Effect of seed treatments on the chemical composition of two amaranth species: oil,sugars, fibres,minerals and vitamins

The effects of seed treatments, including cooking, popping, germination and flour air classification on several components of Amaranthus caudatus and A. cruentus seeds, including oil, sugars, fibre, minerals and vitamins were studied. The lipid, crude and dietary fibre, ash, and sugar contents were 71, 43, 140, 30 and 18 g kg^?1 in raw A. caudatus and 85, 39, 134, 40 and 22 g kg^?1 in raw A. cruentus seeds, respectively. Sucrose was the dominant sugar in the raw and thermal treated seeds of both species, while glucose and galactose were the dominant ones in the high protein and the germinated seed flours. Phosphorus, potassium, magnesium and calcium were the dominant minerals in the raw seeds of both species. Air classification increased the content of minerals by more than 35% while thermal treatments did not affect their content and germination increased the calcium and zinc contents. The ascorbic acid contents were 0.030 and 0.023 g kg^?1 sample in raw A. caudatus and A. cruentus seeds, respectively. All the treatments reduced the ascorbic acid content, with a high effect for the air classification and the germinated seeds dried at 90 °C. The levels of vitamin B complex, including niacin, niacinamide, pyridoxine and riboflavin were increased in the high protein flour fraction (protein contents of these fractions of A. caudatus and A. cruentus were 263.9 g kg^?1 and 246.6 g kg^?1, respectively) and decreased in the thermal treated flours. Germination mostly increased the amounts of those vitamins while drying reduced their amounts. Copyright © 2005 Society of Chemical Industry     

Potential of Amaranthus cruentus BRS Alegria in the production of flour,starch and protein concentrate: chemical,thermal and rheological characterization

BACKGROUND: Amaranth is a little‐known culture in Brazilian agriculture. Amaranthus cruentus BRS Alegria was the first cultivar recommended by Embrapa for the soil of the Brazilian scrubland. In order to evaluate the potential of this species in the production of flour, starch and protein concentrates, the latter products were obtained from A. cruentus BRS Alegria seeds, characterized and compared with the products obtained from the A. caudatus species cultivated in its soil of origin. RESULTS: The seeds of A. cruentus BRS Alegria furnished high‐purity starch and flour with significant content of starch, proteins, and lipids. The starch and flour of this species presented higher gelatinization temperatures and formed stronger gels upon cooling compared with those obtained from the A. caudatus species. This is due to their greater amylose content and a difference in the composition of the more important fatty acids, such as stearic, oleic and linoleic acids, which indicates that they have greater heat stability. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis and differential scanning calorimetry revealed the presence of albumins, globulins, glutelins and prolamins in the protein concentrate, which was obtained as a byproduct of starch production. CONCLUSION: Amaranthus cruentus BRS Alegria has potential application in the production of flour, starch and protein concentrates, with interesting characteristics for use as food ingredients. Copyright © 2010 Society of Chemical Industry     

Seed treatments affect functional and antinutritional properties of amaranth flours

The effects of seed treatments, including cooking, popping germination and flour air classification, on the functional properties and antinutritional factors of Amaranthus caudatus and Amaranthus cruentus seeds were studied. Thermal treatments increased the water absorption with a maximum value of 5.1 and 6.3 g g⁻¹ in flour of popped seeds of both species. Generally, fat absorption increased after the treatments. Air classification and germination followed by drying at low temperature increased the foam stability of the flours, while thermal treatment and germination followed by drying at higher temperatures reduced the foam stability. All treatments except air classification decreased the emulsion stability. Also, all treatments except germination followed by drying at 30 °C increased the flour dispersibility, whereas the soluble nitrogen index was increased in the germinated seed flours and decreased in thermal treated seeds and air‐classified flours. Air classification increased the contents of phenolic compounds and phytate and decreased the contents of enzyme inhibitors, whereas the thermal treatments reduced the contents of phenolic compounds, phytate and enzyme inhibitors to a greater extent for cooking than for popping. Germination followed by drying reduced the level of phenolic compounds, phytate and enzyme inhibitors. Copyright © 2006 Society of Chemical Industry     

In vitro starch digestibility,expected glycemic index,and thermal and pasting properties of flours from pea,lentil and chickpea cultivars

In vitro starch digestibility, expected glycemic index (eGI), and thermal and pasting properties of flours from pea, lentil and chickpea grown in Canada under identical environmental conditions were investigated. The protein content and gelatinization transition temperatures of lentil flour were higher than those of pea and chickpea flours. Chickpea flour showed a lower amylose content (10.8–13.5%) but higher free lipid content (6.5–7.1%) and amylose–lipid complex melting enthalpy (0.7–0.8 J/g). Significant differences among cultivars within the same species were observed with respect to swelling power, gelatinization properties, pasting properties and in vitro starch digestibility, especially chickpea flour from desi (Myles) and kabuli type (FLIP 97-101C and 97-Indian2-11). Lentil flour was hydrolyzed more slowly and to a lesser extent than pea and chickpea flours. The amount of slowly digestible starch (SDS) in chickpea flour was the highest among the pulse flours, but the resistant starch (RS) content was the lowest. The eGI of lentil flour was the lowest among the pulse flours.     

The effects of natural fermentation on the physical properties of rice flour and the rheological characteristics of rice noodles

The effects of fermentation of whole polished rice grains on the physical properties of rice flour and the rheological characteristics of rice noodles were investigated. Natural fermentation had little effect on the crystalline structure of rice starch, as measured by X‐ray diffraction, but the ratio of the crystalline to the amorphous regions increased. The thermal properties of rice flours were determined using differential scanning calorimetry and a rapid viscosity analyser (RVA). The gelatinization temperature, T_p, and the RVA peak viscosity of rice flour decreased, while the gelatinization enthalpy, ΔH, increased after fermentation. The FTIR spectra of fermented and control rice flours were similar. Fermented rice starch granules had slight superficial corrosion when examined using scanning electron microscopy. Fermentation may thus change the amorphous region of the starch granule as well as the chemical components and thereby modify both physical properties of rice flour and rheological characteristics of rice noodles.     

Nutritional study of raw and popped seed proteins of Amaranthus caudatus L and Amaranthuscruentus L

The nutritional value of raw and popped (similar to popcorn preparation) seed proteins of two amaranth species, Amaranthus caudatus L and A cruentus L, was investigated. After popping, the true protein content in A caudatus and A cruentus decreased by 9 and 13% respectively. Among the amino acids, the loss of tyrosine due to the popping effect was the highest, followed by phenylalanine and methionine. Leucine was the first limiting amino acid in the raw samples, followed by lysine, while the reverse order was observed in the popped samples. The in vivo protein quality of raw and popped seeds was tested with male weanling rats and compared with wheat flour and casein samples. There was no difference between the in vivo digestibility of the raw and the popped seeds, although the in vitro digestibility was slightly higher for the popped samples. The protein efficiency ratio (PER) for all the amaranth seed samples was higher than that for the wheat sample, while the PER for the raw amaranth seed samples was close to that for the casein reference protein. The rat blood serum levels of total cholesterol, triglycerides and high‐density lipoprotein cholesterol for all the amaranth samples were lower than those for the reference protein, while the wheat flour sample showed the lowest values. Copyright © 2004 Society of Chemical Industry     

Amaranth starch-rich fraction properties modified by high-temperature heating

The effect of high-temperature fluidized-bed heating on some properties of an amaranth high-starch fraction obtained from Amaranthus cruentus grains was evaluated. A two-factor at three levels factorial experimental design (3²) was adopted, one factor being the heating temperature (190, 200 and 210 °C) and the other, the moisture content of the high-starch fraction (12%, 16% and 20% wet basis). The effects on the responses water solubility, swelling power, amylographic and dynamic responses, crystallinity degree and gelatinization enthalpy were established by using response surface methodology. A partial loss of starch crystalline structure was observed but most of their granular integrity was preserved. As temperature and moisture increased, loss of crystalline structure and degree of gelatinization also increased. The obtained amaranth high-starch flours were of a solid character at low temperature, with high consistency when cooked and low water solubility, which make them suitable for industrial applications.     

Effect of processing and storage time on in vitro digestibility and resistant starch content of two bean (Phaseolus vulgaris L) varieties

Seeds from two commercial bean varieties were cooked and stored for different times and analysed for chemical composition and in vitro starch digestibility. Parallel portions of cooked seeds were dried at 55 °C, milled and stored as flours. In general, protein and ash contents in both samples did not change with storage time, but statistical differences were shown between the two varieties (p < 0.05). Available starch (AS) contents in flours from the ‘negro’ variety did not change (p < 0.05) with storage time and, in general, were higher than in ‘flor de mayo’ samples, whose AS levels decreased during storage. The lower AS in ‘flor de mayo’ flour could be the consequence of formation of resistant starch due to retrogradation. Samples of whole ‘negro’ seeds did not show differences in AS content at 0, 24 and 48 h of storage compared with the corresponding flours, but at 72 and 96 h the AS increased in the whole samples. ‘Flor de mayo’ showed a similar pattern in flour and whole samples, with slightly higher values in the whole seeds. In general, total resistant starch (RS) content in the two varieties was higher in the flours than in ‘whole’ seeds, a fact that is not easy to explain at present. ‘Negro’ flour presented an RS content around 65.0 g kg^?1, and approximately 55.0 g kg^?1 was recorded in ‘flor de mayo’, with slight changes when storage time increased. Whole ‘flor de mayo’ showed significant levels of the retrograded portion of resistant starch (RRS), which did not change with storage time (p < 0.05). However, values were lower than in the flours. A pattern similar to that of the ‘negro’ variety was obtained for ‘flor de mayo’, since the flour exhibited higher amounts of RRS; however, in this variety, the RRS content in ‘whole’ samples decreased after prolonged storage. Flours presented higher amylolysis rates than whole samples, and the ease of digestion increased with storage time. Copyright © 2003 Society of Chemical Industry     

Pasting,thermal, gel texture,resistant starch and colour properties of unripe banana flour from 10 desert banana varieties cultivated in South Africa

Unripe banana flour is a potential commercial ingredient in various food products for increased resistant starch and reduced gluten contents. In the present study, the pasting (rapid visco-analysis), gel texture (penetration test), thermal (differential scanning calorimetry), colour (tri-stimulus colour indices) and the resistant starch properties of unripe banana flour produced from different dessert banana varieties (n?=?10) cultivated in South Africa, were analysed and juxtaposed to wheat and maize flour. The functional properties varied significantly (p?≤?0.05) between banana varieties, and from wheat and maize flours, to various extents. Selected functional property ranges of unripe banana, wheat and maize flours, respectively included; flour colour index (63.16–76.42, 77.34 and 80.96), paste viscosity (405.5–556.6, 124.7 and 115.6 RVU), gelatinization temperature (64.67–71.21, 71.11 and 69.95?°C), gel firmness (7.24–11.44?×?10^??2 N, 3.49?×?10^??2 N and 6.56?×?10^??2 N) and resistant starch content (19.9–47.4, 2.8 and 2.2% w/w). Multivariate analysis (principle component analysis) showed that the unripe banana flours from different varieties were distinguished from each other based on the pasting temperature. The unripe banana flours were distinguished from both wheat and maize flour based on breakdown and peak paste viscosities. The breakdown viscosity was the most positively related measure to the resistant starch content with a linear regression R-squared value of 0.898, indicating a significant role played by granule structure in resistance to enzymatic hydrolysis. The present research demonstrates that selection of appropriate dessert banana variety is important when replacing staple flours (wheat and maize) with unripe dessert banana flour as a functional ingredient.     

Textural quality of sweet dumpling: effect of germination of waxy rice

Effects of germination on components and structural changes of rice flours and, in turn, rheological properties and textural attributes of sweet dumplings were investigated in this study. Germination decreased starch, protein and lipid content, while slightly increased free amino acids content. Starch granular surface corroded, crystalline structure disrupted, and short-range ordered structures and helical structures decreased with germination. Moreover, germination resulted in a decreased paste viscosity and gel intensity of flour and a reduction of hardness and adhesiveness of dumplings. According to the Pearson’s correlation analysis, flours components and starch structures were significantly correlated with flours rheological properties that determined textural attributes of sweet dumplings. The germination contributed to significant changes in flours components and starch structures, which suggested the pretreatment of germination of waxy rice could be a promising pathway to control textural properties of sweet dumplings.     

不同发芽阶段高粱粉理化及功能特性的变化

该实验以白高粱为原料,研究不同发芽时间对高粱粉淀粉组分及含量、淀粉酶活力、热力学、糊化、流变以及功能特性的影响。结果表明,发芽后高粱淀粉酶活力显著上升;总淀粉、直链淀粉和支链淀粉含量显著下降;热力学性质测定结果表明,发芽使糊化焓增加,提高了其稳定性和结晶度,起始糊化温度上升,峰值和终止糊化温度无显著变化;随着发芽时间的延长,高粱粉体系黏度下降,热糊稳定性及冷糊稳定性提高;储能模量和损耗模量低,高粱粉糊的流动性增强;发芽改善了高粱粉的乳化和乳化稳定性、起泡和泡沫稳定性,持油性提高、持水性降低。综上所述,发芽在一定程度上改善了高粱粉的理化及功能特性。     

乳酸菌发酵对燕麦淀粉物化及热力学特性的影响

以燕麦粉为原料,分别利用植物乳杆菌(L.p)和旧金山乳杆菌(L.s)两种乳酸菌对其进行发酵,研究燕麦淀粉在发酵过程中各种物化及热力学特性的变化。结果表明：燕麦粉经过两种菌发酵后pH 值下降,且L.p 发酵的燕麦粉pH 值下降的速率和产酸量都大于L.s。但是到发酵后期,两种乳酸菌发酵的燕麦粉pH 值相近。发酵燕麦淀粉的溶解度和溶胀力都随着温度的升高而增加,在不同温度下,其溶胀力和溶解度在发酵过程中的变化趋势不同,经L.P 发酵的样品的溶胀力低于L.s,但溶解度大于经L.s 发酵的样品。快速黏度分析仪(RVA)和差示扫描量热仪(DSC)分析得到发酵过程中燕麦淀粉的变化：发酵后燕麦淀粉糊化过程中峰值黏度随着发酵时间的延长而降低,糊化起始温度提前,糊化所需时间延长,糊化焓升高,且L.s 发酵样品的糊化焓值高于L.p。发酵后燕麦淀粉的直链淀粉含量在发酵过程中呈上升趋势,L.p 发酵的样品的直链淀粉的含量高于L.s。     

Physical Properties of Starch from Two Genotypes of Amaranthus cruentus of Agricultural Significance in China

Starches were isolated from the two genotypes of Amaranthus cruentus most widely cultivated in China, R104 and K112. These starches, plus a corn starch standard were mixed with either distilled water or a 1% NaCl solution and characterized for gelatinization parameters by Differential Scanning Calorimetry (DSC), pasting properties using a Rapid Visco-Analyzer (RVA), and texture of the cooled gels. Significant findings were: 1. A. cruentus starches had higher gelatinization temperature and higher endothermic energy than corn starch; 2. Wide differences in pasting properties were found between the two A. cruentus genotypes, although the waxy line R104 had lower hot-paste viscosity and set-back than K112; 3. The pasting properties (peak viscosity and set-back), of K112 were similar to those of corn starch. 4. In 1% NaCl solution, compared to distilled water, corn starch set-back decreased while that of the A. cruentus starches increased. Where Amaranthus starch is to be used in food processing applications, careful selection of genotype is necessary to achieve desired functionality.     

Native and modified chayotextle flour effect on functional property and cooking quality of spaghetti

The objective of this research was to study the effect of partially substituting semolina flour by native (NCHF) and modified chayotextle (CHFMD) flours, on the physicochemical properties and cooking quality of spaghetti. Spaghetti was obtained by replacing semolina flour (control) with five different concentrations of NCHF and CHFMD flours (10%, 17.5%, 25%, 32.5% and 40%). The proximal composition of the flours showed that both NCHF and CHFMD flours lower content of protein and fat but higher content of ash and resistant starch (RS). Moreover, the RS content increased due to thermal modification (TM) and that RS remained high, even after the cooking process. Pasting properties such as peak viscosity, breakdown, setback and final viscosity were influenced by NCHF and CHFMD concentrations. Brightness (ΔL^*) was significantly reduced by inclusion of increasing CHFMD levels. True density and water absorption values increased with addition of NCHF and CHFMD, compared to the control spaghetti. The results obtained in this study demonstrated the possibility for producing spaghetti containing up to 40% CHFMD flour, with acceptable quality and functional properties.     

Influence of enzyme active and inactive soy flours on cassava and corn starch properties

The aim of this work was to study the influence of enzyme active and inactive soy flours on the properties of cassava and corn starches. Four starch/soy flour composites were evaluated: cassava/active soy flour (Cas/AS), cassava/inactive soy flour (Cas/IS), corn/active soy flour (Corn/AS) and corn/inactive soy flour (Corn/IS). Starch gelatinization occurred at 58.67°C for Cas and at 64.19°C for corn; gelatinization occurred at higher temperatures when soy flours were present, while ΔH diminished. The presence of AS reduced 80% the retrogradation enthalpy of Cas and 40% that of corn. Cas presented lower pasting temperature than corn starch (67.8 and 76.8°C, respectively) and higher peak viscosity (427.9 and 232.8 BU, respectively). The pasting properties of both starches were drastically reduced by soy flours, and this effect was more noticeable in Cas; AS had higher effect than IS. X‐ray diffraction pattern of retrograded samples showed that both starches recrystallisation (mainly that of Cas) was reduced when AS was added. Tan δ values decreased with AS addition to corn, but they increased when added to Cas. The images obtained using confocal laser scanning microscopy (CLSM) showed that IS was distributed as large aggregates, whereas AS distribution was more homogeneous, especially when incorporated to Cas. These results show that cassava starch interacts specifically with active soy flour (AS, mainly in native state). The delaying effect of AS on cassava starch retrogradation was clearly shown. This finding could be useful in obtaining gluten‐free breads of high quality and low retrogradation rate.     

Wet separation of wheat flours into starch and gluten fractions: the combined effects of water to flour ratio–dough maturation time and the effects of flour aging and ascorbic acid addition

The process of making a dough, allowing time for maturation, dispersing the dough in water and wet sieving/washing to obtain a protein fraction and starch milk was studied using response surface methodology by changing the water to flour ratio in dough making (400–710 g kg^?1), maturation time (45–660 s) and the type of flour. Two grades of bread wheat flour and durum clear flour were studied. The effects of aging at ambient temperature for up to 29 days and the addition of ascorbic acid at 100 or 500 mg kg^?1 flour on separation behaviour were also studied for freshly milled high‐grade (65% extraction) bread wheat flours at constant maturation time, 600 s, and at optimum farinograph water absorption value. The quantities and dry matter contents of the protein fraction and starch milk were measured; a sample of starch milk was centrifuged to obtain decantate, tailings and prime starch fractions, and the dry matter contents of each were determined. All the dried samples were also analysed for protein content. The fractional recoveries of dry matter and protein in the protein fraction, prime starch, tailings and decantate were calculated for each experiment. The acid values of flour oils were also determined on some aged flour samples. The results indicated superior separation characteristics in high‐grade wheat flour compared with lower‐grade flours. The water to flour ratio was more influential than maturation time within the range studied. Contrary to the initial expectation, no statistically significant effect of flour aging was observed in the studies with no additive, and ascorbic acid addition was not found to improve the wet separation behaviour, the separation behaviour becoming even worse at the 100 mg kg^?1 level. Acid value showed a slight increase with time. © 2002 Society of Chemical Industry     

Effect of Chlorine Treatment on Wheat Flour and Starch: Measurement of Thermal Properties by Differential Scanning Calorimetry

Differential scanning calorimetry (DSC) was used to study the effect of chlorine treatment of wheat flour on the heat of gelatinization of the wheat flour and starch. The DSC thermograms were corrected for heat capacity changes and thermal lag. An endothermic transition occurred in both flours and starches at a temperature commonly associated with starch gelatinization. The enthalpy (ΔH) for the starches was concentration dependent. The chlorine treatment did not affect significantly the transition temperatures nor enthalpies of either the flour or the starch isolated from it. Addition of sucrose delayed the onset of gelatinization and increased the ΔH for both treated and untreated wheat flours and starches.     

Changes in characteristics of sweet potato flour prepared by different drying techniques

The changes occurring in the characteristics of sweet potato flour as a result of processing were investigated. Pasting behaviour of drum dried and hot air-dried sweet potato flour was determined using Rapid Visco-Analyser. The pasting characteristics decreased due to gelatinization of starch during processing. The degradation of starch by amylases during hot air drying further lowered the water binding capacity/viscosity and total amylose and increased the digestibility compared to those of drum dried and native flour. Swelling power and solubility of the flours increased as a result of processing which subsequently increased with increase in temperature. Scanning electron micrographs of starch granules showed tendency of clustering, especially in drum dried samples. X-ray diffraction patterns showed alteration from Ca-type to V-type with a marked reduction in crystallinity index as a result of processing. The ¹³C NMR spectra of processed starches showed reduced peak intensities and line widths due to depolymerizing effects, and also pointing to their change in crystallinity.     

Some properties of corn grains and their flours I: Physicochemical,functional and chapati-making properties of flours

The variability in physical (1000 kernel weight and bulk density) and mechanical (rupture force) properties of grains from different Indian corn varieties (African tall, Ageti, Early composite, Girja, Navjot, Parbhat, Partap, Pb sathi and Vijay) were studied. The functional (colour, gelatinization, retrogradation and pasting) and chapati-making properties of flours milled from corn varieties were evaluated. African tall flour showed the highest enthalpy of gelatinization (ΔH_gel), peak-, trough-, breakdown-, final-, and setback viscosities, and L^∗ (84.4) value and resulted in chapaties with higher extensibility (5.76 mm) and of light colour. African tall flour, with the lowest protein content, showed the lowest grain rupture force. Amylose content and hardness of starch gel from African tall were found to be the lowest among all corn varieties. Girja flour, with the lowest transition temperatures and ΔH_gel, showed the lowest extensibility of chapaties made from it. Pearson correlations between physical and textural properties of corn grains and the functional properties of their flours were established. Rupture force of corn grain and protein content of flour showed a negative correlation with peak viscosity of flour (r = −0.917, and −0.863, p < 0.01). The protein content of flours was negatively correlated with L^∗ (r = −0.759, p < 0.01) value and positively with b^∗ (r = 0.635, p < 0.01) value. Pasting temperature of flours showed a significant negative correlation with peak, trough, breakdown, final and setback viscosities (r = −0.836, −0.846, −0.778, −0.871, and −0.847, respectively, p < 0.01). Pearson correlation was also established between the grain and starch properties. Rupture force of corn grains was positively correlated with the amylose content of starch (r = 0.950, p < 0.01).     

DIFFERENTIAL SCANNING CALORIMETRY OF STARCH12

At high water-to-starch (2:1) ratios a single endotherm was obtained for starch gelatinization. As the water-to-starch ratio was decreased the endotherm area decreased and the peak developed a trailing shoulder. At high water-to-starch ratios birefringence is lost over a temperature range of about 7°C. That narrow range increases to about 30°C at a low water-to-starch ratio. Starch and flour gave essentially the same endotherm initiation temperatures. In low-water systems the second DSC peak is much smaller with starch than with flour. It appears that in a starch system, water migrates during gelatinization. In dough, gluten limits that migration. As the level of sucrose was increased in a dough, the transition temperature increased and the gelatinization temperature range decreased. At the levels found in bread doughs both sugar and salt increase starch gelatinization temperatures.