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1.
果蔬中叶酸分析方法研究的进展   总被引:1,自引:0,他引:1  
郭丽琼  曹秋旭  吴厚玖 《食品工业科技》2012,33(10):402-406,411
叶酸是促进母体内婴儿正常生长发育和防止心血管病和肿瘤等不可或缺的一种维生素,其开发与应用已成为世界强化食品研究与开发的热点。本文主要介绍了果蔬中叶酸的结构、特性、提取方法,重点阐述了几种叶酸检测技术的原理、方法和适用范围,并比较其优缺点,最后对叶酸的研究方向和应用前景作了简要阐述。  相似文献   

2.
近十年来由于叶酸在临床方面的应用,使测定叶酸的方法得到了发展。同时,工业生产和科学实验要求测定叶酸的方法尽可能简单、准确。本文在前人工作的基础上,对叶酸的比色法作了简单的探讨。 (一)引言在1935年,人们发现了一个在酵母和肝中富集的、用于猴子抗贫血症的因子,命名为VitaminM(维生素M)。到1939年,在小鸡的肝中又发现了一个抗贫血症的因子,命名为Vitamin BC(维生素BC)。  相似文献   

3.
叶酸作为一碳代谢时的辅因子,是生物体的必需物质,对人体健康至关重要。本文综述了植物源食品中叶酸的类型与结构、叶酸合成途径及相关酶、叶酸代谢调控、发芽富集技术、叶酸提取与检测技术,并对开发快速而准确的叶酸测定方法、研发植物性食品中叶酸的富集与提取技术进行了展望。  相似文献   

4.
叶酸作为甲基供体参与了许多重要的生物化学反应过程。叶酸缺乏会引发新生儿神经管畸形、癌症、心血管疾病等。天然叶酸存在于各类食品中,但稳定性差,在加工过程中会大量损失,生物利用度低。合成叶酸常用于膳食补充剂及强化食品中,相比天然叶酸稳定性较好,生物利用度较高,但存在代谢风险。天然化叶酸是天然叶酸的稳定形式,无代谢障碍,可直接被人体吸收利用。目前,天然叶酸和合成叶酸的稳定性研究通常只聚焦在pH、温度、光照、氧气等其中一个因素。本文对比了天然叶酸和合成叶酸的代谢途径,总结了光照、温度、pH和氧气对天然叶酸和合成叶酸稳定性的影响。另外,介绍了天然化叶酸的研究进展,为其在食品领域中的开发应用提供理论依据。  相似文献   

5.
以人工制备叶酸强化面粉为测试样品,研究了不同包装材料与不同贮藏温度对叶酸强化面粉中叶酸稳定性的影响;并将叶酸强化面粉制成馒头、冷鲜面、面包、曲奇,以这些为测试样品,检测了加工过程中叶酸强化粉产品的叶酸损失率。  相似文献   

6.
叶酸在胚胎期、出生后以及成人期都非常重要,叶酸缺乏会导致多种疾病的发生。近年来,随着国内外相关文献报道,叶酸代谢过程中的关键酶亚甲基四氢叶酸还原酶和甲硫氨酸合成酶还原酶的基因存在多态性,导致个体存在叶酸代谢障碍,由此,对于5-甲基四氢叶酸的开发研究成为关键。本文对叶酸及其代谢过程进行综述,并介绍了活性叶酸及天然化叶酸的研究进展。  相似文献   

7.
研究了pH值、温度、蔗糖浓度、氧化剂浓度、还原剂浓度、光照强度等因素对叶酸稳定性的影响,提出了用啤酒酵母泥提取叶酸,加工成叶酸饮品的适宜工艺条件.  相似文献   

8.
乳酸菌发酵代谢合成叶酸的影响因素   总被引:1,自引:0,他引:1  
对嗜酸乳杆菌以及乳酸乳球菌发酵合成叶酸的影响因素进行了研究。结果表明,乳酸菌代谢合成叶酸的产率为17~100μg/L,菌种、培养时间、pH值、对氨基苯甲酸(PABA)质量浓度会影响乳酸菌合成叶酸的产量。与乳酸乳球菌乳酸亚种相比,嗜酸乳杆菌CH-2生成的叶酸产量要高。不同菌株生成叶酸的能力与pH值有关,嗜酸乳杆菌在pH值为4.2叶酸产率明显下降,乳酸乳球菌乳酸亚种产叶酸的能力则不受pH值影响。添加PABA可以显著提高乳酸菌的叶酸产率。选择适宜的乳酸菌菌株,优化发酵工艺参数可以提高乳及相关食品中叶酸的质量浓度,达到生物方式强化叶酸的效果。  相似文献   

9.
烹饪及贮藏对八种常见叶菜中叶酸含量的影响   总被引:2,自引:0,他引:2       下载免费PDF全文
叶菜是居民膳食叶酸的主要来源,我国叶菜种类丰富。为探明常见叶菜中叶酸含量及日常烹饪、贮藏对其影响,以期最大程度保留叶菜中叶酸,以八种常见叶菜为对象,液相色谱检测分析叶菜中5-甲基四氢叶酸和叶酸含量,并研究水煮、清炒、蒸制及冷藏过程中5-甲基四氢叶酸及叶酸含量变化。结果表明:菠菜中5-甲基四氢叶酸含量最高,为75.32μg/100 g,其它依次为小白菜、大白菜、生菜、紫甘蓝、青菜、甘蓝、油麦菜;叶菜中叶酸含量远低于5-甲基四氢叶酸,甘蓝中甚至无检出;烹饪方法对叶菜中5-甲基四氢叶酸和叶酸含量均有不同程度的影响,蒸制可以较好保持叶菜中叶酸含量,水煮次之,清炒效果最差;从叶酸保持角度考虑,叶菜4℃贮藏不宜超过2 d。选择合理烹饪方式及贮藏时间可有效降低叶菜中叶酸损失,进而有望改善居民叶酸缺乏现状。  相似文献   

10.
大豆叶酸的三酶法提取及微生物检测技术研究   总被引:3,自引:0,他引:3  
采用大豆品种Williams 82为试验材料,用α-淀粉酶、蛋白酶和大鼠血清酶三种酶来提取大豆中的叶酸,并用微生物法对叶酸含量进行测定。利用优化的三酶法,对121份北方地区栽培大豆的种子进行总叶酸含量测定。结果表明:α-淀粉酶、蛋白酶和大鼠血清的组合在8、100、10μl的条件下能够最大程度地提取大豆种子中的叶酸;北方地区121份栽培大豆的种子中叶酸含量为143.57~309.57μg/100g。优化得到的三酶法提取大豆种子中叶酸的方法可行,为今后谷类作物叶酸含量测定提供了参考。  相似文献   

11.
A new chemical approach to the assay of synthetic folic acid has been investigated. Folic acid is cleaved with bisulphite to give a pteridine fraction and p-amino-benzoylglutamic acid. Acid hydrolysis and subsequent esterification converted the aromatic amine to ethyl p-aminobenzoate. This ester, when analysed by gas chromatography (g.l.c.), gave consistent yields averaging 49% from 50 to 1000 μg of folic acid. The recovery being predictable, the percentage yield can be used as a correction factor for unknown samples. The present procedure can be used for synthetic folic acid.  相似文献   

12.
Folates are a group of vitamins vital for the growth and development of the central nervous system. Most of these natural derivatives of folic acid are prone to oxidation and are very sensitive towards heat, temperature, oxygen, and light. Encapsulation of folic acid within inert matrices of a polymer can improve its stability and stop its degradation by light and oxygen. Electrohydrodynamic (EHD) technology is capable of generating fine droplets ranging from micrometers to nanometers in diameter from the breakup of a jet depending on the flow rate and applied electrical potential difference. The aims of this study were to generate nano-sized particles of folic acid encapsulated in sodium alginate (Na alginate) using EHD technology and to study the effect of voltage and flow rate on particle size as well as the structure of the prepared particles. It was established that 40 mg/ml (Na alginate) concentration can be used in single jet EHD technology. However, only 10 mg/ml concentration furnished stable jetting at any applied voltage and flow rate. So, this concentration was utilized and used to encapsulate higher dosages of folic acid. It was observed that the optimum flow rate for obtaining spherical particles of uniform diameter (4.2?±?1.2 μm) was 10 μl/min at a voltage of 12 kV. Upon drying, these particles acquired a diameter in the range of 50–200 nm and became less spherical in shape. As the folic acid concentration is increased from 1 to 10 mg/ml, the percentage yield of particles at a constant Na alginate concentration increased by over 10 % and the corresponding encapsulation efficiency doubled. FTIR spectroscopic studies revealed the presence of folic acid within Na alginate matrices and also no characteristic chemical interaction between them. It can be concluded from the above research findings that, at 10 mg/ml Na alginate concentration, 10 μl/min flow rate, and 12 kV voltage, a high amount of folic acid (5 mg/ml) can be encapsulated within Na alginate matrices, with high percentage yield (70 %) and loading capacity (96 %), generating non-spherical dried beads/particles of 90–150 nm in diameter.  相似文献   

13.
The present study evaluated the release behavior of folic acid from ultrafine sodium alginate-pectin-poly(ethylene oxide) electrospun fibers under in vitro conditions. In aqueous solution, the release of folic acid at pH 1.2 (64%) was significantly higher than at pH 3 (21%). At pH 7.8, the majority of folic acid was released (97%) due to extensive swelling and partial dissolution of the fibers. In simulated gastric juice, the folic acid release profile was similar to that of aqueous solution at pH 1.2. By contrast, using the simulated pH 7.8 intestinal fluid, a lower amount (40%) of folic acid was released as compared with the aqueous alkaline solution. These results showed that the release of folic acid from the alginate fibers is affected by the constituents present in the simulated intestinal fluid, in addition to the pH effect. The in vitro release study showed that the composite alginate electrospun fibers have good potential as a carrier that retains folic acid in acidic food products (pH 3), but selectively releases the micronutrient in the small intestine.  相似文献   

14.
C.A. Boeneke  K.J. Aryana 《LWT》2008,41(7):1335-1343
Development of dairy products with new flavors and health benefits helps the dairy industry increase sales of products as well as provide consumers with products they enjoy. Folic acid is used in the prevention of neural tube defects, heart defects, facial clefts, urinary tract abnormalities, and limb deficiencies. The objective of this study was to determine the effect of different concentrations and stage of addition of folic acid on the physico-chemical and sensory characteristics of lemon yogurt over a storage period. Lemon yogurts were manufactured with 0%, 25%, 50%, 75%, and 100% of the RDA of 400 μg folic acid per 224 ml cup. Folic acid was added before and after pasteurization of yogurt mix. Moisture, ash, fat, and protein concentrations were measured at week 1 only. Folic acid concentration was measured at weeks 1 and 5. Viscosity, pH, TA, syneresis, color, and sensory analysis were measured at weeks 1, 3, and 5. Mean folic acid content values were higher when folic acid was added post-pasteurization. Average mean viscosity values were lower when folic acid added post-pasteurization. Greater syneresis was seen in samples where folic acid was added post-pasteurization. Less viscous yogurts had more free whey resulting in higher syneresis values. Level of folic acid impacted flavor scores. As level of folic acid increased, flavor scores decreased.  相似文献   

15.
Folic acid plays an important role in the prevention of neural tube defects (e.g., spina bifida and anencephaly), heart defects, facial clefts, urinary abnormalities, and limb deficiencies. Milk and milk products serve as a potential source for folic acid fortification because of the presence of folate-binding proteins that seem to be involved in folate bioavailability. Although milk is not a good source of folic acid, fortification could help in the prevention of the above-mentioned defects. The objective of this study was to examine the physicochemical characteristics of reduced fat milks fortified with folic acid. Reduced fat milks were prepared using 25, 50, 75, and 100% of the recommended dietary allowance of 400 μg of folic acid. Treatments included addition of folic acid at these levels before and after pasteurization. Color, pH, fat, protein, viscosity, folic acid concentration, folate-binding protein concentration, folate-binding protein profile, standard plate count, and coliform counts were determined on d 1, 7, 14, and 21. A consumer acceptability test was conducted on d 7. Data from the consumer panel were analyzed using ANOVA (PROC GLM) with means separation to determine the differences among treatments. Data obtained from the color, pH, fat, protein, viscosity, folic acid concentration, folate-binding protein concentration, standard plate count, and coliform counts were analyzed using the GLM with a repeated measure in time. Significant differences were determined at P < 0.05 using Tukey's Studentized Range Test. There were no differences in the electrophoretic mobility of folate-binding protein in the samples. The concentration of folic acid was significantly higher in reduced fat milks fortified with folic acid after pasteurization compared with the treatments in which folic acid was added before pasteurization. The consumer panelists did not find any significant differences in flavor, appearance, or texture of folic acid fortified reduced fat milks compared with that of the control. Fortification of reduced fat milks with folic acid can be accomplished without adversely affecting the product characteristics.  相似文献   

16.
The changes of lifestyle and eating habits of consumers have induced a growth in the demand for functional food. The aim of this work was to study the incorporation of folic acid into apple slices by using ohmic heating (OH) and vacuum impregnation (VI) at 30, 40 and 50 °C and air drying at 50, 60 and 70 °C to obtain an apple snack that is rich in folic acid. The kinetic impregnation of folic acid, texture and color were evaluated. The impregnated samples (VI) at 40 °C and vacuum-impregnated samples with ohmic heating (VI/OH) at 50 °C presented a high content of folic acid, whereas the samples air dried at 60 °C presented an important retention of folic acid. The lowest loss of firmness and color was obtained with the VI/OH treatment at 50 °C with drying at 60 °C. Therefore, the VI/OH treatment at 50 °C followed by drying at 60 °C was determined to be the best process for creating dehydrated apple slices that are rich in folic acid.Industrial relevanceThe aim of this research was to study the incorporation of folic acid into dehydrated sliced apples by using vacuum impregnation/ohmic heating (VI/OH) treatments and air drying technologies and evaluating the mechanical and optical properties of the resulting product. Two technologies, vacuum impregnation (VI) and ohmic heating (OH) were performed at 30, 40 or 50 °C with an electric field intensity of 13 V/cm using conventional heating. The results showed that the samples impregnated of apple slices by VI and VI/OH treatments reached the highest content of folic acid. However, the samples that were dried at 60 °C after impregnation by the VI/OH treatment at 50 °C exhibited an increase in folic acid due to the electropermeabilization effect, which induces retention of folic acid and an increase in the folic acid concentration by decreasing the water content. Under the investigated conditions, the VI/OH treatment at 50 °C followed by air drying at 60 °C may be considered the best processing method to obtain an apple snack that is rich in folic acid.  相似文献   

17.
A pilot scale study designed to quantify the reduction of folic acid during bread baking in Ireland was undertaken. Flour was fortified with different concentrations of folic acid and used to make four different types of commercial bread. The dispersal of folic acid in flour on a pilot scale was variable but better homogeneity would have been achieved in the final bread due to batch size and thorough mixing of the dough. Generally, the heat degradation of folic acid during baking was between 21.9% and 32.1%. Whilst the percentage degradation of folic acid in white pan loaves, white baguettes and brown soda bread were similar the result in wholemeal bread was found to be significantly higher than in other bread types tested. Taking into account all variables affecting folic acid concentration during baking, a concentration of c. 225 μg 100 g?1 folic acid would be needed in flour to deliver commercial bread in Ireland with an average folic acid content of 120 μg 100 g?1 in line with Government requirements.  相似文献   

18.
Ultra Rice®, a reconstituted rice product made by extrusion, has been successfully formulated for the fortification of market rice with vitamin A, iron and vitamin B1. As folic acid deficiency is a major health problem in areas targeted by Ultra Rice® technology, including India, Colombia and Brazil, it seems logical to incorporate folic acid into the existing formulation. The effects of various iron compounds on the storage stability of folic acid were studied. Four commercial ferric pyrophosphate compounds were chosen as iron sources and were added at different concentrations. A food‐grade whitener (TiO2) was also tested for its effects on folic acid stability and product colour. Folic acid was generally stable in the prepared rice formulations under high temperature and humidity (40 °C, 60%RH) – with the best sample retaining 95% and >75% of folic acid after 3 and 9 months of storage, respectively. The work demonstrated that folic acid fortification of rice through Ultra Rice® technology is technically feasible.  相似文献   

19.
The retention of ascorbic acid, riboflavin, niacin, Vitamin B6 and folic acid in dehydrated potato granules and flakes during home preparation and subsequent extended periods of holding at elevated temperatures on a steam table was investigated. Losses were insignificant with all vitamins during the preparation of the mashed potatoes except for riboflavin in the case of granules and folic acid in the case of flakes. Holding the mashed products on a steam table for up to 1 hr reduced the retentions of ascorbic acid and folic acid to 63% and 56% respectively in mashed potatoes made from flakes. Retention values for ascorbic acid in granules amounted to 66–67% and for folic acid they ranged from 78–86%. The holding period exerted little or no effect on retention of riboflavin, niacin, and vitamin B6.  相似文献   

20.
The objective of the present study was to determine whether a dietary supplementation of folic acid, at levels used in our previous studies, would affect ruminal fermentation and the net flux of nutrients across the rumen wall of lactating dairy cows. Approximately 4 wk after calving, 5 lactating multiparous cows were surgically equipped with a ruminal cannula, an ultrasonic flow probe around the right ruminal artery, and indwelling catheters in the right ruminal vein and the ileocolic artery. Cows were fed a total mixed ration served in 7 equal meals per d (i.e., every 3.4 h). The experimental design was an unbalanced crossover arrangement with 3 periods of 4 wk each. The vitamin supplement, incorporated in equal amounts into each meal, was supplied at 0, 3, or 6 mg of folic acid per kg of BW per d. During the last week of each experimental period, blood samples were taken simultaneously from the 2 catheters every 30 min and rumen fluid was collected every 60 min during 2 consecutive meal intervals. Dietary supplementation with folic acid had no effect on milk production (27.2 ± 1.3 kg/d) or DMI (19.9 ± 0.7 kg/d), but milk concentrations and yields of total solids, fat, and protein increased linearly with increasing doses of folic acid ingested. Concentrations of folates in rumen fluid and arterial plasma, averaged over time, increased linearly with the dose of folic acid ingested but the net flux of folates across the rumen wall was not different from zero. Concentrations of butyrate in ruminal fluid decreased quadratically with the daily supply in folic acid. Dietary supplements of folic acid had no effect on pH and osmolality of ruminal fluid, nor on ruminal concentrations of lactate, ammonia, acetate, or propionate, total VFA, or microbial counts. The uptake of urea-N by the rumen wall tended to increase quadratically with the dose ingested but net fluxes of other nutrients were not affected by treatments. These results suggest that the effects of folic acid supplements on lactational performance cannot be explained by effects on rumen metabolism.  相似文献   

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