Rheological and Thermal Properties of Potato Starch

<正>Particle size, rheological and thermal properties of potato starch from Yunnan province of China was investigated. The particle size ranges from 0.429-102.3 μm determined by laser light-scatter. The major flow type of 6 w/v% potato starch was shear-thinning fluid even the shear rate up to 800·s-1, and the gel formed by 6 w/v% potato starch fell to weak gel for its little difference between G′ and G′′, high dependence on frequency and low value of G′(Pa). The hardness and cohesiveness of potato starch gel were 31.3 g and 131.9 g·s, respectively. The thermal properties of potato starch were also determined by DSC at the starch∶ water = 3∶ 1. The To, Tp, and △H of potato starch were 62.23℃, 67.31℃, and 2.22 J·g-1.     

Environment-friendly crosslinking of cornstarch by pentanedioic acid for stabilizing the viscosity of starch paste during warp sizing

Acid-thinned cornstarch was crosslinked with pentanedioic acid to different degrees to enhance viscosity stability of cooked starch paste for replacing the currently used toxic crosslinking agents such as formaldehyde and epichlorohydrin in the preparation of starch sizing agents. The degree of crosslinking was determined according to the stability, adhesion-to-fibers, film properties, desizability, and aerobic biodegradation of crosslinked starch. The degree of crosslinking showed significant effects on the stability, adhesion, desizability, and film properties, but was less sensitive to the biodegradation and wear loss of starch film. Suitable degree of crosslinking resulted in stable viscosity, good adhesion to fibers, strong and bending resistant film, and better desizability. Low degree of crosslinking could be utilized to increase the stability and improve usability of the starch used as warp sizing agent. The degree of crosslinking range (902-477 anhydroglucose units per crosslink) was recommended to stabilize the viscosity of cooked starch paste and improve the sizing properties of starch sizing agents.     

Tertiary Amination/Hydroxypropylsulfonation of Cornstarch to Improve the Adhesion-to-Fibers and Film Properties for Warp Sizing

To investigate the effects of tertiary amination/hydroxypropylsulfonation on the adhesion-to-fibers and film properties of corn starch for warp sizing, a series of tertiary aminated and hydroxypropylsulfonated corn starch (TAHPSS) samples were prepared by the tertiary amination and hydroxypropylsulfonation of acid-hydrolyzed corn starch (AHS) with 2- dimethylaminoethyl chloride hydrochloride (DMC-HCl) and 3-chloro-2-hydroxy-1-propanesulfonic acid sodium salt (CHPS-Na) simultaneously. The adhesion was evaluated by measuring the bonding force of starch to the fibers. The film properties were investigated in terms of tensile strength, breaking elongation, degree of crystallinity, and moisture regain. The results showed that tertiary amination/hydroxypropylsulfonation was able to increase bonding forces of starch to cotton and polyester fibers, enhance breaking elongation and moisture regain of the starch film and to decrease the tensile strength and degree of crystallinity of the film, thereby improving the adhesion and reducing film brittleness. Increasing the level of tertiary amination/hydroxypropylsulfonation was favorable for gradually improving the adhesion and decreasing the brittleness. The TAHPSS showed potential for use in cotton warp sizing.     

Temperatures and ethanol effects on the properties of extruded modified starch

Temperature and blowing agent are major factors influencing the properties of extruded foam materials. This study was conducted to determine the influence of temperature and alcohol content on selected properties and molecular weight of acetylated starch foam. Starch acetate, with degree of substitution of three, was prepared from 70% amylose corn starch and extruded with either 16 or 18% (db) ethanol in a single screw extruder at either 120 or 160°C. Unit and solid densities, specific mechanical energy, compressibility, spring index, water absorption and water solubility indices, glass transition temperature, molecular degradation and degree of substitution (DS) of the starch were measured. The samples extruded at 120°C had lower spring indices and water absorption indices (WAI), but higher compressibility and unit density than acetylated starch extruded at 160°C. The samples extruded with 16% ethanol content on a dry basis had lower spring indices and higher WSI than samples extruded with 18% alcohol. The extruded samples had lower solid density, WSI and WAI as compared to non-extruded acetylated starch. A slight decrease in the average molecular weight was recorded as a result of the extrusion processing. The samples extruded at 160°C had high spring indices and low unit densities and thus were more suitable for use as a loose-fill packaging material.     

Liquid handling properties of hollow viscose rayon/super absorbent fibers nonwovens for reusable incontinence products

To develop reusable incontinence products, blend nonwovens of hollow viscose rayon (HVR) and super absorbent fibers (SAFs) were prepared using a needle-punching process and their liquid handling properties, such as the fluid absorption capacity, fluid retention capacity, fluid absorption under load, moisture evaporation rate, and repeated water absorption were investigated. As the SAF content in the HVR/SAF blend nonwovens was increased, the fluid absorption capacity, fluid retention capacity, and fluid absorption under load increased, whereas the moisture evaporation rate decreased. SAF had a more significant effect on fluid retention than fluid absorption. In the case of HVR/SAF(8/2) and HVR/SAF(7/3), more than 100 % of the fluid absorption capacity was retained even after 5 cycles of repeated water absorption tests. Overall, the HVR/SAF blend nonwovens are good candidates for reusable incontinence products.     

The technology of potato granule manufacture

The production of potato granules, a dehydrated mashed potato product, is in line with a growing trend in the processing of foods toward concentration and improved convenience for use. Several methods for producing potato granules have been developed during the past 30 years. The only one of these methods currently in commercial use in this country is the “add-back” process. This process involves a recycling (adding back) of dried potato granules and mixing the recycled material with freshly mashed potatoes to form a friable moist mixture below 40 per cent moisture content. The moist mixture is held for a period during which moisture equilibration takes place and a reduction in starch solubility and swelling capacity occur. After drying under suitable conditions, the individual cells remain separated and substantially undamaged. Physical damage to the product may cause release of free soluble starch, which manifests itself as an undesirable rubberiness in the reconstituted product. Investigations have revealed relationships of several variables in the process to this specific attribute of quality and to others (e.g., product yield and package density) and have provided useful information for process adjustment to improve the acceptability of potato granules.     

Quaternization/maleation of cornstarch to improve its adhesion and film properties for warp sizing

The aims of this work were to examine the influences of starch quaternization/maleation on the film properties and adhesion-to-fibers of starch, and also to reveal if the quaternization/maleation could improve the adhesion-to-fibers and film properties of starch. A series of quaternized and maleated cornstarch (QMS) with the total degree of substitution (DS) values of 0.02-0.061 were prepared via a quaternization of acid-thinned cornstarch with N-(3-chloro-2-hydroxypropyl) trimethylammonium chloride for introducing 3-(trimethylammonium chloride)-2-hydroxypropyl (TACHP) substituents onto the backbones of starch, and a further maleation with maleic anhydride for the introduction of maleate substituents. The effects of starch quaternization/maleation on paste viscosity, paste stability, adhesion strengths to both cotton and viscose fibers, and film properties of starch were investigated. The degree of crystallinity of starch film was quantitatively obtained from X-ray diffraction analysis. It was found that the quaternization/maleation was able to stabilize the viscosity, increase adhesion strengths of starch to both cotton and viscose fibers, enhance breaking elongation, moisture regain, and bending endurance of starch film, and decrease tensile strength and degree of crystallinity of starch film, thereby improving the adhesion and displaying toughening effect to the film. Increasing the level of starch quaternization/maleation was capable of gradually increasing adhesion and toughness of the film. The quaternization/maleation with the DS values of 0.04-0.061 could be applied for the alleviation of the intrinsic drawbacks (insufficient adhesion and film brittleness) of cornstarch for warp sizing.     

The final established physicochemical properties of steamed bread made from frozen dough: Study of the combined effects of gluten polymerization,water content and starch crystallinity on bread firmness

The gluten polymerization behavior, water content, starch crystallinity and firmness of Chinese steamed bread made from frozen dough were investigated and their correlations were also established in this study. The decreased degree of gluten polymerization in steamed bread was observed by the enhanced SDS-extractable proteins (SDSEPs) upon frozen storage. Less incorporation of glutenin in the glutenin–gliadin crosslinking of steamed bread mainly contributed to the decreased degree of gluten polymerization. The decreased moisture of steamed bread had a significant negative correlation with the sublimated water in frozen dough (r = −0.8850, P < 0.01). Frozen storage also induced an increase in starch crystallinity and bread firmness. A multiple linear regression model with SDS-extractable proteins, water content and melting enthalpy of starch crystals of steamed bread accounted for 86% of the variance in the natural logarithm of firmness and further revealed that starch crystallinity mainly contributed to bread firmness.     

Properties of starch-based foam formed by compression/explosion processing

Single-use foam packaging is used by manufacturers to protect and preserve a wide array of food and industrial products. Starch is one possible alternative material for making foam products. Starch-based foam was made using a compression/explosion process to study its properties and potential for single-use packaging. A feedstock was first prepared which consisted of wheat (WS), corn (CS) or potato starch (PS) that was formed into aggregates (1–3 mm) and conditioned to moisture levels ranging from 8 to 20%. The conditioned aggregates were loaded in an aluminum compression mold heated to 230°C and compressed for 10 s with 3.5 MPa force. The force was instantaneously released resulting in an explosive release of steam as the starch feedstock expanded and filled the mold. The moisture content of the feedstock influenced the density and compressive properties of the foam. Wheat, corn and potato starch feedstock with 17, 17 and 14% moisture content, respectively, produced foam with some physical and mechanical properties similar to those of commercial food containers. The starch foam had the general shape of the mold and appeared similar to polystyrene. The microstructure of the foam revealed a cellular structure with mostly closed cells less than 1 mm in diameter. However, some regions of the foam had a microstructure similar to that of expanded polystyrene except that the cells were much smaller (<0.1 mm).     

Evaluation of ingredient effects on extruded starch-based foams using a supersaturated split-plot design

The aim of this study was to use a supersaturated split-plot design to identify the significant effects of ten ingredients, each at two levels, and two levels of screw speed on selected properties of starch-based packaging foams. Supersaturated designs are special types of fractional factorial designs that allow for evaluating many factors with a minimal amount of experimental material. Rice starch foams were prepared with a twin-screw extruder. The ingredients used were α-cellulose (fiber), potato starch, poly(lactic acid), polystyrene, glycerol, sodium chloride, talc, sodium bicarbonate, citric acid and moisture content of the feed. The properties studied were radial expansion ratio, unit density, bulk spring index, bulk compressibility and Young's modulus. The results showed that the ingredients identified to have significant effects on the properties were the high levels of talc, citric acid, moisture content and the low level of fiber. Low screw speed was found to have greater effect on the properties of the foams than did the high screw speed. It was concluded that the supersaturated split-plot design was successful in identifying the significant ingredients and screw speed that should be used to further investigate the extrusion of starch-based packaging foams.     

Electroneutral cornstarch by quaternization and sulfosuccinylation to improve the adhesion of cold starch paste to raw cotton for low-temperature sizing

The objective of this research was to survey the effects of starch quaternization and sulfosuccinylation on the adhesion of cold starch paste to raw cotton fibers for cotton warp sizing at low temperature. Acid-thinned cornstarch (ATS) was quaternized and then sulfosuccinylated to introduce 3-(trimethylammonium chloride)-2-hydroxypropyl and sulfosuccinate substituents onto its backbones. The electroneutrality of starch samples prepared was achieved by maintaining a constant mole ratio (5.3:1) of the two substituents. A series of electroneutral cornstarch (ECS) samples with different levels of the substituents were derived by altering the feed ratio of the modifying reagents to starch for determining desirable level of starch modification. Adverse influences of cotton wax and starch retrogradation on the adhesion of cold starch paste to raw cotton fibers were evaluated to illustrate the effectiveness of starch quaternization and sulfosuccinylation. It was found that the modification was able to alleviate the adverse influence of starch retrogradation and ameliorate the adhesion to the fibers at low temperature. Higher level of the modification led to less retrogradation and resulted in strong adhesion. Furthermore, the adverse influence of cotton wax on the adhesion could be eliminated after a pre-wetting treatment of raw cotton warps with hot water. The adhesion of ECS paste to raw cotton at 60 °C was statically the same as that of ATS at 95 °C when total DS of ECS was 0.0443 or higher.     

Effect of silk protein fibers on properties of thermoplastic rice starch

Biodegradable polymer was prepared as thermoplastic starch (TPS). Due to poor mechanical properties and high water absorption of TPS, thermoplastic rice starch (TPRS) was modified by reinforcing with natural silk protein fibers, as an alternative choice of fiber reinforcement. Different contents and lengths of silk fibers were varied and used as the reinforcement. Internal mixer and compression molding machine were used to mix and shaped the TPRS/silk composites. It was found that stress at maximum load and Young??s modulus of the TPRS/silk composites significantly increased with the incorporation of silk fibers. Water absorption of the TPRS/silk composites was also dropped by the addition of silk fibers. Moreover, thermal degradation temperatures of the TPRS/silk composites shifted to higher temperatures by the inclusion of the silk fibers. Functional group analysis and X-ray diffraction patterns were analyzed by FI-IR and XRD techniques, respectively. Furthermore, color measurement, morphology and biodegradation by soil burial test were carried out for different TPRS/silk composites.     

Prediction of the water absorption capacity of VIS/PES needle-punched webs using genetic algorithms

Needle-punched webs for wet cleaning wipes were produced using a dry-laid method of web- forming. Fibrous webs with a different content of hydrophilic viscose and hydrophobic polyester fibers, as well as webs made from 100 % polyester fibers, were utilized during this study. The webs were compared in terms of their water absorption capacity on the basis of their basic construction parameters, such as fiber fineness, raw material (e.g. fiber density), and web density. The higher water absorption capacity of the viscose/polyester-blended needle-punched webs was achieved at higher content of viscose fibers which coincide with the higher fiber density, finer fibers, and lower web density. A prediction model regarding water absorption capacity of viscose/polyester needle-punched webs was developed on the basis of the mentioned construction parameters and a non-deterministic modelling method, e.g. genetic algorithms, and could provide a guideline for the engineering of nonwoven webs in order to fit the desired water absorption capacity.     

Proximate composition and some functional properties of extrusion cooked soybean and sweet potato blends.

Mixtures of sweet potato flour and soy flour were made in a pilot mixer. They were moisturized with 18, 25, and 30% water and extruded in a single screw extruder at 80 rpm, using a die of 6mm. Extrusion temperature was maintained at 100 +/- 3 degrees C. Effects of adding soy flour into sweet potato flour, as well as variation in feed moisture on the composition and some functional properties of the extrudates were investigated. Increase in sweet potato content increased carbohydrate values. Protein increased with increase in soy flour. Feed moisture did not significantly (p < or = 0.05) affect extrudate composition. Increase in sweet potato content and feed moisture increased expansion ratio. Bulk density decreased with decrease in feed moisture, but increased with increase in soy flour. Starch content increased as sweet potato content increased. Degree of gelatinization increased with sweet potato content. Lower feed moisture enhanced gelatinization. Water absorption index (WAI) increased as sweet potato content increased. Feed moisture had a slight effect on WAI and water solubility index (WSI). Amylose increased with increase in sweet potato content. Increase in soy flour led to an increase in yellowness (b*) of extrudates.     

Biodegradable plastic made from bean products

The aim of the present work was to explore the suitability of two kinds of bean with typical protein quality and different starch structure to produce moulded specimens by compression. In this work we analysed the possibility of forming new plastic materials from two kinds of bean preparations; with different protein content, in the presence or absence of inherent cellulose material and other biopolymer such as starch. Significant differences were determined in the fine structure of glucopolysaccharides isolated from the different types of bean. Complete moulding of the specimens took place at 20 MPa at a temperature not higher than 140°C, for 7 min. The mechanical properties of the moulded plastics based on soluble protein black bean (BP) were superior in elongation, tensile strength and low water absorption than the soluble protein white bean (WP) variety. However, the addition of boric acid 3% (w/w, in total batch basis) to white bean plastic materials was effective in improving slightly the mechanical properties in the case of their whole flours products (WWF). The gamma radiation was effective to reduce water absorption only in plastics materials with cellulose–starch content (BWF, WWF) and improved their mechanical properties. The gelatinization process of the moulded material was influenced by the predominant lineal structure of the carbohydrate content.     

Water stress during grain development affects starch synthesis,composition and physicochemical properties in triticale

Triticale, a man-made cereal crop developed from a cross between wheat and rye, has excellent agronomic traits to produce starch for bioindustrial applications. The effects of different levels of water stress on expression of starch synthesis genes and starch composition and physicochemical properties were investigated in this study. Three triticale varieties from 5 days post-anthesis were treated with three levels of water stress: low water stress (LWS) at 55–60% of soil moisture, moderate water stress (MWS) at 30–35% soil moisture and severe water stress (SWS) at 10–15% soil moisture. Water stress led to a significant reduction in seed weight at SWS (35–45%). A decrease in starch content was noticeable from MWS onwards and the values were decreased by 42–55% at SWS across all varieties. Such decrease was associated with the reduced expression of starch synthesis genes at 19 days of water stress (DWS). MWS favoured an increase of amylose proportion in triticale starch and it was accompanied by a significant up-regulation of GBSSI expression throughout the grain development. Triticale starch synthesized under water stress showed a reduced population of small granules and an increase of A-type to B-type ratio. SWS caused pitting on starch granules but did not alter the biconcave disc shape of mature granules. An inverse relationship between water stress and a range of starch gelatinization temperature was observed and the MWS environment specifically decreased the peak temperature (Tp) and increased the enthalpy. Our results signify that starch morphology, composition and physicochemical properties in triticale grains could be altered if triticale is grown under drought conditions.     

Sodium hydroxide and trimetaphosphate levels affect properties of starch extrudates

In addition to being consumed as food, starch is considered for replacement of petroleum-based plastics, but imparts negative effect like water absorption and solubilization in water. In this study, the effects of sodium hydroxide and sodium trimetaphosphate concentrations on the water absorption and solubility indices of starch cross-linked by sodium hydroxide and sodium were evaluated. Starch was granulated, and 0.3 kg granulated starch was mixed with 65 ml sodium hydroxide at three concentrations (0.2, 0.6, and 1.0 M), sodium trimetaphosphate at two levels (0.015 and 0.045 kg sodium trimetaphosphate corresponding to 5 and 15% of starch), and water to adjust moisture content to 40% (dry basis). The samples were extruded in a single-screw extruder at a barrel temperature of 130 °C and screw speed of 140 rpm. Phosphorus content and pasting viscosity of starch extrudates showed that starch was cross-linked with phosphorus that was incorporated into starch during extrusion. The extrusion and cross-linking of starch with 5% sodium trimetaphosphate reduced water absorption index, and increasing sodium trimetaphosphate percentage reduced water absorption index further at high levels of sodium hydroxide. On the other hand, the reduction in water solubility of starch extrudates required the extrusion of starch with more than 5% sodium trimetaphosphate, but increasing the sodium hydroxide level increased the water solubility index of extrudates.     

Study on polyacrylonitrile fibers modified by blending with polyethylene glycol

A series of water absorbent porous modified polyacrylonitrile (PAN) fibers were prepared using the blends of PAN and various molecular weight of polyethylene glycol (PEG) by wet-spinning process and water bath post-treatment. The chemical structure and morphologies of the modified PAN fibers were studied. The water transportation, water retention, moisture absorption and mechanical properties of the fibers were discussed. Results show that there is no residual PEG in modified PAN fibers after drawing process in hot water bath and post-treatment. With the increase in PEG molecular weight, the fiber surface grooves become deeper, the inner pore size increases, while the mechanical properties decrease. The water absorbing and transferring capabilities of the modified PAN fibers can be improved in varying degrees due to the different pore structures left by series molecular weight of PEG removing.     

Water stress during grain development affects starch synthesis,composition and physicochemical properties in triticale

Triticale, a man-made cereal crop developed from a cross between wheat and rye, has excellent agronomic traits to produce starch for bioindustrial applications. The effects of different levels of water stress on expression of starch synthesis genes and starch composition and physicochemical properties were investigated in this study. Three triticale varieties from 5 days post-anthesis were treated with three levels of water stress: low water stress (LWS) at 55–60% of soil moisture, moderate water stress (MWS) at 30–35% soil moisture and severe water stress (SWS) at 10–15% soil moisture. Water stress led to a significant reduction in seed weight at SWS (35–45%). A decrease in starch content was noticeable from MWS onwards and the values were decreased by 42–55% at SWS across all varieties. Such decrease was associated with the reduced expression of starch synthesis genes at 19 days of water stress (DWS). MWS favoured an increase of amylose proportion in triticale starch and it was accompanied by a significant up-regulation of GBSSI expression throughout the grain development. Triticale starch synthesized under water stress showed a reduced population of small granules and an increase of A-type to B-type ratio. SWS caused pitting on starch granules but did not alter the biconcave disc shape of mature granules. An inverse relationship between water stress and a range of starch gelatinization temperature was observed and the MWS environment specifically decreased the peak temperature (Tp) and increased the enthalpy. Our results signify that starch morphology, composition and physicochemical properties in triticale grains could be altered if triticale is grown under drought conditions.     

Processing and evaluation of heat moisture treated (HMT) amaranth starch noodles; An inclusive comparison with corn starch noodles

AS, HMT-AS and CS starches were studied for amylose content, swelling power, water absorption capacity, color, particle size (PSA), pasting profile (RVA) and thermal (DSC) properties. Based on the laboratory scale experiments, noodles with good expansion, minimum cooking time and firm texture were prepared. Noodles were successfully prepared from AS, HMT-AS and CS starches. Noodles prepared from native amaranth starch (AS) and heat moisture treated (HMT) were tested for different functional properties and compared to cornstarch noodles. Standardized noodles were evaluated for cooking loss, texture profile (TPA), sensory and micro-structural analysis by SEM. HMT-AS noodles had experience less cooking loss of 20.15 g/100 g in comparison to AS noodles (22.20 g/100 g). The HMT-AS based starch noodles shown firmer texture, along with augmented taste and distinct flavor in comparison to AS and CS noodles.