Starch Purity Research Articles

Starch Recovery Process from the Tiger Nut Horchata Processing Waste

AbstractTiger nut horchata solid residue (HSR) has high starch content (about 23%, dry basis) that can be recovered to valorise this waste, together with other valuable components, such as oil, fibres, or phenolic compounds. In this study, a chemical-free, sustainable process was proposed to obtain starch with good yield and purity. This consists of a high-speed homogenisation step with distilled water, followed by filtration and phase separation by density in the slurry to obtain a starch-rich sediment that can be isolated by decantation. Five minutes of homogenisation at 10,200 rpm allows for obtaining 14.5 g of starch powder per 100 g of dried HSR, with a purity of about 85% and WI of 94.97. Applying 1 washing cycle to the filtering residue increased the starch powder yield up to 17 g/100 dried HSR, without notable losses in starch purity, whereas centrifugation at 15,000 g for 1 h in the phase separation step highly reduced separation time, increasing starch purity up to 92%. Thus, it was possible to recover up to 70% of the starch present in the HSR. The obtained starch had similar morphological characteristics, crystallinity degree, and gelatinisation behaviour to that present in the tiger nut tubers, exhibiting similar thermal stability to that reported for other native starches. Therefore, HSR can be used as a starch source for different uses.

From raw microalgae to bioplastics: Conversion of Chlorella vulgaris starch granules into thermoplastic starch

Microalgae are emerging as a promising feedstock for bioplastics, with Chlorella vulgaris yielding significant amounts of starch. This polysaccharide is convertible into thermoplastic starch (TPS), a biodegradable plastic of industrial relevance. In this study, we developed a pilot-scale protocol for extracting and purifying starch from 430 g (dry weight – DW) of starch-enriched Chlorella vulgaris biomass. More than 200 gDW of starch were recovered, with an extraction yield and starch purity degree reaching 98 and 87 %, respectively. We have characterized this extracted starch and processed it into TPS using twin-screw extrusion and injection molding. Microalgal starch showed similar properties to those of native plant starch, but with smaller granules. We compared the mechanical properties of microalgal TPS with two controls, namely a commercial TPS and a TPS prepared from commercial potato starch granules. TPS prepared from microalgal starch showed a softer and more ductile behavior compared to the reference materials. This study demonstrates the feasibility of recovering high-purity microalgal starch at pilot scale with high yields, and highlights the potential of microalgal starch for the production of TPS using industrially relevant processes.

Effect of oil-droplet and powder size on the retention of allyl sulfide in spray-dried powder using modified starch as emulsifier

In food products, the encapsulation of flavor in a solid matrix is an important process to overcome the limited properties of flavors, and control flavor release. In this study, allyl sulfide (AS) was encapsulated by spray drying using the modified starch Purity Gum 1773 (PG), an octenylsuccinic acid-modified starch (OSA) as an emulsifier and as a part of wall material. The properties of flavor retention and stability after storage were investigated. PG was more effective in forming emulsified AS spray-dried powder than sodium caseinate. A 94% AS retention rate after spray drying was achieved with 12 wt% PG at 50 wt% solid content. Larger oil droplets and larger particle diameters of spray-dried powder exhibited higher retention of AS under the specified storage conditions.

Physicochemical, structure and functional characteristics of Tacca leontopetaloides starches grown in Indonesia

Abstract. Yonata D, Triwitono P, Lestari LA, Pranoto Y. 2023. Physicochemical, structure and functional characteristics of Tacca leontopetaloides starches grown in Indonesia. Biodiversitas 24: 6396-6406. Understanding the physicochemical, structure and functional characteristics of tacca tuber (Tacca leontopetaloides) starch is crucial as a scientific basis for its development, especially in the food industry. Despite the abundance of starch in Indonesian tacca tubers, its potential remains largely untapped. This research aims to determine the physicochemical, structure and functional characteristics of tacca tuber starch from three different regions in Indonesia: Bangkalan, Garut and Sumenep. Wet extraction yielded tacca tuber starch with yields ranging from 21.26 to 26.42%. Significant differences (p<0.05) were observed in proximate composition (ash, lipid, and protein), starch purity (97.35-98.48%), amylose content (32.81-35.26%), and functional properties like swelling power (9.67-10.51 g/g at 95°C), solubility (4.93-5.87% at 95°C), water holding capacity (0.77-0.90 g/g), oil holding capacity (0.62-0.71 g/g), and relative crystallinity (24.22-27.03%). Thermal properties and pasting properties (except breakdown viscosity) exhibited significant variations. The gelatinization temperature profile of tacca tuber starch ranged from 57.92 to 76.38°C, with an ?H value of around 3.81-4.62 J/g. Meanwhile, the temperature of tacca tuber starch paste ranged from 72.12 to 72.88°C. Tacca tuber starch granules are polygonal, elliptical, oval to slightly ellipsoidal, with an average granule diameter of 20.21-40.43 ?m. Based on the X-ray diffraction pattern, tacca tuber starch shows the CA-type, containing orthorhombic and hexagonal structure crystals. Tacca tuber starch has a high lightness (92.01-93.62) and whiteness index (91.68-92.74). In conclusion, the cultivation location significantly influences the physicochemical, structural, and functional characteristics of tacca tuber starch.

Relationship between in vitro digestibility and multi-structures of four unconventional starches from Chinese tropical fruits (sweetsop, avocado, chempedak, and Pouteria campechiana) extracted using an ultrasound method

The development of unconventional starch resources has gained interest in recent years. Herein, we comprehensively characterize avocado seed (ASS), chempedak seed (CPSS), Pouteria campechiana seed (PCSS), and sweetsop pulp (STS) starches extracted using a high-intensity ultrasound method. High starch yields (≥ 23.14 %) and starch purity (≥ 99.17 %) were observed for all samples. ASS, CPSS, and PCSS had an A-type crystal structure, while STS showed a B-type crystal structure. ASS showed the highest weight-average molecular weight, long chain content, average polymerization degree, conformation index, molecular density index, α-1,4-glycosidic bond content, double helix content, amylose content, relative crystallinity, semi-crystalline order, and V-type polymorph content while also exhibiting the lowest radius of gyration and fractal dimension. Consequently, ASS featured a smaller blocklet size than that of CPSS and STS, implying a higher ability of re-association of ASS molecular chains during retrogradation. This resulted in that ASS exhibited a lower breakdown viscosity, higher pasting temperature, and a greater final viscosity than those of CPSS and STS, thereby featuring the lowest contents of rapidly digestible starch (RDS: 1.86%) and slowly digestible starch (SDS: 12.99 %), decreased equilibrium concentration (C∞: 28.48 %), reduced SDS enzymolysis rate (kSDS: 0.48 × 10−2 min−1), and highest resistant starch content (RS) than the others samples. Moreover, compared with STS (11.44 %, 24.63 %, 1.43 × 10−2 min−1, 48.34 %, and 63.93 %), CPSS and PCSS had lower RDS (6.18–7.39 %), SDS (19.68–22.77%), kSDS (0.73–1.16 × 10−2 min−1), and C∞ (35.61–44.22%), while showing higher RS (69.84–74.14 %). These results suggest that STS is a high-GI food, whereas ASS, PCSS, and CPSS are middle-GI foods. Based on statistical analysis, all these results indicated that the lamellar structure ordering, molecular network density, and crystallite size have a significantly negative effect on in vitro digestibility. Therefore, our study provides a theoretical basis for processing unconventional starch-based products.

Pasting and rheological properties of water caltrop starch as affected by the addition of konjac glucomannan, guar gum and xanthan gum

Water caltrop starch (WCS) isolated from the dehydrated water caltrop (DWCS) showed higher content of protein and ash as compared to starch isolated from fresh water caltrop (FWCS), leading to slightly lower starch purity. However, the pasting profiles of DWCS and FWCS are similar under a constant solid content of 4% (w/w). WCS/gum mixed systems contain 0.3%–0.9% gum generally showed higher pasting temperature, peak viscosity, and final viscosity than the starch alone system. The increase in peak and final viscosity during rapid-viscosity analysis was most pronounced for WCS/gum mixed systems with konjac glucomannan (KG), followed by guar gum (GG) and xanthan gum (XG). All WCS/gum mixed systems showed shear thinning and thixotropic characteristics. The extent of pseudoplasticity and shear stability, as evidenced by the smaller flow behavior index (n) and area of the hysteresis loop, was most pronounced for WCS/gum mixed system with XG, followed by mixed systems with GG and KG. Dynamic viscoelastic analysis revealed that the addition of gum increased both the storage and loss moduli of WCS, and lowered the frequency dependence of the loss factor significantly. However, the loss factor of WCS/gum mixed systems was generally higher than that of the starch alone system, implying the addition of gums modified the rheological characteristic of WCS to more viscous dominant behavior.

Morphological, physiochemical and colour characteristics of fresh and cured starch in potato varieties

The present study was conducted to study the morphological, physicochemical and colour characteristics of potato starch extracted by control and combined methods from potato varieties viz., Kufri Chipsona-4, Badshah, Pushkar, Bahar and Sindhuri (fresh and cured). Among these varieties, Kufri Chipsona-4 exhibited maximum percent of small size (< 30 μm) particles (48%). Kufri Sindhuri showed highest starch purity (87.1%) but lowest whiteness (92.2%) whereas, highest whiteness (95.4%) was recorded in starch extracted from Kufri Badshah. Among starch extraction methods, combined method showed significantly lower starch moisture content (11.8%), fat (0.28%), protein (0.31%), ash (0.28%) and crude fibre (0.15%) whereas; starch purity (87.2%), percentage of small size particles (45%) and starch whiteness (96.3%) were observed higher than control methods in all varieties.

Rapid Ultrasound-Assisted Starch Extraction from Sago Pith Waste (SPW) for the Fabrication of Sustainable Bioplastic Film.

The present study was conducted to optimize the extraction yield of starch from sago (Metroxylon sagu) pith waste (SPW) with the assistance of ultrasound ensued by the transformation of extracted starch into a higher value-added bioplastic film. Sago starch with extraction yield of 71.4% was successfully obtained using the ultrasound-assisted extraction, with the following conditions: particle size <250 µm, solid loading of 10 wt.%, ultrasonic amplitude of 70% and duty cycle of 83% in 5 min. The rapid ultrasound approach was proven to be more effective than the conventional extraction with 60.9% extraction yield in 30 min. Ultrasound-extracted starch was found to exhibit higher starch purity than the control starch as indicated by the presence of lower protein and ash contents. The starch granules were found to have irregular and disrupted surfaces after ultrasonication. The disrupted starch granules reduced the particle size and increased the swelling power of starch which was beneficial in producing a film-forming solution. The ultrasound-extracted sago starch was subsequently used to prepare a bioplastic film via solution casting method. A brownish bioplastic film with tensile strength of 0.9 ± 0.1 MPa, Young’s modulus of 22 ± 0.8 MPa, elongation at break of 13.6 ± 2.0% and water vapour permeability (WVP) of 1.11 ± 0.1 × 10−8 g m−1 s−1 Pa−1 was obtained, suggesting its feasibility as bioplastic material. These findings provide a means of utilization for SPW which is in line with the contemporary trend towards greener and sustainable products and processes.

Standardization of process protocol for isolation of starch from mango kernel and its characterization.

The major by-products of mango processing are the seeds, which represent approximately 15-20% of the fruit. The process protocol for isolation of starch from mango kernel was standardized based on starch yield, starch purity and colour values using centrifugation and chemical method. Optimized starches obtained from both methods were further investigated for estimation of functional properties and were characterized through Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, differential scanning calorimetry and pasting properties analysis. The slurry making of mango kernels with a solid-to-water ratio of 1:3 at a centrifugation frequency of 3 times was found to be the best among all the experimental combinations (solid-to-water proportion (1:2, 1:3 and 1:4,w/v) and centrifugation frequency (2, 3 and 4 times)) with a starch yield of 48.43 ± 1.08% and purity of 76.46 ± 0.83%. In the chemical method of starch isolation (washing was done with 0.1mol L-1 NaOH and 0.1mol L-1 HCl at three levels each), the sample treated with 60% (w/v) 0.1mol L-1 NaOH and 10% (w/v) 0.1mol L-1 HCl resulted in 36.50 ± 0.58% starch yield with a purity of 92.03 ± 0.87%. Among the functional properties, the chemically isolated starch showed significantly higher paste clarity (45.79 ± 2.36%) than starch obtained using the centrifugation process (12.50 ± 1.57%). The chemically isolated starch also exhibited better colour attributes, which were very close to those of laboratory-grade starch. Detailed characterization studies inferred that both the starches possessed good functional, structural and thermal properties, indicating suitability for food and non-food applications. © 2021 Society of Chemical Industry.

Physical, chemical and rheological properties of pitomba (Talisia esculenta) seed starch and its application as a thickener and stabilizer in ketchup

The present study aimed to characterize the physical, chemical and rheological properties of starch extracted from pitomba seeds and verify the influence of its addition on the syneresis and viscosity characteristics of ketchup during storage, compared to maize starch. Extraction was performed by grinding the seeds in sodium metabisulfite solution (0.2%) followed by drying at 50 ºC. ketchups were formulated with the addition of 0.5 and 1% pitomba starch, 0.5 and 1% maize starch and a control formulation. Starch showed low percentages of protein, ashes and lipid, starch purity of 77.78%, amylose of 19.25%, apparent density of 0.46 g/cm3 and compact density of 0.66 g/cm3. The starch pastes showed pseudoplastic behavior and imparted significant viscosity, usable in increasing the consistency of fluid foods. Ketchups formulated with addition of pitomba starch showed reduction of syneresis during storage, and the 1% starch concentration can slow down the syneresis process in ketchup at temperatures of 7 and 25 °C, similar to the stabilizing capacity of maize starch. Ketchup viscosity increased with the addition of pitomba and maize starches, but the highest apparent viscosities were obtained in ketchup with addition of pitomba starch during storage

A new method to isolate and separate small and large starch granules from barley and malt

Large lenticular and small spherical starch granules are present in small grains in varying quantities and have different characteristics, affecting how the cereals perform during processing. Separation and isolation of these granules for characterisation is challenging, especially for germinating or malted cereals, because the latter can contain up to a 1000-fold higher α-amylase activity. In this work, a new but simple method is described to isolate starch from barley and malt and separate it in small and large starch granules while avoiding α-amylase activity. A protease treatment at pH 8.0 in the presence of 0.1 M EDTA is used to degrade the protein matrix around the starch granules in an aqueous cereal suspension. After sieving over a 38 μm sieve, highly pure (90.2–95.1 dm%) starch is obtained. Next, sequential sieving over 10 μm and 5 μm sieves results in isolated large and small starch granule fractions with a respective starch purity of 89.8%–93.8% and 76.8%–86.2% and a volume-based granule-type purity higher than 92.9%. Residual EDTA concentration and α-amylase activity in the isolated starch fractions are reduced to a minimum, preventing their interference during the further determination of the starch properties.

Physicochemical, morphological, functional, and pasting properties of potato starch as a function of extraction methods

The potato starch extracted by physical, chemical, and enzymatic methods were analyzed for physicochemical, morphological, functional, and pasting properties. In the physical extraction methods, T1 (water at 30 °C) was found better in starch yield, water absorption capacity (WAC), and whiteness. In the chemical extraction methods, starch from T5 (NaOH-0.25%) had higher WAC, and lower ash content. The starch from T7 (SDS-ME-2%) had higher amylose, starch purity, and lower amylopectin, moisture, fat content. The starch from T11 (NaOCl-5.25%) had higher starch whiteness value. In the enzymatic extraction methods, starch from T13 (cellulase-0.15%) had higher starch yield. Further, the physical (T1), chemical (T5, T7 and T11) and enzymatic (T13) methods were used in combination and had shown the better physicochemical and morphological characteristics of starch. The starch from combined method (T14) had significantly higher yield (12.4%), WAC (259%), swelling power (40.3%), solubility (23.6%), purity (87.3%), and whiteness (95.2%). The starch from combined method also had significantly lower phosphorus (81.7%), protein (0.30%), fat (0.29%), ash (0.26%), crude fiber (0.15%) content, and syneresis (18.8%). The starch from combined method had resulted in the better starch granule structure, pasting properties than most of the other treatments. So, the physical, chemical, and enzymatic treatments in combination can be used for extraction of high-quality starch from potato.

Isolation and characterization of starch from light yellow, orange, and purple sweet potatoes

Sweet potato is attracting increased research attention because of its high nutritional value (e.g., carotene, anthocyanin, and minerals) and the wide application of its starch in foods and nonfoods. Herein, eight Chinese sweet potato varieties were investigated in terms of the physicochemical properties of starches. The lightness values of the eight sweet potato starches were higher than 90, which was satisfactory for starch purity. The average molecular weight (MW) and amylopectin average chain length (ACL) of sweet potato starches ranged from 6.93 × 107 g/mol to 16.57 × 107 g/mol and from 21.85% to 23.00%, respectively. Su16 starch with low amylose content and a large amount of short chains exhibited low crystallinity and thermal properties. These results suggested that the molecular structure of amylose and amylopectin was the main influencing factor in determining sweet potato starch physicochemical properties. The swelling power and water solubility of the starches ranged within 20.14–30.51 g/g and 5.28%–11.71% at 95 °C, respectively. Regarding pasting properties, all the starch samples presented high peak viscosity (>5500 cP) and peak temperature (>78 °C), indicating that sweet potato starch can be used as a thickener. All eight sweet potatoes varieties showed great application potential in the food industry.

Physico-chemical Properties of Starches from Two Varieties of Sweet Potato and Yam Tubers Available in Nigeria

The research sought to investigate the functional properties of starches obtained from four Nigerian root and tubers, yam and sweet potato varieties, in order to facilitate their exploitation as substitute raw material for the local food and pharmaceutical manufacturing industry. The varieties, namely: white yam (Dioscorea rotundata), water yam (Dioscorea alorta), orange flesh sweet potato (Ipomoea batatas) and cream flesh sweet potato (Ipomoea batatas), their respective starches were obtained by wet separation techniques and were analyzed for their pasting properties, physic-chemical properties, starch yield on dry and wet basis, functional, starch purity, amylase and amylo-pectin were undertaken in order to determine their suitability for food and other uses. The peak time, pasting temperature, peak viscosity, holding strength, breakdown, set from peak and set back from through ranged from 7.3 – 8.3 mins, 65.4 – 71.3°C, 511.5 – 1001.2 BU, 860.8 – 871.3 BU, 300.1 – 306.9 BU, 240.8 – 248.1 BU and 400.4 – 510.9 BU respectively. There were significant differences (p&lt;0.05) in the pasting properties. The crude protein, crude fat, crude fibre, ash, moisture and carbohydrate ranged from 1.55 – 1.85%, 0.09 – 0.12%, 0.12 – 0.22%, 1.32 – 2.05%, 10.72 – 11.09% and 85.59 – 86.20% respectively. There were significant differences (p&lt;0.05) in the proximate composition of the starches. The starch yield on dry weight basis, starch weight on fresh weight basis, starch yield from tubers and percentage dry matter ranged from 56.84 – 85.88%, 22.75 – 36.07%, 18.02 – 26.00% and 40.02 – 44.01% respectively. There were significant differences (p&lt;0.05) in the all the parameters. The bulk density, water absorption capacity, oil absorption capacity, gelatinization temperature, starch purity, amylase, amylo-pectin and pH ranged from 0.56 – 0.61g/cm3, 86.8 – 99.4%, 103.2 – 125.4%, 59.78 – 60.42°C, 95.28 – 96.55%, 27.25 – 29.37%, 70.63 – 72.63% and 6.82 – 6.91 respectively. There were significant differences (p&lt;0.05) in all the parameters but no significant difference (p&gt;0.05) in the pH. The starches from yam and sweet potato varieties starches can be exploited for diverse uses based on their different characteristics.

Technological Properties of Beef Emulsions Prepared with a Novel Processed Potato Ingredient (O’Brien’s Best)

ObjectivesThe processed potato ingredient tested in this study was a commercially available ingredient (O’Brien’s Best; Botaniline Foods, LLC) that consists of skinned, sliced potatoes that were cooked to an exact time/temperature to enhance physiochemical properties. The objective of the study was to assess the technological properties of beef emulsion modeling systems prepared with the novel processed potato ingredient (O’Brien’s Best).Materials and MethodsThe meat used in this study was lean ground beef from one master batch of beef that was targeted to 90% lean and 10% fat. The meat batter formulations contained 20% water, 6.15% spice/seasoning, 0.18% Prague powder, and 0.0035% sodium erythorbate, and varying quantities of sodium tri-polyphosphate, salt (NaCl), and binders (processed potato, tapioca starch, or all-purpose binder). In total, eight treatments were formulated and manufactured on three separate, independent occasions (N = 24 experimental units; n = 3 replications). Three treatments were formulated with the novel processed potato ingredient (formulated without phosphate, 0.635% NaCl, and either 5, 10, or 15% the processed potato ingredient). Three treatments were formulated with commercially sourced tapioca starch (formulated without phosphate, 0.635% NaCl, and either 5, 10, or 15% commercial tapioca starch, which was tested to be 78% starch purity). Two treatments were formulated with a commercial formulation [formulated with 0.30% sodium tri-polyphosphate, 10% all-purpose binder (a multi-ingredient proprietary blend binder from Herman Laue Spice Company Inc.; Uxbridge, Ontario), and 1.905% NaCl, or 1.270% NaCl]. Parameters tested were cooking loss, proximate composition of cooked meat batters, texture profile analysis of cooked meat batters, and instrumental color of uncooked and cooked meat batters. Data were analyzed with the GLIMMIX procedure of SAS v9.4 with a fixed effect of treatment and a random effect of replication. Least square means were separated using the PDIFF option with a Tukey-Kramer adjustment. Differences were considered statistically different at P &lt; 0.05.ResultsCooking loss was not different (P = 0.44) among treatments and ranged from 0.64% to 0.77%, indicating acceptable stability for all emulsion formulations in the study. Proximate composition revealed significant differences (P &lt; 0.05) in moisture, protein, ash, and other components (carbohydrates), while lipid content was unaffected. Texture profile analysis revealed that textural properties were generally unaffected (P &gt; 0.05) by treatment, with the exception of less gumminess (P &lt; 0.05) and less chewiness (P &lt; 0.05) in processed potato formulated emulsions compared with the tapioca starch and commercially formulated emulsions. Instrumental color of uncooked emulsions was affected to a greater degree than instrumental color of cooked emulsions. Yet, when tapioca starch was included at high levels (&gt; 10%) in cooked emulsions lightness (L*) and yellowness (b*) were greater (P &lt; 0.05) compared with emulsions formulated with the processed potato ingredient and with the commercial formulations.ConclusionIn summary, the technological properties (cooking loss, texture profile analysis, and instrumental color) of beef emulsion systems were largely unaffected by the processed potato ingredient (despite removal of phosphates and less NaCl) and performed similar to the commercial formulations.

Physicochemical, pasting, crystallinity, and morphological properties of starches isolated from maize kernels exhibiting different types of defects

The present study aims to evaluate the physicochemical, rheological, and safety properties of starches isolated from maize kernels with different types of defects. Starch isolation showed to be a valuable alternative to defective yellow maize kernels, since the presence of the evaluated kernel defects (broken, fermented, rotten, moldy, germinated, insect-damaged, and shrunken and immature kernels) did not provide significant changes on starch purity and colour. Only starch isolated from shrunken and immature kernels exhibited reduced extractability. Starch obtained from germinated kernels exhibited the greatest solubility. While flour from moldy kernels showed 7.5 ppb of aflatoxin A1, 25.0 ppb of aflatoxin A2, and 1229.4 ppb of fumonisin B1, any of these mycotoxins were detected in isolated starch. In sum, minor changes in pasting, thermal, crystallinity, and morphological properties of the isolated starches from defective kernels were determined, which does not impair its use in industrial processes.

Starch extraction potential from plantain peel wastes

The experimental conditions that increase the starch production yield from plantain peel wastes are evaluated in this research in order to determine how the extraction parameters, antioxidant concentration and immersion time, affect the starch production yield and purity. The most favorable conditions are selected after two-way ANOVA statistical analysis.The wet extraction method is used for starch extraction from Green plantain (Musa paradisiaca) peels. Balanced 4×4 factorial design was used for experimental design, with 4 ascorbic acid concentration levels, 4 immersion time levels, and 3 independent replications. The results were later analyzed with PAST v3.14 software for statistical evaluation.Moisture content in plantain peels was an average 87.16%. The starch yield varied from 3.25 to 9.49g starch (average 5.7g) obtained from the original 150g wet plantain peel samples, representing yields varying from 16.6 to 48.5% (average 29%) from dry mass. Higher starch yields are obtained with higher antioxidant concentrations, while immersion time has no-significant effect on the final yield. The starch purity degree varied from 57.52%±0.48% to 69.9%±0.76%.Starch extraction from plantain peel wastes has proven potential for waste use and obtaining value-added products. Average starch yield was 29% (from dry mass), while purity reached almost 70%. Two-way ANOVA analysis reflects the ascorbic acid concentration effect on starch yield while it demonstrates that there is no significant interaction between ascorbic acid concentration and immersion time.

Compositional, morphological, structural and physicochemical properties of starches from seven naked barley cultivars grown in China

Starches from seven naked barley cultivars in China were isolated and investigated for their compositional, structural and physicochemical properties. The range of starch purity, lipid, protein, amylose and amylopectin contents and the amylose/amylopectin ratio for different varieties were 90.58% to 97.95%, 0.01% to 0.02%, 0.31% to 0.45%, 22.72% to 27.49%, 65.89% to 72.64% and 0.31 to 0.39, respectively. The starches from all naked barley cultivars exhibited A-type crystalline packing arrangements and similar granule shapes. The rapid visco analyzer (RVA) results showed the peak viscosity, trough viscosity, breakdown, final viscosity, setback, peak time and pasting temperature of starches ranged from 2977 to 3641cP, 2253 to 2844cP, 474 to 876cP, 3094 to 4320cP, and 729 to 1476cP, 5.53 to 6.80min and 50.25 to 84.35°C, respectively. The transition temperatures (To, Tp and Tc), gelatinization temperature range (ΔTr) and enthalpies of gelatinization (ΔH) measured using a differential scanning calorimeter analyzer (DSC) ranged from 54.07 to 58.47°C, 57.51 to 61.54°C, 65.49 to 72.74°C, and 10.46 to 16.58°C and 7.74 to 9.82J/g, respectively. The various structural and physicochemical properties demonstrated by naked barley starch suggest their broader potential applications of this novel cereal.

Effect of steeping additives on tef starch extraction and its quality

AbstractTef is an indigenous African cereal and considered as lost crop of Africa. There is no research on the effect of steeping additives on the quality of isolated tef starch. A white tef grain was milled and steeped in distilled water, sodium hydroxide, lactic acid, metabisulfite, and a combination of lactic acid and metabisulfite. A combination of metabisulfite and lactic acid improves the starch yield, but steeping with sodium hydroxide produces the highest starch purity (lowest protein content). Both the Rapid Visco Analyzer and a Rheometer showed similar pasting properties of starches independent of the treatment. The different steeping additives showed differences in pasting properties. Sodium hydroxide showed the highest peak, breakdown and set back viscosity compared to the other steeping additives. Extracted tef starches using sodium hydroxide as steeping additives also showed higher gelatinization temperatures. According to principle component analysis (PCA), the different properties of tef starch extracted with sodium hydroxide steeping is apparently due to its lower protein content. SEM and CLSM indicated that sodium hydroxide is a very effective solvent to solubilize the protein matrix surrounding the compound starch granule to produce more single starch granule during extraction. The low protein content probably result in faster water absorption and higher peak viscosity and lower pasting temperature. Different steeping additives can affect the functionality of tef starches and this need to be considered when comparing properties of starches extracted with different additives.

Kinetic study of enzymatic hydrolysis of starch isolated from sorghum grain cultivars by various methods

Sorghum (Sorghum bicolor (L.) Moench) crops as a source of starch was successfully cultivated in the Algerian Sahara. Starches from white and red sorghum grains were isolated under three steeping conditions for wet-milling process. The isolate starches susceptibility towards glucoamylase hydrolysis to glucose and the kinetic parameters (Km, Vmax, Kcat and Kcat/Km) are studied. The yield of starch isolation ranged from 40.37 to 54.79 %. The starch purity, amylose content, swelling power and water solubility index ranged from 90.00 to 99.08 %, 23.78 to 25.89 %, 10.37 to 12.47 g/g and 10.65 to 18.80 %, respectively. The values of Vmax in g.l−1.min−1 for starch isolated by three methods are 0.20, 0.09 and 0.058 for white grains and 0.10, 0.08 and 0.20 for red grains. The glucose concentration values in g.l−1 after 120 min of hydrolysis at the initial concentration of 20 g.l−1 of starch isolated by three methods are 13, 10.20 and 7.80 for white grains and 10, 13.80 and 11 for red ones. The results of kinetic study show that the hydrolysis of starch by glucoamylase from Aspergillus niger are affected by the source of starch and the conditions of starch isolation from grains.