Yam Starch Research Articles

Characterization of Physicochemical and Functional Properties of Starch from Five Yam (Dioscorea Alata) Cultivars in Indonesia

 Abstract—The research aim was to investigate yam starch physicochemical and functional characteristic. Five yam cultivars, yellow, orange, light purple, purple, and dark purple yams were used. SEM examination show three dimensions of starch granule which was round, oval and spherical in shapes. Particle size analysis performed asymmetrical unimoda distribution with 7 to 100 µm range of granule size. The relative crystallinity ranged 20.6 to 30.4% with B-type structure. The amylose and phosphorus content ranged 23.44 to 26.99% and 268 to 365 ppm respectively. These starch physicochemical characters lead to the gelatinization character To, Tp and H ranged 73.9 to 77.4C, 78.0 to 80.7C, and 16.2 to 16.9J/g respectively. Pasting properties showed pasting T and peak viscosity ranged 81.95 to 86.38C, 477.35 to 571.15RVU respectively. All the starches showed G' has higher value than G up to  =5(10) 5 rad/s frequency sweep. No intersection between G' and G graphs were found in OY and PDY up to  =10 7 rad/s, which indicated the strength and stable gel of both cold pasta.

Impact of acid and heat–moisture treatment combination on physicochemical characteristics and resistant starch contents of sweet potato and yam starches

The objective of this study is to investigate formation of slowly digestible starch (SDS) and resistant starch (RS) and change in physicochemical properties of sweet potato and yam starches under a combination of acid and heat–moisture treatments using three mild organic acids including acetic acid, lactic acid and citric acid and heating temperature at 110°C for 8 h. The results show that the SDS and RS in sweet potato starch significantly increased from 6.6 and 14.7% in native starch to 8.7–13.2% and 37.5–42.1% in acid and heat–moisture treated starches, respectively. Likewise, the SDS and RS in yam starch increased from 4.7 and 21.6% in native starch to 10.0–11.3% and 39.0–46.4% in the treated starches, respectively. The RS content in the acid and heat–moisture treated starches was also significantly higher than that of the heat–moisture treated starches without acid hydrolysis. Yam starch produced higher amount of RS under acid and heat–moisture treatment as compared to sweet potato starch at the same condition. Swelling power and viscosity of starches significantly decreased, whereas the solubility significantly increased after treatments. The citric acid had the most impact on RS formation and starch properties, followed by lactic acid and acetic acid. As a result, the combination of acid and heat–moisture treatment is a useful method to produce higher amount of resistant starch, which can be applied for functional foods.

Effects of annealing, acid hydrolysis and citric acid modifications on physical and functional properties of starches from four yam (Dioscorea spp.) cultivars

The effects of annealing, acid hydrolysis and citric acid modification on the physical and functional properties of starches of four Nigerian yam cultivars were studied. Loose (0.3636–0.7658 g/cm3) and packed (0.5606–1.0165 g/cm3) bulk densities and CIE L* of native, and modified starches decreased significantly (p < 0.05) with annealing, but increased significantly with acid hydrolysis and citric acid modification. The CIE a* value and %W (whiteness degree) increased, while b* value reduced with all modifications. The CIE L*, a* and b* values of extracted starches ranged between 74.8–98.3, −4.21–4.80 and 4.40–12.9, respectively. Among the native starches, L* ranked: bitter yam > white yam > water yam > yellow yam. Starch granule shapes varied with cultivar but not with the modifications. Starch granule sizes reduced significantly with the modifications, with increased incidence of small and medium sized granules, and decrease in large sized granules. Short and long length of native white, yellow, water and bitter yam starches ranged from 19.5–54.9 and 15.6–42.9 μm, 27.30–58.50 μm and 15.60–42.90 μm, 23.4–58.5 μm and 15.6–35.1 μm, and 2.50–7.50 μm and 2.50–5.0 μm, respectively. Chemical modifications caused etching, fragmentation and roughening of some granules' edge. The WAC (0.63 g/g–1.047 g/g) increased significantly with acid hydrolysis and citric modification, but reduced significantly on annealing while OAC (0.437 g/g–1.053 g/g) was not significantly affected by the modifications. Generally, alkaline water retention (1.017 g/g–0.670 g/g) and foam capacity of the starches decreased with all the modifications. Annealed yam starches showed better foam stability than citric modified and acid hydrolysed yam starches. Generally, emulsion index (0.337–0.621) increased insignificantly with citric acid modification, while annealing and acid hydrolysis had variable effect.

Detection of Amylose and Amylopectin from Different Yam (D&lt;i&gt;. Opposita&lt;/i&gt; Thunb.) Cultivars by Capillary Electrophoresis

The amylose and amylopectin of starch separated from four different D. opposita Thunb. were investigated by capillary electrophoresis. Nowadays, much research was focused on the utilization of plant starch as an industrial raw material which can effectively reduce the dependence on non-renewable resource. Then, the content of amylose in the starch will largely influence the availability of starches. Most detect methods were not suitable for this detection because of the high molecular mass of starch. This paper described the application of capillary electrophoresis to separate the amylose and amylopectin in four different D. opposita Thunb. and made a differentiation between them based on the well-known affinity of these compounds to iodine. The paper also improved the method of detecting yam starch because the method applying in other starches might appear somewhat different.

Preparation and characterization of resistant starch III from elephant foot yam (Amorphophallus paeonifolius) starch

The purpose of this study was to assess the properties of resistant starch (RS) III prepared from elephant foot yam starch using pullulanase enzyme. Native and gelatinized starches were subjected to enzymatic hydrolysis (pullulanase, 40U/g per 10h), autoclaved (121°C/30min), stored under refrigeration (4°C/24h) and then lyophilized. After preparation of resistant starch III, the morphological, physical, chemical and functional properties were assessed. The enzymatic and retrogradation process increased the yield of resistant starch III from starch with a concomitant increase increase in its water absorption capacity and water solubility index. A decrease in swelling power was observed due to the hydrolysis and thermal process. Te reduced pasting properties and hardness of resistant starch III were associated with the disintegration of starch granules due to the thermal process. The viscosity was found to be inversely proportional to the RS content in the sample. The thermal properties of RS increased due to retrogradation and recrystallization (P<0.05).

Flow and strength properties of cassava and yam starch–glycerol composites essential in the design of handling equipment for granular solids

A research was conducted to determine the flow and strength properties of cassava and yam starch–glycerol composites for their application in the design of hopper or any other storage bin, with a consistent flow during the handling of the granular solids, in the food industry. The flow and strength properties of the bulk materials which include the consolidation, shear and unconfined yield stresses were determined at different bulk densities and glycerol concentrations in the range of 1.5–3.0g/cm3 and 15–25ml glycerol per 100g starch using a uniaxial compression test. The flowability of the bulk solids were classified using Jenike’s flow specifications. The angles of internal and wall frictions of the bulk solids were determined from their yield loci. The hopper half angles were determined from the conical hopper design chart; and the friction factors, which account for the vibration in the arch thickness and the geometric configuration of the composites, were computed empirically. The results show that the compressive strength of the cassava and yam starch–glycerol composites increased significantly with an increase in bulk density and a decrease in the glycerol concentration (p<0.05). The cohesiveness of the composites increase with increasing glycerol concentration, up to 25ml per 100g starch, because of their increasing flow function (1<ff<2). The hopper half angle, friction factor and angles of internal and wall frictions of the cassava starch–glycerol composite at 3.0g/cm3 were 18.0°, 2.48, 43.0° and 26.0°, respectively. The higher angle of wall friction at 3g/cm3 implies that a steeper hopper wall is required for a consistent flow of the granular solids through a hopper.

Physicochemical Properties of Low-Amylose Yam (Dioscorea Spp.) Starches and its Impact on α- Amylase Degradation in Vitro

Starches from four low-amylose yam cultivars, cv.Chinese yam, Bitter yam, Yampie and Akam cultivated in Jamaica were extracted and the relationship between physicochemical properties and in vitro digestibility investigated. A direct correlation between starch physicochemical properties and digestibility of the low- amylose starches was observed. Chinese and Bitter yam starches with the lowest amylose content were found to have the highest digestibility in vitro (21.27 ± 0.01 % and 18.11 ± 0.02 % respectively), while Akam and Yampie starches with higher amylose content had significantly lower percentage digestibility (p<0.05). The mean granular diameter of the starches ranged from 5.4 µm for Chinese yam to 29.58 µm for Yampie. The variations observed in the granular size may have influenced the surface properties of the starches, as Chinese yam was found to have the largest specific surface area (625.91 m2/kg) while Yampie had the lowest (117. 4 m2/kg). The digestibility of the starches was also influenced by granule diameter, specific surface area, crystalline pattern and surface-no. mean of the starches studied.

Physicochemical and Pasting Properties of Starch Extracted from Four Yam Varieties

Yams are not among the most common sources of industrial starch, which are mostly imported at a cost. Exploiting alternative sources of starch would lessen the burden of its importation. Starches from four local varieties of Dioscorea rotundata namely Pona, Labreko, Asobayere and Muchumudu were analyzed for their physicochemical and functional properties. Results obtained showed significant differences (p<0.05) in some physicochemical properties (moisture, ash, starch yield and pH). Moisture, ash, starch yield, pH, amylose, amylopectin, swelling power, solubility and water binding capacities ranged from 7.22 to 7.82%, 024 to 0.86%, 12.61 to 20.89%, 5.57 to 6.25, 27.48 to 31.55%, 68.45 to 72.52%, 10.57 to 12.48%, 8.52 to 9.32% and 175.25 to 182.69% respectively. Asobayere had the highest starch yield (20.89%) and may be exploited for starch production. There were significant differences (p<0.05) in the pasting properties. The pasting temperature ranged from 75.10 (Asobayere) to 77.30°C (Muchumudu). Peak temperature ranged from 81.7 (Asobayere) to 94.8°C (Muchumudu). Peak viscosity for Asobayere, Pona, Labreko and Muchumudu were 726, 614, 685 and 639 BU respectively. Final viscosity ranged from 385 (Pona) to 817 BU (Muchumudu). Values of 385 (Asobayere), 142 (Labreko), 293 (Pona) and 25 BU (Muchumudu) were observed for breakdown viscosity. Labreko had the highest value of 337 BU and Pona the lowest value of 79 BU for setback viscosity. Muchumudu may be used industrially in products that require high unit yield, low viscosity and paste stability at low temperatures. Asobayere and Labreko may be used for foods that require thick and cohesive paste such as fufu and pounded yam due to its high pasting viscosities. Yam starches can be exploited for diverse uses.

Characterization and evaluation of acid-modified starch of Dioscorea oppositifolia (Chinese yam) as a binder in chloroquine phosphate tablets

Chinese yam (Dioscorea oppositifolia) starch modified by acid hydrolysis was characterized and compared with native starch as a binder in chloroquine phosphate tablet formulations. The physicochemical and compressional properties (using density measurements and the Heckel and Kawakita equations) of modified Chinese yam starch were determined, and its quantitative effects as a binder on the mechanical and release properties of chloroquine phosphate were analyzed using a 2³ full factorial design. The nature (X1), concentration of starch (X2) and packing fraction (X3) were taken as independent variables and the crushing strength-friability ratio (CSFR), disintegration time (DT) and dissolution time (t80) as dependent variables. Acid-modified Chinese yam starch showed a marked reduction (p&lt;0.05) in amylose content and viscosity but increased swelling and water-binding properties. The modified starch had a faster onset and greater amount of plastic flow. Changing the binder from native to acid-modified form led to significant increases (p&lt;0.05) in CSFR and DT but a decrease in t80. An increase in binder concentration and packing fraction gave similar results for CSFR and DT only. These results suggest that acid-modified Chinese yam starches may be useful as tablet binders when high bond strength and fast dissolution are required.

Mechanical and Sensorial Characteristics of Cassava and Yam Composite Starch Films

This study was conducted to determine the mechanical properties and sensory acceptability of edible films from cassava and yam composite starches. The tensile strength of the films ranged from 0.28 to 0.60 N/mm2, the elastic modulus and force at break ranged from 0.47 to 1.07 N/mm2 and from 2.9 to 6.5 N, respectively, while other mechanical properties (thickness, elongation at break, strain at peak, elongation at peak and energy to peak) were not significantly different (P > 0.05). The sensory properties of edible films showed that the stickiness, taste and overall acceptability were not significantly different (P < 0.05) but the sensory scores for color of the films were significantly different (P < 0.05). The moisture content of the edible films was not significantly different (P > 0.05) and ranged between 12.30 and 13.50%. Edible films of improved mechanical properties compared to 100% yam starch film have been produced from blend of cassava and yam starches. Practical Applications The use of cassava and water yam starches as a film-forming agent will add value to these crops that are in plentiful supply in most tropical countries, particularly water yam, which is grossly underutilized. Furthermore, findings from this study are capable of providing basic information on the use of biodegradable packaging materials to replace plastic and other nonbiodegradable materials.

Physicochemical properties of three starches derived from potato, chestnut, and yam as affected by freeze‐thaw treatment

Starches derived from chestnut, potato, and yam were compared by freeze‐thaw treatments (FTT) from 1 to 5 cycles under the conditions of −18°C for 24 h and then 30°C for 2 h. The microstructure, crystallinity, thermal properties, and physicochemical characteristics were investigated using SEM, XRD, and DSC. Significant differences were found after the FTT for the three kinds of starches. Honeycomb‐like network structures formed after the first FTT cycle and the structures were broken after the fifth freeze‐thaw cycle. The freeze‐thawed chestnut and yam starches showed typical B‐type crystal structures, which were significantly different from native ones (A‐type and C‐type patterns for chestnut and yam starches, respectively). The thermodynamic parameter values (T0, Tp, Tc, and ΔH) of the freeze‐thawed starches increased with the increase of FTT cycles. Among the three types of starch, yam starch showed the higher freeze‐thaw stability than potato and yam starches. The potato starch had the highest RS content, which makes it a good resource for RS production.

Structural and functional properties of C-type starches

This study investigated the structural and functional properties of C-type starches from pea seeds, faba bean seeds, yam rhizomes and water chestnut corms. These starches were mostly oval in shape with significantly different sizes and contents of amylose, damaged starch and phosphorus. Pea, faba bean and water chestnut starches had central hila, and yam starch had eccentric hilum. Water chestnut and yam starches had higher amylopectin short and long chain, respectively. Water chestnut and faba bean starches showed CA-type crystallinities, and pea and yam starches had C-type crystallinities. Water chestnut starch had the highest swelling power, granule swelling and pasting viscosity, lowest gelatinization temperatures and enthalpy. Faba bean starch had the lowest pasting viscosity, whereas yam starch had the highest gelatinization temperatures. Water chestnut and yam starches possessed significantly higher and lower susceptibility to acid and enzyme hydrolysis, the highest and lowest RDS contents, and the lowest and highest RS contents, respectively.

Physicochemical and functional characterization of yam starch for potential industrial applications

Yam is a significant and highly prized starchy crop in West and Central Africa, but largely underutilized industrially. Functional and physicochemical properties of starches extracted from forty‐three varieties of Dioscorea rotundata, Dioscorea alata, Dioscorea dumetorum, Dioscorea cayenensis, and Dioscorea bulbifera were investigated for their potential industrial utilization. Water binding, swelling, gelation capacity, granule size, amylose/amylopectin, pasting characteristics, paste clarity, and syneresis were determined. Results showed that starches from D. rotundata, D. alata, D. cayenensis, and D. bulbifera had large starch granules (25–50 µm) while D. dumetorum had small granules (7–12 µm). There was variability in the starch granule shapes, which were mostly oval, round, and triangular. The least gelation concentration of the starches was between 4 and 16%. Paste clarity of the starches decreased as storage days increased and all the starches exhibited high syneresis indicating tendencies to retrograde on low storage temperature. There were differences in the pasting characteristics of the yam starches with D. rotundata and D. bulbifera having high peak viscosities compared to others. These differences in functional and physico‐chemical properties of the yam starches are discussed as indicators of the various products for which they can be utilized in both food and non‐food applications.

Functional, thermal and molecular behaviours of ozone-oxidised cocoyam and yam starches

Ozone-oxidised starches were prepared from the native starches isolated from white and red cocoyam, and white and yellow yam cultivars. The native and oxidised starches were evaluated for functional, thermal and molecular properties. The correlations between the amount of reacted ozone and carbonyl and carboxyl contents of the starches were positive, as ozone generation time (OGT) increased. Significant differences were obtained in terms of swelling power, solubility, pasting properties and textural properties of the native starches upon oxidation. The DSC data showed lower transition temperatures and enthalpies for retrograded gels compared to the gelatinized gels of the same starch types. The native starches showed CB-type XRD patterns while the oxidised starches resembled the CA-type pattern. As amylose content increased, amylopectin contents of the starches decreased upon oxidation. Similarly, an increase in Mw values were observed with a corresponding decrease in Mn values upon oxidation.

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&lt;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.

Characterization and Quantification of Zinc Oxide and Titanium Dioxide Nanoparticles in Foods

There has been growing concern in recent years about contamination of foods by engineered nanoparticles (NPs) due to their increasing applications in food packaging materials, pesticides, and other products. In this study, we report a systematic approach to detect, characterize, and quantify engineered NPs (i.e., zinc oxide (ZnO) and titanium dioxide (TiO2) NPs) in food products. A series of concentrations of ZnO and TiO2 NPs from 0.05 to 1 wt% were spiked into corn starch, yam starch, and wheat flour. The presence of engineered NPs in foods was detected and measured by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and transmission electron microscopy. The average sizes of ZnO and TiO2 NPs were around 38 and 40 nm in diameter, respectively. Most ZnO NPs were in either spherical or rod-like shape, while most TiO2 NPs were in a spherical shape. The concentrations of engineered NPs in food samples were measured by inductively coupled plasma optical emission spectrometry. Calibration curves were plotted for quantification of NPs in foods (R 2 = 0.984 and 0.995 for ZnO NPs in corn starch and wheat flour, respectively; R 2 = 0.992 and 0.998 for TiO2 NPs in yam starch and wheat flour, respectively). The results of this study could help develop systematic methodologies for detection, characterization, and quantification of NPs in food matrices.

Structure and digestibility of debranched and hydrothermally treated water yam starch

AbstractDebranched water yam starch was subjected to repeated hydrothermal treatment (HTT), and its physicochemical and structural properties and digestion pattern were investigated. The B‐type crystalline pattern of raw starch was recrystallized to B‐ and CA‐type patterns by debranching and repeated HTT. The degree of relative crystallinity of debranched starch gradually increased and reached its maximum (43.3%) after five repetitions of HTT. The thermal transition temperatures and melting enthalpy of recrystallized starches increased progressively, reflecting the perfection of their crystalline structure, leading to the accumulation of boiling‐stable crystalline structure under repeated HTT conditions. As a result, RS of HTT starches reached a very high level (&gt;92.2%). The boiling‐stable RS content depended on the repetition of this treatment and was maximized (81.0%) after five repetitions.

Effect of different drying methods on the physicochemical and functional properties of Dioscorea opposita Thunb. starch

AbstractThe effect of sulfur fumigation and freeze–drying on the physicochemical and functional properties of Dioscorea opposita Thunb. starch was investigated. Freeze–drying markedly decreased the AM content of starch from 16.68 to 8.59%. Both sulfur fumigation and freeze–drying decreased the protein content but obviously increased the water absorption capacity and swelling power. Sulfur fumigation significantly increased the solubility of starch. Retrogradation tests showed that Chinese yam starch had a poor stability of retrogradation in water, salty, sugar, and acidic medium, but a good stability in alkaline medium. SEM analysis showed that different drying methods had minor effects on the morphological properties of D. opposita cv. Ma starch. Although the pattern of D. opposita cv. Ma starch was C‐type and was not affected by drying methods, sulfur‐fumigation, and freeze–drying increased the crystalline degree of starches from 23.24 to 25.16% and 34.40%, respectively. A minor difference was found in the Fourier transform infrared spectra of native and treatment starches. After sulfur fumigation and freeze–drying, the peak gelatinization temperatures increased from 71.03 to 76.03°C and 83.07°C, respectively, whereas the gelatinization enthalpy and gelatinization range decreased.

Studies on the morphological, crystalline, thermal properties of an under utilized starch from yam Dioscoreae zingiberensis C. H. Wright

AbstractPhysicochemical properties such as AM content, morphology, gelatinization, crystallography and pasting behavior of an under utilized yam starch from Dioscoreae zingiberensis C.H. Wright were characterized by SEM, particle size analysis, X‐ray powder diffraction, DSC, and Brabender viscoamylograph, and compared to commercial potato and maize starches. D. zingiberensis starch had an AM content of 23.62% and exhibited a flattened ovoid shaped granules with majority (87.4%) of them having diameter in the range of 10–50 µm and centering at 21.192 µm. The X‐ray powder diffraction showed A‐type crystalline patterns of D. zingiberensis. Higher values in onset temperature (To, 70.49°C), peak temperature (Tp, 78.53°C) and conclusion temperature (Tc, 85.96°C) of D. zingiberensis. Unlike potato starch, pasting properties of D. zingiberensis starch were somewhat similar to that of maize starch. Pasting onset temperature, maximum, breakdown, and setback viscosity of D. zingiberensis starch were 73.4°C, 309, 46, and 161 BU, respectively. Interestingly, a very stable paste viscosity was observed during high temperature (5 min for D. zingiberensis starch.

The influence of conventional heating and microwave irradiation on the resolution of (RS)-sec-butylamine catalyzed by free or immobilized lipases

The lipases CAL-B, PSL, PSL-C, PSL-D, and A. niger lipase, free or immobilized in starch (obtained from two types of yam, known in Brazil as “cara” (Discorea alata L.) and “inhame” (Colocasia esculenta (L.) Schott) or gelatin films, were used in the acylation of (RS)-sec-butylamine with different acyl donors in various organic solvents applying conventional heating (CH) or microwave (MW) irradiation. In the case of free A. niger lipase, the conversion degrees were three times higher using MW irradiation when compared to conventional heating at 35 oC. Using free A. niger lipase, the (R)-amide was obtained with a conversion degree of 21%, resulting in eep > 99% and E-value (enantioselectivity value) > 200, in 1 min of reaction under MW irradiation. When the A. niger lipase was immobilized in yam starch films, the (R)-amide was obtained in moderate conversions of 8-25% after 3 or 5 min of reaction under MW irradiation, but with higher selectivity (eep > 99% and E > 200) in comparison with the free form (conversion degree of 45%, eep 81% and E value of 18).