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This study aimed to enhance compatibility and thermal stability between thermoplastic starch (TPS) and polylactic acid (PLA) by incorporating citric acid-grafted starch (CA–Starch) at different concentrations (1 and 5%) with varying degrees of substitution for starch derived from sweet potatoes and yams (DY). Blends were produced using a constant TPS/PLA weight ratio of 60:40, both with and without a compatibilizer. The blending process was carried out using a torque rheometer under two distinct conditions. The results exhibited reduced particle sizes in TPS60/PLA40/CA–Starch blends, as evidenced by SEM images displaying improved interaction and smoother surfaces. Significantly, one of the properties that experienced substantial improvement was the compatibility between TPS and PLA, as indicated by reduced phase segregation within the blends. This improvement manifested in enhanced surface morphology, smaller particle sizes, and greater homogeneity in the blends. Additionally, an enhancement in thermal properties, particularly thermal stability, was observed with higher CA content. This study underscores that the incorporation of CA–Starch not only enhances compatibility but also improves thermal stability in TPS60/PLA40 blends, offering potential for the development of biocompatible materials with superior performance. [ABSTRACT FROM AUTHOR]

Copyright of China Condiment is the property of China Condiment and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, the effect of konjac glucomannan (KGM, 0–5%) on the structure, physicochemical properties, and in vitro digestibility of extruded yam starch (EYS) was investigated. The EYS became rougher on the surface and the particle size increased as observed using scanning electron microscopy and particle size analysis. X-ray diffraction and Raman results revealed that the relative crystallinity (18.30% to 22.30%) of EYS increased, and the full width at half maxima at 480 cm−1 decreased with increasing KGM content, indicating the increment of long-range and short-range ordered structure. Differential scanning calorimetry and rheological results demonstrated that KGM enhanced thermal stability and the gel strength of EYS due to enhanced interaction between KGM and YS molecules. Additionally, a decrease in the swelling power and viscosity of EYS was observed with increased KGM content. The inclusion of KGM in the EYS increased the resistant starch content from 11.89% to 43.51%. This study provides a dual-modified method using extrusion and KGM for modified YS with high thermal stability, gel strength, and resistance to digestion. [ABSTRACT FROM AUTHOR]

Purple yam (Dioscorea alata) is a tuber crop found in tropical countries that could be a valuable source of anthocyanins and starch. After anthocyanin extraction, the starch from the extraction residue was isolated using steeping in acid pH (AS), steeping in alkaline pH (KS), and steeping in water (WS). The starch yield was higher in AS (50.86 ± 1.23%), followed by KS (45.90 ± 0.68%) and WS (41.23 ± 4.92%). WS starches presented softer round-oval forms, and AS and KS presented some layers in the spherical structures. Diffractograms showed a characteristic of a B type of starch with crystallinity between 43 and 48% for all isolation methods. Enthalpy of gelatinization was higher in the AS (302.52 ± 29.26 J g−1) than KS (211.40 ± 35.09 J g−1) and WS (265.03 ± 26,58 J g−1). Monomodal distributions with mean volume diameter ranging between 35.58 µm and 36.05 µm were obtained for all isolation methods. As expected, the swelling power (SP) and water solubility index (WSI) increases as temperature increases for starches isolated using AS, KS, and WS. The isolation of starch from the residue of the extraction of anthocyanins from purple yam is suitable using AS, KS, and WS. Although no significant differences among isolation methods were observed in almost physicochemical parameters, AS isolation method produces starches with higher extraction yield and purity. [ABSTRACT FROM AUTHOR]

In this study, the effect of konjac glucomannan (KGM, 0–5%) on the structure, physicochemical properties, and in vitro digestibility of extruded yam starch (EYS) was investigated. The EYS became rougher on the surface and the particle size increased as observed using scanning electron microscopy and particle size analysis. X-ray diffraction and Raman results revealed that the relative crystallinity (18.30% to 22.30%) of EYS increased, and the full width at half maxima at 480 cm−1 decreased with increasing KGM content, indicating the increment of long-range and short-range ordered structure. Differential scanning calorimetry and rheological results demonstrated that KGM enhanced thermal stability and the gel strength of EYS due to enhanced interaction between KGM and YS molecules. Additionally, a decrease in the swelling power and viscosity of EYS was observed with increased KGM content. The inclusion of KGM in the EYS increased the resistant starch content from 11.89% to 43.51%. This study provides a dual-modified method using extrusion and KGM for modified YS with high thermal stability, gel strength, and resistance to digestion.

Starches from two yam species, viz. Dioscorea alata and Dioscorea esculenta were subjected to heat moisture treatment (HMT) with 20 and 30% moisture at 110 °C for 3 h and annealing (ANN) at 1:2 and 1:4 starch to water ratio and 50 °C for 24 h, and their effect on functional, thermal, pasting, morphological, and rheological properties, and in vitro digestibility was investigated. HMT and ANN modifications decreased the swelling and solubility of the starches compared to the native starches. D. alata showed a higher amylose leaching than D. esculenta due to its higher amylose content. An increase in the transition enthalpy (∆H) after ANN and a decrease in ∆H after HMT were observed. ANN modification increased the setback viscosity, while HMT modification decreased the setback viscosity compared to the corresponding native starches of both the species. Both HMT and ANN decreased the peak viscosity, hot paste viscosity and breakdown viscosity of the starch granules. The steady shear and dynamic rheological properties of the starch paste at 25 °C were evaluated by the power-law model and indicated non-Newtonian flow properties with shear-thinning behaviour. ANN modified starch exhibited a greater impact than HMT on the rheological properties, indicating stronger molecular interactions in the pastes. An increase in slowly digestible and resistant starch with a decrease in rapidly digestible starch was noticed after HMT and ANN modifications. [ABSTRACT FROM AUTHOR]

This study was conducted to modify yam starch to create slowly digestible starch (SDS) by the acid method to create the highest SDS starch on the basis of evaluating the effect of citric acid concentration (15 – 45%), temperature (37.5 – 52.5oC) and hydrolysis time (1.5 – 10.5 h) was performed based on the multivariable model by CCD method, and the starch content SDSmax was the dependent response. The results showed that the quadratic model obtained is significant (p < 0.05), the reliability of the model R2 = 0.979 showed that the built regression model is suitable for the data set whether 97.9%. As a result, the highest SDS starch content is 18.052% at an acid concentration of 40,009%, a temperature of 39.962oC and a hydrolysis time of 8.933 h. Solubility increases due to temperature, swelling increases in the range temperature of 50 – 70oC and decreases from 70 – 90oC; the viscosity of starch tends to decrease after denaturation.

The potential uses of starches and flours depend on their physicochemical and functional properties. The chemical composition, functional and pasting properties of starch and flours obtained from some newly developed yam varieties from the Crops Research Institute (CRI), Ghana were evaluated, and compared with the existing local varieties. The results showed that the physicochemical and functional properties varied among the varieties studied. The CRI varieties were grouped in a principal component analysis as moisture (afase pa), amylose content (ahodenfo, soanyinto, afase biri), high starch content, bulk density and water absorption capacity (kukrupa, Mankrong pona, CRI pona). Starch pasting characteristics showed that Mankrong pona, CRI pona and afase pa exhibited stable pastes whereas afase biri, Mankrong pona and, afase soanyinto could be utilized for high-temperature processing. Overall, the new CRI varieties showed considerable functionalities that could be explored for potential food and industrial applications as compared to the existing local varieties.

In order to study the effect of oat β-glucan on yam starch, the yam starch/oat β-glucan blends were prepared by rapid visco analyzer. The gelatinizing properties, thermal properties, rheological properties and digestive properties of the blends were investigated. The gelatinization analysis showed that oat β-glucan could reduce the viscosity and regeneration value of yam starch, and inhibit the short-term regeneration of yam starch. The results of thermal properties showed that the gelatinization enthalpy ΔH of blends was significantly decreased with the addition of oat β-glucan (P

In this study, yam starch was extracted from yam tubers using water and used for preparation of glycerol plasticized and titanium dioxide (TiO2) nanofiller reinforced films. The effects of TiO2 nanofiller concentration on the properties of the film were studied. Concentration of TiO2 nanofiller affects the mechanical and morphological properties of the film. The tensile strength and percent elongation were modeled and optimized by a three-variable, three-level Box-Behnken Design (BBD) using Response Surface Methodology (RSM). An optimal tensile strength (4.68 MPa) and elongation percentage (32.96%) were observed with the model at starch (3.60 g), glycerol (1.40 mL) and TiO2 nanofiller concentration (0.35 g) for the reinforced starch film. The experimental tensile strength and elongation percentage at break were 4.45 MPa and 37.77%, respectively. This shows the model can reasonably predict the optimum tensile strength and elongation of the current biofilms. Moreover, the biodegradability and antimicrobial properties of biofilms prepared at optimum tensile strength and elongation percentage were conducted. About 29% of the initial weight of the film was decomposed in the soil in the first 15 days. Moreover, an E. Coli inhibition zone of 3.25 mm was observed for the TiO2 reinforced films.

Extrusion is a method of processing that changes the physicochemical and rheological properties of starch and protein under specific temperature and pressure conditions. In this study, twin-screw extrusion technology was employed to prepare yam starch–soy protein isolate complexes. The structure and properties of the complexes and their effects on the quality of dough were studied. The results showed changes in the X-ray diffraction, rheology, and in vitro digestibility of the complexes. The extruded starch–protein complex formed an A+V-type crystal structure with the addition of soy protein isolate. A small amount of soy protein isolate could improve the complex's viscoelasticity. As the content of soy protein isolate increased, the content of slow-digesting starch and resistant starch in the complexes increased, and the digestibility decreased. The microstructure of the dough indicated that the network structure of the puffed yam starch–protein complex dough was more uniform than that of the same amount of puffed yam starch. The moisture distribution of the dough showed that with the addition of extruded flour, the closely bound water content of the dough increased, and the weakly bound water content decreased. The hardness, gumminess, chewiness, and resilience of the dough decreased. In conclusion, extruded starch–protein complexes can improve dough quality and provide technical support for the broad application of yam. [ABSTRACT FROM AUTHOR]

This article compared the effects of hot air drying (HAD), infrared drying (IRD), and cold plasma (CP) as a pretreatment on the structure, quality, and digestive characteristics of starch extracted from yam. As the most commonly used drying method, HAD was used as a control. SEM and CLSM images showed that all treatments preserve the integrity of the yam starch. CP caused some cracks and breaks in the starch granules. IRD did not destroy the crystal structure of starch molecules, but made the spiral structure tighter and increased short-range orderliness. However, CP led to the depolymerization and dispersion of starch molecular chains, resulting in a decrease in average molecular weight and relative crystallinity. These molecular conformation changes caused by different processes led to differences in solubility, swelling power, pasting parameters, digestion characteristics, and functional characteristics. This study provided an important basis for the reasonable drying preparation and utilization of yam starch. [ABSTRACT FROM AUTHOR]

In this study, we employed two lactic acid bacterial species, two yeast species, and Bacillus amyloliquefaciens to ferment "Huilou" yam starch. The aim was to explore the effects of fermentation time and microbial species on the structural properties of yam starch. The results showed that fermentation caused an increase in relative crystallinity (29.23 %-37.98 %) compared with native starch (25.69 %). The fermentation process altered the thermal properties of yam starch, leading to higher enthalpy of gelatinization values compared with unfermented starch. Notably, an absorption peak of native starch shifted from 992 cm -1 to 1015 cm -1 upon 2-day fermentation by Bacillus amyloliquefaciens and 5-day fermentation by Lactobacillus plantarum or Pediococcus pentococcus, associated with an increase in the presence of amorphous structures in yam starch. "Huilou" yam starch obtained through lactic acid bacterial fermentation exhibited a significant presence of organic acids, whereas samples derived from Bacillus amyloliquefaciens fermentation were primarily affected by amylase activity. Following yeast fermentation, organic acids and amylase were observed, albeit with relatively low influence. This research reveals that microbial fermentation can potentially alter the structural characteristics of yam starch, which can improve the quality of yam starch-based foods., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Structural and functional properties of starch from purple yam (Dioscorea alata L.) is investigated, and starches from other three yam varieties grown in China are used for comparison. The yam starches show a variety of shapes from oval to elongated or irregular. The amylose content of four yam starches is in the range of 28.3–37.9%. The D. alata L. starch exhibits a typical B‐type X‐ray diffraction (XRD) pattern with a higher relative crystallinity compared with other three yam starches, which show a C‐type XRD pattern. The D. alata L. starch has the higher proportion (20.6%) of long branch chain (Degree of polymerization (DP) ≥ 37) and the lower proportion (11.8%) of short branch chains (DP 6–12), which accounts for its higher thermal stability and lower in vitro enzymatic digestibility. This study provides useful information on the properties of purple yam starch, which would be of use for their application in preparation of foods with low enzymatic digestion. [ABSTRACT FROM AUTHOR]

Starches modified using the precipitation method which are added to edible film formulation were shown to lower water vapor transmission rates and increase the mechanical strength of the film. The effect may not only be due to the changes in starch morphology, but other aspects of the starch granules, such as their size and chemical properties in particular, are also suggested as reasons for improvements to the quality of edible film by modified starches. The aim of this research was to determine physicochemical changes in modified cassava and yam starches using several gelatinisation techniques in the precipitation method. The gelatinisation techniques used in this study were two methods of heating (using a hotplate and autoclave reactor + oven heating) and two types of starch solvent (distilled water and a mixture of distilled water and ethanol 1:1, v/v). The results showed that both cassava and yam starch granules modified using a hotplate at a heating temperature of 100 °C for 30 min were more badly damaged and smaller than those modified using autoclave reactor + oven heating at 140 °C for 1 h. However, the latter suffered more damage and were smaller in size when the heating time was increased to 3–5 h. All techniques applied in the modification increased the intensities of stretching vibration of O–H and C–H, and bound water bending vibration. The use of ethanol in the starch solvent enabled the starches to retain the shape and size of the granules despite the rearrangement of intra and intermolecular bonding as confirmed by FTIR spectra. [ABSTRACT FROM AUTHOR]

The potential uses of starches and flours depend on their physicochemical and functional properties. The chemical composition, functional and pasting properties of starch and flours obtained from some newly developed yam varieties from the Crops Research Institute (CRI), Ghana were evaluated, and compared with the existing local varieties. The results showed that the physicochemical and functional properties varied among the varieties studied. The CRI varieties were grouped in a principal component analysis as moisture (afase pa), amylose content (ahodenfo, soanyinto, afase biri), high starch content, bulk density and water absorption capacity (kukrupa, Mankrong pona, CRI pona). Starch pasting characteristics showed that Mankrong pona, CRI pona and afase pa exhibited stable pastes whereas afase biri, Mankrong pona and, afase soanyinto could be utilized for high-temperature processing. Overall, the new CRI varieties showed considerable functionalities that could be explored for potential food and industrial applications as compared to the existing local varieties. [ABSTRACT FROM AUTHOR]

The effects of carboxymethyl chitosan (CMCS) on the pasting, rheological, and physical properties of yam starch (YS) were investigated. Different concentrations of CMCS were added to the YS, followed by heating paste treatment at 95 °C. Then the blends were subjected to the determination of physicochemical, rheological properties and in vitro digestibility. Our results showed that CMCS reduced the paste viscosity of YS and the addition of CMCS did not effectively inhibit the movement of water molecules. Rheological measurements results showed that YS-CMCS blends exhibited shear thinning behavior. Furthermore, because of the presence of amylose inhibited the swelling of the starch and leaching of amylose, the addition of CMCS had no significant difference between solubility and swelling power of YS. [Display omitted] • Blends based on carboxymethyl chitosan (CMCS) and yam starch (YS) were developed. • CMCS reduced the pasting viscosity of YS-CMCS blends. • CMCS enhanced the solubility of YS-CMCS blends. • CMCS reduced the apparent viscosity, dynamic modulus of YS-CMCS blends. [ABSTRACT FROM AUTHOR]

Extrusion is a method of processing that changes the physicochemical and rheological properties of starch and protein under specific temperature and pressure conditions. In this study, twin-screw extrusion technology was employed to prepare yam starch–soy protein isolate complexes. The structure and properties of the complexes and their effects on the quality of dough were studied. The results showed changes in the X-ray diffraction, rheology, and in vitro digestibility of the complexes. The extruded starch–protein complex formed an A+V-type crystal structure with the addition of soy protein isolate. A small amount of soy protein isolate could improve the complex’s viscoelasticity. As the content of soy protein isolate increased, the content of slow-digesting starch and resistant starch in the complexes increased, and the digestibility decreased. The microstructure of the dough indicated that the network structure of the puffed yam starch–protein complex dough was more uniform than that of the same amount of puffed yam starch. The moisture distribution of the dough showed that with the addition of extruded flour, the closely bound water content of the dough increased, and the weakly bound water content decreased. The hardness, gumminess, chewiness, and resilience of the dough decreased. In conclusion, extruded starch–protein complexes can improve dough quality and provide technical support for the broad application of yam.

The potency of yam starch (Dioscorea alata) as film-forming material together with the potency of chitosan and clove oil as antibacterial materials has led the authors to produce active bioplastics based on these materials. This research was performed to determine the effect of chitosan and clove oil on the physical, mechanical, and barrier properties of yam starch's active bioplastics. The best bioplastics produced were further tested for their antimicrobiological properties. This study used a completely randomized design with five levels of chitosan concentration (1%, 1.2%, 1.4%, 1.6%, and 1.8%) and five levels of clove oil concentration (0.3%, 0.6%, 0.9%, 1.2%, and 1.5%). Each treatment was repeated four times. The results showed that the concentrations of chitosan and clove oil had a significant effect on the thickness and water vapor transmission rate of film but did not affect its solubility and compressive strength much. The use of 1% chitosan or 1.5% clove oil produced biofilms with the lowest water vapor transmission rate. Both plastics also exhibited strong antibacterial activity against Staphylococcus aureus with chitosan bioplastics having a larger inhibition zone than that of clove oil bioplastics. [ABSTRACT FROM AUTHOR]

This paper investigated the effects of twin-screw extrusion treatment on the formation, structure and properties of yam starch-gallic acid complexes. Yam starch and gallic acid were extruded. The microstructure, gelatinization characteristics, and rheological properties of the samples were determined. The microstructure of extruded yam starch-gallic acid complexes presented a rough granular morphology, low swelling, and high solubility. The X-ray diffraction analysis showed that the extruded yam starch-gallic acid complexes exhibited A + V-type crystalline structure. Fourier transform infrared spectroscopy results showed that the extrusion treatment could destroy the internal orderly structure of yam starch, and the addition of gallic acid could further reduce its molecular orderliness. Differential scanning calorimetry analysis showed a decrease in the enthalpy of gelatinization of the sample. Dynamic rheological analysis showed that the storage modulus and loss modulus of the extruded yam starch-gallic acid complexes were significantly reduced, exhibiting a weak gel system. The results of viscosity showed that extrusion synergistic gallic acid reduced the peak viscosity and setback value of starch. In addition, extrusion treatment had an inhibitory effect on the digestibility of yam starch, and enhanced the interaction of gallic acid with yam starch or hydrolytic enzymes. Therefore, extrusion synergistic gallic acid has improved the structure and properties of yam starch-related products, which can provide new directions and new ideas for the development of yam starch. • The addition of gallic acid facilitated the formation of V-type complexes from EYS. • The addition of GA reduced the viscosity of the EYS-GA system. • With the addition increase of GA, the RS of the EYS-GA increased. [ABSTRACT FROM AUTHOR]

The current consumer demand for fresh food and the interest in caring for the environment have driven the development of biodegradable film packaging to replace synthetic films to preserve the integrity of food. The objective of this work was to evaluate the effects of starch modifications (oxidized, cross-linked, and dual: oxidized/cross-linked), starch concentration (1 and 2%), and glycerol concentration (5 and 15%) on water vapor permeability (WVP), mechanical properties (tensile strength and elongation), optical, and structural properties of films based on “hawthorn” yam starch. The WVP of the films was 4.4 × 10−10 to 1.5 × 10−9 g/m∗s∗Pa, where the films with oxidized yam starch showed a 58.04% reduction concerning the native starch. The tensile strength of oxidized yam starch films showed a decrease of 17.51% with an increase in glycerol concentration. For the 1% starch concentration, elongation increased by 17.03% when the glycerol concentration was increased from 5 to 15%. Modification of starch, starch concentration, and glycerol have a significant effect on the barrier, mechanical, physical, and structural properties of films made with yam starch, where films made with oxidized yam starches at a concentration of 1% starch and 5% glycerol showed the best responses of the properties evaluated.

Nuoshanyao (NSY), Tiegunshanyao (TSY) and Huaishanyao (HSY) are the main cultivars of Chinese yam (Dioscorea opposita Thunb.) widely grown in China. The composition, physicochemical properties, morphology, and thermal properties of the starches from these cultivars were investigated in this study. NSY starch (17.0%) was much lower in amylose content than other cultivars (33.4–34.5%). The average particle diameter of the starches ranged from 25.83 to 28.93 μm. Weight-average molecular weights (Mw) and number-average molecular weights (Mn) ranged from 1.29 to 1.84 × 105 g/mol and 5.93 to 8.36 × 104 g/mol, respectively. NSY starch had higher gelatinization temperature (71.5 °C), enthalpy (14.14 J/g), peak viscosity (8590 cP) and swelling power (12.0%) than TSY and HSY. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) tests indicated that Chinese yam starches had CB-type crystalline structure with crystallinity ranging from 21.91% to 27.08% and a short-range ordered structure. T o , T p , Δ H , peak viscosity and swelling power at 95 °C were significantly correlated to amylose content. The low-amylose NSY starch was found to have high gelatinization temperature, enthalpy, peak viscosity and swelling power. These specific physicochemical and structural properties indicated the industrial potential of low-amylose yam starch. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To study the characteristics of tuber starchgranules, firstly, three kinds of common tuber starches were separated and characterized by gravitational field-flow fractionation (GrFFF) instrument, and the ratios of large and small starch granules A/B were calculated. Then, the liquid of peak A and peak B was collected and observed by scanning electron microscope (SEM) to verify the separation result of GrFFF. Secondly, the particle size distribution and crystal characteristics were characterized by particle size analyser, X-ray diffraction (X-ray) and fourier transform infrared spectroscopy (FT-IR). Three kinds of tuber starches all had the bimodal distribution in GrFFF. Peak A contained large particles, and peak B contained small particles. For yam starch, the ratio of starch granules A/B was much higher than 1; for sweet potato starch, the ratio was approximately equal to 1; for tapioca starch, the ratio was much lower than 1. Moreover, the starch granules of sweet potato and tapioca were both A-type crystallinity, while yam starch granules were C-type crystallinity. GrFFF could be used to characterize and separate large and small granules of tuber starches and estimate the ratio of starch granules A/B. Yam starch was suitable for the development of slowly digestible starch (one kind of functional food), which could delay the occurrence of metabolic syndrome, diabetes and cardiovascular diseases. Tapioca starch was suitable for plant capsules, which were safer than gelatin capsule and could prevent the "poison capsule" incident from happening. [ABSTRACT FROM AUTHOR]

An antibacterial film based on Chinese yam starch (D-sorbitol as plasticizer) incorporated with eugenol (YDE) was prepared for pork preservation. The structure of films was characterized and the evaluation of two plasticizers (glycerol and D-sorbitol) on their mechanical and barrier properties was performed to determine the vehicle of eugenol. The release behavior and antimicrobial activity of YDE were investigated and the application of the films for pork preservation was evaluated. The mechanical and barrier properties of films were dependent on plasticizer. The release of eugenol from films was well-controlled by two release mechanisms of diffusion and erosion. YDE displayed good eugenol dose-dependent antibacterial activity which was higher against E. coli than against L. monocytogenes and S. aureus. The film with 3% eugenol can extend the shelf-life of pork beyond 50%, suggesting that the film may have great potential in active packaging for extending the shelf-life of foodstuffs. Image 1 • Mechanical and barrier properties of films are dependent on plasticizer. • Yam starch film incorporated with eugenol shows good antibacterial activity. • Mechanisms of diffusion and erosion coexist for the release control of eugenol. • Antibacterial film can extend the shelf-life of pork shelf-life beyond 50%. [ABSTRACT FROM AUTHOR]

In this study, the synergistic effect of plasma-activated water (PAW) combined with twin-screw extrusion (TSE) on multi-scale structure, physicochemical and digestive properties of yam starch (YS) was studied. PAW-TSE resulted in higher amylose content in YS than TSE alone. Compared with single TSE, the relative crystallinity, short-range ordered degree, and gelatinization enthalpy of YS were increased by PAW-TSE according to the results of X-ray diffraction, Fourier transform infrared, Raman spectroscopy, and differential scanning calorimetry. Furthermore, rapid viscosity and dynamic rheological analysis showed that the peak and breakdown viscosity of PAW-TSE treated YS paste were considerably reduced, and the storage modulus and loss modulus were significantly increased, indicating that the gel strength and thermal stability were improved. In addition, the resistant starch (RS) content of YS treated by PAW-TSE increased from 6.04 % to 21.21 %. Notably, the effect of PAW-TSE on YS enhanced with the preparation time of PAW increased. Finally, correlation analysis indicated that the characteristic indexes of PAW had a significant impact on the long or short-range ordered structure, thermal properties, and in vitro digestibility of YS during extrusion. Therefore, PAW-TSE, as an emerging dual modification technology, will greatly expand the application of extrusion technology. • PAW-TSE improved the crystal structure and double helix structure compared with TSE. • PAW-TSE increased the contents of amylose and RS of YS compared with TSE. • PAW-TSE decreased the viscosity but increased the gel strength of YS. • The effect of PAW-TSE on YS was enhanced as the increase in preparation time of PAW. • These results were attributed to the conductivity, H 2 O 2 and NO 3 − content of PAW. [ABSTRACT FROM AUTHOR]

Heat-moisture treatment, a physical modification method of starch, causes changes in the internal structure of starch and thereby produces resistant starch (RS). In this study, the heat-moisture treatment conditions (moisture content, heating temperature, and incubation time) was optimized to maximise the RS contents of the treated sweet potato and yam starches, using the Box-Behnken design and response surface analysis. The predicted maximised RS content of the treated sweet potato starch (43.9%) was obtained under optimal conditions of 34.76% moisture content, heating temperature of 100.11oC, and incubation time of 6.01h; the predicted maximised RS content of the treated yam starch (36.8%) was obtained under optimal conditions of 30.06% moisture content, heating temperature of 109.68oC, and incubation time of 6.59h using a quadratic model within the range of various process variables. The experimental RS contents of the treated sweet potato and yam starches obtained under optimal treatment conditions were 42.4% and 35.4%, respectively; this confirms that the models were valid and adequate because the predicted data and experiment data did not differ significantly. The results also indicate that the RS contents of the treated sweet potato starch were significantly higher than that of the treated yam starch. As a result, both starch structure and treatment conditions were determined to significantly affect the formation of RS in the heatmoisture treated starches.

Abstract The starch-palmitic acid complex was prepared by the reaction of different concentrations (0.1%–5.0%) of palmitic acid and yam starch. In order to find out the effects of concentration of palmitic acid on the properties of the complex, the physicochemical properties, morphological properties, freeze-thaw stability, antioxidant activity and bile acid binding capacity of complexes were studied. It was found that with the increase of palmitic acid concentration, the complex index of starch-fatty acid increased first and then decreased. When the concentration of palmitic acid was 2%, the complex index was the highest (26.39%). The crystal type has gradually changed from Ca type into mixtures of V-type pattern and B-type pattern when introduced palmitic acid. The water binding capacity, solubility, swelling power and paste clarity were decreased, while the content of resistant starch and freeze-thaw stability were obviously increased. Compared with the native starch, the antioxidant activity and bile acid binding capacity of the complex were significantly increased. All the result showed that the concentration of palmitic acid has a great influence on the physicochemical properties of modified starch and the starch-palmitic acid complexes have higher ability of controlling cholesterol and improving the anti-oxidant activity than native yam. Highlights • Different concentration of palmitic acid-yam starch complexes were prepared. • When the concentration of palmitic acid was 2%, the complex index was the highest. • The palmitic acid-yam starch complex exhibited significant antioxidant activity and bile acid binding capacity. • 2% should be the optimum concentration of palmitic acid combined with yam starch. [ABSTRACT FROM AUTHOR]

Thermal stable polysaccharides from Auricularia auricula-judae (AP) have unique molecularstructures and multiple bioactivities. The effects of AP on the physicochemical properties and in vitro starch digestibility of yam starch (YS) were studied. The addition of AP induced a significant increase in the swelling power, solubility, mean volume diameter and adhesiveness as well as a dramatic decrease in the hardness and gumminess (p < 0.05). AP showed a strong suppressive effect on in vitro starch digestibility. Higher modulus (G′, G″) and stiffness parameters (Aα), and lower order of relaxation function (α), were observed in oscillatory rheological measurements, indicating that the gels were more elastic-like and had higher pseudoplasticity in the presence of AP. Furthermore, AP remarkably decreased the syneresis and storage modulus (G′), and also retarded the retrogradation process of YS gel at 4°C, revealing a synergistic interaction between AP and YS, which could also be demonstrated by scanning electron microscopy. [ABSTRACT FROM AUTHOR]

Pohpohan leaf has the potential to be used as a raw material for nori. However, it has not been fully characterized. Adding yam starch and carrageenan improves the physicochemical and functional characteristics, including antioxidant activity and mineral content. The effect of pohpohan nori with yam starch and carrageenan for antioxidant activity was measured by DPPH, and mineral content was analyzed using SEM-EDX. The results showed that the pohpohan nori has an antioxidant activity between 101.66-146.19 ppm with moderate intensity, and the minerals consist of Na, Mg, S, Cl, K, Ca, and Cu as an active substances for health. [ABSTRACT FROM AUTHOR]

The current scenario of environmental pollution caused by non-biodegradable plastic and depleting non-renewable resources has called upon the need for biodegradable bioplastic production from renewable resources. Starch bioplastics production from underutilized sources is a viable option for packaging materials that are non-toxic, environmentally benign, and easily biodegradable under disposed conditions. Pristine bioplastic production results in some undesirable qualities and hence requires further modification in order to elevate its potential applicability in real-world scenarios. In this work, yam starch was extracted from a local variety of yams through an eco-friendly and energy-efficient process which was further utilized for bioplastic production. The produced virgin bioplastic was subjected to physical modification through the introduction of plasticizers such as glycerol, while citric acid (CA) was employed as modifier in order to produce the desired starch bioplastic film. The different compositions of starch bioplastics were analyzed for their mechanical properties and maximum tensile strength of 24.60 MPa was observed as the best possible experimental result. The biodegradability feature was further highlighted through soil burial test. Apart from their general function of preservation and protection, the produced bioplastic can be employed for pH-sensitive food spoilage detection through the minute introduction of plant-derived anthocyanin extract into it. The produced pH-sensitive bioplastic film showed distinct changes in color upon an extreme change in the pH value and hence has potential to be used as a smart food packaging material. [Display omitted] • Citric acid modified yam starch bioplastics with glycerol were produced. • The films showed a high tensile strength of 24.60 MPa. • Addition of citric acid improved the performance of the films. • HAE containing films showed smart pH sensing auto-color detection capability. [ABSTRACT FROM AUTHOR]

Polysaccharides from Auricularia auricula- judae (AP) have unique functionalities. The influence of AP-blending ratios (0.1-0.8%), temperature, pH, and ionic strength on the rheological interactions of yam starch (YS)-AP blends (YA, 6%) was investigated. YA gels showed shear-thinning behavior with flow-behavior indices of 0.28-0.37 and greater pseudoplasticity in the presence of 0.8% AP. With incremental AP addition, the viscosity and consistency indices significantly increased, whereas the activation energy decreased from 7.55 to 5.12 kJ/mol ( p < 0.05). YA gels exhibited excellent thickening and heat tolerance and behaved as weak gels over an AP concentration range of 0.1-0.4% but as true gels at higher concentrations (e.g. 0.8%). The viscosity/elasticity of the combinations weakened with NaCl addition or extreme pH values. A complex 3-dimensional network structure of the YA system was confirmed by scanning electron microscopy. These results indicated that AP has great potential for functional applications in the starchy food industry. [ABSTRACT FROM AUTHOR]

This work was designed to elucidate selected physicochemical, functional, and structural properties of native and modified yam (Dioscorea rotundata) starch. The isolated starch was chemically modified using 5, 10, 15, 20, and 25% phosphoric acid solution at 50°C for 1 h, and yield, swelling power, gelation, water holding capacity, paste clarity, blue value, and amylose and amylopectin content of the native and modified yam starch were determined. Structural changes in the native and starch modified with 25% phosphoric acid were evaluated using Fourier transform infrared spectroscopy and optical microscopy. The result showed that the yield, swelling power, water holding capacity, paste clarity, blue value and amylose and amylopectin content of native yam starch was 33.38% (217 g), 3.84 g/g, 1.0 v/g, 10%, 0.52 and 25.96, respectively, whereas gelation study of the native and modified starch indicated that native starch was viscous and modified starch firm. However, yield, swelling power, water holding capacity, paste clarity, blue value, and amylose content of modified yam starch reduced in a dose dependent manner with phosphoric acid. The reduction in the values of the various functional properties could be associated with the effect of phosphoric acid on the starch granular structure. The result of Fourier transform infrared spectroscopy and optical microscopy revealed that the yam starch was modified by phosphoric acid with changes in functional groups spectra such as –OH stretch (3177 cm−1), H2O absorbed (1644 cm−1) (amorphous region), C-H stretch (2923 cm−1), CH2O (1253 cm−1), and C-O-C (1078 cm−1) when compared to native starch. The morphology of native and modified yam starch granules ranged from oval to eliptical. However, modified starch granules were rough in surface. In conclusion, the characterized physicochemical and functional properties and structure exhibited by native and modified yam starch indicated that, yam could be a cheap and valuable source of starch for industrial application. [ABSTRACT FROM AUTHOR]

[Display omitted] • Gallic acid (GA)-induced starch film was prepared incorporated with chitosan (CS). • GA and CS increased the mechanical, antibacterial, antioxidant properties of films. • GA/YS/CS films can effectively improve the quality of pork during storage. The widely use of petroleum-based plastics causes serious environmental pollution and oil resource shortage. In this work, biodegradable films were prepared based on gallic acid (GA)-induced Chinese yam starch (YS) and chitosan (CS). The fresh-keeping effect of biodegradable films on the pork meat preservation were investigated. The prepared GA/YS/CS biodegradable films exhibited thinner thickness and better light transmittance, because CS effectively decreased the viscosity of film-forming solution and weaken its internal link structure. The SEM results and mechanical results revealed that the YS, GA, and CS had a good compatibility, GA modification and adding CS markedly improved the tensile strength of YS-based film, because the interaction between CS and starch molecular was facilitate owing to the NH 3 + of CS tended to form hydrogen bonds with the hydroxyl group of starch. Sensory analysis results suggested that GA/YS/CS films can effectively improve the quality of pork during storage compared to the package of polyethylene film. In summary, the prepared GA/YS/CS film in this work had practical application potential in pork preservation due to its excellent mechanical, antibacterial, oxidation resistance properties, and the development and application of biodegradable starch film can greatly reduce the increasingly serious environmental pollution pressure. [ABSTRACT FROM AUTHOR]

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.

Four methods were applied to dry yam slices, and then, starches were isolated from dried yam slices. Starch isolated from fresh yam was as the study control, and physicochemical properties and in vitro digestibility of starches were studied. The results showed that the amylose content ranged from 12.62% to 28.25%, water-binding capacity (WBC) from 111.67% to 262.88%, paste clarity from 2.1% to 6.23%, resistant starch (RS) from 66.60% to 88.49% and crystallinity from 11.27% to 25.52%. Compared with the control starch, hot air-drying at 60 °C significantly decreased amylose content, paste clarity, RS and crystallinity, while increasing the WBC. Low levels of rapidly digestible starch and glucose and high RS levels were found in the starch from freeze-drying yam. Digestibility of the starches was significantly correlated with amylose content, WBC, paste clarity and swelling power. The starch samples were divided into three groups by principal component analysis (PCA). [ABSTRACT FROM AUTHOR]

Starch is the major carbohydrate in yam tubers and can amount up to 80% of the dry matter. The starch quality determines the quality of food and industrial products made from yam tubers. This review summarizes the present knowledge of the isolation, composition, structure, property, modifications, and uses of starches from diverse yam species. Compared with other tuber and root starches, there is a lack of systematic information on the yam starches. This hinders the further development of yams as sustainable crops as well as the value-added processing of the starches. Therefore, suggestions on how to better understand and utilize these starches are provided. [ABSTRACT FROM AUTHOR]

The devastating impacts of climate change on our environment have led to increased research on mitigating these impacts, including fast-tracking original timeline for introduction and use of electric driven vehicles. Electric driven vehicles are considered the most promising and efficient way of securing the environment. However, research into partial or total replacement of energy derived from fossil fuels with renewable energy from plant materials such as neutral spirits (bioethanol) is ongoing. This study was carried out to further explore yam and cassava (tubers) starches as renewable raw materials for bioethanol production. The optimal processing conditions that will yield maximum neutral spirits from yam and cassava substrates were studied. Yam starch produced highest bioethanol in the range of 538–545 L of alcohol per tonne (LA/t) on a dry weight basis (dwb) than cassava starch that produced 508–513 LA/t when both substrates were processed at 142 °C. In contrast, cassava starch produced higher bioethanol in the range of 508–512 LA/t than yam starch that produced 409–416 LA/t when both substrates were processed at 85 °C. The reduced processing temperature of 85 °C caused huge loss of spirit yield (∼128 LA/t) for yam, but did not affect the spirit yield for cassava starch, thus saving cost (energy) for the industry. The use of viscosity reducing commercial enzymes such as β-glucanase (as practised in cereals processing) would be unnecessary in tuber starches processing to neutral spirits, and will further save costs for the industry. • Renewable yam and cassava starches were studied and optimized for neutral spirit/bioethanol production. • Yam starch produced highest bioethanol at 538 – 545 (LA/t); cassava starch produced 508 - 513 LA/t at 142oC. • Cassava starch produced higher bioethanol 508 - 512 LA/t; yam starch produced 409 - 416 LA/t at 85oC. • Viscosity reducing enzymes (β-glucanase) would not be required when processing tuber starch to neutral spirits. • Reduced temperature and no enzyme requirement will save costs (energy and raw material) for the industry. [ABSTRACT FROM AUTHOR]

Highlights: [•] The flow functions of the bulk materials are in the range 1< ff <2. [•] The hopper half angles of the bulk materials at 3g/cm3 were 18.0° and 25.0°. [•] The high angle of wall friction at 3g/cm3 required steeper hopper in design. [•] Flow functions can be used in the characterization of flowability of powders. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Highlights: [•] The molecular features of the non-conventional starches must be studied in order to understand its functional properties. [•] This study focuses the characterization of starches isolated from wild yams to be applied in different industries. [•] Increasing information on wild starches sources will increase its applications. [•] The study denotes the molecular and functional properties of non-conventional starches. [ABSTRACT FROM AUTHOR]

This study investigated the potential of waste materials from yam as a viable alternative and cheaper source of raw material for bio-ethanol production. In a world where the population continues to expand rapidly and high levels of poverty, there may be a conflict in our application of food quality raw materials. Use of human grade raw materials for bio-ethanol production can limit these resources. Rotten yam will not compete as a human food source. Their conversion into bio-ethanol could provide a more appropriate alternative. Good and rotten parts of yam tuber produced alcohol yields of 533 and 528 litres of alcohol per tonne (LA/t) on a dry weight basis (dwb). Yam with varying degrees of rot - 'slight,' 'medium' and 'excessive' gave alcohol yields of 518 LA/t, 512 LA/t and 478 LA/t (dwb) respectively. Yam peel and extremely rotten yam tuber produced alcohol at 240 LA/t and 300 LA/t respectively. Benefit to be gained from this study is that good quality yam flour will be available as food for humans, while use of rotten yam for bio-ethanol production will provide a cleaner environment by eliminating their dumping into the environment thereby reducing environmental pollution and health hazards associated with their decay. [ABSTRACT FROM AUTHOR]

Abstract: Acid modified starches obtained from two species of yam tubers namely white yam –Dioscorea rotundata L. and water yam –D. alata L. DIAL2 have been investigated as intra- and extra-granular disintegrants in paracetamol tablet formulations. The native starches were modified by acid hydrolysis and employed as disintegrant at concentrations of 5 and 10% w/w and their disintegrant properties compared with those of corn starch BP. The tensile strength and drug release properties of the tablets, assessed using the disintegration and dissolution (t 50 and t 80 – time required for 50% and 80% of paracetamol to be released) times, were evaluated. The results showed that the tensile strength and the disintegration and dissolution times of the tablets decreased with increase in the concentration of the starch disintegrants. The acid modified yam starches showed better disintegrant efficiency than corn starch in the tablet formulations. Acid modification appeared to improve the disintegrant efficiency of the yam starches. Furthermore, tablets containing starches incorporated extragranularly showed faster disintegration but lower tensile strength than those containing starches incorporated intragranularly. This emphasizes the importance of the mode of incorporation of starch disintegrant. [Copyright &y& Elsevier]

Abstract: Dialdehyde yam starches (DASs) are prepared and characterized. Compared with native starch, viscosity average molecular weight of DASs decreases, and the extent of degradation depends on content of the aldehyde groups. Fourier transform infrared (FT-IR) spectra confirm that the characteristic peak for Ct 1732cm−1 is enhanced with the increasing of content of the aldehyde groups. Scanning electron microscopy (SEM) micrographs show that the surface of starch granules becomes wrinkled. X-ray diffraction (XRD) patterns clearly indicate that their crystallinity decreases with the increasing content of the aldehyde groups before they become amorphous at higher oxidation states. The experimental results of thermogravimetric analysis (TGA) show that DASs have poor stability as compared to native starch. With the increase in content of the aldehyde groups, the thermal stability of DAS declines gradually. According to the results of differential scanning calorimetry (DSC), gelatinization temperature (T o and T p) of DASs are increased, whereas the gelatinization enthalpy decreased. [ABSTRACT FROM AUTHOR]

Abstract: Effects of water content and mucilage on physico-chemical characteristics of yam (Discorea alata Purpurea) starch have been investigated. Particle size analysis by laser light scattering showed the size of the isolated yam starch granules to be mostly in the range of 10–80μm, and about 1% of starch granules was smaller than 1μm. Decreasing water content from 90% to 40% did not significantly alter the onset temperature (T o) and peak temperature (T p), but raised the conclusion temperature (T c). Mucilage exhibited greater storage modulus (G′) and smaller loss modulus (G″) than the isolated yam starch at water content of 90%. Water content also influenced the effect of mucilage on the rheological properties of starch–mucilage mixture, but did not significantly affect T o and T p. The swelling power measurement and scanning electron microscopy illustrated the presence of mucilage to retard the pasting of starch granules during heating. [Copyright &y& Elsevier]

Abstract: Carboxymethyl starch (CMS) was obtained as a product of the reaction of starch and monochloroacetic acid (MCA) in the presence of sodium hydroxide. The influence of the molar ratio of NaOH/AGU, the molar ratio of MCA/AGU, the reaction time, reaction temperature, and the water content on the degree of substitution (DS) was studied. The optimal molar ratio of NaOH/AGU and MCA/AGU is 2.4 and 1.0, respectively. Increase of the ratio of NaOH/AGU or MCA/AGU leads to an increase in DS, but only to certain extent. The highest values of the DS were obtained when the carboxymethylation was performed at 60°C for 2.5h. The water content in the reaction media ethanol was optimal at 20% (v/v). The scanning electron micrographs (SEMs) revealed that the carboxymethylation affected the structural arrangement of the starch and caused granular disintegration. The particle size distribution (PSD) also displayed that the average particle diameter increased greatly after modification from 37.37μm to 72.88μm. Wide angle X-ray diffractometry (XRD) revealed that starch crystallinity was obviously reduced after carboxymethylation. The new bands at 1600cm−1 and 1426cm−1 in FT-IR indicated that the starch granules were substituted. [Copyright &y& Elsevier]

Yam ( Dioscorea esculenta) starch was modified by carboxymethylation. The effect of reaction parameters, amount of sodium hydroxide (NaOH), amount of sodium monochloroacetate (SMCA), and reaction time on the degree of substitution (DS) of carboxymethyl yam starch (CMS), was studied using the Box–Behnken experimental design. Physicochemical and potency to be a tablet disintegrant of CMS were evaluated. CMS with DS in the range of 0.08–0.19 were obtained. The results from regression analysis indicated that the most important factor in controlling DS was the amount of NaOH followed by SMCA content and reaction time. However, high concentration of NaOH and SMCA lowered the DS. The optimal conditions to achieve the highest DS (0.19) were found to be at molar ratios of NaOH and SMCA to anhydroglucose unit of 1.80 and 2.35, respectively, and with the reaction time of 4.8 h. The swelling power and viscosity of CMS increased with an increase in the degree of modification. CMS showed satisfying tablet disintegrant properties. The tablets containing 1.0–4.0 % CMS disintegrated faster than 5 min. Hence carboxymethyl yam starch can be used as an excellent tablet disintegrant in low concentration. [ABSTRACT FROM AUTHOR]

Abstract: A comparative investigation of the surface properties of starch powders from three species of yam (Dioscorea spp.) was conducted, using corn starch BP as reference standard, with a view to assessing their usefulness as ingredients of tablets/capsule formulations. Significant differences were observed in the physicomechanical properties of the starches obtained from the various yam species. Granular diameter ranged from 5.4 μm (Chinese yam) to 34.5 μm (Round leaf yellow yam). Corn starch BP has a mean granular diameter of 12.3 μm. Chinese yam starch had the highest specific surface area (625.91 m2/kg) while Round leaf yellow yam had the lowest (117. 4 m2/kg); corn starch BP has a specific surface area of 232 m2/kg. The surface tension of the starch mucilage also varied significantly with Bitter yam having the lowest (44.56 mN/m) and Round leaf yellow yam the highest (54.00 mN/m); corn starch had a surface tension of 62 mN/m. X-ray powder diffraction revealed three distinct crystalline patterns: Bitter yam and corn starch displayed the type A while Round leaf yellow yam and Chinese yam displayed the types B and C patterns respectively. In moisture adsorption, all the starches studied displayed monolayer adsorption profiles with rate order of moisture adsorption ranging from 0.92 mg%/h for Chinese yam to 1.07 mg%/h for Round leaf yellow yam starch. Since co-formulated materials will react or interact at the interface, the variations observed in the surface properties suggest a potential for significant botanical specie-dependent differences in performance of starch powder in formulated dosage forms. [Copyright &y& Elsevier]