Influence of Heat‐Moisture Treatment and Acid Modifications on Physicochemical,Rheological, Thermal and Morphological Characteristics of Indian Water Chestnut (Trapa natans) Starch and its Application in Biodegradable Films

Water chestnut starch was subjected to acid modification and heat‐moisture treatment. Hydrochloric acid was used for acid modification at three different concentrations (0.25 M, 0.5 M and 1 M) for 2 h. Modifications did not alter the granule morphology. Heat‐moisture treatment (HMT) resulted in slight reduction in the granular size of the starch granules. Acid modification lowered the amylose content, swelling power, water‐ and oil‐binding capacity but improved the solubility of starch to a considerable level. Light transmittance of acid‐modified (AM) starches improved significantly. A significant reduction in peak, trough, final and setback viscosity was observed by acid‐thinning. In case of heat‐moisture treated starch the final viscosity (F_v) was found to be even higher than the peak viscosity (P_v). Native water chestnut starch exhibited a lower onset temperature (T_o) and peak temperature (T_p) of gelatinization than the corresponding acid‐treated starches. Starch films prepared from native starch exhibited excellent pliability, whereas those prepared from AM and HMT starches showed good tensile strength. Starch films prepared from acid‐treated starches provided better puncture and tensile strength.     

Physicochemical,Thermal, Morphological and Pasting Properties of Starches from some Indian Black Gram (Phaseolus mungo L.) Cultivars

The starches separated from thirteen different black gram cultivars were investigated for physicochemical, thermal, morphological and pasting properties. Amylose content, swelling power, solubility and water binding capacity of starches ranged between 30.2–34.6%, 16.0–22.3 g/g, 14.8–17.3% and 73.5–84.5%, respectively. The diameter of starch granules, measured using a laser‐light scattering particle‐size analyzer, varied from 12.8 to 14.3 μm in all black gram starches. The shape of starch granules varied from oval to elliptical. The transition temperatures (T_o, T_p and T_c) and enthalpy of gelatinization (ΔH_gel) determined using differential scanning calorimetry, ranged between 66.1–71.3, 71.0–76.2, 75.9–80.4°C and 6.7–9.4 J/g, respectively. Pasting properties of starches measured using the Rapid Visco Analyser (RVA) also differed significantly. Pasting temperature, peak viscosity, trough, breakdown, final viscosity and setback were between 75.8–80.3°C, 422–514, 180–311, 134–212, 400–439 and 102–151 Rapid Visco Units (RVU), respectively. Turbidity values of gelatinized starch pastes increased during refrigerated storage. The relationships between different properties were also determined using Pearson correlation coefficients. Amylose content showed a positive correlation with swelling power, turbidity and granule diameter. Swelling power showed a negative correlation with solubility and setback. T_o, T_p and T_c showed positive correlation with turbidity, pasting temperature and were negatively correlated to peak and breakdown viscosity.     

Effect of ionic gums and dry heating on physicochemical,morphological, thermal and pasting properties of water chestnut starch

Starch from water chestnuts (Trapa natans) was isolated and modified by dry heating and hydrocolloids [carboxy methyl cellulose (CMC) and sodium alginate]. Native and modified starches were evaluated for their physicochemical, pasting, thermal and morphological properties. Pasting and thermal properties were studied using Rapid Visco Analyzer (RVA) and Differential Scanning Calorimeter (DSC) respectively. Morphological properties were studied by Scanning Electron Microscopy (SEM). Modification of the starch by dry heating with and without gums reduced paste clarity and increased the water and oil binding capacity; solubility and swelling power decreased. Dry heating of native starch increased peak viscosity; however, with addition of CMC, peak viscosity decreased. Starch modified with CMC and 4 h heating exhibited lowest gelatinization temperature (T₀). Pasting characteristics of native water chestnut starch were largely affected by the addition of gums and/or heat treatment. Overall onset gelatinization temperature reduced with heat treatment and addition of gums. Morphological studies revealed no significant variation in starch granule size. Starch granules were seen agglomerated because of leaching of amylose and granule interspacing decreased with addition of gums.     

Effects of different crop starches on the cooking quality of Chinese dried noodles

To investigate the effects of seven starches made from different crop sources on noodle quality, Chinese dried noodles made from various reconstituted flours were prepared and analysed. Potato starch had better solubility and swelling power than the other starches, leading to higher water absorption, cooking loss and breakage ratio of the potato starch noodles. The correlation results unravelled that the cooking breakage ratio of noodles presented positive correlations with solubility, swelling power, peak viscosity (PV), trough viscosity (TV) and final viscosity (FV) values of starches. Besides, the adhesiveness of noodles showed a positive correlation with conclusion temperature (T_c) and setback viscosity (SV) values of starches. Moreover, the peak temperature (T_p) value of starches was negatively correlated with cooking loss; the granule size of starches had a positive correlation with noodles water absorption; and the peak time (PkT) value of starches represented positive relationships with noodles chewiness, shearing force and breaking strength.     

Molecular and physicochemical characterisation of starches from yam,cocoyam, cassava,sweet potato and ginger produced in the Ivory Coast

Granule sizes, macromolecular features and thermal and pasting properties of starches from seven tropical sources (Florido, Kponan and Esculenta yams, cocoyam, cassava, sweet potato and ginger) were compared with those of several well‐known cereal, legume and tuber starches. The aim of the study was to characterise some non‐conventional starches with a view to possibly marketing them. Amylose content varied from 148 mg g^?1 in Esculenta starch to 354 mg g^?1 in smooth pea starch. For total starches, weight‐average molar mass (M?_w) ranged between 0.94 × 10⁸ and 1.80 × 10⁸ g mol^?1 for potato and normal maize starches respectively. Gyration radius (R?_G) varied from 157 nm for ginger starch to 209 nm for normal maize starch. Gelatinisation enthalpy (ΔH) ranged between 9.8 and 20.7 J g^?1 for wheat and Florido starches respectively. Gelatinisation peak temperature (T_g) varied from 58.1 °C for wheat starch to 87.3 °C for ginger starch. Native starch granule mean diameter ranged between 5.1 and 44.5 µm for Esculenta and potato starches respectively. Cassava and potato starches had the highest swelling power and dispersed volume fraction at all treatment temperatures, while ginger starch had the lowest. Cocoyam starch had the highest and ginger starch the lowest solubility at 85 and 95 °C. Cassava starch was the most stable under cold storage conditions. Roots and tubers such as ginger and cassava produced in the Ivory Coast are new sources of starches with very interesting properties. Thus these starches could be isolated on an industrial level in order to market them. Copyright © 2007 Society of Chemical Industry     

Physical Properties of Starch from Two Genotypes of Amaranthus cruentus of Agricultural Significance in China

Starches were isolated from the two genotypes of Amaranthus cruentus most widely cultivated in China, R104 and K112. These starches, plus a corn starch standard were mixed with either distilled water or a 1% NaCl solution and characterized for gelatinization parameters by Differential Scanning Calorimetry (DSC), pasting properties using a Rapid Visco-Analyzer (RVA), and texture of the cooled gels. Significant findings were: 1. A. cruentus starches had higher gelatinization temperature and higher endothermic energy than corn starch; 2. Wide differences in pasting properties were found between the two A. cruentus genotypes, although the waxy line R104 had lower hot-paste viscosity and set-back than K112; 3. The pasting properties (peak viscosity and set-back), of K112 were similar to those of corn starch. 4. In 1% NaCl solution, compared to distilled water, corn starch set-back decreased while that of the A. cruentus starches increased. Where Amaranthus starch is to be used in food processing applications, careful selection of genotype is necessary to achieve desired functionality.     

Thermal Behavior of Selected Starches in Presence of Other Food Ingredients Studied by Differential Scanning Calorimetery (DSC)–Review

ABSTRACT: This review article highlights the thermal behaviors of selected starches that were studied using differential scanning calorimetery (DSC) with data shown in various research publications. The starches of sago, potato, sweet potato, cassava, yam, and corn are included in this overview. Our examinations indicate that thermal properties are highly affected by the type of starch, its amylose/amylopectin content, and the presence of other food ingredients such as sugar, sodium chloride, water, milk, hydrocolloids, and meat. When the heating temperatures of the starches were increased, the DSC measurements also showed an increase in the temperatures of the gelatinization (onset [T_o], peak [T_p], and conclusion [T_c]). This may be attributed to the differences in the degree of crystallinity of the starch, which provides structural stability and makes the granule more resistant to gelatinization.     

Physico‐chemical characterization of starches extracted from potatoes of the group Phureja

Starch was extracted from twenty‐four accessions of Group Phureja cultivated diploid potatoes, and from two commercial potato (Solanum tuberosum) varieties. Extracted starch samples were characterized and compared to industrial potato starch. Starch from Phureja generally exhibited smaller granule sizes and lower phosphorus content than starch from commercial potatoes. Amylose content and thermal properties (gelatinization temperature and enthalpy) were however in the same range for both groups. Starches from Phureja displayed very distinct pasting behavior from that of commercial potato. The former exhibited lower initial pasting viscosity but higher shear resistance. This may be related to lower starch granule size, causing lower swelling power and solubility. Iodine complexation results seem to indicate that phureja potatoes have higher proportion of amylopectin long chains. Phureja thus appears to be a promising new source of starch with specific physico‐chemical and functional properties intermediate between industrial potato and cereal starches.     

Some Properties of Starch Isolated from Radix Cynanchi bungei

The physicochemical and scanning electron micrograph characteristics of Radix Cynanchi bungei (RCb) starch were investigated. RCb starch presented an apparent amylose content of 20.1%, less than that of potato starch (23.6%), with a granule size ranging from 5 to 15 μm with round, spherical and polygonal shapes and B‐type X‐ray diffraction pattern. The RVA pasting properties of RCb starch were similar to those of potato starch, with pasting temperature of 60.8°C, lower than that of potato starch (64.3°C). The gelatinization parameters of RCb starch were found to be 55.9°C (T_o), 60.0°C (T_p), 66.6°C (T_C) and 13.2 J/g (ΔH) while those of potato starch were 58.9°C, 63.5°C, 68.6°C and 13.2 J/g. Both RCb and potato starch pastes behaved as high shear‐thinning liquids. RCb starch pastes had lower apparent viscosity than potato starch pastes at the same shear rate.     

Influence of modified starches on properties of gluten-free dough and bread. Part I: Rheological and thermal properties of gluten-free dough

The aim of this study was to analyze the influence of chemically modified starches (HDP and ADA) and high amylose corn starch (HACS) on the rheological and thermal properties of gluten-free dough based on corn and potato starches with pectin and guar gum. The results indicate that the dough with the addition of modified starch behaves as weak gel, the value of storage modulus G′ significantly depends on the frequency and the values of tan δ = G″/G′ range from 0.32 to 0.49. Significant influence of hydroxypropylated distarch phosphate (HDP) on the viscoelastic properties of dough was observed. The share of modified starch in the system caused a decrease of the instantaneous and viscoelastic compliance. It also influenced the retardation time and zero shear viscosity. The application of modified starches (HDP and ADA) for dough preparation did not have much impact on the pasting characteristics. However, significant reduction of the onset and end viscosities were found for high amylose starch (HACS). Thermograms obtained for individual dough systems were characterized by the presence of two peaks, associated with the existence of two different starches in the system. No significant effect of modified starch on the onset temperature (T_O) and only a slight effect of HACS starch on gelatinization enthalpy were observed. However, the level of addition of individual starch affected peak and end (T_E) temperatures, depending on the type of preparation.     

Effect of Amylose Content on Gelatinization,Retrogradation and Pasting Properties of Flours from Different Cultivars of Thai Rice

Presently, rice cultivars are categorized according to amylose content into three groups: low, medium and high amylose content cultivars. The correlation of amylose content with gelatinization properties, retrogradation, and pasting properties of eleven cultivars of Thai rice were investigated. Rice flour was prepared from milled rice by the wet grinding process. Onset (T_o), peak (T_p) and conclusion (T_c) temperatures of gelatinization, (determined by DSC) were found to be highly positively correlated with amylose levels. This correlation could be used for prediction of amylose content of rice flour. Low amylose starch could also be characterized by low degree of retrogradation (%R). The data obtained from RVA‐viscograms (peak viscosity, breakdown, setback, and pasting temperature) can be used only for characterization of the group of low amylose starches (waxy rice). It was demonstrated that low amylose rice starch provided the highest peak viscosity and breakdown and the lowest setback and pasting temperature among the groups investigated.     

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.     

Characterization of Pea Starches in the Presence of Alkali and Borax

Refined field pea (Pisum sativum L.) starches were prepared from air‐classified pea starch by washing or from whole pea by wet milling, and analyzed for their physicochemical and pasting characteristics in the presence of alkali and borax. Commercial corn and high amylose corn starches were included in the study for comparative purposes. The two pea starches exhibited similar physicochemical characteristics. Amylose content markedly influenced pasting and other characteristics of the corn starches. Pea starch and high amylose corn starch exhibited little viscosity development during pasting in deionized water. The presence of alkali or borax significantly altered the peak viscosities and cold paste stabilities of all four starches in a concentration dependent manner. Alkali and borax increased peak and cold paste viscosity and reduced syneresis in all cases.     

Effects of annual fluctuation of environmental factors on starch properties in potato tuber development

To test the effects of the annual fluctuation of the environmental factors on the starch properties in potato tuber development, starches were isolated from potato cultivars grown for ten consecutive years (2001–2010) on the experimental farm in Memuro, Hokkaido, the northernmost island of Japan. The median granule size, phosphorus content, and rapid visco‐analyzer pasting properties, peak viscosity, breakdown, and pasting temperature of these starches were analyzed. Daily temperature and precipitation records in Memuro were obtained from the Japan Meteorological Agency. Moreover, the correlation coefficients of yearly accumulated temperature and precipitation from flowering to harvesting with all the starch quality parameters were calculated. No relationships of accumulated temperature with median granule size, peak viscosity, and breakdown were found. The low phosphorus content was slightly associated with the high accumulated temperature. The pasting temperature was significantly and positively correlated with the accumulated temperature, suggesting that the pasting temperature strongly responds to the environmental temperature during potato tuber development. In contrast, all the starch quality parameters were almost irrespective of the precipitation during potato tuber development.     

Granular Structure and Physicochemical Properties of Starches from Amaranth Grain

The granular structure and physicochemical properties of starches isolated from grain amaranth cultivar K112 (Amaranthus cruentus L.) were studied in this study. Detailed physical and chemical analyses were performed by determining the granular morphology, crystallinity, particle size, thermal characteristics, blue value, enzyme susceptibility, and pasting properties. Results showed polygon-shaped A. cruentus L. K112 starch granules. The average diameter was 1.38 μm, in which half of the diameter was <2.91 μm. An A-type X-ray diffraction pattern was revealed with intense peaks of 15.2°, 17.5°, and 23.2°. The peak viscosity was 181 BU and the breakdown value was 2 BU. Amaranth starch obtained the highest pasting temperature (70.7°C) and enzymatic digestibility (absorbance value = 0.41 ± 0.013) compared with corn, cassava, and sweet potato starches.     

Morphological,thermal, rheological and noodle‐making properties of potato and corn starch

A comparison between the morphological, thermal, rheological and noodle‐making properties of corn starch and potato starches separated from five different potato cultivars was made. The granule size and shape of all starches differed significantly. Potato starch granules were comparatively larger than corn starch granules, while the transition temperatures were found to be higher for corn starch. Consistency coefficients and flow behaviour indices measured by back extrusion were higher for potato starches than for corn starch. Stickiness of cooked starch pastes was observed to depend upon their consistency coefficient. The gels made from all potato starches showed higher gel strength than those from corn starch. The gel strength of starches from both corn and potato increased during refrigerated storage. The amylose content, swelling power, solubility and light transmittance values of potato starches were significantly higher than those of corn starch. Noodles made from potato starches had higher cooked weight and cooking loss than corn starch noodles. Texture profile analysis revealed that potato starch noodles also had higher hardness and cohesiveness than corn starch noodles. Hardness of cooked noodles from all starches increased and cohesiveness decreased during storage. Noodles made from starches of higher viscosity exhibited higher hardness and cohesiveness. Textural differences among cooked starch noodles appeared to be associated with morphological, thermal and rheological properties of corn starch and potato starches. © 2002 Society of Chemical Industry     

The influence of Cu(II) ions on physicochemical properties of potato starch oxidised by hydrogen peroxide

The study investigates the influence of Cu(II) ions used as a catalyst on the effectiveness of potato starch oxidation by hydrogen peroxide, and compares the physicochemical properties of the modified starches. The starch was oxidised by H₂O₂ alone and with the addition of Cu(II) ions at three concentrations: 0.1, 0.2 or 0.3 g per 100 g d.m. of starch. The oxidised starches were examined for the content of carboxyl groups, carbonyl groups, amylose and copper, and for water‐binding capacity and water solubility at temperatures of 60 and 80°C. Colour parameters (L*a*b*), susceptibility to retrogradation, thermodynamic characteristics of pasting, intrinsic viscosity and pasting characteristic by RVA were also determined. The results indicate that the concentration of Cu(II) ions added as a catalyst has an effect on both the effectiveness of the oxidation process and the physicochemical properties of starch.     

Relationships Between Selected Properties of Starches from Different Corn Lines

Starch was isolated from the corn lines obtained by crossing two different germ pools (MS and Tux pool) and evaluated for amylose content, swelling power, solubility, water binding capacity (WBC) and syneresis. The gelatinization (T_o, T_p, T_c, ΔH_gel, PHI & R) and pasting (pasting temperature, peak viscosity, breakdown viscosity, final viscosity and set back) properties of starches were measured using Differential Scanning Calorimeter (DSC) and Rapid Visco Analyzer (RVA), respectively. The relationships between different properties were also determined using pearson correlation coefficients. Amylose content was negatively correlated to swelling power and WBC (p < 0.05). Several significant relationships were also observed between thermal and pasting properties of isolated starches. Transition temperatures (T_o, T_p & T_c) and PHI showed positive correlation with peak, trough and breakdown viscosity (p < 0.05). Syneresis of starches was positively correlated to amylose content (p < 0.05).     

Effects of sodium dodecyl sulphate and sonication treatment on physicochemical properties of starch

Effects of sodium dodecyl sulphate (SDS) and sonication treatment on physicochemical properties of starch were studied on four types of starch, namely, corn, potato, mung bean, and sago. The SDS and sonication treatments caused a significant reduction of protein content for all the starches. The SDS treatment did not cause apparent damage on granular structure but sonication appeared to induce changes such as rough surface and fine fissures on starch granules. The combination of SDS and sonication increased amylose content for all starches. This could be attributed to the removal of surface protein by SDS and structural weakening by sonication which facilitated amylose leaching from swollen starch granule. The X-ray pattern for all starches remained unchanged after SDS treatment, suggesting no complexation of amylose–SDS had occurred. Combined SDS-sonication treatment increased swelling and solubility of corn, mung bean, and potato starch. The treated starches showed significant increase in peak viscosity with reduction in pasting temperature, except for potato starch. Results of the present study indicate the possibilities of exploring SDS and sonication treatments for starch modifications.     

Morphological,physicochemical, and pasting properties of modified water chestnut (Trapabispinosa) starch

Selected physicochemical properties of native and modified water chestnut starch (Trapabispinosa) were studied. Single- and dual-modifications were carried out by pregelatinization, acetylation and acid-thinning methods. Chemical modification created unevenness on the surface of starch granule. Swelling power, solubility, and water retention capacity were improved by all modification techniques used. The peak viscosity was reduced in all modified starches as compared to native water chestnut starch. The setback value which is an indication of retrogradation (re-association of starch molecules) tendency in the starch paste was reduced after pregelatinization and acid-thinning but increased by acetylation.