新型甜味剂D-阿洛酮糖研究进展

稀有糖是在自然界中存在但含量极少的一类单糖及其衍生物。D-阿洛酮糖是一种重要的稀有糖,在食品、保健和医疗领域具有重要的应用价值。文中对D-阿洛酮糖的研究进展进行了综述,并展望了发展趋势。     

D-阿洛酮糖的分离纯化

通过生物法以D-果糖为原料生产D-阿洛酮糖,产物的分离纯化采用阴阳离子交换树脂脱色脱盐,再通过DTF-Ca2＋型离子交换树脂进行分离纯化。最佳分离条件：柱温60℃,10mL进样量,1mL/min流速。通过高效液相色谱测定,分离得到的D-阿洛酮糖纯度为98.3%。     

Bioproduction of D-allulose: Properties,applications, purification,and future perspectives

D-allulose is the C-3 epimer of D-fructose, which rarely exists in nature, and can be biosynthesized from D-fructose by the catalysis of D-psicose 3-epimerase. D-allulose is safe for human consumption and was recently approved by the United States Food and Drug Administration for food applications. It is not only able be used in food and dietary supplements as a low-calorie sweetener, but also modulates a variety of physiological functions. D-allulose has gained increasing attention owing to its excellent properties. This article presents a review of recent progress on the properties, applications, and bioproduction progress of D-allulose.     

D-阿洛酮糖 3-差向异构酶基因在枯草芽孢杆菌中的表达

将D-阿洛酮糖3-差向异构酶(DPE)基因利用PCR进行扩增,与枯草芽孢杆菌载体p MA5连接,构建重组质粒p MA5-cbdpe。重组质粒转入枯草芽孢杆菌Bacillus subtilis WB800感受态细胞,利用卡那霉素筛选和PCR鉴定,获得一株DPE重组枯草芽孢杆菌菌株。该重组菌株无需诱导即可产生DPE酶,18 h时酶活可达6.8 U/m L。该酶最适p H为7.0,最适温度为55℃,与大肠杆菌表达的DPE酶酶学性质相似。结果表明,DPE酶可在枯草芽孢杆菌中表达。     

Antioxidative Activity and Gelling Rheological Properties of Dried Egg White Glycated with a Rare Keto-hexose through the Maillard Reaction

ABSTRACT: The functional properties of egg white (EW) glycated with a rare D-psicose and 2 alimentary sugars (D-fructose and D-glucose) were investigated. Glycation led not only to the formation of cross-links but also to the formation of antioxidative substances to EW, the extent of which depended on the sugar used, modification, and incubation time. The temporal development of browning and fluorescence of psicose-EW was relatively faster than those of fructose-EW and glucose-EW. The psicose-EW showed the greater 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5carboxanilide (XTT) reducibility, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid radical scavenging activity, and gelling rheological properties. These results indicated that psicose-EW as a food ingredient might have the ability to improve gelling behavior and decrease oxidation reactions during food processing and storage.     

D-Psicose,a Sweet Monosaccharide,Ameliorate Hyperglycemia,and Dyslipidemia in C57BL/6J db/db Mice

ABSTRACT: D-psicose has been implicated in glycemic control in recent animal and human studies. In this study, the effects of D-psicose on glycemic responses, insulin release, and lipid profiles were compared with those of D-glucose and D-fructose in a genetic diabetes model. C57BL/6J db/db mice were orally supplemented with 200 mg/kg BW of D-psicose, D-glucose, or D-fructose, respectively, while diabetes control or wild type mice were supplemented with water instead. D-psicose sustained weight gain by about 10% compared to other groups. The initial blood glucose level maintained from 276 to 305 mg/dL during 28 d in the D-psicose group, whereas a 2-fold increase was found in other groups (P < 0.05) among diabetic mice. D-psicose significantly improved glucose tolerance and the areas under the curve (AUC) for glucose among diabetes (P < 0.05), but had no effect on serum insulin concentration. The plasma lipid profile was not changed by supplemental monosacchrides, although the ratio of LDL-cholesterol/HDL-cholesterol was ameliorated by D-psicose. The administration of D-psicose reversed hepatic concentrations of triglyceride (TG) and total cholesterol (TC) by 37.88% and 62.89%, respectively, compared to the diabetes control (P < 0.05). The current findings suggest that D-psicose shows promise as an antidiabetic and may have antidyslipidemic effects in type 2 diabetes.     

Protective effect of D-psicose against testicular atrophy induced by di(2-ethylhexyl) phthalate

The pollutant di(2-ethylhexyl) phthalate (DEHP) is a suspected reproductive toxicant. To clarify the protective effect of D-psicose on DEHP-induced testicular atrophy, we exposed rats to 1% DEHP via their diet while receiving D-psicose supplementation. A significant negative correlation was found between plasma mono(2-ethylhexyl) phthalate (MEHP) concentrations and relative testicular weight in rats given the 1% DEHP-containing diet for seven?days. There was, however, no significant difference in testicular weight compared with control in rats given the 1% DEHP-containing diet plus 2% D-psicose-supplemented water. Rats given the 1% DEHP-containing diet for 14?days showed severe testicular atrophy. Conversely, those given the diet plus 2 or 4% D-psicose-supplemented water did not develop testicular atrophy and exhibited complete spermatogenesis. Testicular weight was also restored almost completely by D-psicose. But, incomplete but significant protection was noted in rats receiving a 2% DEHP-containing diet plus 4% D-psicose-supplemented water for 14?days. The present study shows the almost complete protective effect of D-psicose against DEHP-induced testicular atrophy. Although the reproductive toxicity of DEHP in human beings remains unclear, D-psicose may act as a protective agent against oxidant-mediated testicular injury in mammals, including human beings.     

Clostridium bolteae ATCC BAA-613 D-塔格糖3-差向异构酶的诱导表达、纯化及活性研究

D-塔格糖3-差向异构酶是生物法生产新型功能性因子D-阿洛酮糖最为有效的酶。一种新型的能够编码D-塔格糖3-差向异构酶的基因CLOBOL₀0069被克隆,它来源于Clostridium bolteae ATCC BAA-613。以pUC57为克隆载体,以pET-22b（+）为载体质粒,E.coli BL21（DE3）为宿主细胞,构建了基因重组工程菌。IPTG诱导剂诱导目的蛋白的表达;通过镍柱亲和层析,杂蛋白与目的蛋白得到了很好的分离。对纯化的重组蛋白样品进行SDS-PAGE分析,在约32ku处出现明显的特征条带。通过活性研究表明,Clostridium bolteae ATCC BAA-613 DTEase属于DTEase家族,并具有较高的生物转化率,反应10h后转化率达到20%。     

Clostridium scindens ATCC35704中的D-塔格糖-3-差向异构酶的克隆表达、纯化及活性研究

D-阿洛酮糖作为一种新型低热量功能性甜味剂,可以通过D-塔格糖-3-差向异构酶家族,以D-果糖为底物C-3位异构化得到。一个新的来源于微生物Clostridium scindens ATCC 35704中ZP 0243228的D-塔格糖-3-差向异构酶基因(CS-DTE),通过克隆并成功导入E.coli BL21(DE3)中,构建了基因重组菌,诱导目的重组基因过量表达;经亲和层析纯化的重组蛋白样品进行SDS-PAGE分析,在约31 ku处出现显著的特征蛋白条带;通过对其活性检测表明,该重组酶分别以D-塔格糖和D-果糖为底物,可以生成D-山梨糖和D-阿洛酮糖,转化率分别为8.6%和27.9%。     

D-塔格糖-3-差向异构酶及其应用

D-塔格糖-3-差向异构酶（D-tagatose-3-epimerase,DTE）家族,是催化酮糖类单糖C-3位置的差向异构化反应的一类酶,也是稀有糖生产中的核心酶.随着稀有糖在食品、保健品、医药中间体等领域的广泛应用,利用DTE酶家族制备稀有糖备受关注.本文对DTE酶家族的DTEase和DPEase的来源、酶学特性、蛋白结构以及DTE酶家族在稀有糖生产中的应用现状等方面进行了综述,最后对DTE酶家族的研究趋势进行了展望.