Preparation of Amphoteric Starches During Aqueous Alcoholic Cationization

Use of an aqueous alcoholic-alkaline solvent allowed cationization and phosphorylation to be combined in simultaneous or sequential processes in the production of amphoteric starch. Degrees of substitution required by the paper industry were obtained in normal corn, pea and barley starches, and in waxy corn and barley starches without the need for drying and heating the cationic starches to complete the phosphorylation reaction. The amphoteric starches had increased welling power, lower gelatinization temperatures, improved paste consistency and stability, and increased α-amylase digestibility than native controls, while gel syneresis after cold storage was eliminated.     

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。     

An Aqueous Alcoholic-Alkaline Process for Cationization of Corn and Pea Starches

To develop a more efficient process for cationization of corn and pea starches, the effects of gelatinization inhibitor, type of solvent and solvent concentration, starch: water ratio, reaction temperature and 2-chloro-3-hydroxypropyltrimethylammonium chloride (CHPTAC) concentration on rate and efficiency of cationization of corn und pea starches in an aqueous alcoholic-alkaline solvent were studied during 24h of reaction time. The use of watermiscible organic solvents in the aqueous alkaline media eliminated the requirement for a gelatinization inhibitor to minimize starch swelling. The alcohol concentrations which produced high reaction efficiencies were 35-75% ethanol or 2-propanol. Optimum conditions for the reaction included 65% ethanol, 50°C and a starch:water ratio of 1:1 (w/w). The degree of substitution (DS) value increased linearly with CHPTAC concentration up to O,2M CHPTAC, but reaction efficiency (RE) decreased at the O,2M CHPTAC concentration. Cationization of starch in the aqueous alcohol solvent would be an alternative to aqueous processes because of the higher DS and reaction efficiencies that were achieved more rapidly and without the aid of other gelatinization inhibitors.     

Production and characterization of digestion‐resistant starch by the reaction of Neisseria polysaccharea amylosucrase

Recombinant amylosucrase (200 U/mL) from Neisseria polysaccharea was used to produce digestion‐resistant starch (RS) using 1–3% (w/v) corn starches and 0.1–0.5 M sucrose incubated at 35°C for 24 h. Characterization of the obtained enzyme‐modified starches was investigated. Results show that the yields of the enzyme‐modified starches were inversely proportional to the original amylose contents of corn starches. After enzymatic reaction, insoluble RS contents increased by 22.3 and 20.7% from 6.9% of waxy and 7.7% of normal corn starches, respectively, using 3.0% starch as acceptor and 0.3 M sucrose as donor, while amylomaize VII showed the lowest increase (8.5%) in RS content. The crystalline polymorph of these enzyme‐modified starches resulted in the B‐type immediately after enzymatic reaction. The enzyme‐modified starches displayed higher melting peak temperatures (85.6–100.6°C) compared to their native starch counterparts (70.1–78.4°C). After enzymatic reaction, pasting temperature increased in waxy (71.9 → 77.6°C) and normal corn starches (75.3 → 80.6°C), and the peak viscosity of waxy corn starches increased from 264 to 349 RVU, whereas that of normal corn starches decreased from 235 to 66 RVU.     

Effects of Cationization on Functional Properties of Pea and Corn Starches

Amylography, scanning electron microscopy and storage tests demonstrated that native pea starches were highly resistant to granule disintegration during heating in dilute slurries, resulting in low hot paste viscosity, high retrogradation and syneresis. Cationization at degrees of substitution of 0.02 to 0.05 reduced the pasting and gelatinization temperatures, increased peak viscosities and set-back on cooling but eliminated syneresis after storage at 4°C and − 15°C. The principal effects of cationization were to promote rapid granule dispersion at low pasting temperatures, yielding a molecular dispersion of amylose and amylopectin on heating to 95°C. On cooling, the gel structures were firm and the cationic groups controlled the realignment of starch chains during low temperature storage.     

Cationization of Waxy and Normal Corn and Barley Starches by an Aqueous Alcohol Process

When an aqueous alcoholic-alkaline solvent was used, cationization of normal and waxy corn and barley starches was achieved with high degrees of substitution (DS) and reaction efficiency (RE) in the absence of gelatinization inhibitor salts. Ethanol was a more effective solvent than methanol or 2-propanol, and alcohol concentrations could vary between 35–65%. Maintaining a starch to water ratio of 1:1 (w/w) was critical, but DS values were proportional to the concentration of cationic reagent, 3-chloro-2-hydroxypropyltrimethylammonium chloride. At 50°C, cationization was essentially complete within 6h but nearly the same DS could be achieved in 1h at 70°C.     

The suitability of barley and corn starches in their native and chemically modified forms for volatile meat flavor encapsulation

In order to minimize the evaporative flavor loss and to improve flavor stability, the encapsulation potential of native corn and barley starches [waxy corn starch (CW), regular corn starch (CR), waxy barley starch (BW), regular barley starch (BR)] and their chemically modified counterparts (succinylated starches: CWS; CRS; BWS; BRS and octenyl succinylated starches: CWOS; CROS; BWOS; BROS) were investigated. Four different types of synthetic flavors, namely benzaldehyde, dimethyl trisulfide, 2-mercaptopropionic acid and benzothiazole, were selected. Succinylated corn and barley starches were more effective than the native starches and octenyl succinylated starches in the flavor retention. Succinylated regular starches (CRS and BRS), in particular, showed better retention ability than waxy starches. As compared to β-cyclodextrin (βCD, which is a widely used wall material in the microencapsulation of essential oils or flavors), the succinylated regular starches showed better flavor retention capabilities. Benzaldehyde and benzothiazole were retained to a higher extent by all starches (native and modified) as compared to dimethyl trisulfide and 2-mercaptopropionic acid (as measured just after preparation). None of the starches (native or modified) showed substantial decreases in flavor retention during their 4-week storage at 50 °C. In contrast, βCD showed a rapid decrease in flavor retention during the first 2 weeks of storage (from 88 to 49%) and the amount reached ∼45% at the end of 4 weeks. Also, the flavor retained by succinylated starches, based on extraction of volatile flavors in headspace, were higher than those of native and octenyl succinylated starches. CRS and BRS were noticeably superior to others. Findings showed that all starches investigated are potential wall materials for microencapsulation of volatile flavors with CRS and BRS being the best.     

The Reactivity of Native and Autoclaved Starches from Different Origins Towards Acetylation and Cationization

Native potato, waxy corn, corn, wheat, filed pea and lentil starches were autoclaved at 15 psi, 121°C for 1min. Scanning electron micrographs of the native and autoclaved starches showed no changes in granular surfaces and shapes. In all starches, the X-ray intensities at most of the d-spacings between 3-18 Å increased upon autoclaving, being more pronounced in potato. The X-ray patterns of cereals and legumes remained unchanged, while that of tuber (potato) became more cereal-like. Differential scanning calorimetry of the starch samples revealed that autoclaving increased the gelatinization transition temperatures of wheat but decreased that of potato; the changes observed in waxy corn, corn, field pea and lentil starches were very small. The gelatinization enthalpy of all native starches decreased upon autoclaving while the percentage decrease was highly marked in potato. Image analysis of the native and autoclaved starches revealed changes in the granule size distribution patterns. Also, the population mean area of all native starch granules considerably increased upon autoclaving. Acetyl binding capacity, measured at 5% and 10% acetic anhydride addition levels, was higher in autoclaved than in native starches. Furthermore, autoclaving had no influence on starch cationization, studied at 3% and 6% reagent addition levels. The results indicated that the changes in starch molecular organization caused by autoclaving enhanced its reactivity towards acetylation but not cationization.     

Starch Properties of a Waxy Mutant Line of Hull‐less Barley (Hordeum vulgare L.)

Endosperm starch isolated from an amylose‐free waxy mutant hull‐less barley line, Shikoku Hadaka 97, had an amylose content of 0.3% and higher swelling power than ordinary waxy barley cultivars/lines with amylose contents of 2.2—6.5%. A highly significant correlation was observed between amylose content and swelling power among waxy barley starches. No clear differences were detected in the chain‐length distribution profiles or thermal properties between the amylose‐free starch and ordinary waxy starch. The chain‐length distribution profile of waxy barley starch was slightly different from that of normal barley starch. Gelatinization temperatures and gelatinization enthalpy of waxy barley starch were higher than those of normal barley starch. Significant correlations were observed between amylose content and thermal properties of starch samples analyzed. Waxy barley starch stained with a concentrated iodine‐potassium iodide solution showed a ghost‐like appearance.     

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.     

Physicochemical Characteristics and Functional Properties of Starch from a High β-Glucan Waxy Barley

The physicochemical properties and functional characteristics of starch from a high β-glucan waxy barley were compared with those of starches isolated from normal and high amylose barleys. Amylose content of the starches ranged from 1.9 to 34.8%. There was no relationship between amylose content and water binding capacity and gelatinization temperature of the starches. Amylose content and swelling power as well as enzyme susceptibility were negatively correlated. Waxy barley starches had a lower solubility than amylose-containing starches. High amylose barley starch registered no swelling in the Amylograph. Amylose content in starch proved to be very important for good bread- and cake baking quality. Waxy starches did not produce acceptable breads and cakes. The starch from the high β-glucan barley variety “Shonkin” will be suitable as a thickening agent, but not as an ingredient in bakery products.     

Properties of Korean Amaranth Starch Compared to Waxy Millet and Waxy Sorghum Starches

Characteristics of waxy type starches isolated from amaranth, waxy millet and waxy sorghum harvested in Korea were evaluated. Shapes of all starch granules were polygonal or slightly round and the surfaces of waxy millet and waxy sorghum starch granules showed visible pores. Amylose contents of the three starches were between 3.2–6.0% and amaranth starch showed the highest water binding capacity (WBC) (130.7%). The swelling power and solubility of amaranth starch studied at 65.0–95.0°C increased about 13.7‐ and 14.0‐fold, respectively, with increase in temperature. Swelling power of waxy sorghum starch was the highest (72.6 at 95°C) among the starches studied, while amaranth starch had a constant swelling power and its rate of solubility increasely only slowly at temperatures higher than 75°C. From RVA data, initial pasting temperatures of amaranth, waxy sorghum and waxy millet starches were 75.7, 73.3 and 75.2°C, respectively. Peak viscosity, breakdown, and setback from trough of amaranth starch were 68.3, 16.7 and 7.5 RVU, respectively, which were the lowest values among the starches investigated. Using DSC, onset temperature of gelatinization of amaranth starch was 1.5–4.0°C higher than those of waxy sorghum and millet starches, corresponding to the RVA result. The enthalpies of gelatinization of the starches studied in our laboratory were in the range of 8.5–12.7 J/g with decreasing order of waxy sorghum > amaranth > waxy millet starch.     

Morphological,Thermal, Pasting,and Rheological Properties of Barley Starch and Their Blends

Native barley starch, as well as its blends with corn, wheat, and rice starch at different ratios of 75:25, 50:50, 25:75 were examined in terms of morphology, thermal, pasting, rheological, and retrogradation properties. Amylose content varied between 10.9–41.4% in rice, corn, wheat, and barley while it ranged from 18.02–38.40% in blends of barley starch with rice, corn, and wheat. A rapid visco analyzer showed that barley starch and its blends having low amylose content exhibited higher peak viscosity, breakdown, and setback than the high-amylose-containing starches and their blends. Amylose content was found to be negatively correlated with swelling power while it exhibited nonlinear relationship with solubility index. The transmittance of starch suspension stored at 4°C decreased during storage up to 6 days. Barley starch granules were largest (<110 μm) in size followed by wheat (<30 μm), corn (<25μm) and rice (<20μm) starches. Gelatinization temperatures (To, Tp, Tc) and enthalpies of gelatinization (ΔHgel) of starches from different sources also differed significantly. Corn and rice starches showed higher transition temperatures in general than those from wheat and barley; however, they showed higher ΔHgel values. Barley starch showed a higher tendency towards retrogradation than the cereal starches. Barley starch showed highest peak G′, G″ and lower tan Ð than corn, rice and wheat starches during the heating cycle. This study showed that the magnitude of changes in their properties during blending depends on the amylase content and morphological characteristics.     

Structure,functionality, and digestibility of acetylated hulless barley starch

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

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.     

Amylopectin structure of heat–moisture treated starches

The effects of heat–moisture treatment (HMT; moisture content of 25%, at 100°C for 24 h) on starch chain distribution and unit chain distribution of amylopectin in normal rice, waxy rice, normal corn, waxy corn, normal potato, and waxy potato starches were investigated. After HMT, starch chain distribution (amylose and amylopectin responses) of waxy corn and potato starches were identical to those of untreated starches, whereas the chromatographic response of waxy rice starch showed a slight decrease, but with a slight increase in peak tailing. This result indicated that HMT had no (or very limited) effect on the degradation of amylopectins. Analysis of unit chain distribution of amylopectins revealed that waxy characteristics affected the molecular structure of amylopectin in untreated starches, i.e., the CL of normal‐type starches was greater than that of waxy‐type starches. After HMT, the CL and unit chain distribution of all starches were no different than those of untreated starches. The results implied that changes in the physico‐chemical properties of HMT starches would be due to other phenomena rather than the degradation of amylopectin molecular structure. However, the thermal degradation of amylopectin molecules of waxy starches could occur by HMT at higher treatment temperatures (120 and 140°C).     

A comparison of native and acid thinned normal and waxy corn starches: Physicochemical, thermal, morphological and pasting properties

The starches isolated from normal and waxy corn varieties were hydrolyzed with hydrochloric acid (0.14 mol equivalent/L) and evaluated for physicochemical and functional properties. Acid thinning decreased the amylose content and swelling power but increased the solubility. The light transmittance of acid thinned (AT) starch pastes was higher than those of their native starches after similar storage intervals. The scanning electron microscopic observation demonstrated that the acid thinning did not cause any disruption of the granular crystalline structure. Native normal corn starches showed lower onset temperature (T_o) and peak temperature (T_p) as compared to their counterpart AT starches, whereas the reverse was observed for waxy corn starch. Enthalpy of gelatinization (ΔH_gel) was lower in AT normal and waxy starches as compared to their native starches. The percentage of retrogradation (%R) was significantly higher for native corn starches as compared to their AT starches. A significant reduction in peak—(P_V), trough—(T_V), breakdown—(B_V), final—(F_V), and setback viscosity (S_V) was observed by acid thinning, and the reduction was more pronounced in AT waxy starches. Among AT starches, AT waxy starch showed the lowest values of P_V, T_V, B_V, F_V and S_V.     

Starch from hull-less barley: II. Thermal,rheological and acid hydrolysis characteristics

Gelatinization, granular swelling, amylose leaching, viscosity and acid susceptibility characteristics of starches isolated from 10 hull-less barley (HB) genotypes [zero amylose (CDC Alamo), waxy (CDC candle, SB 94794, SB 94912, and SB 94917), normal amylose (Phoenix, CDC Dawn, SR 93102, and SB 94860) and high amylose (SB 94893 and SB 94897)] were monitored by differential scanning calorimetry (DSC), swelling power (SP), solubility, Brabender viscoamylography, and reaction with 2.2 N HCl (at 35 °C), respectively. DSC data showed that T_o, T_p, T_c, T_c–T_o, and ΔH ranged from 50.1–56.1, 58.1–64.5, 71.0–75.8, 17.9–24.0 °C and 9.6–14.2 J/g of amylopectin, respectively. In compound waxy (SB 94917) and compound normal (SR 93102 and SB 94860) starches, T_o and T_c–T_o were lower and higher, respectively, than in the other starches. ΔH followed the order: compound normal>waxy>normal≈zero amylose>high amylose>compound waxy. The SP followed the order: zero amylose>waxy>compound normal>normal>high amylose. A rapid increase in solubility occurred at lower temperatures (<70 °C) for zero amylose HB starch, however, this increase was gradual for the other starches. At 90 °C, solubility followed the order: high amylose>compound normal>normal>waxy. Zero amylose and waxy HB starches exhibited lower pasting temperatures, higher peak viscosities, and higher viscosity breakdown than normal HB starches. The extent of acid hydrolysis followed the order: zero amylose>compound waxy>waxy>normal>compound normal>high amylose. High correlations were observed between physicochemical properties and structural characteristics of HB starches.     

Effect of cooking time and ingredients on the performance of different starches in white sauces

The effect of white sauce ingredients and increased cooking time at 90 °C on the degree of gelatinization of corn, waxy corn, rice, potato and modified waxy corn starches was studied. The changes in pasting properties, linear viscoelastic properties, and microstructure were determined. In all the native starches in water, a longer cooking time at 90 °C caused greater starch granule swelling and more leaching of solubilized starch polymers into the intergranular space. These effects were more noticeable in the waxy corn and potato starches. The potato starch was the most affected, with complete disruption of the starch granules after 300 s at 90 °C. The microstructural changes which transformed a system characterized by starch granules dispersed in a continuous phase (amylose/amylopectin matrix) into a system with an increase in the continuous phase and a decrease in starch granules were associated with a decrease in system viscoelasticity. The elastic moduli were higher in the sauce than in the starch in water system. However, with the exception of potato starch, the white sauce showed lower viscoelasticity than the starch in water system. The white sauce ingredients decreased the effect of cooking time on the starch gelatinization process, particularly in potato starch.     

Physicochemical Properties of Field Pea, Pinto and Navy Bean Starches

Legume starches were compared for physicochemical properties that may explain differences in functional properties. Field pea starch had higher amylose, greater swelling power and solubility, and lower pasting temperatures than pinto and navy bean starches. Scanning electron microscopy (SEM) showed that field pea starch had larger, more irregularly shaped granules and more broken large granules than pinto or navy starches. The most starch damage was observed for field pea. Pinto and navy bean starches had greater resistance to swelling at 60°C than field pea indicating a more strongly bonded micellar network. Higher cold paste viscosity was observed for navy bean and field pea.