Higher Peak Viscosity Research Articles

Effect of Nitrogen and Sulfur Fertilization on Accumulation Characteristics and Physicochemical Properties of A- and B-Wheat Starch

The effects of nitrogen (N) fertilization at the rates of 0 and 230 kg hm(-2) combined with selected sulfur (S) fertilization rates of 0, 46, 56, 77, and 115 kg hm(-2) on A- and B-wheat starch granule accumulation, composition, and thermal and pasting properties were investigated. Scanning electron micrographs revealed that A- and B-starch granules accumulation during grain filling can be influenced significantly by N and S fertilization, and B-granules tend to be more sensitive to S fertilization than A-starch granules. The doses of nitrogen and sulfur fertilization on starch properties were not positively correlated; higher concentration of fertilizers failed to cause a higher effects. N230S46 and N230S56 treatment resulted in the higher peak viscosity, trough viscosity, breakdown viscosity, final and setback viscosity, and gelatinization temperature (To, Tp, Tc) according to differential scanning calorimeter (DSC) and rapid visco analyzer (RVA), respectively.

Effect of harvesting periods on the morphology and physico‐chemical properties of trifoliate yam starches

AbstractTrifoliate yam starches from white and yellow cultivars were isolated and characterized by SEM, granule size analysis, pasting properties and swelling characteristics at different harvesting periods were studied. The starch yield ranged from 5.09 to 12.07%. White trifoliate yam had the highest starch yield at 9 months and this was significantly different (p<0.05) from others. The scanning electron micrograph revealed the presence of smooth surface granules with polygonal granule size ranging from 2.58 to 3.58 µm in diameter. Amylose and starch contents ranged from 14.65 to 17.44% and 40.73 to 63.34%, respectively. Peak viscosity ranged from 199.77 to 373.71 RVU, holding strength from 77.68 to 167.84 RVU, breakdown 96.79 to 217.14 RVU, final viscosity 149.84 to 267.58 RVU, setback 50.34 to 112.27 RVU. White trifoliate yam starch at 7 months had the highest peak viscosity and breakdown but it exhibits high value in holding strength at 8 months. White trifoliate yam starch harvested at 10 months had the highest swelling power at 60 and 80°C while at 90°C, the highest value was recorded for starch at 11 months. The yellow starch at 10 months had higher swelling power at 90°C. Harvesting of trifoliate yam at different periods produced starches that can be used for different purposes.

Extraction of starch from hulled and hull-less barley with papain and aqueous sodium hydroxide.

Starch was isolated from hulled (VJM 201) and hull-less (BL 134) barley with papain and aqueous sodium hydroxide treatments. For enzyme-assisted extraction, barley was steeped in water containing 0.2% SO2 + 0.55% lactic acid at 50° ± 2°C for 4-5h. The slurry was mixed with 0.4-2.0g papain/kg barley and incubated at 50° ± 2°C for 1-5h. Aqueous sodium hydroxide (0.01-0.05M) was added to the finely ground barley meal. The alkaline slurry was incubated at ambient temperature (25° ± 2°C) for 15-60min. The starch and grain fractions were isolated by screening and centrifugation. Increases in the time of treatment significantly affected the fiber, centrifugation and non-starch residue losses. Concentration of papain and sodium hydroxide had negligible effect on extraction losses. The enzyme-assisted extraction efficiency of starch was higher (80.7-84.6%) than the alkaline method (70.9-83.7%). The hulled barley showed higher extraction efficiency than the hull-less barley. The slurry treated with 0.4g papain/kg barley for 5h and 0.03M sodium hydroxide for 60min produced maximal yield of starch. Barley starch showed desirably high pasting temperature, water binding capacity and hold viscosity; and low final and setback viscosity compared with the commercial corn starch. The alkaline extracted hull-less barley starch showed exceptionally high peak and hold viscosities.

Influence of Wheat-Milled Products and Their Additive Blends on Pasta Dough Rheological, Microstructure, and Product Quality Characteristics.

This study is aimed to assess the suitability of T. aestivum wheat milled products and its combinations with T. durum semolina with additives such as ascorbic acid, vital gluten and HPMC (Hydroxypropyl methyl cellulose) for pasta processing quality characteristics such as pasta dough rheology, microstructure, cooking quality, and sensory evaluation. Rheological studies showed maximum dough stability in Comb1 (T. aestivum wheat flour and semolina). Colour and cooking quality of Comb2 (T. durum semolina and T. aestivum wheat flour) and Comb3 (T. aestivum wheat semolina and T. durum semolina) were comparable with control. Pasting results indicated that T. aestivum semolina gave the lowest onset gelatinization temperature (66.9°C) but the highest peak viscosity (1.053 BU). Starch release was maximum in Comb1 (53.45%) when compared with control (44.9%) as also proved by microstructure studies. Firmness was seen to be slightly high in Comb3 (2.430 N) when compared with control (2.304 N), and sensory evaluations were also in the acceptable range for the same. The present study concludes that Comb3 comprising 50% T. durum semolina and 50% T. aestivum refined wheat flour with additives would be optimal alternate for 100% T. durum semolina for production of financially viable pasta.

장기 저장된 쌀의 품질 특성

The purpose of this study was to investigate the physicochemical and pasting properties of long-term stored domestic and imported rice supplied for food processing from government-controlled public rice stocks. Goamibyeo, which was bred for processing and harvested in 2011, was selected as the control rice for comparison. Rice was dry-milled, and the amylose contents of stored rice were 12~13%. Stored rice kernels were significantly harder than those of control, whereas damaged starch content and water absorption of flour were not significantly different from those of control. Overall, long-term stored domestic and imported rice showed high peak viscosities along with high viscosities of both hot and cold pastes. Both imported and domestic rice demonstrated insufficient properties for making 100% flat rice noodles or bread. They showed the greatest shrinkage during cooling after baking. Although their levels of cooking loss were less than that of control, stored rice showed a less elastic and softer cooked noodle texture compared to control flour.

Functional characterization of native starches through thermal and rheological analysis

Native starch samples (corn, rice, and tapioca starches) were prepared in an aqueous slurry and dough system, and their functional properties were evaluated in terms of thermal and rheological characteristics. The pasting property results of starch slurries showed that rice starch exhibited the lowest peak temperature, whereas the highest peak viscosity was observed in tapioca starch. When starch suspensions were subjected to dynamic oscillatory temperature sweep testing, the increased storage moduli and reduced tan δ derived from starch gelatinization were clearly observed in all starch samples, showing that the gelatinized starch granules became more elastic. Steady shear measurements revealed the shear-thinning behaviors of starch pastes, which were dominant in tapioca starch, compared to the other starches. In addition, the distinct endothermic peaks of starch gelatinization were observed at 73.15, 62.25, and 70.55°C for corn, rice, and tapioca starches, respectively and these trends were in good agreement with the pasting and viscoelastic results. However, upon incorporation of the native starches to a wheat dough system, the highest dough consistency during heating and cooling was observed in corn starch probably due to the rigidity of its particle. Thus, the physicochemical response of native starches to temperature appeared to be different in different concentration regimes.

Chemical, Functional and Pasting Properties of Defatted Starches from Cowpea and Soybean and Application in Stiff Porridge Preparation

The effects of defatting on the chemical, functional and pasting properties of starches from cowpea and soybean and their application in stiff porridge preparation were studied. Conventional cassava starch served as standard. Defatting of cowpea and soybean resulted in higher yield. Defatted starches also had higher amylose contents with low protein, fat and ash contents than full fat starches. In addition, defatted starches from cowpea and soybean had higher water absorption capacity, swelling power, blue value index and low bulk density, higher peak viscosity, trough, final viscosity, setback values than full fat cowpea and soybean starches while cassava starch had higher peak time and pasting temperature than the legume starches. The full fat starches from soybean and cowpea had high breakdown and low setback values than the defatted samples and control. The extensibility values of defatted starches were significantly (p ≤ 0.05) higher than full fat starches but lower than control. There was no significant (p ≥ 0.05) difference in texture and appearance of stiff porridges prepared from cowpea, soybean and cassava starches. Similarly, there was no significant (p ≥ 0.05) difference in mouldability, stickiness and overall acceptability between defatted starches and control but significantly different (p ≤ 0.05) with the full fat starches. It is therefore concluded that consumption of such stiff porridges could be beneficial to individuals requiring decreased and/or slow starch digestibility such as diabetic patients and long distance athletes since legume starches are known to have low starch digestibility.

Evaluation of the Functional Properties of Promising Dioscorea trifida L. Waxy Starches for Food Innovation

Few natural waxy starches are offered to the industry demand. Therefore, the morphological, physical, and chemical characteristics of “Mapuey” waxy starch were assessed. Amylose contents of starches isolated from Dioscorea trifida L. (“Mapuey”) landraces cultivated in the Amazons of Venezuela were lower (<8.1%) than commercial Mapuey starch (>8.7%). DSC onset gelatinization temperatures varied from 71.1 to 73.2°C. All starches exhibited B-type patterns, with degrees of crystallinity varying from 28% to 33%. The highest crystallinity was found for the starches exhibiting the highest amylose content. At 90°C, solubility and swelling power varied from 2.3 to 4.3% and 20.9 to 32.8%, respectively. Gel clarity was variable from 20.8 to 62.1%. A 5% starch suspension induced a high RVA peak viscosity between 1667 and 2037 cP. This natural waxy yam resource is a promising ingredient for food industry.

Isolation, composition, morphological and pasting properties of starches from rice cultivars grown in Nigeria

AbstractThe isolation, composition, morphology and pasting properties of rice starches from different rice cultivars (N2R, Nerica II rice; IGR, Igbemo rice; ILR, Ilaje rice; and EAR, Efon Alaye rice) were studied. The starches were isolated from their flours by using a modified deproteination method in 0.1% NaOH. The highest starch yield of 65% was obtained from EAR with a residual protein of 0.41% and lowest starch yield of 45.70% from IGR with a residual protein of 0.42%. The AAM concentration of rice starches ranged from 21.88 to 26.04%. The sizes of the starch granules obtained from SEM were between 3 and 8 µm, some of the granules were individual (single) while others were fused (compound granules). The starch granules were small, polygonal and irregular in shape. The pasting parameters were evaluated using rapid visco analyser (RVA). Significant differences were observed in individual pasting parameters such as peak viscosity (PV), breakdown viscosity (BV), final viscosity (FV) and setback viscosity (SV). Cooked ILR starch had the highest PV (279.69 RVU; rapid viscosity units) and BV (52.50 RVU) when compared to the other starches. In contrast, N2R showed the highest FV (329.92 RVU) and SV (102.50 RVU), the latter due to the high concentration of AAM. The results revealed that cultivar has an effect on composition and pasting properties of rice starch.

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

AbstractThe 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.

The functional properties, pasting and baking behaviour of chemically modified sour cassava starches

Starches obtained from three varieties of cassava (Manihot palmata Muell), (4(2)1425 (V1), NR84104 (V2) and NR84293 (V3)) were fermented and chemically modified. The functional and pasting properties of the starches were investigated and the possible contributions of these properties to the explanations of the baking potentials of the starches. The hydrophilic nature of the starches was found to improve strongly after fermentation, while the hydrophobic tendency decreased. The fermented acetylated starches gave the highest value for the swelling index (SWI) and these values were significantly different (p ≤ 0.05) (with the exception of the acid-thinned starches). The pasting temperature for all the starches ranged from 71.9 to 77.6°C and the pasting time was higher in the fermented starches. The peak viscosity (PV) ranged from 151.58 to 317.75 RVU in V1, 154.08 to 249 RVU in V2 and 86 to 243.75 in V3. With the exception of unfermented acetylated starches (AcUFCS) all the modifications reduced the PV of the native starch. AcUFCS had the highest PV (317.75 RVU). Although, the different modification showed different effect on the sensory properties of the wheat/starch bread, highest score for the overall acceptability was associated with the unfermented acetylated starches. Key words: Cassava, fermentation, modification, viscosity, specific volume.

Influences of India’s Local Wheat Varieties and Additives on Quality of Pasta

The present study aims to explore the feasibility for utilization of semolina from Triticum aestivum and Triticum dicoccum in place of Triticum durum semolina in pasta processing. Pasta samples were prepared from the above mentioned wheat semolina with and without additives (ascorbic acid, dry gluten powder, hydroxy propyl methyl cellulose, and glycerol mono stearate) using lab scale extruder. Pasta samples were evaluated for pasting, protein profiles, cooking, texture, color, sensory, and microstructure parameters. The results indicated that T. aestivum semolina gave the lowest onset gelatinization temperature (66.9 °C) but the highest peak viscosity (1,053 BU). The T. aestivum pasta had a cream color (b = 15.69) while the T. dicoccum pasta was brownish (b = 11.91, a = 5.89). The cooking loss was more in the case of T. aestivum pasta (8.20%) compared with T. durum (6.90%) and T. dicoccum (7.12%) samples. Texture studies indicated that T. aestivum pasta had the least ratings on shear value (1.80 N) and overall sensory score of 6.21 N whereas shear value of 2.42 N and sensory scores of 6.89 after T. dicoccum pasta was comparable with that of T. durum pasta (2.46 N and 7.19 N). Scanning electron micrograph studies supported this. It was observed from the results obtained from gel filtration chromatograph that protein subunits play an important role in deciding pasta-making quality of different wheat species. The study also indicated that pasta quality of T. aestivum and T. dicoccum could be improved with unique combination of additives.

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.

Effect of Mild Treatments on Some Physicochemical and Pasting Characteristics of Flour from Two Cocoyam Cultivars

Effect of mild treatments namely; one-step annealing (AN), partial-nixtamalization (NIX) and phenolic-admixture (VAN) on some physicochemical and pasting characteristics of flour prepared using two cocoyam cultivars was studied. Both annealing treatment and phenolic admixture resulted in high peak viscosities (PVANwhite = 322.50 RVU; PVVAN = 306.67 RVU) of samples comparative to low peak viscosity white = 227.25 RVU) of the control for white cultivar. Similarly, the peak viscosities (PV red = 310.70; PVVANred = 296.45) of samples were higher than the peak viscosity (PVred = 225.42 RVU) of the control for red cultivar. Assessment revealed positive set back viscosities (SBVAN = + 9.30 RVU; SBVAN = + 21.33 RVU) for both the varieties after annealing treatment. Partial- NIX treatment showed molecular depolymerization. Interaction of treatments at levels employed in this study showed no synergistic effect. The pH of treated and control samples were within low acid range for foods. Mild treatment could be useful for tempering cocoyam flour for preparation of bakery and similar pasta products.

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

AbstractStarch 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.

Production and Physicochemical Properties of 2‐Octen‐1‐Ylsuccinic Derivatives from Waxy Corn Starch

Waxy corn starch was esterified with 2-octen-1-ylsuccinic anhydride (OSA) using response surface methodology. The molecular structure and paste properties were also investigated. Results indicated that the optimum parameters for esterification were as follows: reaction period 4 h, temperature 36.7 °C, pH of reaction system 8.3, concentration of starch slurry 36.9%, and amount of OSA 3%. The degree of substitution was 0.0187 and the reaction efficiency was 80.6%. The ester carbonyl group in OSA starch was characterized by Fourier Transform Infrared Spectroscopy at 1723 cm(-1). Compared with native starch, OSA derivative had higher peak viscosity, better freeze-thaw stability, and decreased gelatinization temperature and digestibility by porcine pancreatic alpha-amylase. Scanning electron microscopy showed that the gels from OSA starch had less and smaller pores; however, the native starch gels changed to sponge-like structure after 4 freezing/thawing cycles. The OSA modified waxy corn starch offered a potential to be used in frozen foods. (a) To optimize operating conditions to achieve OSA modified waxy corn starch with a high degree of substitution; (b) to give a deeper insight into the physicochemical properties of OSA modified waxy corn starch, which offered a potential to be used in frozen foods.

Physicochemical properties of starches from two different yam (Dioscorea opposita Thunb.) residues

The starches obtained from two different yam residues, which were treated with alkali(starch-A) or enzyme (starch-E), were studied and compared with yam starch isolated using ordinary method (starch-O) for morphological, crystalline pattern, thermal, and pasting properties. The results revealed that the amylose content of three starches ranged from 19.47 to 22.17%. The granule surfaces of starch-A and starch-E were as smooth as that of starch-O. The crystalline pattern of the three starches was a C-type. The transition temperatures (To, Tp and Tc) varied from 70.11 to 73.64, 79.23 to 81.74, and 84.30 to 86.65 oC, respectively. The starch-E showed the highest Δ Hgel, followed by the starch-A, while it was lowest for the starch-O. According to the viscosity measurement, starch-O had the lowest pasting temperature, highest peak viscosity and breakdown viscosity, which were contrary to those of starch-E.

Physicochemical and Digestibility Properties of Double-Modified Banana (Musa paradisiaca L.) Starches

Banana starch was chemically modified using single (esterification or cross-linking) and dual modification (esterification-cross-linking and cross-linking-esterification), with the objective to increase the slowly digestible starch (SDS) and resistant starch (RS) concentrations. Physicochemical properties and in vitro digestibility were analyzed. The degree of substitution of the esterified samples ranged from 0.006 to 0.020. The X-ray diffraction pattern of the modified samples did not show change; however, an increase in crystallinity level was determined (from 23.79 to 32.76%). The ungelatinized samples had low rapidly digestible starch (RDS) (4.23-9.19%), whereas the modified starches showed an increase in SDS (from 10.79 to 16.79%) and had high RS content (74.07-85.07%). In the cooked samples, the esterified starch increased the SDS content (21.32%), followed by cross-linked starch (15.13%). Dual modified starch (cross-linked-esterified) had the lowest SDS content, but the highest RS amount. The esterified and cross-linked-esterified samples had higher peak viscosity than cross-linked and esterified-cross-linked. This characteristic is due to the fact that in dual modification, the groups introduced in the first modification are replaced by the functional group of the second modification. Temperature and enthalpy of gelatinization decreased in modified starches (from 75.37 to 74.02 °C and from 10.42 to 8.68 J/g, respectively), compared with their unmodified starch (76.15 °C and 11.05 J/g). Cross-linked-esterified starch showed the lowest enthalpy of gelatinization (8.68 J/g). Retrogradation temperature decreased in modified starches compared with unmodified (59.04-57.47 °C), but no significant differences were found among the modified samples.

Isolation and partial characterization of Mexican taro (Colocasia esculenta L.) starch

AbstractTaro starch was isolated from Mexican variety and its morphological, physicochemical, and molecular characteristics were evaluated. Yield starch (in dry basis) was 81%, and this starch had low AM content (2.5%). Taro starch granules showed a mixture of shapes with sizes between 1 and 5 µm. Taro starch presented an A‐type XRD pattern with a crystallinity level of 38.26%. Solubility and water retention capacity did not change in the temperature range of 50–70°C and thereafter they increased as temperature increased too. Taro starch showed high peak viscosity due to its high AP content. The peak temperature of gelatinization of taro starch was 80.6°C with an enthalpy value of 10.6 J/g, with low retrogradation rate due to its low AM content. Weight‐average molar mass (Mw) and gyration radius (Rz) of taro starch were 1.21 ± 0.8 × 109 g/mol and 424 ± 70 nm, respectively. Taro tuber could be an alternative for starch isolation with functional and physicochemical characteristics for food and non‐food applications.

Isolation and characterization of Mexican chayote tuber (Sechium edule Sw.) starch

AbstractStarch was isolated from Mexican chayote tubers (Sechium edule Sw.) and the yield, physicochemical, rheological, and molecular characteristics were investigated. Commercial potato was used for comparison. Starch yield was 49% with a purity of 89.1%. AM content of chayote tuber starch was 26.3%. Birefringence was shown in chayote tuber starch and granules had diverse shapes such as spherical, oval, and polygonal, with size between 10 and 25 µm. B‐type XRD pattern was shown by chayote tuber starch. Chayote tuber starch had higher peak viscosity (PV) than potato starch and the maximum PV for chayote tuber starch was obtained at lower temperature. Flow properties of chayote tuber starch showed higher hysteresis than potato at the same concentration. In chayote tuber and potato starches, G′ > G″ at both temperatures. Chayote tuber starch presented slightly lower gelatinization temperatures, but slightly higher enthalpy of gelatinization than potato starch, and similar retrogradation rate (due to the enthalpy value of the phase transition) were found in both tuber starches. Chayote tuber starch presented higher Mw and Rz values than potato starch. Chayote tuber could be an alternative for starch isolation with specific physicochemical and molecular characteristics.