| Purine (C5H5N4) is an important component of nucleic acids, and one of the important matter in organism metabolism. Body synthesis, nucleic acids decomposition of human tissue and food intaking are the main sources of purine. While intaking of purine-rich foods long-term along with some induced factors can cause purine metabolism diseases, such as gout. We should pay more attention to limit excessively intaking purine-rich food besides traditional medical trement.Meat and seafood contain much purine. especially in animal innards (liver) and gravy. the content even reaches as much as1%. However, there is no accurate data on purine content of food in our food composition table, it is reported that values of purine content of food vary greatly. Therefore, the establishment of accurate, simple and feasible method for the detection of food purine content, and accurate detection of the purine content of various foods can provide datas for supplementing and improving food composition database, as well as can provide the basis for the dietary of patients with gout and other disorders of purine metabolism, which have important public health significance to prevent hyperuricemia and gout.The purine content in edible fungue such as mushroom and flmmulina was determined by high performance liquid chromatography (HPLC). The conditions for extraction of the edible fungue and separation of several purines by HPLC were optimized. The contents of adenine. xanthine and hypoxanthine were determined. Some technological parameters used in the process of edible fungues may have an effect upon purine content, and the effects of purine content in the sample were researched.1. The optimum chromatographic separation of mobile phase and its proportion, column temperature and flow-rate has been determined in the determination of hplc. The HPLC determination method of adenine. xanthine and hypoxanthic has established. The optimization of chromatographic conditions:Eclipse XDB-C18reversed-phase chromatography column (4.6×250nm,5μm), methanol/water(5/95)as mobil phase, flow velocity at0.8ml/min, column temperature at30℃. sample size20μl detection of ultraviolet wavelength for254nm.2. The contents of adenine. xanthine and hypoxanthine in mushroom were determined by HPLC. There is a comparison of purines extracion efficiency between HCLO4hydrolysis and ultrasonic extraction. Several factors impact on the extraction rate in ultrasonic extraction, e.g.:solid-to-liquid ratio, time and temperature of extraction have been investigated. The experiment showed that the best conditions of ultrasonic extraction:take2g sample, added8ml water,60℃ultrasonic extraction90min. centrifuge for10min at5000r/min speed, then extract twice. Choose the uoltrasonic extraction method which only take water as extraction agent, could avoid interruptions and pollutions of organic solvents. Compared with HCLO4hydrolysis, this method is convient, simple.3. Purines in several common edible fungues have been determined by HPLC, and the specific data:mushroom36.4±1.22mg/100g, flammulina33.52±1.16mg/100g, pleurotus ostreatus,pleurotus cornucopiae25.14±0.97mg/100g, agaricus bisporus23.47±1.56mg/100g, pleurotus eryngii15.63±0.84mg/100g, straw mushroom12.27±1.13mg/100g. agrocybe cylindraceal2.22±0.75mg/100g, the data base of purines in common edible fungus has been established.4. Some technological parameters such as heating, acity, colour protection, hardening and microwave used in processes of edible fungues may have an effect upon purine content, and the effects of purine content in the sample were researched in order to understand the purine dynamic changes of edible fungus in the course of working. The research showed that:there is a little decrease in dehydrated mushroom removing moisture content influence. Different pH caused different changes, and different purines varied differently. There is a high point of purines at pH3.0and reverse at pH4.0. Within20min boiled time, purine content decreased by more than80%. and after then the decline tends to gentle. Microwave heating have little implication to purine content. Vc can reduce purine content in sample, and2‰Vc made purine content to decrease to a minimum. Na2S2O5could reduce purin content in sample, and also there is a lowest point at2%o concentration.5. We divided flammulina velutipe into soluble and insoluble fraction, and dried into powder, respectively then the purines were determined. The results as follows:flammulina velutipe whole powder1.2534mg/g. flammulina velutipe soluble power1.2375mg/g, flammulina velutipe insoluble powder0.7031mg/g. Make distinctions among the whole powder, soluble and insoluble fraction. It turned out purines in insoluble fraction was the lowest, in which the purine content droped by43%than the whole powder. These datas provides a reference for the scientific and reasonable apply of flammulina products. |
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