Waxy Starch Research Articles

Catalyst-free esterification of high amylose starch with maleic anhydride in 1-butyl-3-methylimidazolium chloride: The effect of amylose content on the degree of MA substitution

The limited reactivity of starch towards maleic anhydride (MA) affords maleate with a low degree of MA substitutions (CC and COOH groups). In this study, we investigated the relationship between the starch structure, controlled by its amylose (AM)/amylopectin (AP) ratio, and the DS of starch maleates using C4[mim]Cl as the recyclable media, and catalyst. The results indicated that starches with varying AM/AP ratio produced maleates with comparable CC groups (DSNMR = 0.06–0.07). Following dissolution, the high amylose (DStitration = 1.17, yield = 69.2 %) and regular starches (DStitration = 1.17; yield = 59.3 %) produced high DStitration maleates (COOH groups) at MA/AGU ratio of 12:1 (80 °C, 10 min). Comparatively, DStitration value of waxy starch maleates (DStitration = 0.88, yield = 59.3 %) was lower than AM-based starches, possibly due to the crosslinking tendency of AP branches consisting of carboxylic end-groups. Interestingly, DStitration value for EHCS (1.17) ranged between its bulk (DSNMR: 0.06) and surface distribution of MA (DSSXPS 1.7); therefore, we considered it reliable for future reference.

Thermal, Morphological, and Mechanical Properties of Regular and Waxy Maize Starch Films Reinforced with Cellulose Nanofibers (CNF)

Abstract Biodegradable films were prepared using regular and waxy starch and reinforced with cellulose nanofibers (CNF) from eucalyptus. Both films were characterized by their optical, structural, barrier, thermal and mechanical properties. The films presented a homogeneous, smooth surface without bubbles or cracks and good handling characteristics. Both films showed a mixture of B and V-type diffraction patterns. The water solubility of the samples decreased after the incorporation of nanocellulose. The water vapor permeability for both sources significantly reduced after incorporating nanocellulose at 0.5% and 1%. It is possible to observe that the addition of CNF increased the thermal stability of the starch films. On the other hand, the incorporation of nanocellulose improved either the mechanical resistance of the starch films.

Influence of xanthan gum on the short- and long-term retrogradation of potato starches of various amylose content

Effect of the 0.05 and 0.20% (w/w) admixture of xanthan gum (XG) upon short and long-term retrogradation of 4, 5 and 6% potato starch gels was studied in relation to the amylose/amylopectin ratio in the starches. Recorded mechanical spectra, gel texture, syneresis, resistant starch content and x-ray patterns of the normal and waxy potato starch gels revealed that XG promoted the formation of a three-dimensional gel network independently on the amylose/amylopectin ratio. It meant that XG favored the short-term retrogradation after samples preparation. Simultaneously, the presence of XG in admixture with potato starch hindered and promoted long-term retrogradation of the gels of normal and waxy starch gels, respectively.

Improving mechanical and barrier properties of thermoplastic starch and polysaccharide nanocrystals nanocomposites

Thermoplastic starch (TPS) films were developed with normal maize starch matrix using glycerol, D-isosorbide and 1,3-propanediol as plasticizers. Besides, TPS nanocomposite films were prepared incorporating waxy starch nanocrystals (WSNC) and cellulose nanocrystals (CNC) into the normal maize starch matrix plasticized with glycerol. Both TPS films and TPS nanocomposite films were obtained by extrusion/compression method. Their mechanical and barrier properties were analyzed, as well as their viscoelastic behavior. According to the results the TPS films plasticized with D-isosorbide presented the highest transparency and the best mechanical and barrier properties, whereas 1,3-propanediol was not suitable as it was lost during the thermomechanical processing leading to brittle materials. Glycerol plasticized TPS nanocomposites were developed by incorporating polysaccharide nanocrystals, either WSNC (0, 1, 2.5 and 5 wt%) or 1 wt% of both WSNC/CNC in different proportions, in order to approximate the values to those of D-isosorbide films. The effect of both the type and the content of nanocrystal on the viscoelastic behavior and mechanical and barrier properties were investigated. The results suggested that effective interfacial hydrogen bonding interactions were achieved by extrusion/compression processing, obtaining tensile strength, strain at break and Young’s modulus increments higher than 100% for nanocomposites reinforced by only 1 wt% of polysaccharide nanocrystals, both WSNC alone and also combining WSNC/CNC in different ratios.

PROSPECTS FOR THE USE OF PHYSICAL MODIFICATION STARCH IN FOOD PRODUCT TECHNOLOGY WITH COLLOID STRUCTURE

The aim of research is studying the rheological properties of gelatinized starch dispersions based on physical modification starches, depending on technological factors. Realization of the research aim will allow to obtain products (sauces, filler creams for confectionery products, etc.) using physical modification starches that are capable of selling products with specified structural and mechanical indicators, quality and safety indicators. And also ensure the rational use of raw materials, reduce the complexity of the technological process of production of culinary products. The current trends in the development of starch technology for physical modification and their use in food technology are analyzed. A review of literature data has become the background for the use of these starches in food technology, which primarily draws attention to the colloidal stability of food systems. A decrease in viscosity (the tendency ηmax=>ηmin) indicates the destruction degree of structural elements under the influence of mechanical stress and thermolysis. Tapioca starches “Endura”, “Indulge” and waxy maize starch “Prima” have practically the same values η (min) and η (max), which indicates the stability of the structure of gelatinized starch dispersions. This is probably due to the fact that grains with a monodisperse fraction (≈83 %) swell and gelatinize equivalently. A study of the effect of acids on the formation and stability of gelatinized starch dispersions shows that the most pronounced stability is characterized by dispersions based on Prima waxy starch and Endura tapioca. The gelatinized starch dispersions based on corn starch amylopectin exhibit low stability during the maximum peak gelatinization depending on the effect of sugar and acid. A thermodynamic study of physical modification starches wi carried out, which confirms the amount of energy expended on unpacking the starch grain, which confirms the initial gelatinization of starches.

Rapid Estimation of Parameters for Gelatinization of Waxy Corn Starch.

Starch gelatinization is an important process due to the prevalence of starch usage in industries such as cosmetics and food production. In this study, the gelatinization of waxy corn starch (WCS) was investigated with the goal of providing an option for the rapid determination of starch gelatinization characteristics. The procedure used in the study was solely based on differential scanning calorimetry (DSC), which is an established technique for the determination of thermal characteristics of starches. A sequence of experiments was conducted to determine the excess water condition, an estimate of the minimum gelatinization temperature, and gelatinization time. These parameters were found to be ≥65 wt.% water, 75–85 °C, and 10 min, respectively. The estimation of the minimum gelatinization temperature was determined from the thermal properties of the WCS as obtained by DSC. The obtained parameters resulted in complete WCS gelatinization, and, thus, the sequence of procedures used in the study could possibly be used for rapid waxy starch evaluation.

Outstanding Characteristics of Thai Non-GM Bred Waxy Cassava Starches Compared with Normal Cassava Starch, Waxy Cereal Starches and Stabilized Cassava Starches.

Waxy cassava roots of nine varieties successfully developed in Thailand by a non-genetic modification (non-GM), conventional breeding method were used for extracting starches and their starch physico-chemical properties were evaluated and compared with normal cassava starches, commercial waxy starches (i.e., waxy maize starch and waxy rice starch) and commercial stabilized starches (i.e., acetylated starch and hydroxypropylated starch). All waxy cassava varieties provided starches without amylose while normal cassava starches contained 18%–20% amylose contents. As determined by a Rapid Visco Analyzer (RVA) at 5% (dry basis), waxy cassava starches had the highest peak viscosity and the lowest setback viscosity. Cooked paste of waxy cassava starches had the greatest clarity and stability among all starches during storage at 4 ℃ for 7 days as evidenced by its high light transmittance (%T) at 650 nm. No syneresis was detected in waxy cassava starch gels after subjecting to four freeze-thaw cycles (4 weeks) indicating high potential use of waxy cassava starches, free from chemicals, to replace stabilized starches as thickening and texturing agents in food products.

Використання індукованого мутагенезу для створення пшениці м’якої ярої з крохмалем типу ваксі

The purpose. To establish efficient doses of -irradiation of grain of wheat for formation of its amylose-free genotypes, and to create on this basis a line for the further selection of grades of wheat with starch of waxy type. Methods. Biophysical, biochemical, computing-analytical, morphometric. As mutagen factor they used g-irradiation of 60Co in different doses (100; 150 and 200 Gr (Gray)). Lines of wheat irradiated with the purpose of improvement of their adaptive potential to natural settings of Ukraine. Well adapted grade of wheat Kharkivska 30 was irradiated with the purpose of induction of waxy mutation. Results. Effective doses of -irradiation for creation of amylose-free lines of soft spring wheat were established. They selected specific primers to waxy genes in all three genomes of hexaploid wheat. For each pair of primers the comfort temperature of amplification was specified. By means of molecular markers mutant genotypes of wheat with amylose-free type of starch were selected. On the basis of mutant genotypes and local grades they created and transmitted in laboratory of selection of spring wheat 2 lines with waxy starch. Conclusions. The carried out researches have confirmed efficiency of use of the induced mutagenesis for creation of genotypes of soft spring wheat with amylose-free type of starch. On the basis of mutant samples with the changed distillation characteristic of starch new lines of soft spring wheat with a complex of valuable economic attributes — Liutescens 12/16 and Liutescens 30/16 are created. The first line is characterized by early growth, duration of vegetative period — 90–93 days, durability to lodging, average productivity — 2,2–3 t/hectare, protein content — 13,1–14,2%, amylopectin in starch — 99,8–99,9%. At the second line vegetative period — 89–91 days, resistant to lodging, height of plants — 50–52 cm, average productivity — 2,3–3,1 t/hectare, protein content — 13,3–14,4%, amylopectin in starch — 99,8–99,9%.

Impact of granule hydration on maize and wheat starch chemical reactivity at the granular and molecular levels

Granular and molecular reaction patterns of maize and wheat starches (normal and waxy genotypes) were investigated in relation to extent of granule hydration (equilibrated at 25, 55, 75, 86 or 100% relative humidity [RH]; moisture range ≈ 10–40 g/100 g starch) within a model reaction system utilizing a fluorescent reagent (5-(4,6-dichlorotriazinyl)aminofluorescein). The greatest incremental increase in granule hydration (49–80%) and overall extent of reaction (30-76-fold) occurred between 86 and 100% RH, likely accentuating the starch glass transition temperature (Tg), which was depressed to room temperature via gradual granule hydration. Under limited hydration conditions (25–86% RH; presumably below Tg), reaction was confined to granule surfaces, whereas under conditions of sufficient hydration/plasticization (100% RH; presumably above Tg), reaction occurred throughout the granule matrix, dramatically increasing reaction of amylose and amylopectin branch chains. For normal starches, amylose was more inert to reaction in low moisture conditions (25–87% RH), indicating either a lesser prevalence at granular surfaces or insufficient hydration to react. Waxy starches exhibited more homogenous granular reaction patterns and greater overall extents of reaction than their respective normal starch counterparts, due to reactivity differences amongst amylose and amylopectin medium and long chains. Findings also provide insights for manipulating granular/molecular reaction locale in “dry” starch modifications.

Characterization of waxy starches phosphorylated using phytic acid

Waxy maize and waxy rice starches were subjected to dry heating in the presence of phytic acid at 120 °C for 6 or 24 h under alkaline conditions to induce phosphorylation. Dry heating at 120 °C for 24 h with phytic acid increased the residual phosphorus content of waxy maize and waxy rice starches from 11.5 to 92.9 ppm and from 27.5 to 79.3 ppm, respectively. 31P Nuclear magnetic resonance (NMR) analysis revealed the presence of monostarch monophosphate in the treated starches. The pasting viscosity of the starches was substantially changed by the phosphorylation, showing increases in peak viscosity, breakdown, and setback viscosity, but decrease in pasting temperature. Paste clarity and swelling power also increased after phosphorylation. Reduced melting temperature and enthalpy were observed for the phosphorylated starches. Thus, phytic acid is an effective reagent for phosphorylating starch to improve its pasting properties.

Impact of annealing on the hierarchical structure and physicochemical properties of waxy starches of different botanical origins

The effect of annealing on structure and physicochemical properties of four different waxy starches were investigated to understand the mechanism of annealing in the absence of amylose. Granule morphology, X-ray pattern, molecular order, and gelatinization enthalpy remained unchanged upon annealing. Relative crystallinity of waxy corn starch increased from 42.4 to 46.1% on annealing, while it remained unchanged in other starches. Annealing increased the gelatinization temperatures, while it decreased the temperature range. Waxy potato starch showed the highest increase in To, where it was 8.1 °C after 72 h of annealing. Viscosity profiles were only slightly affected by the annealing treatment. Susceptibility towards amylolysis increased in waxy corn and waxy barley, while it decreased in waxy potato and waxy rice. This study demonstrated that even in the absence of amylose, annealing caused changes in the structure and properties, however, the extents of these changes varied depending on the botanical origin.

Modification of cereal and tuber waxy starches with radio frequency cold plasma and its effects on waxy starch properties

The use of carbon dioxide-argon gas radio frequency cold plasma in modifying waxy rice, maize and potato was explored in this paper. Treatment with plasma at 120 W or 0 W (carbon dioxide-argon gas mixture only) resulted in significant increases in the enthalpy of gelatinization of all three waxy starches. Treatment with plasma or gas resulted in a significant increase in the resistant starch content of maize and potato with rice increasing only after gas treatment. Significant decreases were observed in the setback and final viscosities after 120 W treatment in all starches. Plasma and gas treatment resulted in a 5.5% and 2.8% decrease in crystallinity of potato but not rice and maize starch. NMR results showed the presence of V-type single helices in mostly maize and rice starches. Carbon dioxide-argon radio frequency cold plasma served as a useful tool in modifying the properties of all three waxy starches.

Waxy barley starch as raw material for healthy food products

The article justifies the expediency of the breeding of barley cultivars with waxy starch, grain of which can be raw material for functional food production. The study purpose was to create food barley cultivars with waxy starch. To accomplish this, qualitative parameters of barley accessions were determined, and starting material was selected for breeding. The study was conducted at the Plant Production Institute named after V.Ya. Yuriev of NAAS in 2015–2017. Twenty four chaffy and naked barley accessions of different origin were taken as the test material. Grain quality parameters of wild type and waxy accessions were compared. The yield, protein and starch contents, endosperm vitreousness, and antioxidant activity were shown to depend both on growing conditions and on genotypes. High nutritional quality of waxy barley cultivars was proved, videlicet, significantly higher content of oil compared with accessions with wild type starch and lower vitreousness of endosperm in chaffy accessions. Accessions with very valuable characteristics were selected: line 12-1014 with high digestibility of protein (61.75 mg tyrosine/g protein for pepsinolysis + trypsinolysis), line 12-945 with high antioxidant activity (2.02 mg chlorogenic acid equivalent/g), line 12-954 with a high content of oil (3.75%) and awnless line 14-1183 with a high content of polyunsaturated ω-3 linolenic acid (6.09%). These lines are valuable both as starting material for the breeding of food cultivars, and directly for functional food production. Waxy cultivars Shedevr and Amil were submitted to the state variety trials. Grain of these cultivars is noticeable for high contents of starch (>60%), oil (3.45–3.47%) and fiber (3.65–3.70%). Antioxidant activity is also sufficiently high (1.94–2.07 mg chlorogenic acid equivalent/g). Being low vitreous (40–43%), cultivars Shedevr and Amil can be used for production of flakes and flour, including extruded flour.

Effect of amylose content in morphological, functional and emulsification properties of OSA modified corn starch

Octenyl succinic starch esters were prepared from three corn starches with different amylose content; namely, waxy (5.43%), normal (25.16%) and Hylon VII (65.84%). The degree of substitution varies from 0.0103 for waxy starch to 0.0125 for Hylon VII, meaning that the degree of substitution is positively correlated with the amylose content. Scanning electron microscopy images showed that the esterification reaction affected only the granule surface while leaving the integrity of the granules. Solubility and water retention capacity were increased with the OSA modification, with the effect more pronounced for higher amylose contents. X-ray analysis revealed that the crystallinity type was not affected by esterification. FTIR analysis corroborated the changes in the hydrated and ordered structures of starch granules. Emulsification tests showed that octenyl succinic starch ester was an effective emulsifier for stabilization of oil-in-water emulsions. In particular waxy and Hylon VII starches induced high stabilization degrees as revealed by long-term stability of oil-in-water emulsions.

The Use of Waxy Starch and Guar Gum in Total Substitution of Vegetable Oil in Extruded Snack Aromatization

Vegetable oil is used by the extruded snacks industries to fixate aromas and salt in proportions between 10 and 20%. Consumers have restricted the consumption of these products due to the high content of lipids and low nutritional value. In order to obtain a low-fat option, this work aimed to reduce the lipids content of extruded snacks by replacing vegetable oil with waxy maize starch and guar gum. The snacks were manufactured in an INBRA RX50 mono screw extruder using corn grits as a base ingredient. The snacks were flavoured with five coatings formulations varying the concentration of waxy maize starch (1-4%) and guar gum (0.25-1.0%). A total of 15% solution by weight of snacks was applied, and the control treatment consisted in vegetable oil only. The products were evaluated for moisture content, total lipids, radial expansion index, specific volume, apparent density, retraction index, instrumental hardness (Texture Analyzer TA-XT Plus - Stable Micro Systems) and sensory evaluation with 100 non-trained panellists. Moisture and lipid contents were determined in 0 and 30 days of storage. Temperatures of 65 °C were required for waxy starch solution preparation, lowering the temperature to 50°C for the formulations with the addition of guar gum. The results indicated that it was possible to replace the vegetable oil by waxy maize starch and guar gum in the aromatisation of the snacks, as the products presented similar moisture content, specific volume, apparent density, retraction index, sensory acceptance and instrumental hardness (p > 0.05). Furthermore, the products presented a reduction of 11-13% in the lipid content. The addition of waxy maize as the only substitute would be recommended, because of the quality characteristics of the products and the absence of significant influence with the addition of guar gum. The snacks produced in the present study would be a healthier option to the consumer.

Nutritional evaluation of two barley cultivars, without and with carbohydrase supplementation, for broilers: metabolisable energy and standardised amino acid digestibility

ABSTRACT 1. Two experiments were conducted to assess the nitrogen-corrected apparent metabolisable energy (AMEn; Exp. 1; 288 Ross 308 male broilers at d 14; 36 cages with eight birds each) and coefficient of standardised ileal digestibility (CSID) of amino acids (AA; Exp. 2; 336 Ross 308 male broilers at d 21; 42 cages with eight birds each) of two barley cultivars for broilers in comparison to wheat, without or with a multi-component non-starch polysaccharide (NSP) degrading enzyme. A 3 × 2 factorial arrangement of treatments was used in both experiments with three types of grains (normal starch hulled barley [NSH], waxy starch hull-less barley [WSHL], and wheat) and two levels of enzyme supplementation (0 and 200 g/tonne of feed). Enzyme supplemented diets contained 406 and 128 of endo-1, 4-β-xylanase and endo-1, 3 (4)-β-glucanase units per kg of feed, respectively. 2. Analysis showed that the starch content was higher in NSH (610 g/kg) than in wheat (537 g/kg) and WSHL (554 g/kg), and the composition of starch differed markedly among the grain types. The β-glucan content was considerably higher in WSHL (68.6 g/kg) compared to NSH (38.5 g/kg) and wheat (7.74 g/kg). The contribution of soluble fraction to the total non-starch polysaccharides was higher in WSHL (38.2%) compared to NSH and wheat (17.1% and 13.3%, respectively). 3. A significant (P < 0.01) interaction was observed between the grain type and enzyme supplementation for AMEn. The WSHL, with the highest content of β-glucan, showed the greatest response to enzyme supplementation for AMEn. 4. Birds fed wheat- and WSHL-based diets had the highest and lowest CSID of nitrogen and most of AA, respectively, with NSH diets being intermediate. Regardless of grain type, enzyme supplementation increased (P < 0.05) the CSID of nitrogen. 5. These data suggest that β-glucan content plays an important role in determining the digestibility of nutrients in barley for broilers, resulting in a better feeding value for NSH over WSHL. Supplementation of a multi-component NSP-degrading enzyme can improve the feeding value of barley in broiler diets by increasing the digestibility with the effect being more pronounced in WSHL barley.

The Contribution of Different Subunits of Intestinal Mucosal α-glucosidases to the Glucose Release from Starches (P08-090-19)

ObjectivesTo analyze the role of each subunit from Sucrase-Isomaltase (SI) and Maltase-Glucoamylase (MG) on the glucose production from corn starch (NC), Waxy starch (WX) and Hylon V (HLV) starch predigested with pancreatic amylase (Amy). MethodsThe starches were selected based on their ratios of α-1,4 and α-1,6 linkages. Starches were predigested with Amy for 0, 10, 20, 30, 60 and 120 min. After predigestion starches were hydrolyzed with different combinations of recombinant C terminal (C) and N terminal (N) subunits of Sucrase-Isomaltase (SI) and Maltase-Glucoamylase (MG), each at the relative maltase activity of: 40% C-SI, 20% N-SI, 32% C-MG and 8% N-MG, resembling the observed in the human intestinal mucosa. Glucose release was quantified by a real-time glucose oxidase-peroxidase method at 37°C. ResultsC-MG subunit hydrolyzed the three starches without predigestion by Amy at rates of 2.9 ± 0.02, 2.5 ± 0.02 and 2.4 ± 0.05 ng/min of glucose for WX, HLV and NC, respectively. C-SI subunit produced only 0.9 ± 0.02 ng/min glucose from the starches not predigested by Amy. After 30 min of Amy predigestion, the rates of glucose release by C-MG were modified to 13.3 ± 0.09, 12.3 ± 0.08 and 11.6 ± 0.08 ng/min for HLV, NC and WX, respectively. The same predigestion modified glucose release by C-SI subunit to 3.9 ± 0.02, 4.7 ± 0.08 and 5.8 ± 0.03 for WX, NC and HLV, respectively. In starches predigested 60 or 120 min, C-MG subunit alone or together with N-MG showed lower activity than expected, suggesting the occurrence of substrate inhibition. Together the four MG and SI subunits showed clear differences on the rates of glucose production from the starches predigested with Amy for 120 min (22.8 ± 0.133 for WX, 26.4 ± 0.2 for NC and 26.7 ± 0.8 for HLV; all ng/min) which correlated with the glucose production by the N and C SI subunits together (15.5 ± 0.9 for WX, 19.4 ± 0.09 for NC and 23.85 ± 0.12 for HLV; all ng/min). ConclusionsWe found complex interactions among the starch structure, extent of amylase digestion and the rate of glucose release by each C and N subunits of SI and MG. Thus, the rate of intestinal starch digestion depends on the structure of the starches, the predigestion by amylase and, importantly, the relative abundance and catalytic properties of the individual subunits of MG and SI. Funding SourcesConsejo Nacional de Ciencias y Tecnología (CONACyT), Mexico.

Characterization and proposal of potential use in foods of coproducts from waxy maize wet milling

Abstract The aim of this study was to characterize the corn gluten feed and corn gluten meal originated from waxy maize wet milling industry, in relation to its microbiological risk and physical, chemical and functional properties. The wet residues showed microbiological standards for human consumption. Maize gluten meal was characterized by having high protein content (32 g 100 g-1), lipids (16 g 100 g-1) and carbohydrates (45 g 100 g -1), whereas the maize gluten feed contains high content of dietary fiber (44 g 100 g -1). The maize gluten feed and maize gluten meal have high potential for application as food ingredient. The high dietary fiber, suggests its use as a promising ingredient to increase the availability of fibers, thereby increasing attractiveness and nutritional quality of food. Furthermore, the use of this coproduct of waxy starch may be an alternative to traditional fibers used in the production of bakery products already before with claimed functional and health properties.

Complexation of Amylosucrase-Modified Waxy Corn Starch with Fatty Acids: Determination of Their Physicochemical Properties and Digestibilities.

In this study, starch-lipid complexes were prepared using normal corn starch (NC) and amylosucrase-modified waxy corn starch (ASWC) with myristic acid (C14:0) and palmitic acid (C16:0). The amylosucrase modification elongated branch chains in waxy corn starch leading to an increase of apparent amylose content (29.7%) similar to that of NC (29.0%). The X-ray diffraction of starch-lipid complexes revealed a V-type pattern, a clear indication of complex formation. The ability of the ASWC to complex with fatty acids was greater than that of NC. Interestingly, the changes in relative crystallinity, thermal parameters, and digestion properties according to the complexation showed opposite patterns in NC and ASWC. This study found that the structure of ASWC contributes to the formation of starch-fatty acid complexes and suggested that the ASWC can be preferred over NC in a delivery system. PRACTICAL APPLICATION: Amylopectin has been considered to be incapable of forming complexes with fatty acids due to its short chain length and steric hindrance. Through this study, an appropriate enzymatic modification of the molecular structures of waxy starches could make a complexation of waxy starches with fatty acids possible. The findings of this study suggest a promising perspective for utilization of waxy starch as a carrier material of lipophilic molecules.

Measurement of froth zone and collection zone recoveries with various starch depressants in anionic flotation of hematite and quartz

This paper reports the measured froth zone (Rf) and collection zone (Rc) recoveries in the flotation of pure quartz, pure hematite, and a quartz-hematite mixture with one of three corn starches with different mass ratios of amylose to amylopectin: waxy starch (0:100), normal starch (27:73), and Gelose 50 (50:50). The flotation tests were carried out at continuous mode using a three-product column at different pHs and starch concentrations with sodium oleate as collector and calcium chloride as activator. It was found that both Rf and Rc were significantly affected by pH and starch type and concentration. In the flotation of pure quartz or hematite, addition of each of the corn starches tested would decrease the Rf and Rc, with the effects following the order of waxy starch > normal starch > Gelose 50. The decreases in Rf and Rc coincided with the increase in the aggregate size caused by addition of these starches. Possible correlations between Rf, solid flux at the pulp-froth interface and Rc were examined. In the flotation of the quartz-hematite mixture, the changes in Rf and Rc of Fe caused by varying starch type and dosage were consistent with those in the flotation of pure hematite.