Preparation and physicochemical properties of modified jackfruit starches

Modifications of jackfruit starch, extracted from the cotyledons of Artocarpus heterophyllus Lam. (Thong Prasert cultivar), were carried out to obtain a pregelatinized starch, three (m-, n- and i-) carboxymethyl starches, a hydroxypropyl starch and a phosphate cross-linked starch. Physicochemical properties of native and modified jackfruit starches were comparatively investigated. Pregelatinized, hydroxypropyl, and cross-linked starches were insoluble or partially soluble in water at room temperature, while carboxymethyl starches were soluble with good overall water uptake. Scanning electron microscopic images revealed that granules of most modified jackfruit starches retained the native appearance and crystal structure, with the exception of pregelatinized starch and two (n- and i-) carboxymethyl starches, which showed significant breakage of granules. X-ray diffraction patterns corroborated to suggest the loss of crystallinity in these modified starches. Thermal analysis showed a significant decrease in the gelatinization temperature of hydroxypropyl starch with no change in enthalpy, while higher gelatinization temperature and less enthalpic value were observed for pregelatinized starch. Pregelatinized and hydroxypropyl starches showed temperature-dependent improvement on swelling and solubility, while cross-linked starch exhibited less solubility. Aqueous solution of m-carboxymethyl starch yielded the highest apparent viscosity with improved heating-cooling stability.     

Isolation and characterization of Mexican jackfruit (Artocarpus heterophyllus L) seeds starch in two mature stages

Starch was isolated from jackfruit (Artocarpus heterophyllus L) seeds grown in México at different stages of fruit maturity and ripeness. Seeds represent about 8–15% from the fruit that can weigh around 2–36 kg. Proximate composition of seeds showed a high protein content (ca. 22%). Starch yield was 14% with a purity of 81% in both ripeness stages and AM content was lower (12.27%) than other non‐common starch sources. The starch granules in physiological mature (PM) and consumption ripeness (CR) jackfruit showed birefringence with diverse shapes such as semi‐oval or bell shapes. The size of starch granules for PM ranged between 3 and 9.5 µm and for CR between 3 and 12 µm. A‐type XRD pattern was similar to cereal starches. PM starch had higher peak viscosity than CR, but CR did not show breakdown; both starches presented setback during cooling. Thermal properties of gelatinization and retrogradation in PM and CR starches were similar. Characterization performed on this non‐common starch showed that it could be an alternative to use in food systems.     

Comparative Studies on Physico-Chemical Properties of Starches from Jackfruit Seed and Mung Bean

The physico-chemical properties of starch from jackfruit seed and mung bean were investigated. Jackfruit seed starch had much higher resistant starch content (26.99%) than that of mung bean starch (4.04%). Furthermore, jackfruit seed starch had a higher gelatinization temperature (T_o) that required more gelatinization energy (ΔH) compared to mung bean starch. However, mung bean starch had higher amylose content and its granules were much larger than that of jackfruit seed starch. Mung bean starch had the highest peak viscosity, breakdown, and setback whereas jackfruit seed starch had the highest pasting temperature. Amylopectin chain length of mung bean starch contained higher proportion of short chains (degrees of polymerization 6–12) but lower proportion of very long chains (degrees of polymerization > 37 ) comparing with jackfruit seed starch. The X-ray diffraction patterns showed both starches to be Type-A crystallinity. In addition, both starch gels showed higher the storage modulus (G′) than the loss modulus (G?) designating as rubber like material. However, mung bean starch gel exhibited higher G’ and less tan δ than that of jackfruit seed starch indicating much stronger of gel structure.     

Studies on the properties of citrate derivatives of cassava (Manihot esculenta Crantz) starch synthesized by microwave technique

Cassava starch citrates with degree of substitution (DS) ranging from 0.005 to 0.063 were synthesized by the microwave‐assisted reaction of cassava starch with citric acid. A response surface small composite design was used to study the effect of different reaction conditions, viz. time, temperature and reagent concentration. All these variables significantly affected the substitution level in the modified starches. The DS increased with increase in the time of reaction and temperature. However, reagent concentration had a negative effect on the DS. The modified starches showed higher viscosity with lower breakdown, lower setback and higher final viscosities in comparison to native starch. Differential scanning calorimetry showed that the modified starches exhibited a decrease in gelatinization temperatures, T_o, T_p, T_e, in comparison to native starch. However, the heat of gelatinization was not significantly affected. The citrate derivatives exhibited reduced swelling volume and enhanced water binding capacities. They were found to be less susceptible to enzyme hydrolysis than native starch. Copyright © 2007 Society of Chemical Industry     

Effect of Cross‐linking with Epichlorohydrin on the Properties of Cassava (Manihot esculenta Crantz) Starch

Cassava starch was cross‐linked with epichlorohydrin (EPI) at 45°C for 2 h in three different media which include water, water in the presence of a phase transfer catalyst (PTC) and N,N‐dimethylformamide (DMF). The products were characterized by determining their physicochemical, thermal and retrogradation properties. In aqueous medium, the use of a PTC, tetrabutylammonium bromide (TBAB) produced derivatives with higher degree of cross‐linking than those prepared without the use of the catalyst. The degree of cross‐linking was found to be higher using the same concentration of EPI when the reaction was carried out in DMF. At low levels of cross‐linking, the peak viscosity of the cross‐linked starches increased in comparison to that of the native starch. With increasing degree of cross‐linking, the peak viscosity showed a significant reduction. The swelling volume, solubility and light transmittance of the starch pastes were lower for the modified starches. The cross‐linked starches showed slightly reduced values for the gelatinization temperatures, T_onset, T_peak and T_end. The enthalpy of gelatinization of the modified starches increased with increase in the degree of cross‐linking. The modified starches exhibited higher water‐binding capacities (WBC) than the native starch; but with increase in the degree of cross‐linking, there was a gradual decrease in WBC. The in vitro alpha amylase digestibility of the modified starches decreased gradually with increase in the level of cross‐linking.     

Influence of prior acid treatment on physicochemical and structural properties of acetylated sorghum starch

Influence of prior acid treatment on acetylation of starch isolated from an Indian sorghum cultivar was investigated. The starch was acid thinned (AT) using 0.1, 0.5, and 1 M HCl for 1.5 h and then acetylated (Ac) with acetic anhydride (8% w/w). The acid thinning and subsequent acetylation appeared to reduce the percentage acetylation as indicated by degree of substitution. Ac‐AT starches exhibited significantly different physicochemical, thermal, pasting, and gel textural properties from those of AT and Ac starches. Starches after dual modification showed higher solubility, lower AM content, gelatinization temperatures, retrogradation, peak viscosity, and gel hardness than native starch. Enthalpy and range of gelatinization were observed to be higher in dual modified starches than native starch. However, no significant changes in granule morphology or crystalline pattern of Ac‐AT starches were observed compared with native starch.     

改性玉米淀粉的物理化学研究

对天然玉米淀粉和五种化学改性玉米淀粉的糖化性质进行了比较。改性玉米淀粉包括下列五种,磷酸淀粉,交联磷酸淀粉,醋酸淀粉A,醋酸淀粉B和羟丙基淀粉。使用差热扫描量热计测定了糊化的热力学参数,同时用显微镜观察了糊化过程。研究表明,五种改性玉米淀粉的糊化热都比天然的玉米淀粉小,测量冷的淀粉糊的流动性质表明只有羟丙基玉米淀粉比天然玉米淀粉的帖度高。     

Physicochemical Properties of Canna edulis Ker Starch on Heat-Moisture Treatment

Canna edulis Ker starch was modified by heat-moisture treatment at moisture levels ranging from 18 to 27 g/100 g starch and its physicochemical properties were investigated. Amylose content, swelling power, solubility as well as water and oil absorption capacity in native starch were higher than in all treated starches. However, alkaline water retention and acid susceptibility of native starch were lower, along with different extent of amylose leaching. The result in the X-ray diffraction measurement revealed that the crystalline type of the starch gradually changed from B-type to A-type, and the degree of crystallinity changed. Investigation on thermal properties showed that the gelatinization enthalpy decreased, whereas the onset temperature, peak temperature, concluding temperature and transition temperature range increased in modified starch than in native starch. In addition, all modified starches exhibited remarkably low values of peak viscosity, hot pasting viscosity and final viscosity, compared to those of native starch.     

Effect of acid concentration and treatment time on acid–alcohol modified jackfruit seed starch properties

The properties of starch extracted from jackfruit (Artocarpus heterophyllus Lam.) seeds, collected from west Assam after acid–alcohol modification by short term treatment (ST) for 15–30 min with concentrated hydrochloric acid and long term treatment (LT) for 1–15 days with 1 M hydrochloric acid, were investigated. Granule density, freeze thaw stability, solubility and light transmittance of the treated starches increased. A maximum decrease in the degree of polymerisation occurred in ST of 30 min (2607.6). Jackfruit starch had 27.1 ± 0.04% amylose content (db), which in ST initially decreased and then increased with the severity of treatment; in LT the effect was irregular. The pasting profile and granule morphology of the treated samples were severely modified. Native starch had the A-type crystalline pattern and crystalline structure increased on treatment. FTIR spectra revealed slight changes in bond stretching and bending. Colour measurement indicated that whiteness increased on treatment. Acid modified jackfruit seed starch can have applications in the food industry.     

Properties of jackfruit seed starch oxidized with different levels of sodium hypochlorite

The effect of active chlorine concentrations (1–5%) on the properties of jackfruit seed starch was investigated. Both the carbonyl and carboxyl contents of the oxidized starches generally increased with progressive increases in the active chlorine concentration. No evidences of alteration in the morphology and X-ray diffraction pattern were observed after oxidation, while the decrease in relative crystallinity was found. The swelling power of the oxidized starch tended to decrease with the active chlorine levels, particularly at a low level of active chlorine (1–3%). No significant differences in the peak temperature (Tp) and the end temperature (Te) were found between the native and the oxidized starches, while the oxidized starches had lower onset temperatures (To). Parameters, such as pasting temperature, peak viscosity, and setback, decreased with the concentration of active chlorine. In addition, lower syneresis and turbidity were found in all oxidized starches during refrigerated storage compared to the native starch.     

Effect of Heat-Moisture Treatment and Acid Modification on Rheological, Textural, and Differential Scanning Calorimetry Characteristics of Sweetpotato Starch

Sweetpotato starches were characterized to understand the changes upon modification by acid and heat‐moisture treatment (HMT) in the rheological, differential scanning calorimetry (DSC), and textural characteristics of starch isolated from the sweetpotato variety PSP‐21 and to compare these findings with those of commercially available arrowroot starch. The native sweetpotato starch had a Type A pasting profile characterized by a high peak viscosity (PV) (741.5 rapid viscoanalyzer unit [rvu]), with a high breakdown (378.8 rvu) and low cold paste viscosity (CPV) (417.6 rvu). After HMT, there was a marked decrease in the PV (639.1), a very slight breakdown (113.5 rvu) and an increase in CPV (759.5 rvu), more like a Type C pasting profile. However, acid modification did not notably change the pasting profile of native sweetpotato starch. The DSC characteristics were also affected significantly after modifications. The gelatinization temperature parameter to onset (T_o) decreased significantly after HMT and acid modification. The gelatinization enthalpy decreased during HMT from 15.98 to 14.42 J/g. The gel strength of acid‐modified starch was the highest compared with that of HMT and native sweetpotato and arrowroot starches.     

Pasting,Thermal, Hydration,and Functional Properties of Annealed and Heat-Moisture Treated Starch of Sword Bean (Canavalia gladiata)

The effects of annealing (ANN) and heat-moisture treatments (HMT) on the physicochemical and functional properties of Sword bean starches were investigated. The pasting properties differ significantly among the starches, with peak viscosity ranging from 399.17 RVU to 438.33 RVU; however, all the starches exhibited ‘Type C’ class with restricted swelling. The HMT starches had the highest gelatinization temperature, while change in enthalpy of gelatinization, ΔH_gel of the native starch, was higher (13.82 J/g) than that of the modified starches (1.39–6.74 J/g). The solubility and swelling power of all the starches increased as the temperature increased. The oil and water absorption capacity of the starches ranges between 3.24–3.91 g/g and 2.42–3.35 g/g, respectively. HMT (at 25 and 30% moisture level) changes the X-ray diffraction pattern of the starch from Type ‘B’ to Type ‘C’. The Scanning electron micrograph results revealed the starch granules with smooth ellipsoids and indentation in their centre, hydrothermal modification showed little effect on the morphology and size of the granules. Hydrothermal modification improved the physicochemical and functional properties of the starch without destroying the granule of the starch.     

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.     

Physicochemical Properties of Starch Isolated from Bracken (Pteridium aquilinim) Rhizome

Bracken (Pteridium aquilinum) is an important wild plant starch resource worldwide. In this work, starch was separated from bracken rhizome, and the physicochemical properties of this starch were systematically investigated and compared with 2 other common starches, that is, starches from waxy maize and potato. There were significant differences in shape, birefringence patterns, size distribution, and amylose content between bracken and the 2 other starches. X‐ray diffraction analysis revealed that bracken starch exhibited a typical C‐type crystalline structure. Bracken starch presented, respectively, lower and higher relative degree of crystallinity than waxy maize and potato starches. Ordered structures in particle surface differed among these 3 starches. The swelling power tendency of bracken starch in different temperature intervals was very similar to that of potato starch. The viscosity parameters during gelatinization were the lowest in waxy maize, followed by bracken and potato starches. The contents of 3 nutritional components, that is, rapidly digestible, slowly digestible, and resistant starches in native, gelatinized, and retrograded starch from bracken rhizome presented more similarities with potato starch than waxy maize starch. These finding indicated that physicochemical properties of bracken starch showed more similarities with potato starch than waxy maize starch.     

Indigestible Starch of P. lunatus Obtained by Pyroconversion: Changes in Physicochemical Properties

Lima bean (Phaseolus lunatus) starch was modified using pyroconversion to produce non‐digestible starch and the functional properties of the pyrodextrinized starches were evaluated. Reaction conditions included: starch/2.2 M HCl ratio (80:1 and 160:1, w/v); temperature (90°C and 110°C) and reaction time (1 and 3 h). “In vitro” indigestible starch and color difference (ΔE) were determined and used as response variables. The optimum product was recovered from native starch treated with a 160:1 starch/HCl ratio, at 90°C for 1 h, which produced modified starches containing 49.5% indigestible starch and ΔE of 18.86. Starch pyrodextrinization decreased the amount of enzymatically available starch through formation of atypical glycosidic bonds that are not digested by the amylases and maltooligosaccharidases in the small intestine of humans. Compared to the P. lunatus native starch, the pyrodextrinized starch exhibited increased paste and gel clarity (52.7%T), solubility (88.7%), and swelling power (26 g water/g starch), a higher gelatinization temperature range (72.5–89.8°C) and lower viscosity. This process can be considered a promising treatment for production of resistant starch (RS) from P. lunatus.     

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 cationization on DSC thermal profiles,pasting and emulsifying properties of sago starch

Cationic sago starches were prepared using an aqueous alkaline process with different levels of cationic reagent 3‐chloro‐2‐hydroxypropyltrimethylammonium chloride (0.01–0.10 M ), sodium hydroxide (0.03–0.86 M ) and reaction temperature (30–62 °C). The degree of substitution (DS), reaction efficiency, thermal and pasting properties of cationic sago starches were analysed. Emulsifying and fat binding properties of native sago starch, cationized sago starch and commercial chitosan were compared at two different pH values (4 and 7). Degree of substitution increased with an increase in concentration of cationic reagent or NaOH, or reaction temperature. The reaction efficiency was proportional to the concentration of NaOH and reaction temperature but inversely proportional to the cationic reagent concentration. The highest DS and reaction efficiency achieved was 0.06 and 79%, respectively. The pasting temperature and gelatinization enthalpy of cationic starch (DS 0.06) were lower compared with native sago starch. Cationization increased the peak viscosity and breakdown of the starch paste but decreased the setback. The presence of cationic groups significantly increased emulsion stability, emulsion viscosity and fat binding capacity of sago starch. However, the cationic sago starch was still inferior to chitosan, which showed the highest emulsion stability, emulsion viscosity and fat binding capacity. There was no significant difference between the surface tension values of native and cationic sago starch and chitosan. The influence of pH on emulsifying properties was not significant. The emulsion stability of the cationic sago starch improved due to an increase in viscosity and fat binding capacity but not its surface active property. Copyright © 2004 Society of Chemical Industry     

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.     

韧化处理对不同玉米淀粉理化特性的影响

以不同直/支链比例的普通玉米淀粉和蜡质玉米淀粉为材料,在40、50、60℃进行韧化处理,研究韧化处理对玉米淀粉理化特性的影响。结果表明：韧化处理的两种玉米淀粉颗粒形貌有较小变化。韧化处理后,两种淀粉的溶解度和膨胀度随着处理温度的升高而降低;所有韧化处理过的玉米淀粉黏度低于原淀粉,起糊温度高于原淀粉;韧化处理后淀粉的糊化温度升高,热焓变化不大。     

Physicochemical characterization of chemically modified corn starches related to rheological behavior,retrogradation and film forming capacity

An integral approach of chemical modification effects on physicochemical and functional properties of corn starch was performed using different and complementary techniques. Acetylated, acetylated crosslinked, hydroxypropylated crosslinked, and acid modified corn starches were analyzed. Substitution and dual modification reduced significantly amylose concentration. Chemical modification decreased granules crystallinity degree. A significant increase in swelling power was observed in substituted and dual modified starches at 90 °C, besides these treatments decreased gelatinization temperature and enthalpy. Acid modified starch pastes showed a Newtonian behavior while substituted and dual modified ones exhibited a viscoelastic response. Dynamic rheological properties of modified starch pastes were not affected by post gelatinization time while native starch pastes developed a more rigid structure during storage. Retrogradation of substituted starch pastes after 12 days at 4 °C was reduced, since syneresis degree and hardness increase were significantly lower than those of native pastes. It was demonstrated that only substituted and native starches exhibited film forming capacity.