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.     

Use of amaranth,quinoa and kañiwa in extruded corn-based snacks

Amaranth (Amaranthus caudatus), quinoa (Chenopodium quinoa) and kañiwa (Chenopodium pallidicaule) are pseudocereals regarded as good gluten-free sources of protein and fiber. A co-rotating twin screw extruder was used to obtain corn-based extrudates containing amaranth/quinoa/kañiwa (20% of solids). Box–Behnken experimental design with three independent variables was used: water content of mass (WCM, 15–19%), screw speed (SS, 200–500 rpm) and temperature of the die (TEM, 150–170 °C). Milled and whole samples were stored in open headspace vials at 11 and 76% relative humidity (RH) for a week before being sealed and stored for 9 weeks in the dark. Hexanal content was determined by using headspace gas chromatography. Extrudates containing amaranth presented the highest sectional expansion index (SEI) (p < 0.01) while pure corn extrudates (control) presented the lowest SEI and greatest hardness (p < 0.01). SEI increased with increasing SS and decreasing WCM. In storage, whole extrudates exposed to 76% RH presented the lowest formation of hexanal. This study proved that it was possible to increase SEI by adding amaranth, quinoa and kañiwa to pure corn flour. The evaluation of lipid oxidation suggested a remarkable stability of whole extrudates after exposure to high RH.     

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.     

Agronomical and nutritional evaluation of quinoa seeds (Chenopodium quinoa Willd.) as an ingredient in bread formulations

Quinoa is an Andean seed crop of many potential uses. In 2009 a field trial was carried out to explore the potential for quinoa growing in climatic conditions of South Eastern Europe. Even under rainfed conditions, without fertilization, a seed yield as high as 1.721 t ha⁻¹ was obtained. Seed quality was remarkably good, with protein content ranging from 15.16 to 17.41 % on a dry weight basis, depending on whether seeds were processed. Amino acid and mineral composition revealed the potential of quinoa seeds as a valuable ingredient in the preparation of highly nutritious foods. Quinoa seeds had higher contents of most essential amino acids, especially lysine, than wheat flour. Dehulled quinoa seeds, devoid of saponins, were included into wheat bread formulations, with up to 20%, which resulted in a positive effect on the rheological characteristics of dough. Furthermore, protein content in bread was increased by around 2%. Sensory characteristics of breads were excellent also at the 20% supplementation level. The study of bread supplemented with quinoa seeds could enable the development of a range of new baking products with enhanced nutritional value.     

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.     

Chemical composition and nutritional potential of yam bean seeds (Pachyrhizus erosus L. Urban)

Pachyrhizus erosus seeds were analysed for proximate composition, minerals, protein fractions, antinutritional factors, and rotenoids. The seeds showed a high content of proteins, lipids, Fe and Ca, in comparison to other legumes. Glutelins constitute the highest protein fraction, followed by globulins. Antinutritional substances detected as tannins, hemagglutinating activity and trypsin inhibitory activity, were in low concentrations. Seeds were also processed to obtain a flour which showed proper characteristics, good in vitro digestibility, significant rotenoid reduction level and amino acid composition rich in essential amino acids, except methionine.     

Contribution of low molecular weight antioxidants to the antioxidant screen of germinated soybean seeds

Soybean seed of the Mazovia variety (Glycine max) were germinated in the dark at a constant temperature of 25°C up to 168 h (24 h × 7). Changes in content of low molecular weight antioxidants (LMWA) in the course of germination were studied. The analyzed compounds were: total phenolics, soluble proteins, tocopherols (-T, -T, -T, -T), reduced and oxidized glutathione, L-ascorbic acid and L-dehydroascorbic acid. The changes in total antioxidant status (TAS) and the peroxyl radical-trapping capacity (PRTC) of the processed seeds were measured and compared to those of the raw seeds. On the basis of data obtained, the contribution of LMWA to the TAS of raw and germinated soybean seeds was calculated. The results showed a very high molar percentage contribution of phenolic compounds (49.7%) in opposition to glutathione (7.0%), tocopherols (4.0%) and soluble protein (5.7%) to the total TAS of raw soybean seeds. The germination process led to the increased contribution of phenolic compounds (67.7%), soluble proteins (9.3%) and ascorbic acid (4.4%) to the total TAS of germinated seeds and as a result, a decrease in the antioxidant gap was observed compared to the total TAS of raw soybean seeds. This study showed that the contribution of experimentally obtained total PRTC to the total TAS of raw and germinated soybean seeds after seven days ofthe process was 48% and 25.2%, respectively. The PRTC results were comparable to those obtained in TAS only when calculation was done by multiple mean values for content of investigated compounds and their relative potency with respect to Trolox. The PRTC values obtained in this manner were higher than those obtained experimentally indicating that high molecular weight antioxidants as well as are able to quench peroxyl radicals as well as low molecular weight antioxidants. Therefore, calculation of PRTC is a more accurate method that eliminates the puzzling question of unidentified antioxidants shown as the antioxidant gap in the TAS assay.     

Effects of germination and kilning on the phenolic compounds and nutritional properties of quinoa (Chenopodium quinoa) and kiwicha (Amaranthus caudatus)

Quinoa (Chenopodium quinoa) and kiwicha (Amaranthus caudatus) are nutritious pseudocereals that originate from the Andean region. The aim of this research was to study the effect of germination and the subsequent kilning on the phenolic compounds and proximate composition in selected Peruvian varieties of quinoa (“Chullpi”) and kiwicha (“Oscar Blanco”). The germination process was carried out for 24, 48 and 72 h at 22 °C, and the kilning was performed with samples germinated for 72 h by drying the seeds at 90 °C for 5 min. Both processes increased the protein content of the samples. However, lipid content was reduced during germination. On the other hand, germination and kilning clearly increased the concentration of total phenolic compounds in both quinoa and kiwicha. Germination for 72 h either with or without kilning process resulted in a significant (p < 0.05) increase in the total content of phenolics compared to untreated materials, which was especially due to coumaric acid and a kaempferol tri-glycoside in quinoa and caffeoylquinic acid in kiwicha. Based on the results, germination and kilning may improve the nutritional quality of the Andean grains, encouraging the usage of the processed grains as ingredients in functional products for people with special gluten-free or vegetarian diets.     

Effect of fermentation on the nutritional quality and functional properties of infant food formulations prepared from bambarra-groundnut,fluted-pumkin and millet seeds

Weaning foods were formulated by complementation of millet with bambarra groundnut seeds and fluted pumkin seeds. The proximate composition of the individual seeds and the formulations were determined. The composite flour blend containing the highest quantity of fluted pumkin seeds was found to have the highest protein and fat contents (24 and 8% respectively). Functional properties of formulated weaning foods were evaluated. The effect of fermentation on the nutritional quality of the products were determined by animal feeding experiments. The feed intake, weight gain and PER values were evaluated. Fermentation was found to improve the nutritional quality of the formulations. The fermented composite mixture of millet, bambarra groundnut and fluted pumpkin flour (1:1:2) was found to have the highest PER value of 2.1. This suggests that this fermented product will support growth in children better than other formulations.     

提高湖南省杂交棉种质量水平的商榷

在市场经济迅速发展、种子生产、流通量不断增加和加入WTO的新形势下，充分提高湖南省棉种的质量水平，推动棉种产业化的健康发展，对农民增收、农村稳定具有重大的现实意义。本文简要介绍了提高湖南棉种质量水平的紧迫性和可行性。在此基础上提出了提高棉种质量水平促进产业化发展的几点建议。     

提高湘杂棉质量认证制度的思索与探讨

2002年省内外累计推广湘杂棉160万公顷。新增产值34．5亿元以上。其辐射网络遍及湖南、湖北、江西、浙江、河南、安徽等牛长江中下游流域棉区。为进一步搞好湘杂棉新品种的开炭与扩繁工作，本文主要从三个方面阐述了提高相杂棉棉种质量的管理办法，这对推动棉种产生化的健康发展，对农民增收、农村稳定具有重大的现实意义。     

Evaluation of the effect of processing techniques on the nutrient and antinutrient contents of pearl millet (Pennisetum glaucum) seeds

This work was undertaken to evaluate the effect of soaking, sprouting, cooking and fermentation or their combinations on the nutrient and antinutrient contents of pearl millet seeds. Standard assay procedures were adopted to determine both the nutrient and the antinutrient concentrations of the products. The synergistic effect of cooking and fermentation improved the nutrient quality. The antinutrients were reduced to safe levels to a greater extent than did any of the other processing techniques or their combinations employed.     

花生籽仁不同发育时期不同部位主要营养成分变化

本研究以不同油酸花生品种为材料,对籽仁含油量、脂肪酸和蔗糖含量累积规律和基豆先豆间差异及籽仁不同部位差异进行分析。结果表明,随着花生籽仁的发育,含油量增加且高油品种含油量积累速率高于低油品种,蔗糖含量下降;不饱和脂肪酸逐渐增加,饱和脂肪酸和超长链饱和脂肪酸逐渐下降,亚麻酸逐渐降低到消失,其中高油酸材料棕榈酸、亚油酸和亚麻酸的下降速率以及油酸的上升速率高于普通油酸材料。各材料脂肪酸在基豆和先豆间无显著差异,而含油量基豆高于先豆。成熟籽仁胚中棕榈酸、亚油酸、花生烯酸、山嵛酸和二十四碳烷酸含量显著高于子叶,含油量、硬脂酸和油酸含量低于子叶,在胚中约含有0.5%左右的亚麻酸,而子叶中未检测到亚麻酸。本研究结果为选育品质优的油用型和食用型花生品种具有指导意义。     

Mycoflora and nutritional value of shelled melon seeds (Citrulus vulgaris Schrad.) in Nigeria

Thirteen fungi were isolated from mouldy shelled melon seeds. The fungi more frequently isolated included species ofMucor (11.25%),Rhizopus (13.75%),Aspergillus (36.25%),Macrophoma (2.50%),Penicillium (8.75%),Alternaria (5.00%),Fusarium (8.75%),Botrytis (6.25%),Torula (3.75%) andGeotrichum (3.75%). Healthy, shelled melon seeds inoculated withFusarium solani for 7 or 14 days caused increases in the free fatty acid (f.f.a.) content of the healthy seeds from an initial value of 1.06% to 2.19% after 7 days and 4.23% after 14 days. Similar results were obtained when other fungal isolates were used as inocula butFusarium solani effected the greatest increase in the f.f.a. content followed byAspergillus niger andPenicillium notatum. The fungi also caused decreases in the crude protein from 35.51% to 25.16%, crude fibre from 4.30% to 1.35% and total carbohydrate content from 4.28% to 3.01% of the seeds after 14 days infection. Aflatoxin was detected (0.20µg/g) in the infected seeds being sold in the markets and also from seeds inoculated with spores (0.40µg/g) ofA. flavus and (0.50µg/g) from a mixture of spores of variousAspergillus strains after incubation for 14 days.     

桃色顶孢霉发酵液对大豆的促生及其抗逆酶活性的影响

本实验采用了管碟法和种子萌发法研究了实验室分离获得的桃色顶孢霉对茄病镰刀菌F. solani.的拮抗作用以及对大豆的促生作用,并采用愈创木酚法、紫外吸收法、氮蓝四唑光化还原法研究了顶孢霉发酵液对POD、CAT、SOD三种抗逆酶活性的影响。结果表明：顶孢霉发酵液对镰刀菌菌丝生长有明显抑制作用,菌丝变稀疏。大豆种子经不同浓度桃色顶孢霉发酵液处理后,萌发率及种子酶活性均产生变化。不同浓度的发酵液对种子萌发促进作用不同,当发酵液浓度为10%时,胚根长,胚芽长,胚根鲜重,胚芽鲜重均达到最高值,分别为2.91cm,0.037g,4.07cm,0.1666g。与对照相比分别提高了49.37%,63.24%,30.54%,45.80%。当处理种子的发酵液浓度为60%时,种子萌发率最高为83.67%,与对照相比提高了23.90%;酶活性最强,POD、CAT和SOD分别为683U、160.67U和301U,与对照相比分别提高 73.50%,43.78%,76.73%。初步证实了桃色顶孢霉发酵液中含有能够促进大豆种子的萌发及抗逆酶活性升高的物质。     

Comparative study of microorganisms and sensory attributes of condiments from the fermentation of different seeds

Seeds of African locust bean, melon, castor oil bean and soybean were processed and fermented for 3 days to produce local condiments in the laboratory with a method that simulated the traditional production process. Microorganisms associated with their fermentation and the organoleptic properties of the products were compared.Altogether, seven species of bacteria were involved in the fermentation. These included fiveBacillus spp. and one species each ofPseudomonas andStaphylococcus. Their occurrence vary between the seeds on the different days of fermentation. However,Bacillus spp. were present in all the seeds throughout the fermentation period. The sensory evaluation preference rating for the four products was highest for soybean condiment, followed by that made from locust bean. Melon condiment was the least preferred among the four products. Statistical analysis showed that there were significant differences (P0.05) among the four products for each of the four organoleptic properties evaluated by the judges and also for titratable acidity. Glutamic acid level of soybean condiment was highest (0.31%) among the four products with that of melon being the lowest (0.04%). These results could serve as useful indices for the development of starter culture and optimization of production process in commercializing the production of these local condiments.     

Effect of soy-fortification method on the fermentation characteristics and nutritional quality of fermented maize meal

Studies were conducted to develop an appropriate household/small-scale enterprise level technique for the production of soy-fortified fermented maize dough (or meal) by comparing different treatments, processing methods and fortification levels. The effects of fortification method of the Ghanaian traditional fermented maize dough with raw or heat-treated whole soybeans and full-fat soyflour at 0%, 10% and 20% replacement levels, on the rate of fermentation and product quality were investigated. Sensory characteristics, trypsin inhibitor activity, amino acid pattern, proximate composition and hot paste viscosity were used as the indices of quality. Addition of whole soybeans to maize before milling and fermentation reduced the fermentation time by 60% while increasing the protein content by 24% and 70% respectively for 10% and 20% levels of fortification. A significant improvement was also achieved in the amino acids pattern of the fortified dough. However, raw whole soybeans imparted an undesirable color and beany flavor and an appreciable concentration of trypsin inhibitor activity (TIA) to the dough. Boiling soybeans for 20 min before incorporation into the maize for milling and fermentation was found necessary for desirable flavor and low levels of TIA. Little or no changes in the pasting viscosity characteristics occurred in samples containing boiled soybeans, while the usual method of fortifying maize meal with soy flour was found to severely depress the pasting viscosity characteristics and drastically reduced the acidity of the fermented dough. Based on the findings of the study, the most appropriate technique for the production of soy-fortified high protein fermented maize dough has been suggested to involve incorporation of boiled whole soybeans in soaked maize before milling and fermentation for improved sensory characteristics, enhanced nutritive value and optimal functional properties.