characteristics (pH, brix and turbidity) and steady shear rheological properties (apparent viscosity η, consistency coefficient K, shear stress σ and flow-behavior index n) of salep–starch mixtures (SSM); namely, salep–corn starch mixture (SCSM), salep–wheat starch mixture (SWSM) and salep–potato starch mixture (SPSM). The linear, interaction and quadratic effects of the processing variables were also modeled to develop predictive models for the tested properties to optimize the effect of these variables (salep and each starch type) using ridge analysis involved with RSM. It was concluded that salep and all starch types increased the apparent viscosity (η), shear stress (σ) and consistency coefficient (K) values; decreased the flow-behavior index (n) values of SSM samples. Salep was observed to vastly increase the viscosity of mixture samples when mixed with corn, wheat or potato starches. However, potato starch exhibited very different performance as compared to the other starches in terms of the physicochemical and steady shear rheological properties. The ridge analysis used to optimize these effects revealed that maximum η (0.84, 0.46 and 1.38 Pa s), and K (16.64, 6.48 and 28.86 Pa sⁿ) values for the SCSM, SWSM and SPSM samples, respectively would occur at salep = 0.54% and starch = 2.83% w/w.     

Synthesis and partial characterization of octenylsuccinic starch from Phaseolus lunatus

Phaseolus lunatus starch was modified by esterification with octenyl succinic anhydride (OSA) and reaction effect evaluated in terms of chemical composition, gelatinization, pasting and emulsification properties. Succinylation was done using a 2³ factorial design with four replicates of the central treatment. Evaluated factors and levels were OSA concentration (1% and 3%), pH (7 and 9) and reaction time (30 and 60 min). Succinyl group percentage was the response variable. The optimum treatment was a reaction with 3% OSA at pH 7 for 30 min, which produced 0.5083% succinyl groups and 0.0083° of substitution. No significant changes were observed in proximate composition between the native and derivative starches. Apparent amylose level decreased notably from 32.4% to 23.6% due to OSA inclusion. Succinylation decreased starch gelatinization temperature (75.3–64.6 °C), decreased enthalpy (10.7–9.7 J/g), increased viscosity (700–1000 BU), increased emulsifying capacity (0.47–0.53 ml oil/ml sample), and made emulsions more stable over time. Starch modification did not, however, improve stability in heating–cooling processes.     

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.     

不同来源的淀粉制备淀粉磷酸单酯的性能及应用

本文比较了马铃薯淀粉、蜡质玉米淀粉、木薯淀粉、小麦淀粉及经磷酸化后产品的物理性能，着重研究了其粘度及糖、盐对其粘度的影响并比较了磷酸化对糊的透明度、冻融稳定性及其对发泡体系的影响，结果表明不同淀粉制得的淀粉磷酸单酯的性能有很大差别。在蛋糕中的应用试验表明，在蛋糕中添加淀粉磷酸单酯可以增加比容并延长其货架寿命。     

Molecular structure and physicochemical properties of Hylon V and Hylon VII starches illuminated with linearly polarised visible light

Aqueous suspensions (30 g/100 g) of Hylon V and Hylon VII high amylose corn starches were illuminated with linearly polarized visible light for 5, 15, 25 and 50 h. For each native and illuminated starch sample, weight average molecular weight, M_w, and hydrodynamic radius, R_g, of starch polysaccharide molecules were measured by high pressure size exclusion chromatography coupled with multiangle laser light scattering and refractometric detectors (HPSEC-MALLS-RI). Additionally, X-ray diffraction patterns, intrinsic viscosity, kinetic of alpha-amylolysis together with iodine binding properties and distribution of amylopectin structural units were established for each starch sample. Changes in molecular weight M_w of starch polysaccharide chains eluted under whole polysaccharide peaks and values of intrinsic viscosity of corresponding starch samples observed in the course of illumination indicated that illumination of both starches studied, with linearly polarized visible light (LPVL), induced first depolymerysation followed by repolymerisation reaction of starch polysaccharide chains. Illumination induced rearrangements of the molecular structure of polysaccharide chains of illuminated Hylon V and Hylon VII starches led to significant changes of their physicochemical properties as compared with native starches.     

Chemical composition,digestibility and emulsification properties of octenyl succinic esters of various starches

Octenyl succinate starches are commonly used as emulsifiers and texturizing agents in many food-systems. Rice, tapioca, corn, wheat and potato starches were modified with octenyl succinic anhydride (OSA) at 3% level. Structural characterization, molecular weight, starch digestibility and physical properties of starch granule stabilized emulsions were studied for modified starches. Modified potato (0.022) and wheat (0.018) starches had the highest and lowest degrees of OSA substitution, respectively. For all starches, amylose and amylopectin molecular mass was significantly (P < 0.05) lower for OSA starches. OSA modification may have hydrolyzed the small amylose and amylopectin chains, or caused rearrangement of the starch molecules. Although the starch modification improved emulsification properties, botanical source showed more influence on this parameter. Overall, botanical source had more influence on functional properties than degree of substitution. Further studies on OSA group distribution and fine molecular structure of amylopectin and relationship with functional properties will be important.     

Influence of enzyme active and inactive soy flours on cassava and corn starch properties

The aim of this work was to study the influence of enzyme active and inactive soy flours on the properties of cassava and corn starches. Four starch/soy flour composites were evaluated: cassava/active soy flour (Cas/AS), cassava/inactive soy flour (Cas/IS), corn/active soy flour (Corn/AS) and corn/inactive soy flour (Corn/IS). Starch gelatinization occurred at 58.67°C for Cas and at 64.19°C for corn; gelatinization occurred at higher temperatures when soy flours were present, while ΔH diminished. The presence of AS reduced 80% the retrogradation enthalpy of Cas and 40% that of corn. Cas presented lower pasting temperature than corn starch (67.8 and 76.8°C, respectively) and higher peak viscosity (427.9 and 232.8 BU, respectively). The pasting properties of both starches were drastically reduced by soy flours, and this effect was more noticeable in Cas; AS had higher effect than IS. X‐ray diffraction pattern of retrograded samples showed that both starches recrystallisation (mainly that of Cas) was reduced when AS was added. Tan δ values decreased with AS addition to corn, but they increased when added to Cas. The images obtained using confocal laser scanning microscopy (CLSM) showed that IS was distributed as large aggregates, whereas AS distribution was more homogeneous, especially when incorporated to Cas. These results show that cassava starch interacts specifically with active soy flour (AS, mainly in native state). The delaying effect of AS on cassava starch retrogradation was clearly shown. This finding could be useful in obtaining gluten‐free breads of high quality and low retrogradation rate.