藜麦皂苷研究进展

藜麦(Chenopodium quinoa Willd.)是南美洲特有的一种植物,其叶片、花、果实、籽实和种皮中富含皂苷,藜麦皂苷是一种苦味物质和抗营养因子。目前常用的皂苷提取方法主要有溶剂提取法、酸碱水解法、沉淀法、超临界CO_2法及超声波萃取法等。近年来的研究表明,藜麦皂苷具有抗氧化、抗肿瘤、抑菌、免疫调节等药理活性,这些特性都使藜麦皂苷成为医学、保健品、食品等行业的重点研究对象。本文主要对藜麦皂苷的研究现状、结构组成、提取方法、分离纯化、分析测定、生物活性、以及环境对藜麦皂苷的影响进行了概述,以期为藜麦的进一步研究开发提供参考。     

Afrosimetric estimation of threshold saponin concentration for bitterness in quinoa (Chenopodium quinoa Willd)

Taste testings and saponin estimation by a simple afrosimetric method showed that quinoa containing 0·11% saponins or less (corresponding to foam heights of 1·0 cm or less) can be considered sweet. A variation of the standard afrosimetric method is described which reduces total analysis time from 73 to 7 min. Used with the proper precautions, this rapid method, in which quinoa producing foam heights of 1·3 cm or less is considered sweet, is suitable for selecting promising low-saponin varieties in field trials and for monitoring the efficacy of abrasive dehulling (polishing) as a debittering process.     

Saponins of quinoa (Chenopodium quinoa): Effects of processing on their abundance in quinoa products and their biological effects on intestinal mucosal tissue

Quinoa (Chenopodium quinoa) is a valuable source of protein in some parts of South America, and it is likely to be exploited further in both developing and industrialised countries. However, quinoa seeds contain significant levels of saponins which are potential antinutrients. In the present study, the effects of processing on the quantity and composition of saponins in quinoa products were determined, and the biological effects of quinoa grain and cereal products containing high or low levels of saponins were investigated both in vitro and in vivo in the rat. Quinoa saponins were shown to be membranolytic against cells of the small intestine and to cause an increase in mucosal permeability in vitro. Unwashed bitter quinoa caused a significant food aversion and poor food conversion efficiency in rats. However, processing quinoa, during the manufacture of an infant cereal, reduced the concentration and membranolytic activity of saponins, and increased the palatability and nutritional quality of the cereal product to a level similar to that of a wheat-based cereal product.     

Occurrence of sapogenins in leaves and seeds of quinoa (Chenopodium quinoa Willd)

Seeds of the Andean seed crop quinoa usually contain saponins in the seed coat. Saponins give a bitter taste sensation and are a serious antinutritional factor. Therefore selection of sweet genotypes with a very low saponin content in the seeds is a main breeding goal. However, selection for sweet genotypes is retarded by cross‐pollination. Early identification of sweet and bitter quinoa genotypes before anthesis would speed up breeding considerably. The ability to distinguish sweet and bitter genotypes was investigated in a glasshouse and in a field experiment. In the glasshouse experiment the content of sapogenins was determined in leaves of sweet and bitter quinoa genotypes at successive stages of plant development and finally in the seeds. Detectable amounts of sapogenins were found earliest 82 days after sowing in leaves of both sweet and bitter quinoa genotypes. The total sapogenin content in leaves of sweet and bitter genotypes increased during plant development but remained lower than the content found in the seeds. The sapogenin content in seeds of sweet genotypes varied from 0.2 to 0.4 g kg⁻¹ dry matter and in seeds of bitter genotypes from 4.7 to 11.3 g kg⁻¹ dry matter. The difference in sapogenin content between leaves and seeds was much higher in bitter genotypes than in sweet genotypes. Hederagenin was the major sapogenin found in leaves, and oleanolic acid in seeds. In the field experiment it was found that the content of sapogenins in the leaves of F2 plants of crosses between both quinoa types did not differ between sweet and bitter genotypes. The obtained results demonstrated that sweet genotypes could not be selected before anthesis on the basis of the sapogenin content in the leaves. © 2000 Society of Chemical Industry     

Cell wall phenolics and polysaccharides in different tissues of quinoa (Chenopodium quinoa Willd)

Quinoa (Chenopodium quinoa Willd) is an Andean pseudo-cereal, of the Chenopodiaceae family, which is currently being studied for introduction in Northern Europe as an alternative to industrial crops. The aim of this work was to verify existence in quinoa of the distinctive cell wall features identified in other Chenopodiaceae, ie presence of pectin-bound ferulic acid and dehydrodiferulic acids. Alcohol-insoluble solids (AIS) were prepared from leaves, stems and roots of mature quinoa plants, representing 0.10, 0.20 and 0.47 g g⁻¹ respectively of the fresh weight. Ferulic acid and dehydrodiferulic acid derivatives were present in all the organs, with the highest concentrations in the leaves with 2.1 and 0.5 mg g⁻¹ AIS respectively. The ratio of dehydrodiferulic acid to ferulic acid was highest in the roots. Pectins extracted by hot HCl from AIS of leaves were rich in ferulic acid (3.4 mg g⁻¹), but also highly acetylated (DAc 20), and rich in rhamnose, two characteristics encountered in other Chenopodiaceae. © 1999 Society of Chemical Industry     

Performance of quinoa (Chenopodium quinoa Willd) flour in the manufacture of gluten‐free spaghetti

The objective of this work was to assess the performance of mixtures of corn and quinoa (Chenopodium quinoa Willd) flours in the development of a spaghetti‐type product. Cooking quality (loss of solids, volume increase, weight increase), texture (adhesiveness, elasticity), peak and final viscosities and moisture content of the pre‐gelatinised flour mixtures were the physical parameters studied. The mean values for loss of solids, weight increase, volume increase, adhesiveness and moisture were 162 g kg⁻¹, 2.3 times, 2.6 times, 2090.7 g and 384 g kg⁻¹ respectively. Peak viscosity and elasticity provided information relevant, yet not definitive, to both formulation and processing of the product. However, the model developed was predictive for final viscosity. The combination of independent variables that resulted in higher elasticity values, desirable for spaghetti, were short thermal treatment and low‐to‐medium quinoa additions. All peak viscosities were low with respect to the untreated flour. For final viscosity, however, the best combinations were short heat treatments across the entire range of quinoa contents. Sensory acceptability testing of the spaghetti by a consumer panel was also included. © 2000 Society of Chemical Industry     

Nutritional and functional characterisation of hydrolysates from quinoa flour (Chenopodium quinoa) using two proteases

The objective was to study the nutritional and functional properties of hydrolysates from quinoa (Chenopodium quinoa) obtained by enzymatic hydrolysis of defatted quinoa flour (DQF). The commercial enzymes alcalase and flavourzyme were used to obtain the hydrolysates defatted quinoa flour hydrolysate with alcalase (DQFA) and defatted quinoa flour hydrolysate with flavourzyme (DQFF), respectively, after 3 h of digestion at 50°C and pH 8. The degree of hydrolysis (47.32%), yield (31.05%) and protein recovery (88.80%) values were higher in DQFA; however, its protein content (48.34%) was lower compared to that of DQFF (55.06%). Also, DQFA had a solubility greater than 57% over a wide pH range (2–10) and good foam stability (70–90%). On the other hand, DQFF presented adequate emulsifying activity (61.30 m²/g), emulsifying stability (158.62 min) and foaming capacity (131%). Due to the high content of macro- and micronutrients and adequate emulsifying and foaming properties, DQFA and DQFF could be used as ingredients in various processed food products and protein supplements.     

Effect of alkaline extraction on the structure of the protein of quinoa (Chenopodium quinoa Willd.) and its influence on film formation

It is important to produce hydrophobic edible protein films for use in foods. The aim of this study was to evaluate the effect of alkaline extraction of quinoa proteins (QP) on the structure and their film‐forming ability without plasticiser. QP were extracted between pH 8 to 12, and their structure was evaluated by PAGE‐SDS, size‐exclusion HPLC light scattering, fluorescence spectroscopy and SH and SS. Film was characterised by FTIR, SEM, tensile strength, barrier and colour. Structural changes of QP showing that alkalinisation over pH 10 produce significant denaturation/aggregation/dissociation structural changes in QP. pH 12 was the condition to form a film (film₁₂). FTIR showed hydrogen bonds and hydrophobic film interactions. Film₁₂ had 16.6 ± 3.8% elongation and 15.7 ± 1.1 MPa tensile strength, and water vapour permeability was 5.18 ± 0.38 g mm m^?2 day^?1 kPa^?1. Film₁₂ had a brownish colour. A high degree of denaturation/aggregation/dissociation of QP structure is required to form a film without plasticiser.     

Insights into the nutritional value and bioactive properties of quinoa (Chenopodium quinoa): past,present and future prospective

In recent years, quinoa gained increased attention due to its great adaptability to harsh environmental conditions, high nutritional values and high preference as ingredients of gluten-free and functional foods. In order to improve the diet and direct the population to a better health, the search for new foodstuffs suitable for a healthy lifestyle and proper diet is still ongoing and quinoa seeds are one of these food raw materials. It is a promising variety for human consumption and nutrition in the world, as it has higher nutritional and health values than traditional cereal grains, such as high concentration of protein, fatty acids, tocopherols, phytosterols, phenolic compounds, and low glycaemic index and gluten-free nature. Its consumption is not spread worldwide due to lack of knowledge regarding nutritional and health benefits of quinoa among consumers. This review summarises the nutritional values, bioactive properties, antinutritional factors, and uses of quinoa seeds and oils.     

Characterisation and enzymatic hydrolysis of nettle (Urtica dioica L) deproteinated biomass

Non-starch polysaccharides (NSP) were obtained from deproteinated nettle biomass and characterised for pectin, hemicellulose and cellulose content. The nettle deproteinated biomass (NDB) represents 52·4% (w/w) of the dry nettle biomass and contains 695·5 g kg^?1 NSP. The pectin, hemicellulose and cellulose amounts are 196·7, 334·5 and 128·5 g kg^?1, respectively. The high content of pectins and hemicelluloses may make the NDB an important source of dietary fibre. The NSP were hydrolysed by crude enzymatic preparations and both their biodegradability and the amount of simple sugars released have been determined. In the best conditions more than 40% of the NSP were hydrolysed with a considerable increase of sugars. These enzymatic treatments could be used to improve the feed digestibility of the biomass or to obtain bioenergetic compounds by fermentation of the hydrolysed sugars.     

Physicochemical and rheological properties of purees based on Mafafa (Xanthosoma robustum) and quinoa (Chenopodium quinoa Willd.) with the addition of cryoprotectants

Growing interest in processed frozen products with similar characteristics to natural products has generated the study of new products in the food industry field. The characteristics of each matrix, the process of elaboration, composition, and structure of the additives and the interactions amongst these modify the food's texture, structure, physical and sensory properties and, hence, interfere directly with consumer acceptance. This research studied the effect of adding cryoprotectors during frozen storage on the rheological, physicochemical, structural, and microbiological properties in a Mafafa‐quinoa‐olive oil puree. To carry out the study, the rheological properties were determined through dynamic oscillatory tests and in steady state; likewise, the physicochemical properties (humidity, color, pH, and syneresis) were analyzed. Regarding physicochemical properties, the humidity content in the purees formulated varied between 57 and 74%, without important variation (p > .05) with respect to the formulation, however, in the storage during the freezing/thawing process, this parameter diminished in greater proportion in those purees containing carrageenan as cryoconservant. Both the addition of cryoconservants and the storage time affected significantly (p < .05) the puree's syneresis, with the degree of exudation being lower in the formulation containing xanthan gum at 1% w/w. During the freezing/thawing process, decreased apparent viscosity was noted. Additionally, the analysis of the viscoelastic properties of the purees evidences that already described, given that a significant effect (p < .05) was observed of the formulation of purees in the elastic component G′, in contrast with a notable decrease in the viscous component G″.     

藜麦的营养成分、健康促进作用及其在食品工业中的应用

藜麦(Chenopodium quinoa)是一种营养丰富的假谷物,具有多种保健作用,被誉为"超级谷物"。藜麦突出的营养保健作用成为国内外学者关注的热点。详细综述了藜麦的宏量营养素、微量营养素和植物化学物质的组成特点;抗氧化、抗癌、降糖降脂、抗炎抗菌等多种健康促进作用;藜麦在食品工业中的应用前景,目的是为我国藜麦的全面利用以及相关产品研发提供科学依据。     

Interrelationships among seed yield, total protein and amino acid composition of ten quinoa (Chenopodium quinoa) cultivars from two different agroecological regions

BACKGROUND: Quinoa is a good source of protein and can be used as a nutritional ingredient in food products. This study analyses how much growing region and/or seasonal climate might affect grain yield and nutritional quality of quinoa seeds. RESULTS: Seeds of ten quinoa cultivars from the Andean highlands (Bolivia/Argentina site) and Argentinean Northwest (Encalilla site) were analysed for seed yield, protein content and amino acid composition. Grain yields of five cultivars growing at Encalilla were higher, and four were lower, compared with data from the Bolivia/Argentina site. Protein contents ranged from 91.5 to 155.3 and from 96.2 to 154.6 g kg^?1 dry mass for Encalilla and Bolivia/Argentina seeds respectively, while essential amino acid concentrations ranged from 179.9 to 357.2 and from 233.7 to 374.5 g kg^?1 protein respectively. Significant positive correlations were found between the content of essential amino acids and protein percentage. CONCLUSION: It appears that there are clear variations in seed yield, total protein content and amino acid composition among cultivars from the two sites. Essential amino acid composition was more affected than grain yield and protein level. The study revealed that both environmental and climatic factors influence the nutritional composition of quinoa cultivars growing in different agroecological regions. Copyright © 2011 Society of Chemical Industry     

Innovations in Health Value and Functional Food Development of Quinoa (Chenopodium quinoa Willd.)

Quinoa (Chenopodium quinoa Willd., Amaranthaceae) is a grain‐like, stress‐tolerant food crop that has provided subsistence, nutrition, and medicine for Andean indigenous cultures for thousands of years. Quinoa contains a high content of health‐beneficial phytochemicals, including amino acids, fiber, polyunsaturated fatty acids, vitamins, minerals, saponins, phytosterols, phytoecdysteroids, phenolics, betalains, and glycine betaine. Over the past 2 decades, numerous food and nutraceutical products and processes have been developed from quinoa. Furthermore, 4 clinical studies have demonstrated that quinoa supplementation exerts significant, positive effects on metabolic, cardiovascular, and gastrointestinal health in humans. However, vast challenges and opportunities remain within the scientific, agricultural, and development sectors to optimize quinoa's role in the promotion of global human health and nutrition.     

藜麦发芽过程中蛋白质与皂苷及淀粉消化特性的变化规律

发芽是改善谷物质构及其营养价值的一种高效的加工方式。本文研究了藜麦发芽过程中蛋白质与皂苷及淀粉消化特性的变化规律。结果显示,发芽显著地提高了藜麦中粗蛋白和可溶性蛋白含量,分别增加了5.38%和17.55%。随着发芽时间不断增加,藜麦总淀粉、直链淀粉及支链淀粉含量分别减少25.95%、4.86%和29.53%,而还原糖含量增加了26.60%。发芽处理显著改善了藜麦种子的淀粉消化性能。发芽前藜麦种子中快消化淀粉、慢消化淀粉及抗性淀粉的百分含量分别为38.45%、43.64%和17.90%。发芽48h后,快消化淀粉的百分含量显著地增加至53.46%,而慢消化淀粉及抗性淀粉的百分含量分别下降至40.42%和6.11%。此外,发芽后藜麦种子中总皂苷含量显著增加了16.46%。研究表明,发芽的藜麦种子含有更好的营养价值和消化性能,可以用于加工功能性食品,促进人体健康。     

Enzyme activities in cocoa beans during fermentation

The activities of endoprotease, aminopeptidase, carboxypeptidase, invertase (cotyledon and pulp), polyphenol oxidase and glycosidases were studied during heap fermentation of ICS-95 cocoa beans. These enzymes are of key importance in flavour precursor formation and in pigment degradation during cocoa fermentation. Optimal extraction and assay conditions were established to characterise the enzymes reactions and to quantify and compare enzyme activities during cocoa fermentation. The enzymes exhibited large differences in pH optima and stability during fermentation. Aminopeptidase, invertase (cotyledon and pulp) and polyphenol oxidase were strongly inactivated, carboxypeptidase was partly inactivated, whereas endoprotease and glycosidases remained active throughout the fermentation. Since many enzymes are inactivated during fermentation, it is generally recognised that the actual period of enzyme action is short. Although our results confirmed total inactivation for some enzymes, we show that several key enzymes are not completely inactivated during fermentation. Therefore, some enzyme reactions can continue throughout the whole fermentation process. Only polyphenol oxidase was strongly inactivated during sun and artificial drying of the beans. The other enzymes were stable during the drying process. Enzymes like endoprotease and glycosidases are still active in properly fermented and dried beans. © 1998 SCI.     

不同色型藜麦对高脂膳食小鼠脂代谢的影响及机制

为了探索同一产地、不同色型藜麦对高脂膳食小鼠脂代谢的影响。将50 只SPF级雄性健康小鼠适应性喂养7 d后,根据体质量随机分为空白对照组、模型组、白藜麦组、黑藜麦组和红藜麦组,干预时间为8 周。实验结束后,测定其Lee’s指数、腰围、腹部脂肪质量,血清和肝脏组织的总胆固醇（total cholesterol,TC）、甘油三酯（triglyceride,TG）、低密度脂蛋白胆固醇（low-density lipoprotein cholesterol,LDL-C）、高密度脂蛋白胆固醇（low-density lipoprotein cholesterol,HDL-C）等脂代谢相关生理生化指标;并采用实时荧光定量聚合酶链式反应（quantitative real-time polymerase chain reaction,qPCR）和蛋白质免疫印迹检测肝脏胆固醇和脂质代谢关键基因mRNA和蛋白相对表达量。结果表明：与模型组相比,白、黑、红藜麦可降低小鼠Lee’s指数、腰围、腹部脂肪质量;显著下调小鼠血清、肝脏组织的TC和TG水平（P＜0.05）,显著上调小鼠肝脏组织的HDL-C水平（P＜0.05）;显著下调小鼠肝脏3-羟基-3甲基戊二酸单酰辅酶A还原酶（3-hydroxy-3-methylglutaryl CoA reductase,HMG-CoAr）和固醇调节元件结合蛋白（sterol regulatory element binding protein,SREBP）-1c的mRNA及蛋白相对表达量（P＜0.05）,其中白、黑、红藜麦的HMG-CoAr mRNA相对表达量分别下调了56.22%、72.55%和27.77%,蛋白相对表达量分别下降了53.02%、29.72%、29.80%;SREBP-1c mRNA相对表达量分别下调了62.96%、45.50%和21.27%,蛋白相对表达量分别下降了20.79%、23.97%、20.26%;明显提高AMP活化蛋白激酶α（AMP-activated protein kinase alpha,AMPKα）、低密度脂蛋白受体（low density lipoprotein receptor,LDL-R）、肝X受体（liver X receptor,LXR）、过氧化物酶体增殖物激活受体α（peroxisome proliferators-activated receptor-α,PPARα）和胆固醇7α-羟化酶（cytochrome P450 family 7 subfamily A member 1,CYP7A1）的mRNA相对表达量和LDL-R、PPARα的蛋白相对表达量,其中白、黑、红藜麦的LDL-R mRNA相对表达量分别升高了243.86%、273.04%和121.93%,蛋白相对表达量分别上调了18.02%、17.16%、22.45%;PPARα mRNA相对表达量分别升高了62.45%、87.54%和126.91%,蛋白相对表达量分别上调了54.26%、51.10%、33.82%。结论：不同色型藜麦均可改善高脂膳食小鼠脂代谢紊乱,其中白藜麦和黑藜麦效果优于红藜麦,其机制可能与降低胆固醇合成和减少脂肪酸从头合成有关。