Physicochemical and thermal properties of starches separated from corn produced from crosses of two germ pools

Feasibility of replacing waxy rice with waxy or sweet-waxy corn viewed from the structure and physicochemical properties of starches

To explore the feasibility of substituting waxy rice with waxy or sweet-waxy corn, eight varieties of waxy and sweet-waxy corns were selected, including three self-cultivated varieties (Feng nuo 168, Feng nuo 211, and Feng nuo 10). Their starches were isolated and used as research objects, and commercially available waxy rice starch (CAWR) and waxy corn starch (CAWC) were used as controls. X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, rapid viscosity analyzer, and rotational rheometer were used to analyze their physicochemical and structural characteristics. The morphologies of all corn starch granules were generally oval or round, with significant differences in particle size distributions. All ten starches exhibited a typical A-type crystal structure; however, their relative crystallinity varied from 20.08% to 31.43%. Chain length distribution analysis showed that the A/B ratio of Jing cai tian nuo 18 and Feng nuo 168 was similar to that of CAWR. Peak viscosities of corn starches were higher than that of CAWR, except for Feng nuo 10, while their setback values were lower than that of CAWR. Except for Feng nuo 10, the paste transparency of corn starches was higher than that of CAWR (10.77%), especially for Jing cai tian nuo 18 (up to 24%). In summary, Jing cai tian nuo 18 and Feng nuo 168 are promising candidates to replace CAWR in developing various rice-based products.

Molecular morphology & interactions, functional properties, rheology and in vitro digestibility of ultrasonically modified pearl millet and sorghum starches

The present research investigated to study the effect of ultrasound treatment on isolated pearl millet starch (PMS) and sorghum starch (SS). Ultrasonication was applied to PMS and SS for 10, 15, and 20 min. Ultrasonically modified pearl millet and sorghum starches evaluated for their techno-functionality, pasting profile, morphology, in vitro starch digestibility, XRD, and molecular interactions. Ultrasound treatment increased water and oil absorption capacity, swelling power, and solubility with treatment time. For ultrasonicated PMS and SS, a significant increase (p < 0.05) in paste clarity (PC) (70.05 % and 67.23 %), freeze-thawing stability (FTS), gel consistency (GC) (25.05 mm and 32.95 mm), and in vitro starch digestibility were observed (57.70 g/100 g and 50.29 g/100 g), whereas no significant changes were recorded for the color values after the ultrasound treatment. Variations in pasting property were also observed in ultrasonicated starches with treatment duration. SEM images confirmed ultrasonication mainly forms pores and indentations on starch granule surface. FTIR spectra and X-ray diffractogram for ultrasonicated starches revealed a slight decrease in the peak intensity and A-type X-ray pattern with lower relative crystallinity (RC) than the native starches. G' > G″ value, indicating the elastic behavior and lower tan δ value, depicting viscous behavior and high gel strength.

Plantain based dough meal: nutritional property, antioxidant activity and dyslipidemia ameliorating potential in high-fat induced rats

Background

Dyslipidemia is an aberrant rise in blood lipids due to diet and lifestyle. It has implicated as the major risk factor for developing hypertension among other diseases. This study was designed to evaluate plantain based dough meal nutritional property, antioxidant activity and dyslipidemia ameliorating potential in high-fat induced rats.

Methods

The flour blends, i.e., PSC (Plantain 70%, Soycake 30%), PSR (Plantain 65%, Soycake 30%, Rice-bran 5%), PSO (Plantain 65%, Soycake 30%, Oat-bran 5%), PSRO (Plantain 60%, Soycake 30%, Rice-bran 5%, Oat-bran 5%) and controls (100% Plantain flour & Cerolina) were evaluated for chemical, antioxidants and antihyperlipidemia.

Results

Protein, fiber and energy composition varied from 2.2–4.97 g/100 g, 16.44–19.59 g/100 g and 369.7–385.5 kcal/100 g, respectively. Essential amino acid index and predicted-biological values of the foods ranged from 68.31–76.31% and 62.19–71.48%, respectively. Phenolic profiles (mg/g) were gallic acid (25.33–31.26), caffeic acid (2.75–4.61), ferulic acid (5.16–12.73), luteolin (16.31–23.60), kaempferol (21.51–30.64), quercetin (24.28–37.13), chlorogenic acid (42.25–59.78), myricetin (28.41–38.41), 3,5-dicaffeoylquinic acid (27.17–41.59) and 4, 5-dicaffeoylquinic acid (39.96–51.28). The antioxidant activity of PSRO on ABTS, DPPH, FRAP, Fe2+ chelation and OH free radicals was higher than other foods. Atherogenic index, coronary risk index and log (TG/HDL-conc.) of rats fed on experimental foods were lower than recommended values.

Conclusion

The study established that PSRO had higher antioxidant and anti-hyperlipidemia properties; hence, it may be suitable as a functional food.

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.

Interaction of Squid (Dosidicus giga) Mantle Protein with a Mixtures of Potato and Corn Starch in an Extruded Snack, as Characterized by FTIR and DSC

The majority of snacks expanded by extrusion (SEE) are made with vegetable sources, to improve their nutritional content; it has been proposed to incorporate squid (Dosidicus gigas), due to its high protein content, low price and high availability. However, the interaction of proteins of animal origin with starch during extrusion causes negative effects on the sensory properties of SEE, so it is necessary to know the type of protein-carbohydrate interactions and their effect on these properties. The objective of this research was to study the interaction of proteins and carbohydrates of SEE elaborated with squid mantle, potato and corn. The nutritional composition and protein digestibility were evaluated, Fourier transform infrared (FTIR) and Differential Scanning Calorimetry (DSC) were used to study the formation of protein-starch complexes and the possible regions responsible for their interactions. The SEE had a high protein content (40-85%) and biological value (>93%). The melting temperature (Tm) was found between 145 and 225 °C; the Tm values in extruded samples are directly proportional to the squid content. The extrusion process reduced the amine groups I and II responsible for the protein-protein interaction and increased the O-glucosidic bonds, so these bonds could be responsible for the protein-carbohydrate interactions.

Effects of drying temperature and genotype on morphology and technological, thermal, and pasting properties of corn starch

The objective of this study was to evaluate the effects of drying temperature (30, 50, 70, and 90 °C) and genotype (yellow floury corn, white floury corn, and yellow flint corn) on the morphology and technological and thermal properties of corn starch. The white and yellow genotypes with floury endosperm (soft) had spherical starch granules, while the granules of the yellow flint genotype were polyhedral. White floury corn showed higher extraction yield, higher resistance during granules' swelling before the physical collapse, as it was not affected by the increase in drying temperature, and at 90 °C it presented higher breakdown and energy necessary for gelatinization. There were peak viscosity and gelatinization enthalpy reduction on starch from yellow floury corn and yellow flint corn according to the increase in drying temperature. Drying temperatures below 50 °C are indicated for all genotypes studied. White floury corn is indicated due to the higher extraction yield presented. Yellow floury corn is indicated for application in chilled and frozen products due to lower starch retrogradation. The yellow flint corn is indicated for application as a thickening agent due to higher gel hardness.

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.

Variance of Zein Protein and Starch Granule Morphology between Corn and Steam Flaked Products Determined Starch Ruminal Degradability Through Altering Starch Hydrolyzing Bacteria Attachment

The current study investigated differences of γ-zein protein contents and starch granule characteristics between raw and steam flaked corns and their influences on ruminal starch hydrolyzing bacteria (SHB) attached to corn grain. Two types of raw (Corn1 and Corn2) and their steam-flaked products (SFCorn1 and SFCorn2) were applied to explore physiochemical structures and SHB attachment. SDS-PAGE was conducted to detect γ-zein protein patterns, scanning electron microscope, and small angle X-ray scattering were performed to obtain starch granule morphology, while crystallinity, DQ starch, and DAPI staining were applied to quantify SHB. The steam flaking process destroyed γ-zein proteins and gelatinized starch granules. The median particle size of Corn1 and Corn2 starch granules increased from 17.8 and 18.0 μm to 30.8 and 26.0 μm, but crystallinity decreased from 22.0 and 25.0% to 9.9 and 16.9%, respectively. The percentage of SHB attached to Corn1 residues decreased (p = 0.01) after 4 h incubation, but SHB attached to SFCorn1 residues increased (p = 0.03) after 12 h incubation. Thus, the differences of γ-zein proteins and starch granule physiochemical structures between raw and steam flaked corn played an important role in improving the rate and extent of starch ruminal degradation through altering the process of SHB attached to corn.

Characterization of amylose and amylopectin fractions separated from potato, banana, corn, and cassava starches

Analytical techniques such HPSEC, DSC, and TGA have been employed for amylose determination in starch samples, though spectrophotometry by iodine binding is most commonly used. The vast majority of these techniques require an analytical curve, using amylose and amylopectin standards with physicochemical properties similar to those found in the original starch. The current study aimed to obtain the amylose and amylopectin fractions from potato, banana, corn, and cassava starches, characterize them, and evaluate their behavior via thermogravimetric curves. Blue amylose iodine complex and HPSEC-DRI methods have obtained high purity amylose and amylopectin fractions. All molecular weights of the obtained amylose and amylopectin fractions were similar to those presented in other reports. Different results were obtained by deconvolution of the amylopectin polymodal distribution. All amyloses presented as semi-crystalline V-type polymorphs, while all amylopectin fractions were amorphous. The T_g of all V_amyloses presented were directly proportional to their respective crystalline index. TGA evaluations have shown that selective precipitation of amylose with 1-butanol strongly changes its thermal behavior. Therefore, the separation procedure used was an ineffective pathway for obtaining standards for thermal studies.

Rheological behavior of wheat starch and barley resistant starch (type IV) blends and their starch noodles making potential

Barley starch citrate (BSC), a type IV resistant starch (RS) is associated with numerous health benefits when incorporated in bakery products. Physicochemical, pasting and rheological properties of the wheat starch (WS) and wheat starch-barley starch citrate (WS-BSC) blends and textural and sensorial attributes of wheat starch noodles incorporated with BSC at 10, 20, 30 and 40% were evaluated. As the level of BSC increases, physico-chemical properties were reduced. Except pasting temperature all pasting parameters were decreased as the proportion of BSC increased in WS. All WS-BSC blends possessed decreased viscosity with increasing resistant starch type IV (RS4), which was well described by the Herschel-Bulkley model. As compared to WS, Firmness, springiness, cohesiveness and chewiness of BSC blends gels were decreased by addition of BSC. Study revealed a remarkable decrease in resistance of wheat starch gel by increasing the BCS substitution level. The results concluded the possibility of blending of BSC with WS up to 20% to produce noodles of acceptable quality.

Impact of acid and oxidative modifications, single or dual, of sorghum starch on biodegradable films

The objective of this study was to evaluate the effects of acid and oxidation modifications on sorghum starch, as well as the effect of dual modification of starch on the physical, morphological, mechanical, and barrier properties of biodegradable films. The acid modification was performed with 3% lactic acid and the oxidation was performed with 1.5% active chlorine. For dual modification, the acid modification was performed first, followed by oxidation under the same conditions as above. Both films of the oxidized starches, single and dual, had increased stiffness, providing a higher tensile strength and lower elongation when compared to films based on native and single acid modified starches. However, the dual modification increased the water vapor permeability of the films without changing their solubility. The increase in sorghum starch concentration in the filmogenic solution increased the thickness, water vapor permeability, and elongation of the films.

Polyvinyl alcohol:starch:carboxymethyl cellulose containing sodium montmorillonite clay blends; mechanical properties and biodegradation behavior

The focuses of this study were to investigate the effect of sodium montmorillonite clay (MMT-Na) content on the physical properties and extent of enzymatic hydrolysis Polyvinyl Alcohol (PVA): Starch (S): Carboxymethyl Cellulose (CMC) nanocomposites using enzyme <alpha>−amylase. The results of this work have revealed that films with MMT-Na content at 5 wt% exhibited a significantly reduced rate and extent of starch hydrolysis. The results suggest that this may have been attributed to interactions between PVA:S:CMC and MMT-Na that further prevented enzymatic attack on the remaining starch phases within the blend. The total solids that remained after 4320 min were 65.46 wt% (PVA:S:CMC); 67.91 wt% (PVA:S:CMC:1% MMT-Na); 78.43 wt% (PVA:S:CMC:3% MMT-Na); 80.24 wt% (PVA:S:CMC:5% MMT-Na). The rate of glucose production from each nanocomposite substrates were decresed significantly as the MMT-Na percentage increased from 0 to 5% (W/W). At the level of 5% (W/W) MMT-Na, the films showed the lowest rate of glucose production values (18.95 μg/ml h). With the increase of the MMT concentration from 0 to 5%, the UTS increased 5 from 18.36 to 20.38 MPa, however, the strain to break (SB) decreased noticeably from 35.56 to 5.22%.

Isolation and physicochemical characterisation of starch from cocoyam (Colocasia esculenta) grown in Malawi

BACKGROUND

The aim of this study was to determine the physicochemical properties of starches isolated from Malawian cocoyams and compare them with those of cassava and corn starches.

RESULTS

The purity of the isolated starches varied from 851 to 947 g kg(-1) and pH from 4.93 to 6.95. Moisture, ash, protein, fat and amylose contents ranged from 104 to 132, 0.3 to 1.5, 3.5 to 8.4, 0.9 to 1.6, and 111 to 237 g kg(-1), respectively. Cocoyam starches gave higher potassium and phosphorus but lower calcium levels than the other starches. The shape of starch granules varied from spherical to polygonal with cocoyam starches displaying smaller-sized granules than cassava and corn starches. Cocoyam starches gave a higher wavelength of maximum iodine absorption and blue value but lower reducing capacity values than cassava and corn starches. The extent of acid hydrolysis of the starches also differed. Cocoyam starches exhibited amylopectin molecules of higher molecular weights but amylose molecules of lower molecular weights than cassava and corn starches. Cocoyam starches exhibited lower water absorption capacity and swelling power, paste clarity and viscosity but higher solubility, gelatinisation temperatures and retrogradation tendencies than cassava and corn starches.

CONCLUSIONS

The physicochemical properties of native Malawian cocoyam starches vary among the different accessions and differ from those of cassava and corn starches.