Quinoa Samples Research Articles

Antimicrobial Potential and Phytochemical Content of Six Diverse Sources of Quinoa Seeds (<i>Chenopodium quinoa</i> Willd.)

Antimicrobial potential of quinoa seeds from six diverse seeds, grown in three distinctive geo-graphical zones of Chile, was correlated with their total phenolic content (TPC), total flavonoid content (TFC) and total saponin content (TSC). The six seeds were Ancovinto, Cancosa, Cahuil, Faro, Regalona and Villarrica. A significant influence of quinoa source on chemical composition of seeds was observed. Extracts of all quinoa samples showed antimicrobial activity in the range of 8.3 - 14.8 mm inhibition zone for E. coli and 8.5 - 15.0 mm inhibition zone for S. aureus. Cancosa seeds had the highest antimicrobial action. The TPC and TFC ranged from 3.71 to 16.55 mg GA/100 g d.m. and 7.77 to 14.37 mg QE/100 g d.m., respectively. TSC varied from 1.78 to 3.08 g/100 g d.m. A cor-relation between TFC and antimicrobial activity was found. In conclusion, the six types of quinoa seeds were identified as potential sources of antioxidant compounds and antimicrobial activity.

Chemical characteristics and mineral composition of quinoa by near‐infrared spectroscopy

Quinoa (Chenopodium quinoa Willd.) has been traditionally used as a foodstuff in the Andes and it has gained increasing interest in recent years owing to its high nutritional value. The potential of near-infrared spectroscopy (NIRS) for estimating chemical compounds in quinoa was studied because of the possibility of conducting direct measurement without prior sample treatment. The use of NIRS technology with a remote reflectance fiber-optic probe for the analysis of major compounds and mineral composition of 48 quinoa samples was studied. The calibration of the NIRS instrument was conducted using modified partial least squares (MPLS) analysis. This allowed the determination of protein (16.0-20.2 g 100g⁻¹), crude fiber (1.8-3.1 g 100g⁻¹), fat (4.4-7.5 g 100g⁻¹), calcium (298.8-1164.5 mg kg⁻¹), iron (0-948.5 mg kg⁻¹) and phosphorus (2735.0-4543.3 mg kg⁻¹). The correlation coefficients (RSQ) were 0.83 for protein, 0.73 for crude fiber, 0.93 for fat; 0.60 for calcium; 0.76 for iron and 0.75 for phosphorus. The robustness of the equations obtained was verified by external validation on unknown quinoa samples. NIRS with fiber-optic probe provides an alternative for the determination of chemical compounds of quinoa, faster and at lower cost, with results comparable with chemical methods.

Daidzein and Genistein contents in seeds of quinoa (Chenopodium quinoa Willd.) from local ecotypes grown in arid Chile

The contents of bioactive compounds of quinoa (Chenopodium quinoa Willd.) are poorly known. We analyzed two isoflavones (daidzein and genistein) by HPLC in three local ecotypes of quinoa seeds from three different geographical and genetic regions in Chile: (a) Extreme North, with prevailing conditions of high temperature and dryness (local ecotype R49); (b) Center, with milder climate (local ecotype UdeC9); and (c) South, with cold, humid environment (local ecotype BO78). Genetic-driven differences among cultivars were tested by homogenizing the culture conditions of the three seed sources. In addition, seven commercial samples of quinoa purchased at local food markets were analyzed and compared to our experimental harvested seeds. In all samples daidzein content was higher than genistein (P<0.05). The northern ecotype R49 exhibited higher content of isoflavones compared with the other two (UdeC9 and BO78), all grown under the same experimental conditions. Daidzein ranged from 1.15 (R49) to 0.70 (BO78) mg/100g, while genistein varied from 0.25 (R49) to 0.05 (UdeC9) mg/100g. Ecotype R49 had 1.6 and 1.7 fold higher daidzein contents than UdeC9 and BO78, respectively (P<0.05). In the commercial samples, the daidzein/genistein ratio ranged from 25.2 to 3.9, daidzein ranged from 2.05 to 0.78mg/100g, and genistein ranged from 0.41 to 0.04mg/100g. To the best of our knowledge, this is the first report on the contents of daidzein and genistein in quinoa seeds. The study demonstrates that, besides its well-recognized nutritional value, quinoa possesses an excellent potential as a source of these health-promoting bioactive compounds.

Multivariate calibration by near infrared spectroscopy for the determination of the vitamin E and the antioxidant properties of quinoa

Quinoa is a pseudocereal that is grown mainly in the Andes. It is a functional food supplement and ingredient in the preparation of highly nutritious food. In this paper we evaluate the potential of near infrared spectroscopy (NIR) for the determination of vitamin E and antioxidant capacity in the quinoa as total phenol content (TPC), radical scavenging activity by DPPH (2,2-diphenyl-2-picryl-hydrazyl) and cupric reducing antioxidant capacity (CUPRAC) expressed as gallic acid equivalent (GAE).For recording NIR a fiber optic remote reflectance probe applied directly on the quinoa samples without treatment was used. The regression method used was modified partial least squares (MPLS). The multiple correlation coefficients (RSQ) and the standard prediction error corrected (SEP(C)) were for the vitamin E (0.841 and 1.70mg100g−1) and for the antioxidants TPC (0.947 and 0.08mgGAEg−1), DPPH radical (0.952 and 0.23mgGAEg−1) and CUPRAC ( 0.623 and 0.21mgGAEg−1), respectively.The prediction capacity of the model developed measured by the ratio performance deviation (RPD) for vitamin E (2.51), antioxidants TPC (4.33), DPPH radical (4.55) and CUPRAC (1.55) indicated that NIRS with a fiber optic probe provides an alternative for the determination of vitamin E and antioxidant properties of the quinoa, with a lower cost, higher speed and results comparable with the chemical methods.

Phenolic Compounds and Saponins in Quinoa Samples (Chenopodium quinoa Willd.) Grown under Different Saline and Nonsaline Irrigation Regimens

Quinoa is a pseudocereal from South America that has received increased interest around the world because it is a good source of different nutrients and rich in antioxidant compounds. Thus, this study has focused on the effects of different agronomic variables, such as irrigation and salinity, on the phenolic and saponin profiles of quinoa. It was observed that irrigation with 25% of full water restitution, with and without the addition of salt, was associated with increases in free phenolic compounds of 23.16 and 26.27%, respectively. In contrast, bound phenolic compounds were not affected by environmental stresses. Saponins decreased if samples were exposed to drought and saline regimens. In situations of severe water deficit, the saponins content decreased 45%, and 50% when a salt stress was added. The results suggest that irrigation and salinity may regulate the production of bioactive compounds in quinoa, influencing its nutritional and industrial values.

Impact of air-drying temperature on nutritional properties, total phenolic content and antioxidant capacity of quinoa seeds ( Chenopodium quinoa Willd.)

Quinoa has gained an increasing interest in recent years due to its nutritional value (rich in protein, fat, dietary fibre, ash, carbohydrates and minerals). Furthermore, it is an excellent source of natural antioxidants such as vitamin E and other phytochemicals. Dehydration of quinoa between 40 and 80 °C was performed in order to evaluate the effect of air-drying temperature on these quality attributes. When comparing the fresh with the corresponding dehydrated quinoa samples, it was shown that the drying operation led to reductions of 10% in proteins, 12% in fat and 27% in both fibres and ashes. In fresh quinoa, potassium and copper were found to be the most and least abundant minerals, respectively. Sucrose was the predominant sugar, followed by fructose and glucose. Overall antioxidant activity was affected by drying temperatures. Thermal degradation, especially at 60, 70 and 80 °C, resulted in a notable reduction in TPC. However, vitamin E showed an important increase at 70 and 80 °C. The antioxidant capacity presented similar values at 40, 50 and 80 °C due to temperature/drying time equivalent processes.

Effects of processing on the nutraceutical profile of quinoa

Quinoa flour was subjected to a variety of thermal processes. Both unprocessed and processed quinoa samples were subjected to successive extractions in methanol and ethyl acetate solvents. Effects of processing were gauged via comparison of HPLC chromatograms of the quinoa extracts. Quinoa flour subjected to processing via roasting and extrusion resulted in a significant impact on the chemical profile when compared to unprocessed quinoa flour. Steam pre-conditioning had minimal effects on the chemical profile of quinoa flour. Process-enhanced isolate from roasted and extruded quinoa possessed a molecular weight of 480 D, was dissolved in methanol and ethyl acetate, and possessed a NMR spectra reminiscent of a terpenoid compound. This research suggests that thermal processing of quinoa flour can result in degradation of saponin molecules. Saponin decomposition may influence sensory or pharmacological properties.

Dough and Breadmaking Properties of Wheat Flour Substituted by 10% with Germinated Quinoa Flour

Dough physical properties and baking quality of wheat flour substituted by 10% with non germinated quinoa flour (control), 24-h, 48-h and 72-h germinated quinoa flours were studied. The stability time and valorimeter value of the control and 24-h germinated quinoa flour substituted wheat flours were significantly longer and higher than those of 48-h and 72-h samples. The 10% substitution of germinated quinoa flour for wheat flour made distinctly harder dough than that of the control. The low amount of total and inner gas generations was observed for the 48-h and 72-h samples, as compared with those of the control and 24-h germinated quinoa samples. SEM observations showed that the gluten matrix of the control and 24-h germinated quinoa flour substituted wheat dough seemed to be more extended and more dispersed than those of 48-h and 72-h samples. The loaf volume of bread made from 24-h germinated quinoa flour substitution for wheat flour was the largest among the germinated samples; however, no significant differences were observed between the control and 24-h samples.

Characterization of Amaranth and Quinoa Starches.

Starch granules were prepared from mature grains of 9 samples of Amayanthus and 4 samples of Chenopodium quinoa. By the ordinary gel permeation chromatograph (GPC) of Pseudomonas isoamylase-debranched starch materials, the amylose content of amaranth starches was in a range of 0-28%. Thus, we confirmed that there were normal, low amylose, and waxy types of amaranth starches. The amylose content of quinoa starches was 25-27%. The ratio of short chains to long chains of amylopectin of these starches was in a range of 2.2-3.3 and somewhat lower than or similar to that of normal maize starch. Isoamylase-debranched materials were separated by HPLC with a differential refractometer (RI) and low-angle laser light-scattering photometer (LALLS) as detectors as one means, and by high-performance anion exchange chromatography with a pulsed amperometric detector (HPAEC-PAD) as the other. We found that amylopectins of Amayanthus and Chenopodium quinoa had increased amounts of long B chains and decreased amounts of short chains as compared to the waxy maize amylopectin, however, they had increased amounts of short chains with DP (degree of polymerization) from 8 to 12. Amaranth starches had slightly higher temperatures of gelatinization (T0, Tp and Tc) and smaller heats of gelatinization (d H) by differential scanning calorimetry (DSC) as compared to normal maize starch. Quinoa starches showed lower T0, T p and T and smaller ΔH. Amaranth and quinoa starch granules were digested by amylases faster than those of normal maize.

Effect of processing on in vitro digestibility of protein and starch in quinoa seeds

The in vitro digestibility of protein in raw quinoa assessed by an enzymic method was 78%, significantly (P &gt; 0.01) lower than that of casein, 91%, and also somewhat lower (P &gt; 0.01) than that of the raw washed quinoa sample, 83%. the process used to remove the outer layers of the seeds containing saponins increased the protein digestibility significantly (P &gt; 0.01), by 7%. Heat treatments increased protein digestibility over that of raw quinoa samples. Only the cooked sample treated for 60 min presented a slightly lower protein digestibility, 77%, than those obtained for other heat‐treated samples.The temperature, time and moisture used in cooking and autoclaving of whole seeds of quinoa did not improve starch digestibility significantly. the digestibility of the starch in the raw and precooked samples was 72 and 77%, respectively, after drum drying and about 64% after extrusion in both cases. Precooking at 60°C for 20 min does not improve the digestibility of the quinoa starch.

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 microns 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 degrees 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 degrees C. The in vitro digestibility of raw quinoa starch determined by incubation for 60 min with alpha-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%).

Saponins, phytic acid, tannins and protease inhibitors in quinoa ( Chenopodium quinoa, Willd) seeds

The seeds of quinoa ( Chenopodium quinoa, Willd), a food crop of the Andean region of Latin America, contain protein of good quality and high amounts of carbohydrates, fat, vitamins, and minerals. An industrial process for manufacturing infant food using quinoa as a basic raw material is being developed. The presence of antinutrients are of importance in this context, and this paper deals with saponins, phytic acid, tannins and protease inhibitors in quinoa seeds. The samples of quinoa analysed in this experiment contained two main types of saponins. The amount of saponin A (β- d-glucopyranosyl -[β- d-glucopyranosyl -(1 → 3)-α- l -arabino- pyranosyl-(1 → 3)]-3-β-23- dihydroxy-12- en-28- oate methyl ester) was 0·7% of the dry weight and that of the saponin B (β- d-glucopyranosyl -[β- d-glucopyranosyl -(1 → 3)-α- l -arabino- pyranosyl-(1 → 3)]-3-β-23- dihydroxyolcan-12- en-28- oate was 0·2% of the dry weight. These were the major saponins found in the quinoa bran collected while polishing the seeds. After scrubbing and washing, the level of saponin-A remaining in the seeds decreased to 0·31% of the dry weight, and saponin-B was completely removed by this process. The content of phytic acid in the quinoa seeds was about 1% of the dry matter, and scrubbing and washing reduced the phytic acid content of the seeds by about 30%. Neither protease inhibitor nor tannins were detected in the quinoa seeds.