酿造黄酒用粮食原料中嘌呤的检测研究

建立了酿造黄酒用粮食原料中嘌呤含量的多组分高效液相色谱分析方法。采用三氟乙酸∶甲酸(1∶1)在沸水浴下水解样品30 min,氮吹除去大部分酸,然后调pH值至5~7,用滤膜过滤后进液相色谱分析。色谱条件:流动相0.02 mol/L KH2PO4-H3PO4缓冲溶液(pH4.07);色谱柱Waters Atlantis T3;流速1 mL/min;检测器为紫外检测器,检测波长为254 nm;柱温为30℃;进样量10μL。在0.1~20 mg/L浓度范围内,各嘌呤(鸟嘌呤、次黄嘌呤、黄嘌呤、腺嘌呤)的峰面积与浓度呈良好线性关系,相关系数大于0.9999。各组分平均加标回收率在84.8%~102.1%之间,RSD在2.4%~9.8%之间。将该方法应用于粮食原料中嘌呤的检测,结果显示,几种粮谷中小麦的嘌呤含量最高,黍米的含量最低。     

超高效液相色谱法检测58种大豆中的4种嘌呤化合物

嘌呤化合物是大豆中重要的天然毒素,过量摄入会诱发高尿酸血症和痛风。为揭示嘌呤化合物在不同大豆中的含量水平,本文建立检测大豆中4种嘌呤化合物的超高效液相色谱法,并对我国58种主栽大豆中4种嘌呤化合物——鸟嘌呤、腺嘌呤、黄嘌呤和次黄嘌呤的含量进行检测。结果表明,该方法在线性范围(0.2~10 mg/L)线性关系良好(R2>0.9995),检出限为0.0412~0.1001 mg/L,精密度RSD小于0.6000%,腺嘌呤、鸟嘌呤、黄嘌呤、次黄嘌呤RSD值依次为1.1103%,1.0728%,1.3762%,0.9457%,4种嘌呤化合物加标回收率在92.5902%~-100.1373%之间。试验确定了理想的提取溶剂(等体积三氟乙酸、甲酸溶液)及水解时间(30 min)。不同大豆品种中嘌呤含量为高蛋白品种>常规品种>高油、蛋脂双高品种,无腥大豆品种中嘌呤含量差异较大(2 013.06~2 824.54 mg/kg)。     

高效液相色谱法测定牛羊杂碎等肉类中嘌呤及尿酸

建立同时测定肉类食品中尿酸、鸟嘌呤、次黄嘌呤、黄嘌呤和腺嘌呤的高效液相色谱分析方法,并测定肉类样品中上述4种嘌呤及尿酸的含量。色谱条件:资生堂CAPCELL PAK-C_(18)(4.6 mm×250 mm,5μm)色谱柱,柱温30℃;流动相为7×10~(-3)mol/L KH_2PO_4-H_3PO_4(pH=3.83),流速1.0 mL/min;检测器为紫外检测器,检测波长254 nm;进样量10μL。结果:在上述条件下4种嘌呤和尿酸分离和测定效果良好,4种嘌呤和尿酸的质量浓度和峰面积在0.05~50μg/mL线性范围内线性关系良好,相关系数均在0.999 6以上,检出限在0.010~0.024μg/mL之间,精密度检测RSD为0.25%~0.81%,各组分回收率为92.0%~105.0%,方法精密度RSD为6.27%~11.09%。结论:该方法简便,快捷,可靠,各组分分离度好,可应用于肉类食品中嘌呤和尿酸的同时分析测定。     

反相高效液相色谱法同时测定黄酒中4种游离嘌呤

建立了一种简单、快捷的黄酒中4种游离嘌呤含量的高效液相色谱分析方法。在0.5~20 mg/L浓度范围内,各嘌呤的响应值与其相应浓度呈良好线性关系,相关系数大于0.9990,相对标准偏差在0.8%~1.5%,检出限在0.02~0.17 mg/L,加标回收率在89%~105%,符合分析测试要求。实验黄酒中游离腺嘌呤、鸟嘌呤、次黄嘌呤及黄嘌呤的含量分别为4.30 mg/L、1.29 mg/L、2.93 mg/L与3.92 mg/L。     

HPLC法测定豆浆中的嘌呤含量

利用HPLC法对豆浆中的嘌呤物质进行检测分析,建立腺嘌呤、鸟嘌呤、黄嘌呤和次黄嘌呤4种嘌呤物质的多组分检测条件并进行方法评价。研究表明:利用Zorbax C18反相色谱柱(4.6 mm×250 mm,5.0μm),流动相以KH2PO4缓冲液(0.02 mol/L,p H 3.0),在流速1.0 m L/min,柱温25℃,进样量10μL,检测波长(λ1)为254 nm的条件下,豆浆中的4种嘌呤达到最好分离,其精密度和回收率小于2%。     

固相萃取-反相高效液相色谱法测定小麦中的嘌呤类物质

采用Sep-PakC18 萃取柱,建立了固相萃取-反相高效液相色谱法测定啤酒酿造辅料小麦中的嘌呤类物质含量的方法.该方法准确可靠,重现性好,4种嘌呤的回收率为90.6%～96.4%,相对标准偏差(RSD)小于3%.腺嘌呤(Ade)、鸟嘌呤(Gua)、黄嘌呤(Xan)和次黄嘌呤(Hyp)的最低检测限依次为0.1,0.2,0.1,0.5mg/L.     

水煮加热对鱼肉中四种嘌呤含量的影响

目的:通过检测经过水煮的黄花鱼和鲤鱼中腺嘌呤、鸟嘌呤、黄嘌呤、次黄嘌呤的含量,探索在高温水煮过程中嘌呤含量的变化,希望以此为人们的健康饮食提供科学的指导基础。方法:采用高效液相色谱进行检测。将生样品在蒸馏水中煮10、20、30、40、60min,后分别采这5点的子样品。并以三氟乙酸∶甲酸∶水(5∶5∶1)在90℃下水解样品12min,浓缩后以0.02mol/LKH2PO4(pH=4.0)为流动相,流速1.0mL/min,柱温30℃,进样量10μL,DAD二极管矩阵检测器检测,检测波长254nm。结果:水煮过程中鱼肉嘌呤含量在10min内迅速降低,10~40min缓慢减低,40~60min保持稳定。鱼汤中嘌呤含量在10min内迅速升高,10~60min缓慢升高。200g鲤鱼中腺嘌呤含量在水煮加热过程中升高,鸟嘌呤含量无明显变化,总嘌呤和次黄嘌呤组分含量下降,200g黄花鱼的总嘌呤及4种嘌呤组分含量在水煮加热过程中下降。结论:鱼肉中嘌呤总含量在水煮加热过程中下降,黄花鱼和鲤鱼中4种嘌呤组分含量在加热过程中变化不一致。     

尿酸和嘌呤在水和磷酸盐缓冲介质中溶解度的测定

目的：测定尿酸和4种嘌呤（鸟嘌呤、次黄嘌呤、黄嘌呤、腺嘌呤）在水和磷酸盐缓冲介质中的溶解度,以期为嘌呤在体内的代谢及其终产物尿酸对心血管作用的研究提供参考。方法：在室温20℃下,将上述5种物质分别溶于蒸馏水及磷酸盐缓冲液（0.05 mol/L,p H=7.40）中制成饱和溶液,采用紫外分光光度法分别测定其浓度。结果：在水中的溶解度由高至低依次为腺嘌呤（66.15 mg/100 m L）、次黄嘌呤（39.95 mg/100 m L）、尿酸（6.23mg/100 m Ll）、黄嘌呤（1.14 mg/100 m L）和鸟嘌呤（0.17 mg/100 m L）;在磷酸盐缓冲液中溶解度由高至低依次为尿酸（194.54 mg/100 m L）、腺嘌呤（65.22 mg/100 m L）、次黄嘌呤（29.27 mg/100 m L）、黄嘌呤（2.27 mg/100m L）和鸟嘌呤（〈0.1 mg/100 m Ll）。结论：尿酸在磷酸盐缓冲液中的溶解度远远高于水中,是水中的32倍;腺嘌呤、次黄嘌呤和黄嘌呤在2种介质中的溶解度相近,鸟嘌呤在2种介质中均最难溶,甚至在磷酸盐介质中几乎不溶。     

LC-MS/MS法分析清爽型黄酒中的嘌呤含量

嘌呤是引起痛风的关键因素,检测黄酒中的嘌呤含量具有重要意义。本研究建立了一种采用液相色谱串联质谱法(LC-MS/MS)测定黄酒中嘌呤含量的方法。结果表明,清爽型黄酒中鸟嘌呤为0.67 mg/L,次黄嘌呤为0.62 mg/L,腺嘌呤为0.82 mg/L,总含量为2.12 mg/L。LC-MS/MS法样品加标回收率在98.2%-100.6%之间,相关系数大于0.995,相对标准偏差为3.8%-5.2%。     

高效液相色谱测定脱脂豆粕中嘌呤含量

为检测脱脂豆粕中嘌呤含量,利用高氯酸水解豆粕样品中的核酸,采用高效液相色谱法测定豆粕粉中嘌呤含量。测定结果表明:色谱柱为Ultimate AQ-C18(4.6 mm×250 mm,5μm);柱温25℃,进样量10μL,流速1.0mL/mim,紫外检测器波长254 nm;流动相为水、冰乙酸、四丁基氢氧化铵以997∶1.5∶1.5的比例混合,再与无水甲醇以99∶1混合。以此方法测定的腺嘌呤、鸟嘌呤、黄嘌呤、次黄嘌呤的精密度RSD分别为0.31%,0.27%,0.50%,0.41%;回收率分别为89.00%,86.90%,88.10%,81.30%。通过此方法测定脱脂豆粕粉中的嘌呤含量为253.0 mg/100g。     

Technical note: A new high-performance liquid chromatography purine assay for quantifying microbial flow

An HPLC method was developed to quantify the purines adenine and guanine and their metabolites xanthine and hypoxanthine in hydrolysates of isolated bacteria and omasal digesta and to assess the effect of using either purines only or purines plus metabolites as microbial markers for estimating microbial flow from the rumen. Individual purines and their metabolites were completely resolved on a C18 column using gradient elution with 2 mobile phases. Intraassay coefficient of variation ranged from 0.6 to 3.1%. Hydrolytic recovery of the 4 purine bases from their corresponding nucleosides averaged 101% (control), 103% (when added to bacterial isolates), and 104% (when added to omasal digesta). Mean concentrations of adenine, guanine, xanthine, and hypoxanthine were, respectively, 53, 58, 2.8, and 3.5 μmol/g of dry matter in omasal bacteria and 10, 12, 7.5, and 7.5 μmol/g of dry matter in omasal digesta, indicating that xanthine plus hypoxanthine represented 5% of total purines in bacterial hydrolysates but 41% of total purines in digesta hydrolysates. A significant negative relationship (R² = 0.53) between the sum of adenine and guanine and the sum of xanthine and hypoxanthine in digesta samples (but not bacterial isolates) indicated that 89% of the adenine and guanine originally present in ruminal microbes were recovered as xanthine and hypoxanthine. These results suggested that, when total purines are used as the microbial marker, both purines and their metabolites should be quantified and used to compute microbial nonammonia N and organic matter flows.     

Assessment of the uricogenic potential of processed foods based on the nature and quantity of dietary purines.

Foods rich in nucleic acids, which elevate serum uric acid levels, are restricted in the diets of hyperuricemic individuals. This restriction has been based on the amount of total dietary nucleic acids or all purines, assuming no differences in uricogenic effects of individual purines (adenine, guanine, hypoxanthine, and xanthine). However, inspite of their biochemical similarity, purines are metabolized differently and produce different uricogenic effects in animals and humans. Among the four purine bases, adenine and hypoxanthine have been reported to be more uricogenic than guanine and xanthine. Moreover, free adenine has been shown to be more uricogenic than its nucleoside or nucleotide when fed to animals. Changes in the contents of purines and release of free bases have been reported to occur during various cooking procedures such as stewing, roasting, boiling, and broiling of meat, poultry, and fish products. The differences in metabolic effects of individual purines, and modification in the amount and form of purines caused by processing would suggest that the uricogenic potential of processed foods should be based on the nature and quantity of dietary purines. Recent data on purine contents of processed foods, and information on metabolic effects of dietary purines are reviewed to assess the uricogenic potential of processed foods.     

Selected Nutrients in Ground and Mechanically Separated Veal

Paired samples of ground veal (GV) and mechanically separated veal (MSV) were analyzed for moisture, protein, crude fat, ash, cholesterol, purine bases and nucleic acids. The MSV product was lower than the GV in protein and hypoxanthine and higher in crude fat, ash, cholesterol, adenine and guanine, DNA and total nucleic acids than the ground product. There were no differences between the products in moisture, xanthine, RNA or total purines. The data are limited but indicate that until more data are available, care should be exercised in using high levels of this product in formulations to be consumed by people with a tendency to hyperuricemia or hypercholesterolemia.     

Effect of allicin and its mechanism of action in purine removal in turbot

Low-purine food is not only the focus of gout patients, but also the focus of contemporary green diet development. Fish are usually considered as high-purine foodstuff because of the high nutritional value and high purine content. Therefore, it is necessary to reduce purine content in fish to ensure that they are suitable for patients with hyperuricemia or gout. In this study, the effect of allicin on purine reduction in turbot during cooking was investigated using high-performance liquid chromatography, and the change of xanthine oxidase (XO) activity was also studied. Molecular docking analysis was further performed to elucidate the mechanism of purine reduction by allicin. The results revealed that in the step of soaking, allicin could reduce purine content in fish by slightly enhancing XO activity, promoting hypoxanthine transformation into xanthine. The removal of total purines in experimental and control group reached 70.45% and 57.20%, respectively. Moreover, allicin could change the thermal stability of xanthine by providing an acidic environment, resulting in the rapid decrease of xanthine and hypoxanthine levels by boiling. Thus, this study provides a simple method to decrease purine levels, suggesting a possibility that allicin can function as a purine remover in food.     

Nucleic Acid, Purine and Proximate Analyses of Mechanically Separated Beef and Veal

Deoxyribonucleic acid (DNA), ribonucleic acid (RNA), purine (adenine, guanine, hypoxanthine and xanthine) and proximate analyses of mechanically separated (MS) beef and veal were conducted to verify and evaluate changes in nucleic acid content which may result from mechanical separation. DNA and total nucleic acid levels were higher in both MS beef and veal whereas RNA levels were higher only in MS beef compared to hand deboned (HD) counterparts. Adenine, guanine and xanthine levels were higher in MS beef and veal, and hypoxanthine levels were lower compared to HD counterparts. Total purine content of MS beef did not differ from HD beef, whereas the purine content of MS veal was slightly higher than HD veal. It would appear that the addition of MS products to the diet would not significantly alter total purine consumption and hence should pose no risk to hyperuricemic individuals.     

Dietary purines in vegetarian meat analogues

BACKGROUND: The meat alternatives market offers a wide range of products resembling meat in taste, flavour or texture but based on vegetable protein sources. These high protein–low purine foods may find application in a low purine or purine‐free diet, which is sometimes suggested for subjects with increased serum urate levels, i.e. hyperuricaemia. RESULTS: We determined purine content (uric acid, adenine, guanine, hypoxanthine, xanthine) in 39 commercially available meat substitutes and evaluated them in relation to their protein content. Some of the products contained a comparable sum of adenine and hypoxanthine per protein as meat. Analysis of variance showed an influence of protein source used. Mycoprotein‐based products had significantly higher contents (2264 mg kg^?1) of adenine and hypoxanthine per kg of 100% protein than soybean‐based products (1648 mg kg^?1) or mixtures consisting of soybean protein and wheat protein (1239 mg kg^?1). CONCLUSION: Protein‐rich vegetable‐based meat substitutes might be generally accepted as meat alternatives for individuals on special diets. The type of protein used to manufacture these products determines the total content of purines, which is relatively higher in the case of mycoprotein or soybean protein, while appearing lower in wheat protein and egg white‐based products. These are therefore more suitable for dietary considerations in a low‐purine diet for hyperuricaemic subjects. Copyright © 2010 Society of Chemical Industry     

低嘌呤酿酒酵母的ARTP法诱变育种

采用常压室温等离子体(ARTP)诱变育种系统对酿酒酵母菌株A、B分别进行诱变,选育诱变菌株发酵的啤酒用高效液相色谱(HPLC)法测定腺嘌呤、鸟嘌呤、黄嘌呤、次黄嘌呤的含量,4种嘌呤在1~16 mg/L的测定范围内,相关系数R20.999,具有良好的线性关系。实验结果表明:诱变酵母菌株A-3发酵啤酒中嘌呤含量为77.67 mg/L,比初始菌株A的101.64 mg/L降低23.6%;诱变酵母菌株B-4发酵啤酒中嘌呤含量为76.26 mg/L,比初始菌株A的96.84 mg/L降低21.3%。诱变菌株A-3、B-4进行连续传代10次并进行发酵啤酒实验,诱变菌株A-3、B-4的发酵性能、发酵啤酒中总嘌呤含量和啤酒品质保持稳定。这表明ARTP诱变方法选育低嘌呤酿酒酵母菌种是可行的。     

Metabolites of nucleic acids in bovine milk

To investigate metabolites of nucleic acids in milk as by-products of protein biosynthesis, a method for determination of pyrimidine and purine compounds by reversed-phase high-pressure liquid chromatography was developed. Reproducibility of the measured compounds was 2%. Recovery of the main constituents averaged about 99%. In addition to orotic acid, allantoin, and uric acid, the free bases hypoxanthine, xanthine, and guanine, the ribonucleosides uridine, cytidine, and pseudouridine, and the ribonucleotides, guanosine 5'-monophosphate and cytidine 5'-monophosphate, were quantified in milk samples of Holstein-Friesian cows. Milk production from days 45 to 65 of lactation influenced concentrations of individual metabolites differently. Concentrations of orotic acid, allantoin, and uric acid decreased with increasing milk production, whereas concentrations of uridine, cytidine, pseudouridine, hypoxanthine, xanthine, and guanine remained unchanged. The results allowed conclusions on rate limiting steps of catabolic pathways of pyrimidines and purines and indicated relationships with protein biosynthesis. A possible role of metabolites of nucleic acids as taste factors and as substrates for milk microbes is suggested.