New processing of lupin protein isolates and functional properties

A growing demand for functional plant proteins could be identified, which properties are customized for specific applications and formulations as food ingredients. Native lupin proteins (α, β, γ) conglutin have a good solubility at appropriately chosen conditions. A novel procedure has been proposed to maintain the native protein properties. Lupin proteins are extracted from hexane deoiled lupin. The protein product type E comprises high molecular weight proteins (α, β‐conglutin( which are separated using alkaline extraction and acid precipitation procedures. The protein product type F is enriched in the γ‐conglutin fraction and is separated from the acid pre‐extract applying cross flow filtration at pH 7–8. For the zirconium oxide membrane the filtration rate can be increased by appropriately chosen pH conditions up to 70 l/m²h. Lupin protein fraction (type E and F) are highly soluble protein isolates with outstanding emulsification, salt tolerance and foaming properties. These new lupin proteins (type E and F) offer extremely interesting properties for application in food systems and are available from pilot plant fractionation.     

Functional Properties of Lupin Protein Isolates (Lupinus albus cv Multolupa)

Lupin protein isolates were prepared by alkaline extraction and precipitation at pH 5.1, 4.2 and 4.9 and their functional properties investigated. Solubility, emulsification capacity, swelling and gelation properties were determined under different conditions of pH, ionic strength and heat treatment. Lupin protein isolates showed better solubility than soybean isolate and a similar emulsification capacity. Swelling and gelation were found to be inferior, but when modifications in the methods of isolate preparation were introduced these properties were significantly improved. Consequently, it is possible to consider lupin proteins as a potential substitute for soybean proteins in food applications.     

Technological strategies to improve gelation properties of legume proteins with the focus on lupin

There is a growing demand for plant protein due to the increasing number of consumers looking for healthier food options. Protein from the legume seed lupin is a viable plant protein source due its high protein content and agricultural sustainability of lupin production. Lupin protein is however underutilised in food manufacturing due to its poor gelling and thickening properties. This review uncovers the link between lupin protein structural properties and its poor gelling functionality. It will compare lupin with other legume proteins in terms of protein structure and gel quality. Current knowledge of legume protein gelation processes, factors controlling gelation mechanisms and methods for evaluating gel quality will be presented. Finally, green and efficient protein modification technologies to improve gelation will be detailed. This review also reveals the scarcity of information on approaches to improve the poor gelation properties of lupin protein, highlighting the need for research in this area.     

Functional Properties of Lupin Seed (Lupinus mutabilis) Proteins and Protein Concentrates

Functional and electrophoretic properties of the seed flour and a protein concentrate prepared by alkaline extraction from lupin seeds (Lupinus mutabilis, cultivar H-6) were investigated. SDS-PAGE indicated presence of 13 and 12 subunits in the seed flour proteins and the protein concentrate, respectively. Lupin protein concentrate had good water and oil absorption and gelation properties. Solubility of lupin proteins was minimum at a pH of 4.0 but increased rapidly beyond pH 5.0. Foaming capacity of the protein concentrate could be improved by increasing concentration as well as by adding NaCl and was influenced by pH and incorporation of certain carbohydrates. Emulsion properties of lupin proteins were concentration and pH dependent. Moist heat improved the in vitro digestibility of the seed proteins. The seed flour as well as the protein concentrate did not have detectable trypsin, chymotrypsin, and α-amylase inhibitory activities.     

胶束化和碱溶酸沉提取羽扇豆蛋白的物化特性

利用胶束化和碱溶酸沉2 种提取方法从羽扇豆中提取羽扇豆蛋白,并对2 种方法提取羽扇豆蛋白的物化特性进行研究。结果表明：羽扇豆蛋白分子质量主要集中在18～90 kDa之间,是由多种分子质量的蛋白组成。碱溶酸沉提取羽扇豆蛋白的氨基酸总含量（66.2%）显著（P＜0.05）高于胶束化提取羽扇豆蛋白的氨基酸总含量（27.8%）。2 种提取方法提取羽扇豆蛋白的等电点pI接近5.0。胶束化提取羽扇豆蛋白的持水性显著（P＜0.05）高于碱溶液酸沉法提取的羽扇豆蛋白,而持油性无显著差异（P＞0.05）。碱溶酸沉法提取羽扇豆蛋白的起泡性在pH 2.0～6.0之间显著减小,在pH 6.0时起泡性最低,其泡沫稳定性的变化趋势与其起泡性类似。而胶束化提取羽扇豆蛋白的起泡性受pH值的影响不显著（P＞0.05）。胶束化提取的羽扇豆蛋白在pH 4.0时乳化性最小,然后随pH值的升高蛋白乳化活性也随之增加,2 种提取方法所提羽扇豆蛋白在pH 10.0时乳化活性最高。碱溶酸沉法提取的羽扇豆蛋白在pH 4.0时溶解度最小,而随着pH 4.0～10.0的增加,蛋白溶解度迅速增加。而胶束化提取羽扇豆蛋白的溶解度随pH 2.0～10.0的升高也逐渐增大。该研究为羽扇豆蛋白在食品工业中的开发与应用提供一定理论支持。     

Effect of different pasteurization conditions on bioactivities of Lupinus albus protein isolates

Lupin protein isolate was extracted following the procedure in European Patent (EP 1024 706 B1) in order to use lupin protein for food and pharmaceutical applications. The acid insoluble/neutral pH soluble protein isolate was pasteurized at 65-125 °C for 10-1000 s. The objective of this study is finding out reasonable pasteurization condition for food use, or for good bioactivities like radical scavenging, angiotensin converting enzyme inhibition, and bile acid binding activity. Pasteurization at 65 °C for 10 s did not reduce the microbial count of the protein sufficiently for use in foods. The chemical composition of lupin protein isolates had no change by various pasteurization. The angiotensin converting enzyme inhibition decreased and the DPPH radical scavenging capacity increased after high temperature treatment at 125 °C. The sodium cholate binding capacity was not affected by tested conditions. Pasteurization at higher temperature is useful for producing selective bioactive fractions with suitable microbiological properties.     

Development of real-time PCR assays for the detection of lupin residues in food products

Lupin is a legume from the Leguminosae family that is used, amongst other, for human nutrition. In Europe, lupin is used as a substitute for soy in bakery and dietary products and recently its consumption has increased significantly. Unfortunately lupin is known to trigger allergic reactions in sensitised individuals and therefore its use in food products requires a mandatory declaration on the label in accordance with Directive 2007/68/EC. To protect the allergic consumer the availability of detection methods for the identification of lupin in food products is required. Here we present the development of two real-time polymerase chain reaction (PCR) methods that allow the detection of lupin-specific DNA as a marker for the presence of this allergenic ingredient in food products. Genomic DNA sequences coding for conglutin genes were chosen as targets for the detection of lupin. One primer set and probe was designed for the amplification of a 153 bp fragment of α-conglutin; another primer set and probe was designed for the detection of a 150 bp δ-conglutin amplicon. Lupin at a level of 10 mg/kg food matrix could be detected in cookies baked from a lupin containing dough using the α-conglutin method. Since lupin is used in bakery products the effects exerted by heat treatments on lupin detection by real-time PCR have been investigated. Enzyme-linked immunosorbent assay (ELISA) analyses were performed in parallel to compare the detection of lupin DNA with that of lupin protein in market products. Qualitative ELISA results confirm results obtained by the real-time PCR methods targeting α- and δ-conglutin.     

罗非鱼肌浆蛋白源抗氧化肽的制备、分离纯化及其体外抗氧化活性

采用木瓜蛋白酶对罗非鱼肌肉蛋白组分(肌浆蛋白、肌原纤维蛋白、基质蛋白)进行酶解,研究罗非鱼不同蛋白组分酶解产物的抗氧化活性,并通过超滤、凝胶过滤色谱、反相高效液相色谱对高活性肌浆蛋白组分抗氧化肽进行分离纯化,同时对纯化后的抗氧化肽氨基酸组成予以分析.结果表明:罗非鱼肌浆蛋白酶解物(tilapia sarcoplasmi...     

Phytochemical composition and bioactivities of lupin: a review

Lupin is a nonstarchy grain legume with high protein, dietary fibre and low fat contents. The industrial shift of lupin seed utilisation from feed to food has recently increased the scientific interest to explore its phytochemical composition and biological activities. Lupin seeds contain significant amounts of polyphenols, carotenoids, phytosterols, tocopherols, alkaloids and peptides with antioxidant, antimicrobial, anticarcinogenic and anti‐inflammatory activities. Among polyphenols, genistein and their derivatives (isoflavones) are of great importance because of their phytoestrogenic potential. This comprehensive review will help out the readers in understanding the phytochemicals present in lupin and their benefits.     

Development of a real-time PCR method for the simultaneous detection of soya and lupin mitochondrial DNA as markers for the presence of allergens in processed food

Lupin and soya are members of the Leguminosae family which are recognised as some of the richest source of vegetable proteins. Lupin- and soya-containing products are available on the EU market and could cause severe adverse reactions in allergic individuals, even if consumed at low concentrations. In this context the development of methods for reliable detection of these allergens in food products is a useful tool for the surveillance of established legislation on food labelling within the EU. This work described the development of a duplex real-time PCR method allowing the simultaneous detection of traces of lupin and soya in processed food based on a specific TaqMan® probe designed on a mitochondrial tRNA-MET gene. A set of primers and probes was designed for the amplification of a 168 and 175 bp fragment of lupin and soya mitochondrial DNA, respectively. The performance of the method was established using lupin and soya flours and cookies baked from lupin- and soya-containing dough (different concentrations and baking times). The PCR platform yielded consistent and repeatable results. The specificity of the system was tested with DNA from 28 plant species. The sensitivity of the method was suitable to detect allergenic ingredients in the low mg per kg range. Both lupin and soya at a level of 2.5 mg per kg food matrix could be detected in cookies baked at 180 °C for 10 min. The method was successfully applied to bakery (e.g. bread) and vegetarian (e.g. non-meat sausages) food products that contain or may contain soya and/or lupin as ingredient or contaminant (according to the declaration on the product label).     

Chemical, nutritional and sensory properties of bread supplemented with lupin seed (Lupinus albus) products

Sweet lupin Lupinus albus seed flour (SLSF), two sweet lupin protein isolates (SLPI-I and SLPI-II) and sweet lupin seed protein concentrate (SLSPC) were added to wheat flour (WF) in an amount of 3, 6, 9 and 12% of wheat flour. The effects of lupin products supplementation on physical dough properties were studied using a Brabender farinograph. Loaves were prepared from the various blends using the straight dough procedure and then evaluated for volume, crust and crumb colour, crumb texture, flavour and overall quality. Water absorption, development time and dough weakening were significantly (P < 0.05) increased as the lupin product levels increased in all doughs; however, dough stability decreased. Lupin products could be added to WF up to 9% level (SLPI-I and SLPI-II) and 6% level (for other lupin products), without any observed detrimental effect on bread sensory properties. No significant (P > 0.05) differences were recorded in loaf volume between control and breads containing SLPI-I and II (up to 9% level) and SLSPC (up to 3% level). Addition of lupin products increased the content of protein and total essential amino acids, especially lysine. The addition also improved in-vitro protein digestibility.     

A real-time PCR method for the detection and quantification of lupin flour in wheat flour-based matrices

Lupin flour is growingly being used in bakery products, mainly as a soybean protein substitute. The aim of the present work was to detect and quantify the presence of lupin flour in wheat-based foods using a newly set up qPCR system based on SYBR green. Although DNA sequence information for lupin is scarce, it has been possible to design a primer pair highly specific for the target gene and devoid of any primer-dimers amplification capacity. Lupin flour revealed to be a difficult matrix, since large amounts of compounds tend to co-purify with DNA, even adopting well established extraction protocols. Nonetheless, the primers used allowed to reach high PCR efficiencies and did not show any cross-reactivity with DNAs extracted from various plant and animal foods. The sensitivity achieved was 7 pg of lupin DNA, corresponding to a percentage of less than 0.1% of lupin flour in the foods.     

Lupin seed γ-conglutin: Extraction and purification methods - A review

BackgroundLupin, the largest legume crop in Australia, is gaining global attention because of its unique protein γ-conglutin, which has shown promise as a nutraceutical for controlling blood glucose level and thus reducing the risk of type II diabetes development. Type II diabetes is a chronic condition affecting millions of individuals worldwide, which urgently requires natural side effect free therapies as alternatives to currently used drugs. Purification of γ-conglutin opens up a new avenue for high-value products from lupin seeds as nutraceuticals, the market for which is predicted to reach US$ 250 billion by 2018 (Dutta, Mahabir, & Pathak, 2013).Scope and approachPreviously, several research groups have reported trials on extracting and purifying proteins from lupin seed. However, most of these methods have focussed on protein isolates as food ingredients. Very few reports have aimed to purify γ-conglutin from the total proteins, but the methods reported are time-consuming and unsuitable for commercial scale production of high purity γ-conglutin due to the involvement of many processing steps for nutraceutical application. Hence there is a need to fully understand all reported γ-conglutin extraction and purification processes in terms of their advantages and limitations, so that an effective scalable purification process for nutraceutical grade γ-conglutin may be designed in the future.Key findings and conclusionsThis article reviews reported extraction and purification methods for γ-conglutin, to provide a basis for the development of novel purification technique/process for this potentially highly valuable protein.     

Some chemical properties of white lupin seeds (Lupinus albus L.)

Lupin seeds (Lupinus albus L.), grown in Turkey, were investigated. Density, thousand grain weight, and hectolitre weight of seeds were 1.16 g/cm³, 411.4 g, and 68.12 kg/100 l, respectively. The results showed that lupin contained high amounts of protein (32.2%), fibre (16.2%), oil (5.95%), and sugar (5.82%). Oil of seeds was composed of 13.5% saturated, 55.4% monounsaturated, and 31.1% polyunsaturated fatty acids. Sucrose constituted 71% of total sugar content of seeds. Lupin seeds contained 3.9 mg/kg of thiamin, 2.3 mg/kg of riboflavin and 39 mg/kg of niacin. It can be concluded that lupin is an excellent food material with a high nutritional value.     

Emulsifying and Foaming Properties of Different Protein Fractions Obtained from a Novel Lupin Variety AluProt‐CGNA® (Lupinus luteus)

The use of vegetable proteins as food ingredient is becoming increasingly important due to their high versatility and environmental acceptability. This work describes a chemical characterization and techno‐functional properties (emulsifying and foaming properties) of 3 protein fractions obtained from a protein‐rich novel lupin variety, AluProt‐CGNA^®. This nongenetically modified variety have a great protein content in dehulled seeds (60.6 g protein/100 g, dry matter), which is higher than soybean and other lupin varieties. A simple procedure was utilized to obtain 3 different fractions by using alkali solubilization and isoelectric precipitation. Fractions 1 and 3 were mainly composed of protein and polysaccharides (NNE), whereas fraction 2 was mainly composed by protein (97%, w/w). Fraction 3 presented interesting and potential foaming properties in comparison to the other fractions evaluated in the study. Besides, its solubility, foaming and emulsifying capacity were practically not affected by pH variations. The 3 fractions also presented good emulsion stability, reaching values above a 95%. SDS‐PAGE showed that fractions 1 and 2 contained mainly conglutin α, β, and δ, but in different ratios, whereas fraction 3 contained mainly conglutin γ and albumins. The results of this work will provide better understanding for the utilization of each protein fractions as potential ingredients in food industry.     

Nutritional,Health, and Technological Functionality of Lupin Flour Addition to Bread and Other Baked Products: Benefits and Challenges

Lupin is an undervalued legume despite its high protein and dietary fiber content and potential health benefits. This review focuses on the nutritional value, health benefits, and technological effects of incorporating lupin flour into wheat-based bread. Results of clinical studies suggest that consuming lupin compared to wheat bread and other baked products reduce chronic disease risk markers; possibly due to increased protein and dietary fiber and bioactive compounds. However, lupin protein allergy has also been recorded. Bread quality has been improved when 10% lupin flour is substituted for refined wheat flour; possibly due to lupin-wheat protein cross-linking assisting bread volume and the high water-binding capacity (WBC) of lupin fiber delaying staling. Above 10% substitution appears to reduce bread quality due to lupin proteins low elasticity and the high WBC of its dietary fiber interrupting gluten network development. Gaps in understanding of the role of lupin flour in bread quality include the optimal formulation and processing conditions to maximize lupin incorporation, role of protein cross-linking, antistaling functionality, and bioactivity of its γ-conglutin protein.     

Effect of acid- and alkaline-aided extractions on functional and rheological properties of proteins recovered from mechanically separated turkey meat (MSTM)

Functional and rheological characteristics of acid- and alkali-extracted proteins from mechanically separated turkey meat (MSTM) have been investigated. Extractions were carried out at 4 pH values (2.5, 3.5, 10.5, and 11.5). The study demonstrated that alkali and acid extractions resulted in significant (P < 0.0001) decreases of cooking and water loss compared to raw MSTM; however, the cooking loss was found to be similar (P = 0.5699) among the different protein isolates. Proteins extracted at pH 10.5 showed the lowest (P = 0.0249) water loss. Emulsion and foaming properties were found to be slightly higher in alkali-extracted proteins compared to those for acid extractions. The myofibrillar protein fraction showed better ability to form and stabilize emulsions compared to sarcoplasmic proteins. Myofibrillar proteins also showed better foam expansion; however, foam volume stability was similar for both myofibrillar and sarcoplasmic protein fractions. Textural characteristics (hardness, chewiness, springiness, and cohesiveness) of recovered proteins were found to be unaffected (P > 0.05) by different extraction pH. The protein extracted at pH 3.5 formed a highly viscoelastic gel network as evidenced by storage modulus (G') values, whereas the gel formed from proteins extracted at pH 10.5 was found to be the weakest. The work also revealed that acid treatments were more effective for removal of total heme pigments from MSTM. Color characteristics of protein isolates were markedly improved compared to the initial material and tended to be better when subjected to acid extractions. PRACTICAL APPLICATION: Mechanically separated meat is one of the cheapest sources of protein obtained by grinding meat and bones together and forcing the mixture through a perforated drum. The use of mechanically separated turkey meat (MSTM) for the production of further processed poultry products is limited due to its undesirable color and textural properties. Recovery of proteins from MSTM using pH shifting process will help the poultry processors to get better returns and also create opportunity to produce functional food ingredients.     

Storage Proteins of Glandless Cottonseed Flour

The salt-soluble storage protein isolate of defatted glandless cottonseed flour was separated by gel filtration column chromatography into six fractions (I to VI). Column and thin-layer gel filtration showed that these fractions had molecular weights of >600,000, 280,000, 127,000, 63,500, 10,700, and <2,000, respectively. Treating fraction I protein with dilute alkali dissociated a component that migrated upon gel filtration with fraction VI. Both fractions I and VI were yellow and the color intensified at alkaline pH, suggesting the presence of bound flavonol and gossypol pigments. Because of its large size and low (16.6%) protein content, fraction I was thought to be fragments of membrane and aleurone gram globulins. Gradient polyacrylamide gel electrophoresis (PAGE) showed that the proteins in each fraction being completely recovered from column chromatography were represented in the pattern of the initial isolate. The proteins in fractions II and III have similar ammo acid compositions, except that III is low in methionine, cystine and tryptophan and II is low in tyrosine and phenylalanine. The amino acid composition of fraction I was also similar to fractions II and III, while unique patterns were noted for fractions V and VI. Fraction VI was rich in lysine and arginine.     

羽扇豆蛋白的提取及性质研究

采用碱溶酸沉法对羽扇豆蛋白进行提取,利用响应面法对羽扇豆蛋白的提取工艺进行优化,得到最佳提取工艺是:pH为9.9,液料比15.7,温度为55.5℃,提取时间为30.4min,蛋白最佳得率为13.2%。按照Osborne蛋白分级提取方法对羽扇豆蛋白进行了精细分类,分别得到了羽扇豆清蛋白、球蛋白、醇溶蛋白和谷蛋白,其中球蛋白含量最高。羽扇豆蛋白的功能性质,包括溶解性、持水持油性、乳化性质,也进行了测定。