Extrusion processing characteristics of quinoa (Chenopodium quinoa Willd.) var. Cherry Vanilla

Extrusion processing characteristics of Cherry Vanilla quinoa flour (Chenopodium quinoa Willd) were investigated using a three factor response surface design to assess the impact of feed moisture, temperature, and screw speed on the physicochemical properties of quinoa extrudates. Specific mechanical energy (SME) required to extrude this quinoa variety was higher (250–500 kJ/kg) than previously reported for quinoa. The following characteristics of the extrudates were observed: expansion ratio (1.17–1.55 g/cm³), unit density (0.45–1.02 g/cm³), water absorption index (WAI) (2.33–3.05 g/g), and water solubility index (WSI) (14.5–15.87%). This quinoa flour had relatively low direct expansion compared to cereal grains such as corn or wheat, suggesting that it is not well suited for the making of direct expanded products. The study further suggests that there is a need to understand the processing characteristics of new quinoa varieties for cultivation. Understanding extrusion and other quality traits in advance will help to select the appropriate varieties that would allow food processors to meet consumer needs.     

Nutritional quality of the protein in quinoa (Chenopodium quinoa,Willd) seeds

The nutritional quality of protein in quinoa seeds has been determined by amino acid assay and by animal feeding experiments. The amino acid composition of the protein in raw quinoa and washed quinoa show similar pattern. The first limiting amino acids were the aromatic amino acids thyrosine + phenylalanine giving a chemical score of 86 for protein in raw quinoa and 85 for protein in washed quinoa. Threonine was the next limiting amino acid followed by lysine. The amount of lysine and sulfur amino acids (methionine + cystine) was relatively high. In general, the content of essential amino acids in quinoa is higher than in common cereals. The animal experiments showed NPU values of 75.7, BV of 82.6 and TD value of 91.7 for the protein in raw quinoa. Results of the in-vitro enzymatic methods showed that the digestibility of the protein in quinoa is comparable to that of other high quality food proteins. The corresponding experiments carried out with samples of guinoa seeds, which have been processed to remove the saponins, showed that, the saponins do not exert any negative effect on the nutritive quality of the protein.     

Properties of starch and dietary fibre in raw and processed quinoa (Chenopodium quinoa,Willd) seeds

We investigated certain properties of starch in raw and in heat-treated samples of quinoa, properties that are of importance to the nutritional quality of an infant food currently being developed. Scanning electron microscopy of the starch in raw seeds showed polygonal granules (0.6 to 2.0 µm diameter) to be present both singly and as spherical aggregates. Thermograms (DSC) of the flours showed one transition phase for gelatinisation of the starch and another for the amylose-lipid complex. The gelatinisation temperature of the starch was 67°C. Cooked samples manifested the highest degree of gelatinisation (97%), followed by the drum-dried (96%) and autoclaved (27%) samples. Separation of the starch on a SEPHAROSE CL-2B column showed the quinoa starch to be affected by the heat treatment, manifesting changes in the degree and extent of degradation. The amylograph viscosity of the quinoa flour showed no distinct peak for pasting, but the viscosity remained constant after gelatinisation. Cooking and autoclaving modified the viscosity of the paste. The drum-dried sample manifested a higher initial viscosity at 25°C. Thein vitro digestibility of raw quinoa starch determined by incubation for 60 min with -amylase was 22%, while that of autoclaved, cooked and drum-dried samples was 32%, 45% and 73%, respectively. Saponins did not affect the digestibility of the starch, though they tended to increase the amylograph viscosity. The total dietary fibre content in the cooked sample (11.0%) was significantly lower than that in the autoclaved (13.2%), drum-dried (13.3%) or raw samples (13.3%), while the insoluble dietary fibre fraction in the samples did not change with heat treatment. However, as compared with that of raw quinoa, the soluble dietary fibre fraction was reduced significantly both by cooking (0.9%) and by autoclaving (1.0%).     

Physicochemical and functional properties of soluble dietary fiber from different colored quinoa varieties (Chenopodium quinoa Willd)

As it is well documented that the phytochemical composition and bioactive profile of quinoa are influenced by different phenotypes, we analyzed the physicochemical and functional characteristics of different quinoa soluble dietary fiber (SDF). SDF was prepared through ultrasound-assisted enzymatic extraction from three colored quinoa brans. After purification, the yield of SDF from white (W-SDF), red (R-SDF) and black quinoa bran (B-SDF) was 2.2%, 5.7% and 5.9%, respectively. Compared with R-SDF and B-SDF, W-SDF had a higher molecular weight (1.72 × 10⁶ Da) and lower zeta-potential (- 32.16 mV), although their monosaccharide composition and Fourier transform infrared spectroscopy (FT-IR) results showed no obvious differences. The transmission electron microscope (TEM) image suggested that R-SDF exhibited a more complex and loose structure than W-SDF and B-SDF. Moreover, R-SDF exhibited higher thermal stability, gel forming capacity, bile acid binding capacity, water-holding capacity and glucose adsorption capacity than those of B-SDF and W-SDF. Taken together, SDF extracted from quinoa especially from red quinoa might be a promising candidate for the development of novel functional food ingredients.     

Chemical and nutritional evaluation of two amaranth (Amaranthus cruentus)-based infant formulas

The objective of this study was to calculate, prepare and evaluate the Protein Efficiency Ratio (P.E.R.) and Net Protein Utilization (N.P.U.) of two infant formulas made with amaranth (Amaranthus cruentus). Both formulas were formulated to match a previously developed and tested soy-oats infant formula. No significant differences were found between the three formulas with respect to corrected Protein Efficiency Ratio (P.E.R.) and Net Protein Utilization (N.P.U.) values. Only the product made with the 1-R fraction of amaranth was found to have a significantly lower P.E.R. than casein.Paper presented at the Annual Convention of the Institute of Food Technologists, Anheim, California, U.S.A., June, 1990.     

Prolonged tempe-type fermentation in order to improve bioactive potential and nutritional parameters of quinoa seeds

The effect of 40 h solid-state fermentation with Rhizopus oligosporus on selected parameters of white and coloured quinoa was studied, as compared to standard (30 h) product and cooked seeds.The reducing power (RP) and the activity against synthetic free radicals of standard tempe were higher by on average 140% (white) and 64% (coloured quinoa) than that of cooked seeds. The OH scavenging activity was increased by more than 7 fold (white), and over 2 fold (coloured quinoa). Prolongation of the fermentation caused further improvement in this potential, on average by 27% (OH, RP) and 24% (DPPH, ABTS⁺ assays). The soluble phenols i.e. vanillic acid, protocatechuic acid and rutin levels in 40 h tempe were significantly higher than in cooked quinoa. Fermented products contained 470% (white) and on average 150% (coloured quinoa) more riboflavin and 100% more thiamine (white quinoa) than cooked seeds. The levels of total protein, free amino acids and proteins releasable during the in vitro digestion, were improved as a result of 40 h fermentation. The essential amino acids profile of quinoa tempe was consistent with the reference pattern.The prolonged tempe-type fermentation of quinoa can be recommended as a method of the value-added food production.     

Process,structure and texture of extruded whole wheat

Whole wheat is well known by consumers as a health-providing ingredient. Nevertheless, in extruded products it leads to textures that are less favorable to consumer preference compared to its refined flour. An understanding of the effect of extrusion on whole wheat properties is therefore necessary to improve its texture. Whole wheat flour was extruded under varying conditions of water content (18 or 22%), screw speed (400 or 800 rpm) and barrel temperature (140 or 180 °C) and its physicochemical properties were measured. Changing the extrusion conditions significantly modified the volumetric expansion index (between 9.1 and 20.6) and longitudinal expansion (between 0.93 and 2.98) of the samples. Interestingly, changing the extrusion conditions did not significantly modify the sectional expansion. Increasing barrel temperature, water content or screw speed decreased the shear viscosity of the melt. This can be explained by plasticizing effects and modification of starch properties. The change in shear viscosity at the die can mostly explain the effect of process conditions on volumetric expansion of the extruded whole wheat. The stress at rupture of the extruded samples was varied between 0.49 and 1.86 MPa depending on process conditions. It was the lowest at high water content and low screw speed.     

Agglutinating activity of alcohol-soluble proteins from quinoa seed flour in celiac disease

The edible seeds of the quinoa plant contain small quantities of alcohol-soluble protein which, after peptic-tryptic digestion, are unable to agglutinate K562(s) cells. When separated by affinity chromatography on sepharose-6B coupled with mannan, peptic-tryptic digest separated in two fractions. Fraction B peptides (about 1% of total protein) were shown to agglutinate K562(s) cells at a very low concentration, whereas peptides in fraction A and in the mixed fraction A+B were inactive, suggesting that fraction A contains protective peptides that interfere with the agglutinating activity of toxic peptides in fraction B.     

Composition and secondary structure of proteins isolated from six different quinoa varieties from China

Due to its high nutritional value, quinoa has recently been attracting worldwide attention. The composition and secondary structure of proteins isolated from quinoa varieties from other countries have been determined, but proteins from Chinese quinoa varieties have not been described. The aim of this research was to determine the composition and secondary structure of proteins isolated from six different quinoa varieties from China. In all varieties, the protein content was 69.62–73.14%. The fat content and ash content were all less than 2%. The starch content was 20.67–23.12%. The amino acid composition and secondary structures of quinoa protein isolates (QPIs) purified from six Chinese quinoa varieties were investigated by using a combination of amino acid analysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and Fourier transform infrared spectroscopy (FTIR). The results revealed that QPIs, with molecular weights ranging from 10.0 kDa to 50.0 kDa, were rich in essential amino acids. In addition, glutamic acid was the most abundant amino acid found in the quinoa protein isolates. The remaining amino acid contents were balanced, except for tryptophan. The secondary structures of QPIs have been quantified by the deconvolution of the amide I band of the FTIR spectrum of QPIs. The main secondary structure in quinoa isolate protein was the β-sheet (from 30.86% to 36.88%). These results will be promising guides for the use of QPIs in food processing and additives.     

Processing and evaluation of heat moisture treated (HMT) amaranth starch noodles; An inclusive comparison with corn starch noodles

AS, HMT-AS and CS starches were studied for amylose content, swelling power, water absorption capacity, color, particle size (PSA), pasting profile (RVA) and thermal (DSC) properties. Based on the laboratory scale experiments, noodles with good expansion, minimum cooking time and firm texture were prepared. Noodles were successfully prepared from AS, HMT-AS and CS starches. Noodles prepared from native amaranth starch (AS) and heat moisture treated (HMT) were tested for different functional properties and compared to cornstarch noodles. Standardized noodles were evaluated for cooking loss, texture profile (TPA), sensory and micro-structural analysis by SEM. HMT-AS noodles had experience less cooking loss of 20.15 g/100 g in comparison to AS noodles (22.20 g/100 g). The HMT-AS based starch noodles shown firmer texture, along with augmented taste and distinct flavor in comparison to AS and CS noodles.     

Physicochemical properties and in vitro digestion of extruded rice with grape seed proanthocyanidins

To characterize the impact of grape seed proanthocyanidins (GSPAs) on the physicochemical properties and in vitro digestibility of extruded rice, the XRD, RVA, DSC, FT-IR, micro-CT, as well as the in vitro digestion model was applied. Compared with normal rice, the extruded rice with different proportions of GSPAs (0–1.5%) increased the color depth, enhanced the porosity, and changed the semi-crystalline structure of extruded rice from an A-type to a mixture of A- and V-types. The viscosity and thermal properties of extruded rice with GSPAs were also changed noticeably. Additionally, a significantly lower equilibrium hydrolysis and k constant were observed in extruded rice with GSPAs (p < 0.05). Those results indicated that extruded rice with GSPAs could be an attractive approach to produce rice starchy food with low digestibility.     

Kinetics of starch digestion and functional properties of twin-screw extruded sorghum

The time-course of starch digestion in twin-screw extruded milled sorghum grain was investigated using an in-vitro procedure based on glucometry. The sorghum grains were hammer-milled, and extruded at three levels each of moisture and screw speed. Irrespective of the extrusion conditions, extruded and non-extruded milled sorghum grain exhibited monophasic digestograms, and the modified first-order kinetic and Peleg models adequately described the digestograms. Extrusion increased the rate of digestion by about ten times compared with non-extrudates. Starch gelatinisation varied in the extrudates, and microscopy revealed a mixture of raw, gelatinised and destructured starch and protein components in the extrudates. Starch digestion parameters significantly (p < 0.05) correlated with extruder response and various functional properties of the extrudates. Extrusion conditions for maximum starch gelatinisation in milled sorghum grain for fastest digestion as an efficient animal feed were interpolated, as well as the conditions for directly-expanded extrudates with potential for human food, where minimum starch digestion is desired.     

Physical and nutritional qualities of extruded weaning foods containing sorghum,pearl millet,or finger millet blended with mung beans and nonfat dried milk

Sorghum, pearl millet, and finger millet flours (60% of each) were blended with toasted mung bean flour (30%) and nonfat dry milk (10%) and extruded (Brabender single screw) to make precooked, ready-to-eat, weaning foods. The extruded foods had high cold paste viscosity, but their cooked paste viscosity was lower than that of the respective blends. Chemical scores of the extruded foods were 78 for sorghum, 80 for pearl millet, and 96 for finger millet. Protein digstibility corrected amino acid scores (PD-CAS) were similar for pearl millet (68%) and finger millet (69%); PD-CAS for sorghum was 57%. Total dietary fiber content of the foods ranged from 7.6 to 10.1%, with the soluble dietary fiber content of the foods being about 10% higher than that of the corresponding blends. Extrusion enhanced the in vitro protein digestibility of foods, but no marked difference occurred in the in vitro carbohydrate digestibility among the unprocessed blends and the extruded foods. The net protein ratio, protein efficiency ratio, and biological values were higher for the finger millet food than for the pearl millet food, probably because of the higher lysine content of the finger millet protein.Contribution No. 95-253-J of the Kansas Agricultural Experiment Station.     

Effect of home processing on total and extractable calcium and zinc content of spinach (Spinach oleracia) and amaranth (Amaranthus tricolor) leaves

Spinach (Spinacia oleracia) and amaranth (Amaranthus tricolor) leaves were stored in polyethylene bags and without packing for 24 and 48 hours in a refrigerator at 5 and 30 °C in polyethylene bags. The fresh leaves were also dried (oven and sun); blanched (5, 10 and 15 min) and cooked in an open pan and a pressure cooker. The processed leaves were analysed for total and extractable calcium and zinc content. The Ca and Zn content of these leaves varied from 1320 to 2120 and 11.70 to 12.60 mg/100 g DM and the percentage HCl-extractability was 77.82 to 81.92 and 85.16 to 86.15, respectively. No significant effects of drying and storage were observed on total Ca and Zn content and HCl-extractability while blanching and cooking resulted in significant improvement of HCl-extractibility of these two minerals. Thus, cooking and blanching are good ways to improve the HCl-extractibility of Ca and Zn.     

Crop water use indicators to quantify the flexible phenology of quinoa (Chenopodium quinoa Willd.) in response to drought stress

Models can play an important role in agricultural planning and management. Thermal time accumulation is a common way of describing phenological development in crop models, but the sensitivity of this concept to water stress is rarely quantified. The effect of pre-anthesis droughts on the timing of anthesis and physiological maturity was assessed for quinoa (Chenopodium quinoa Willd.) var. ‘Santa Maria’, with the help of two field experiments (2005–2006 and 2006–2007) in the central Bolivian Altiplano. Various treatments with different sowing dates and irrigation applications were considered. To evaluate the effect of drought stress on crop development, drought stress during the first 60 days after sowing was assessed with three different stress indicators: the number of days that the soil water content of the root zone was above a threshold, the average relative transpiration, and the sum of daily actual transpiration, standardized for reference evapotranspiration (∑(T_a/ET₀)). The best indicator to quantify the effect of pre-anthesis drought stress on phenological development was ∑(T_a/ET₀) cumulated until 60 days after sowing. This indicator showed a significant logarithmic relation with the time to anthesis and time to physiological maturity. Correlations of the drought stress indicator with thermal time accumulation were better than with calendar time accumulation. Due to an effect of post-anthesis droughts, the correlations of the drought stress indicator with the time to anthesis were stronger than with the time to physiological maturity. It was also demonstrated that deficit irrigation can contribute to a better agricultural planning due to a better control of the phenological development of quinoa. The proposed relations can be used for modeling phenological development of quinoa in drought prone regions and for efficient deficit irrigation planning.     

Effect of extrusion process variables on physical and chemical properties of extruded oat products

The purpose of this research was tostudy the effects of initial moisture levels andextrusion temperatures on bulk density, waterabsorption and water solubility indexes, viscosity,and color of extruded oat products. The dehulledgrains were ground in a Brabender Quadrumat Seniormill and the coarse fraction, with higher amounts ofcrude protein, lipids, and dietary fiber content, wereconditioned to moisture levels of 15.5–25.5% andextruded in a Brabender single-screw laboratoryextruder. The water absorption index of extrudateswere relatively low (4.16–6.35 g gel/g sample) butincreased as the initial moisture of the raw materialas well as the extrusion temperature was elevated.The water solubility index was inversely proportionalto the extrusion temperature. Initial viscosity of thepaste increased with the increase of raw materialmoisture and extrusion temperature, while the maximumviscosity (at a constant temperature) diminished withthe increase of temperature. Products with lowervalues of L* (luminosity) and greater values ofa* (red) and b* (yellow) were obtained athigh moisture rates and at a 120 ^°C extrusiontemperature.     

The comparison of the effect of added amaranth,buckwheat, chickpea,corn, millet and quinoa flour on rice dough rheological characteristics,textural and sensory quality of bread

Gluten free (GF) flour (amaranth, buckwheat, chickpea, corn, millet and quinoa) was blended with rice flour to compare their impact on dough rheological characteristics and bread quality. The potential of some GF-rice blends in breadmaking has already been studied on blends with prevailing content of rice flour. The impact of added flour may be expected to rise with increasing amount of flour; therefore blends containing 30 g/100 g, 50 g/100 g and 70 g/100 g of GF flour in 100 g of GF-rice blend were tested. Under uniaxial deformation, peak strain was not impacted by the addition of GF flour; stress (12.3 kPa) was, however, significantly (P < 0.05) decreased (2.9–6.2 kPa). The reduction initiated by the presence of buckwheat, chickpea, quinoa and partly amaranth, together with thermally-induced dough weakening initiated by buckwheat and quinoa flour, may be related to significantly better crumb porosity. Overall acceptability of composite breads containing amaranth, chickpea and quinoa was negatively impacted by the aroma and taste of these flours. Higher potential to improve rice dough behavior and bread quality was found in the blend containing buckwheat flour (30 g/100 g; 50 g/100 g). Millet and corn flour deteriorated dough and bread quality.     

Dietary fiber and other functional components in two varieties of crude and extruded kiwicha (Amaranthus caudatus)

Two varieties (Centenario and Oscar Blanco) of Andean native grain, kiwicha (Amaranthus caudatus), were evaluated as sources of dietary fiber and of some bioactive compounds. The impact of low-cost extrusion on the content of these components was studied for technological applications. The content of total dietary fiber in Centenario was higher (16.4%) than in Oscar Blanco (13.8%). In both varieties, the content of total and insoluble dietary fiber decreased during the extrusion process. In Centenario, the content of soluble dietary fiber increased, from 2.5 to 3.1% during the extrusion process. The content of phytic acid in raw kiwicha was 0.3% for both varieties, and the content of total phenolic compounds was 98.7 and 112.9 mg GAE/100 g of sample, for Centenario and Oscar Blanco, respectively.     

苋菜、小麦和玉米对铯的吸收和积累差异

苋菜、小麦和玉米用石英砂和Hoagland营养液进行盆栽培养,3叶期时,向培养液中添加不同浓度铯(0、0.5、1、5、10、20 mmol/L CsCI),在处理后第7、14、21、28天取样,分析3种植物对铯的吸收富集差异.结果表明:苋菜、小麦和玉米中铯含量均与处理浓度和时间呈显著正相关,在20 mmol/L铯浓度下处理28 d后达到最大值;苋菜对铯的富集能力和富集系数远远高于小麦和玉米,在处理浓度小于1 mmol/L时,小麦和玉米对铯的吸收富集无显著差异,但随着处理浓度的增加和处理时间的延长,小麦对铯的富集能力显著高于玉米;苋菜、小麦和玉米的根、茎、叶对铯的吸收富集也存在显著差异,苋菜叶片是主要的富集器官,富集量表现为叶、茎、根依次减小,而小麦和玉米的根是主要富集器官,富集量表现为根、茎、叶依次减小;铯显著抑制苋菜、小麦和玉米的生长发育,随着处理浓度的增加,生物量显著降低,根冠比显著增加.本研究结果表明苋菜是一种铯富集能力强的具有较高潜在应用价值的铯污染修复植物,而小麦和玉米是铯低富集植物.