Evaluating the Effects of Wheat Cultivar and Extrusion Processing on Nutritional, Health-Promoting, and Antioxidant Properties of Flour.

Wheat has been considered one of the most important staple foods for thousands of years. It is one of the largest suppliers of calories in the daily diet, which is added to many different products. Wheat is also a good source of health-benefiting antioxidants. This study aims toinvestigate the changes in the antioxidant properties, such as total phenol content, 2,2-diphenyl-1-picrylhydrazyl (DPPH), metal chelating activity, 2,2'-azino-bis (3-ethylbenz-thiazoline-6-sulfonic acid) diammonium salt (ABTS+) scavenging activity, and color intensity, during the extrusion processing of six different wheat cultivars. The extrusion factors evaluated were 15% feed moisture and two extrusion temperatures (150 and 180°C). Extrusion processing increased antioxidant activity (DPPH, metal chelating activity, and ABTS+ scavenging activity), whereas total flavonoids content and total phenolic content were decreased. The L* values of wheat flours increased significantly (p < 0.05) after extrusion at 150 and 180°C, 15% mc. Furthermore, redness was decreased from control wheat cultivars (range: 0.17-0.21) to extrusion at 150°C (range: 0.14-0.17) and 180°C (range: 0.1-0.14). The study suggests that extruded wheat could improve the antioxidant potential in food products.

Octenyl Succinic Anhydride Modified Pearl Millet Starches: An Approach for Development of Films/Coatings.

Pearl millet starches were modified at pH 8.0 using 3.0% octenyl succinic anhydride (OSA), and their pasting, rheological properties, and in vitro digestibility were analyzed. The degree of substitution (D.C.) of OSA-modified starches varied from 0.010 to 0.025. The amylose content decreased after modification, while the reverse was observed for swelling power. After OSA modification, the pasting viscosities (peak, trough, setback (cP)) of the modified starches increased compared to their native counterparts. G' (storage modulus) and G″ (loss modulus) decreased significantly (p < 0.05) compared to their native counterparts during heating. Yield stress (σo), consistency (K), and flow behavior index (n) varied from 9.8 to 87.2 Pa, 30.4 to 91.0 Pa.s., and 0.25 to 0.47, respectively. For starch pastes, steady shear properties showed n < 1, indicating shear-thinning and pseudoplastic behavior. The readily digestible starch (RDS) and slowly digestible starch (SDS) contents decreased, while the resistant starch (R.S.) content increased. After OSA treatment, the solubility power of the starches increased; this property of OSA starches speeds up the biodegradability process for the films, and it helps to maintain a healthy environment.

Effect of selected physical and chemical modifications on physicochemical, pasting, and morphological properties of underutilized starch from rice bean (Vigna umbellata).

Starch was extracted from the rice bean which is largely underutilized and modified by physical (i.e. heat moisture treatment and retrogradation) and chemical (i.e. esterification and acid alcohol modification) methods. Both, physical and chemical modifications significantly (p < 0.05) affected the physicochemical, pasting, particle size and morphological properties of rice bean starch. Both amylose content and swelling power reduced after physical and chemical modifications. Among modified starches, retrograded starch showed higher solubility (8.56%) at 90 °C. Retrogradation also resulted in higher values of water (251%) and oil absorption (106%) capacities in comparison to other modified starches. Physical modifications greatly influenced the pasting properties in comparison to chemical modifications. The particle size distribution followed the order: native starch (659.8 nm) > heat moisture treated (434.3 nm) > retrograded (355.4 nm) > esterified (218 nm) > acid alcohol treated starch (234.5 nm). The study revealed that the particle size of rice bean starch was reduced by both physical and chemical modifications. FE-Scanning electron microscopy was used to study the morphological characteristics of starches and it was observed that retrogradation had a pronounced effect on the starch granules morphology.

Unraveling the Bioactive Profile, Antioxidant and DNA Damage Protection Potential of Rye (Secale cereale) Flour.

Six different solvents were used as extraction medium (water, methanol, ethanol, acidified methanol, benzene and acetone) to check their phenolics extraction efficacy from flour of two rye cultivars. Rye extracts with different solvents were further analyzed for the estimation of phytochemicals and antioxidant properties. Different tests (TPC, TAC, DPPH, FRAP, ABTS, RPA and CTC) were performed to check the antioxidant properties and tannin contents in extracts. A bioactive profile of a rye cultivar indicated the presence of total phenolic compounds (0.08-2.62 mg GAE/g), total antioxidant capacity (0.9-6.8 mg AAE/g) and condensed tannin content (4.24-9.28 mg CE/100 g). HPLC was done to check phenolics in rye extract with the best solvent (water), which indicated the presence of Catechol (91.1-120.4 mg/100 g), resorcinol (52-70.3 mg/100 g), vanillin (1.3-5.5 mg/100 g), ferulic acid (1.4-1.5 mg/100 g), quercetin (4.6-4.67 mg/100 g) and benzoic acid (5.3 mg/100 g) in rye extracts. The presence of DNA damage protection potential in rye extracts indicates its medicinal importance. Rye flour could be utilized in the preparation of antioxidant-rich health-benefiting food products.

Synthesis and characterization of nano starch-based composite films from kidney bean (Phaseolus vulgaris).

This study was aimed to synthesize and evaluate the nano starch-based composite films by the addition of nano starch in film formulation at 0.5, 1, 2, 5 and 10% level of total starch. The acid hydrolysis technique was used to reduce the size of starch granules of kidney bean starch. The physicochemical properties of both native and nano starch were determined. Nano starch showed a higher value for swelling power, solubility, water and oil absorption capacity when compared with native starch. The particle size of kidney bean nano starch was 257.7 nm at 100% intensity. The size of starch granule affects various properties of films. The thickness, solubility and burst strength of the composite films were increased significantly (p ≤ 0.05) with an increase in the concentration of nano starch in film formulation. While the moisture content and water vapour transmission rate (WVTR) were decreased significantly (p ≤ 0.05) with an increase in the concentration of nano starch in film formulation. The results suggested that kidney bean starch could be used for the development of packaging films. The utilization of nano starch in film formulations had an additional advantage in improving the film properties.

Rheological, thermal, and structural properties of high-pressure treated Litchi (Litchi chinensis) kernel starch.

Starch isolated from litchi kernel was subjected to high-pressure (HP) treatment at selected pressures (300, 450 and 600 MPa) for 10 min, and evaluated for its rheological, morphological, thermal and structural properties. The amylose content of native litchi kernel starch (LKS) was 17.4%, which increased significantly upon pressurization. The temperature sweep test of the untreated starch sample resulted in the peak G' and G″ values of 3417 and 283 Pa, respectively, and those values decreased after pressurization. Oscillatory rheological measurements showed the frequency dependency of tested starch pastes. Furthermore, the mechanical rigidity of the starch pastes improved with pressure treatment. Morphological studies revealed that starch granule structure remained intact after pressurization; however, pressure >450 MPa resulted in surface roughness and small cavities. HP treatment significantly influenced thermal properties of LKS, in particular at 450 and 600 MPa, where a significant drop in the transition temperatures and enthalpy values were recorded. The HP-treated starch samples exhibited distinct X-ray diffraction pattern of native LKS i.e. the blend of A- and B-type allomorphs with a predominating A-type crystalline structure. Upon pressure treatment, the disappearance of 2θ peak at 5.6° and significant changes in peak intensities confirmed the structural change in the starch matrix.

Kinetic, rheological and thermal studies of flaxseed (Linum usitatissiumum L.) oil and its utilization.

In present study kinetic, thermal and rheological characteristics of oil isolated from flaxseed were studied and because of high content of α-linolenic acid (essential omega-3 fatty acid), flaxseed oil was incorporated in muffins by replacing fat/shortening at different levels (10%, 20%, 30% and 40%). To evaluate rheological behaviour, the experimental data of flow behaviour for flaxseed oil was fitted to Power law model, consistency index (K) and flow behaviour index (n) and Arrhenius parameters (activation energy and frequency factor) were evaluated. The n value of the oil treated at 10, 15, 20, 25 and 30 °C were found between 0.8 to 0.9, which suggested the non-Newtonian fluid behaviour of flaxseed oil. Thermal properties of flaxseed oil was evaluated using DSC (differential scanning calorimetry). The flaxseed oil possessed three endothermic and one shoulder peak. Gas chromatography revealed the fatty acids composition qualitatively and quantitatively and flaxseed oil is dominated by unsaturated fatty acids. Saturated oil was replaced with flaxseed unsaturated fat and results showed that substituting oil with flaxseed fat at level upto 20% produced muffins possessed the better texture, colour, aroma, mouth feel and overall quality score. Practical application: Modern diet lifestyle demands of healthy natural foods represent a challenge for food manufacturers to lead towards the healthy new trends. Fats imparts lubrication, texture, flavour and acceptability therefore used as major ingredients in bakery goods. Fats contains saturated fatty and dietary intake of saturated fatty acids in excess amount leads to many health disorders. Therefore, substitution of saturated fatty acid with PUFAs (omega-3 and omega-6) for the protection against diseases and metabolic disorders may be a solution for healthy and nutritious product development.

Quantification of phenolic acids and antioxidant potential of wheat rusks as influenced by partial replacement with barley flour.

This study was investigated to evaluate the phenolic acid composition, antioxidant potential and acceptance of rusk prepared by the progressive replacement of wheat flour with barley flour. The wheat-barley blends rusks were also evaluated for their pasting and sensorial properties. The pasting characteristics of wheat flour was influenced by barley flour incorporation with a increase in peak and final viscosity values with increasing amount of barley flour. The results revealed that incorporation of barley flour into wheat flour improved the nutritional and bioactive compounds profile. The free radical scavenging activities towards DPPH and ABTS+ was found to be higher for wheat-barley blends rusk in comparison with wheat rusk. As evident from total phenolic content, total flavonoids contents and antioxidant activities, barley flour was found to be rich in bioactive compounds in comparison with wheat flour. Supplementation of rusks with 30% barley flour were suggested to be nutritionally superior with an acceptable sensory score and is a successful approach to enrich rusks with nutrients.

Antioxidant characterization and in vitro DNA damage protection potential of some Indian fenugreek (Trigonella foenum-graecum) cultivars: effect of solvents.

Indian fenugreek cultivars were characterized for their antioxidant properties and bioactive compounds were quantified using high performance liquid chromatography (HPLC). The extraction efficiencies were compared for two extraction solvents [aqueous ethanol (50%) and methanol]. The bioactive properties studied were total phenolic content (TPC), total flavonoids content (TFC), condensed tannin content (CTC), 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonate) (ABTS+), 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, total antioxidant capacity (TAC), and reducing power activity (RPA). Aqueous ethanol extracts showed higher TPC, TFC, ABTS+, TAC and RPA as compared to methanol. However, methanolic extracts showed higher CTC and DPPH activity. Higher TPC [45.3 and 45.4 mg gallic acid equivalents (GAE)/g dry weight basis (dwb)], DPPH (93.0 and 93.2%), ABTS+ (98.3 and 98.5%), RPA [40.9 and 44.9 mg quercetin equivalents (QE)/g dwb], were observed for cv.RMT-143 and cv.RMT-365, respectively. TFC (20.5 mg catechin equivalents (CE)/g dwb) and CTC (9.3 mg CE/g dwb) were found the highest for cv. Kasoori methi. Quantification of phenolic compounds using HPLC revealed higher amount of gallic acid (in Kasoori methi), ascorbic and p-coumaric acid (HM-57), benzoic and cinnamic acid (RMT-143) and catechol (only in RMT-365). Significant (p < 0.05) protection against in vitro plasmid deoxyribonucleic acid (DNA) (pBR322) oxidative damage was observed for fenugreek extracts.

Development, characterization, and biocompatibility of zinc oxide coupled starch nanocomposites from different botanical sources.

Starch nanoparticles (SNP) were prepared from different botanical sources (wheat, potato, mung bean, water chestnut and mango kernels) and these were further coupled with zinc oxide (ZnO) to form starch nanocomposites. The nanocomposites were characterized for their particle size, morphological properties, energy dispersive X-ray spectroscopy (EDX) and their biocompatibility was analyzed by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, using HeLa cells. From the morphological results, it was observed that ZnO forms super molecules with SNP. Further, EDX studies also confirmed the presence of zinc in coupled molecules. The size distribution of ZnO coupled SNP from different botanical sources revealed that the average diameter of nanocomposites ranged between 506 and 1209 nm. ZnO coupled starch nanocomposites were found to be biocompatible with 77-90% cell viability up to 24 h on HeLa cells. Among all botanical sources studied, ZnO coupled mung bean starch nanocomposite showed the highest cell viability (75% up to 50 h) while ZnO coupled potato starch nanocomposite showed the lowest cell viability (65% up to 50 h).

Functional, thermal and rheological behavior of fenugreek (Trigonella foenum-graecum L.) gums from different cultivars: A comparative study.

Fenugreek gum (FG) was isolated from six different Indian fenugreek cultivars and studied for their functional, structural, thermal and rheological attributes. The highest yield (13.5%) was observed for cultivar RMT-365. All galactomannans depicted good water and oil holding capacities ranging from 2009 ± 5.5 to 2099.9 ± 2.5% and 523.5 ± 3.5 to 553.0 ± 2.0%, respectively. DSC thermograms of FG revealed the presence of one endothermic and one exothermic peak. For endothermic transition of gums from different cultivars, enthalpy change (Δ Ha) ranged from 234.2 to 351.8 J/g while for exothermic transition, Δ Ha values ranged from 72.0 to 102.1 J/g, much lower as compared with endothermic peak. The effect of variable shear rate on viscosity of 1% FG solutions showed their shear thinning behaviors for all the cultivars, whereby the viscosity decreased with increasing shear rate. Frequency sweep tests indicated typical viscoelastic fluid behavior for all the gum solutions. Increase in the magnitude of G' and G″ of FG solutions was observed with an increase in frequency. A detailed understanding of different chemical, functional and thermal properties of FG could surely enlarge the radius of its application and eventually aid in its utilization in different food, pharma and cosmetic products.

Effect of cross-linking on physico-chemical, thermal, pasting, in vitro digestibility and film forming properties of Faba bean (Vicia faba L.) starch.

Faba bean starch was crosslinked (CL) at different levels (1, 3 & 5%) using sodium trimetaphosphate and studied for physicochemical, thermal, pasting and in vitro digestibility characteristics. Further, films were prepared from these starches and characterized for moisture content, thickness, water solubility, opacity, water vapor permeability (WVP) and mechanical properties. Amylose content, swelling power and solubility decreased after modification. CL resulted in decrease in peak viscosity (PV) whereas pasting temperature increased; CL (5%) showed the lowest PV (6474 mPa.s). Steady shear properties showed flow behavior index values <1 for starch pastes, indicating pseudoplastic and shear-thinning behavior. Thermal properties of CL starches showed higher transition temperatures and enthalpy of gelatinization (ΔHgel) as compared to native starch. ΔHgel values of CL starches ranged from 10.70 to 14.20 J/g whereas for native starch, the value was 9.47 J/g. CL resulted in increased resistant starch (from 49.8 to 61.1%), the highest value was for CL (5%). CL starch films exhibited lower moisture content, water solubility and WVP. Film thickness, however, was not affected by modification. CL (5%) starch film showed the highest tensile strength (14.28 MPa) and the lowest elongation at break (25.62%). CL resulted in improved mechanical and barrier properties of starch films.

Oat starch: Physico-chemical, morphological, rheological characteristics and its applications - A review.

Oat starch is getting attention owing to its usefulness and potential in a number of food and non-food applications. Starch is by far the main component of oat grains and possesses some unique chemical, physical, and structural properties when compared with other cereal starches. Oat starch offers untypical properties such as small size of granules, well-developed granule surface and high lipid content. Variation in amylose and amylopectin proportion along with the properties associated with the amylopectin molecule makes diversity in composition of oat starch. The pasting and rheological properties of oat starches control food product quality. This review articles outlines the recent developments in understanding of the starch isolation, chemical composition, morphology, pasting, rheological and thermal characteristics and various application of oat starch. Potential applications of oat starches are also reviewed.

Physical, structural and thermal properties of composite edible films prepared from pearl millet starch and carrageenan gum: Process optimization using response surface methodology.

The present study aimed at developing edible composite films from pearl millet starch (PMS) and carrageenan gum (CG) blends. Central composite rotatable design of response surface methodology was used to optimize concentrations of PMS (2-5%), carrageenan (1-3.5%) and glycerol (15-35%) for the development of composite film. The optimization was done on the basis of responses viz. thickness, water vapor permeability (WVP), solubility and tensile strength (TS). Both starch and carrageenan concentrations positively affected the TS of films, whereas the reverse trend was observed with increased concentration of glycerol. The optimum level of different parameters resulting in a composite film with maximum TS and lower WVP and solubility values were obtained under conditions of 4.9% starch, 5% carrageenan and 15.73% plasticizer concentrations. The melting temperature of optimized PMS/CG film was higher than PMS film. Morphological studies exhibited homogeneous structure of PMS film while PMS/CG composite film had rough, coarser and slightly irregular surface. The stretched regions in Fourier-transform infrared spectroscopy and Differential Scanning Calorimeter analysis confirmed the miscibility and thermal stability of different components of PMS/CG composite films. The results indicated that the developed optimized PMS/CG film possessed lower WVP, solubility but higher transparency and TS in comparison to PMS film.

A novel starch from Pongamia pinnata seeds: Comparison of its thermal, morphological and rheological behaviour with starches from other botanical sources.

Pongamia pinnata seed (PPS) starch was studied for its physicochemical, thermal, rheological and morphological properties. As PPS starch is a novel starch, it was compared with corn, mung bean, potato, pearl millet and mango kernel starches. Peak, trough and final viscosity of PPS starch was found the lowest as compared to other starches. Plots of shear stress versus shear rate for starch pastes were plotted and fitted to Herschel-Bulkley model. Yield stress and consistency index value of starch pastes varied between 6.5 and 58.9 Pa and 1.4-10.6 Pa s, respectively. During frequency sweep testing, G' and G'' values of starch pastes varied between 33 and 484 Pa and 18-71 Pa, PPS starch paste had the lowest values. Transition temperatures (Tο, Tp, Tc) for PPS starch was 61.5, 72.1 and 82.9 °C, respectively. Scanning electron microscopy of PPS starch showed small to large and round to oval shape starch granules with small pitches on their surface.

Aspergillus oryzae Fermented Rice Bran: A Byproduct with Enhanced Bioactive Compounds and Antioxidant Potential.

Rice bran (RB) is a byproduct of the rice industry (milling). For the fermentation process and to add value to it, RB was sprayed with fungal spores (Aspergillus oryzae MTCC 3107). The impact of fermentation duration on antioxidant properties was studied. Total phenolic content (TPC) determined using the Folin-Ciocalteu method, increased during fermentation until the 4th day. The antioxidant activity analyzed using the 2,2 Diphenyl-1' picrylhydrazyl (DPPH) assay, total antioxidant activity (TAC), 2,2'-azinobis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS+) assay, reducing power assay (RPA) and hydroxyl free radical scavenging activity (HFRSA) for fermented rice bran (FRB) were determined and compared to unfermented rice bran (URB). TAC, DPPH, ABTS+ and RPA of FRB increased till 4th day of fermentation, and then decreased. The specific bioactive constituents in extracts (Ethanol 50%) from FRB and URB were identified using high performance liquid chromatography (HPLC). HPLC confirmed a significant (p < 0.05) increase in gallic acid and ascorbic acid. On the 4th day of fermentation, the concentrations of gallic acid and ascorbic acid were 23.3 and 12.7 µg/g, respectively. The outcome of present investigation confirms that antioxidant potential and TPC of rice bran may be augmented using SSF.

Impact of high pressure processing on the rheological, thermal and morphological characteristics of mango kernel starch.

The effect of high pressure (HP) processing at selected pressures (300, 450 & 600 MPa) for 10 min on physico-chemical and morphological properties of mango kernel starch (MKS) were studied. Peak viscosity of MKS increased with the increase in pressure up to 400 MPa, and then decreased at 600 MPa. During frequency sweep, native and pressurized pastes exhibited predominantly solid-like behaviour in frequency range (0.1-100 rad/s), with G' > G″. Temperature sweep test showed G' and G″ values of native MKS of 1568 and 224 Pa, respectively; pressurization decreased values for both the moduli. tan δ of starches was <1, indicating their elastic behaviour. Shear stress versus shear rate plots for all starch pastes showed shear-thinning behaviour. Thermal properties showed elevation in onset and peak temperatures after pressurization. HP treatment also resulted in narrowing the range (Tc-To) for pressurized MKS. Native MKS had ∆Hgel of 5.23 J/g, which upon pressurization reduced significantly (p < 0.05). The endothermic peak, even at 600 MPa did not completely disappear, indicating incomplete gelatinization of starch. The granular structure was not affected by pressure treatment even after 600 MPa. The surface of native MKS appeared smooth whereas HP treatment resulted in rough surface of the starch granules.

Experimental and modeling studies of the flow, dynamic and creep recovery properties of pearl millet starch as affected by concentration and cultivar type.

Starch from pearl millet varieties viz. ProAgro 9444 and HHB 67, selected on the basis of amylose content was studied for steady, dynamic and creep recovery characteristics as affected by concentration (3-15%). ProAgro 9444 and HHB 67 possess amylose content of 20.21% and 15.05%, respectively. Starch gel exhibited shear thinning behavior with flow behavior index <1, well described by Herschel Bulkley model (R2 > 0.969) at all the concentrations. The starch pastes were thixotropic and the extent increased with increasing concentration and amylose content. Dynamic shear properties obtained within the linear viscoelastic region suggested weak gel like behavior at all concentrations, except 3% starch from HHB 67 which was categorized as dilute solution. Weak gel like behavior at other concentrations was supported by tan δ < 1, and the gel from ProAgro 9444 was more elastic. Power law analysis of data from mechanical spectra also reflected weak gel behavior except for 3% HHB 67. High amylose and increasing concentration favored gel formation as magnitude of temperature at peak G' and G″ were lower. Creep compliance followed Burger model at higher concentrations whereas 3% HHB 67 exhibited Newtonian behavior. The strain recovery increased with increase in starch concentration and amylose content.

Dynamic, shear and pasting behaviour of native and octenyl succinic anhydride (OSA) modified wheat starch and their utilization in preparation of edible films.

Starch-based edible films could offer non-chemical means for preserving perishable commodities. The present research investigated the effectiveness of native and heat treated Octenyl succinic anhydride (OSA) modified wheat starch in edible film making. Pasting and rheological properties of the native and OSA modified starch as well as antioxidants and sensorial attributes of coated and non-coated grapes were evaluated. The peak and final viscosity of the OSA modified wheat starch (1270 Pa and 1589 Pa) was found to be higher than native starch (1120 Pa and 1490 Pa). Magnitude of G' and G″ was slightly increased with the increase of frequency. Modified starches showed lesser values for Peak G' as compared to native starch. G' and G″ values of native starch were 2145 and 250 Pa whereas for OSA modified starch, these values were 1780 and 190 Pa. Results exhibited that starch based coating have potential to maintain total phenolic content, total carotenoids and scavenging activities as well as the shelf life and quality of grapes for 13 days. The coated grapes were also found microbiologically safe for human consumption. OSA modified starch based coating was found to be more effective as compared to native wheat starch. Therefore, this study suggested that the edible coating with good water barrier properties will be beneficial for fruit processors to enhance the shelf-life of fresh produce.

Physicochemical, rheological, morphological and in vitro digestibility properties of pearl millet starch modified at varying levels of acetylation.

Pearl millet (PM) starch was reacted with acetic anhydride at different concentrations (1.25, 2.5, 3.75 & 5.0%) and its physicochemical, rheological, morphological and in vitro digestibility properties were compared with native starch. The acetyl (%) and degree of substitution (DS) of acetylated starches ranged between 1.07 and 2.15% and 0.040-0.081, respectively. Swelling power and solubility of acetylated PM starch increased progressively upto 3.75% level of acetylation, however, further increase in acetylation levels resulted in a decrease. Peak, setback and final viscosities of acetylated PM starches were higher than their native counterpart starch. Both native and acetylated PM starches showed similar A-type X-ray diffraction patterns. During heating, storage modulus (G') and loss modulus (G″) of acetylated starches ranged between 753 and 1177Pa and 96-129Pa, respectively. G' was much higher than G'' at all the values of angular frequency studied. Both native and acetylated PM starch pastes showed flow behaviour index value of <1. For acetylated starches, both, yield stress and consistency index values were higher than native starch. Readily digestible and slowly digestible starch contents of acetylated PM starches varied between 44.3 and 45.5% and 27.3-32.5%, respectively, the highest values observed for starch acetylated at 3.75% and 1.25% acetic anhydride concentrations.