巩固灭鼠先进城区期间鼠情监测研究

目的 掌握鼠类密度季节消长，为灭鼠先进城区巩固工作提供科学依据。方法 设立48个有代表性的监测点，分别采用粉迹法、夹日法和盗食法。结果 台州城区以褐家鼠为优势鼠种，1999～2004年月平均鼠密度粉迹法为1．00％～2．33％．夹日法为0．13％～0．85％，盗食法为0．28％～1．33％；出现2～3月和9～10月两个密度高峰，重点单位鼠密度显著高于居民区、一般单位和窗口单位。结论 春、秋两季是突击灭鼠的最佳时机，做好重点单位的灭鼠、防鼠是巩固灭鼠先进城区的重点。     

ELISA法与HPLC法检测太湖水中藻毒素的比较研究

目的：比较ELISA法与HPLC法检测水中微囊藻毒素含量的异同。方法：利用基于抗MC—LR多克隆抗体建立的间接竞争ELISA和HPLC法分别检测太湖中不同检测点、不同时期采集的大量水样中的MC—LR含量。结果：ELISA法和HPLC法相对误差平均值为8．62％，相关性检验t值为0．9996。在加标浓度为0．5～12．5ppb时，ELISA法回收率为94．84％～116．51％，HPLC法回收率为86．14％～92．18％。结论：两种方法具有良好的相关性，但ELISA法比HPLC法前处理简单，快速，回收率较好，更适合基层检测部门使用。     

酒中甲醇简易检测法研究

吸收了品红亚硫酸法、对品红亚硫酸法、盐酸苯肼法的优点，建立了一种检测酒中甲醇含量的的变色酸比色法。其工作曲线的相关系数ｒ＝０．９８４５，回收率为７６％～１１２％，ＣＶ值为２．４～６．１％，与国标法比较，无显著性差异（Ｐ＞０．０５）。灵敏度为０．０９ｍｇ／ｍｌ，符合食品卫生标准要求。     

脉冲进样原子吸收光谱法直接测定全血中的铁,锌,铜

在可供检测微量元素的人体材料中，血液最具代表性。在各种分析方法中，原子吸收光谱法应用较普遍。在前处理中，稀释法污染少，处理简单。为了减少患者的痛苦，我们采用手指血作为测定样品，采样方便迅速无交叉感染。本文提出了用0．1％TritonX-100稀释血液，火焰原子吸收光谱法直接测定全血中铁、锌、铜的方法。3种元素的平均回收率分别为97．9％、99．6％、97．4％；回收率范围为90．3％～104．8％、93．5％～103．6％、91．0％～106．0％；变异系数分别为2．21％、1．37％、2．19％。1实验部分实验所用水均为石英亚沸水，试剂为优级纯…     

血中铅、镉的干灰化石墨炉原子吸收光谱测定法

目的建立高温干灰化前处理石墨炉原子吸收光谱法测定血中铅、镉的方法。方法采用高温干灰化法消解血样，应用石墨炉原子吸收光谱法测定血中铅、镉，并与湿式消解法进行比对。结果采用高温干灰化前处理方法测得铅的工作曲线为Y=0．0039X-0．0009，r=0．9996；镉为：Y=0．0112X-0．0004，r=0．9996。精密度铅为1．5％～2．8％，镉为2．3％～3．1％。回收率铅为95．6％～98．6％，镉为93．6％～98．4％。通过样品检测结果的统计学分析说明，2种方法测定结果之间差异无统计学意义。结论高温干灰化前处理法可用于测定血中铅和镉。具有相关性好、重现性好、准确度高、分析速度快、操作简便及减少污染等优点。     

电感耦合等离子体发射光谱法测定鸡蛋黄牛奶中9种元素

利用电感耦合等离子体发射光谱法同时测定食物样品中９种元素。拟定了测试方法，回收率为８９．１％～１０９．５％，变异系数１．１％～１０．３％，检测限０．００１２～０．３３，均满足分析要求。为食品中多元素分析提供了快速、准确的分析方法     

石墨炉原子吸收法直接测定蒸馏酒中铅、锰含量

目的：探讨蒸馏酒中铅、锰含量的测定方法。方法：用石墨炉原子吸收法直接测定。结果：方法的检出限铅为0.0012mg／L，锰为0．0009mg／L线性范围铅为0．0050～0．1000mg／L，锰为0．0025～0．2000mg／L。回收率铅为95．0％～110％，锰为96．0％～106％。结论：该法具有操作简便、快捷，基体干扰少，灵敏度高等优点；与国标方法无显著性差异。     

火焰原子吸收法对白酒中锰的直接测定

本文研究了火焰原子吸收法对白酒稀释液的直接测定，白酒样品稀释成１０％的乙醇含量经ＨＮＯ３酸化后进行分析，方法简便迅速，对２０份样品分别进行标准曲线法和标准加入法两种类型测定，前者变异系数为０．９３％～２．１０％，后者为１．１７％～２．８１％，前者的加标回收率为９５．４％～１０７％，实验证明，火焰原子吸收法测定白酒中锰含量的方法是值得推广应用的。     

猪肉及罐头中己烯雌酚的高效液相色谱分析

ＨＰＬＣ法测猪肉及罐头中己烯雌酚，色谱柱为Ｃ（１８）径向加压柱，流动相为乙醇和水（９９＋１），紫外检测波长２８０ｎｍ。该法的回收率在９７．０％～１０１．５％之间，变异系数为２．１％～５．１％，最小检出量为０．０２μｇ。     

共沉淀-石墨炉原子吸收光谱法测定高盐食品中的铅和镉

目的：建立一种石墨炉原子吸收光谱法测定高盐食品中的铅和镉的实验方法。方法：采用氢氧化镁共沉淀法捕集铅和镉，使铅、镉离子与干扰组分分离，通过优化实验条件，选择最佳石墨炉工作条件，对高盐食品中的铅和镉进行测定。结果：铅在0～80ng／ml范围内线性关系良好，r=0．9993；镉在0～8ng／ml范围内线性关系良好，r=0．9991。样品加标回收率铅为94％～104％，镉为92％～105％。方法的检出限铅为1．8ng／ml，镉为0．15ng／ml。相对标准偏差铅为3．16％～4．15％，镉为2．90％～4．20％。结论：该法能显著降低高盐食品中氯化钠的基体干扰，具有良好的精密度和准确度。     

Phytic acid added to white-wheat bread inhibits fractional apparent magnesium absorption in humans

BACKGROUND: Phytic acid has been reported to impair the absorption of minerals and trace elements such as calcium, zinc, and iron in humans. However, limited information is available on the effect of phytic acid on magnesium absorption. OBJECTIVE: The objective was to evaluate the effect of phytic acid on fractional apparent magnesium absorption in humans. DESIGN: Two stable-isotope studies were performed with 8-9 healthy adults per study. Test meals were based on 200 g phytic acid-free wheat bread; test meals with and without added phytic acid were served on days 1 and 3 according to a crossover design. Phytic acid was added in amounts similar to those naturally present in whole-meal (1.49 mmol) and in brown bread (0.75 mmol). Each test meal was labeled with 0.7 mmol (25)Mg or 1.1 mmol (26)Mg. The total magnesium content was standardized to 3.6 mmol in all test meals. Apparent magnesium absorption was based on fecal monitoring. RESULTS: The addition of phytic acid lowered fractional apparent magnesium absorption from 32.5 +/- 6.9% (no added phytic acid) to 13.0 +/- 6.9% (1.49 mmol added phytic acid; P < 0.0005) and from 32.2 +/- 12.0% (no added phytic acid) to 24.0 +/- 12.9% (0.75 mmol added phytic acid; P < 0.01). The inhibiting effect of phytic acid was dose dependent (P < 0.005). CONCLUSION: The results show that fractional magnesium absorption from white-wheat bread is significantly impaired by the addition of phytic acid, in a dose-dependent manner, at amounts similar to those naturally present in whole-meal and brown bread.     

Influence of vegetable protein sources on trace element and mineral bioavailability

Vegetable protein sources are often mixed with cereals for complementary feeding. Both contain high levels of phytic acid, which can inhibit trace element and mineral absorption. In adults, phytic acid has been reported to inhibit the absorption of iron, zinc, calcium and manganese but not copper. There are far fewer studies in infants. Phytic acid is a strong inhibitor of iron absorption in both infants and adults, but its influence on zinc absorption in infants seems to be modest and perhaps most important in children recovering from infection. The influence of phytic acid on calcium and magnesium absorption would seem of minor importance. Because iron and zinc deficiencies are widespread in infants and young children in developing countries, the bioavailability of iron and zinc from complementary food is a major concern. Iron absorption may be as low as 2-3% from porridge based on whole-grain cereals and legumes (phytic acid approximately 1 g/100 g) even in iron-deficient subjects. Decreasing phytic acid by 90% ( approximately 100 mg/100 g dried product) would be expected to increase absorption about twofold and complete degradation perhaps fivefold or more. More modest reductions in phytic acid content may not usefully improve iron absorption. Complete enzymatic degradation of phytic acid is recommended. If this is not possible, it is recommended that the molar ratio of phytic acid to iron in an iron-fortified food be <1, preferably <0.5. At these low levels of phytic acid (20-30 mg/100 g dried product), zinc absorption should be satisfactory.     

Antioxidant and type 2 diabetes related functional properties of phytic acid extract from Kenyan local food ingredients: effects of traditional processing methods

Emerging scientific evidences reveal that phytic acid has several positive effects on human health. The antioxidant and type 2 diabetes related enzyme inhibition properties of phytic acid extract prepared from raw and traditionally processed local grains and vegetables collected from Kenya were evaluated. Phytic acid content of raw grains and vegetables ranged between 2.81-3.01 and 0.29-3.23 g/100 g DM, respectively. The phytic acid extract from raw samples revealed 59%-89% of DPPH radical scavenging capacity, 27-3,526 mmol Fe(II)/g extract of reducing power, 20%-72% of α-amylase inhibition activity and 8%-91% of α-glucosidase inhibition activity. Cooking and roasting improved the antioxidant and health relevant functionality of phytic acid extracts obtained from Kenyan local vegetables and grains, respectively.     

Dephytinization of a complementary food based on wheat and soy increases zinc, but not copper, apparent absorption in adults

Complementary foods based on cereals may contain high amounts of phytic acid, which binds strongly to minerals and trace elements. The objective of the study was to evaluate the effect of dephytinization of a cereal-based complementary food on zinc and copper apparent absorption in adults. A dephytinized complementary food (<0.03 mg phytic acid/g) and one containing the native phytic acid concentration (4 mg/g) were labeled extrinsically with stable isotopes ((70)Zn and (65)Cu). Apparent zinc and copper absorption was based on fecal excretion of nonabsorbed labels in 9 adults, using a crossover design. Stable isotopes were quantified by thermal ionization MS. Apparent fractional zinc absorption was significantly higher (P = 0.005; Student's paired t test) from the dephytinized complementary food (34.6 +/- 8.0%; mean +/- SD) than from the complementary food with native phytic acid concentration (22.8 +/- 8.8%). Apparent fractional copper absorption did not differ (P = 0.167; 19.7 +/- 5.1% dephytinized vs. 23.7 +/- 8.1% native phytic acid). These results clearly demonstrate the beneficial effect of dephytinization of a complementary food on fractional absorption of zinc but not of copper in adults. The long-term nutritional benefits of dephytinization of complementary foods should be evaluated in young children.     

Zinc absorption from a low-phytic acid maize

BACKGROUND: Phytic acid reduction in cereal grains has been accomplished with plant genetic techniques. These low-phytic acid grains provide a strategy for improving the mineral (eg, zinc) status in populations that are dependent on grains, including maize (Zea mays L.), as major dietary staples. OBJECTIVE: The objective was to compare the fractional absorption of zinc from polenta prepared from maize low in phytic acid with that prepared from a wild-type isohybrid maize (control) after short-term consumption by adults whose habitual diet is low in phytic acid. DESIGN: Healthy adults served as their own control subjects in a crossover design. All meals on 1 d consisted of polenta prepared from a low-phytic acid maize homozygous for the recessive low phytic acid 1-1 (lpa1-1). On the preceding or following day, all meals consisted of polenta prepared from a sibling isohybrid homozygous wild-type maize with a "normal" phytic acid content. The low-phytic acid maize contained approximately 60% less phytic acid than did the wild-type maize. All test meals were extrinsically labeled with zinc stable-isotope tracers. The fractional absorption of zinc was determined on the basis of fecal enrichment. RESULTS: The molar ratios of phytic acid to zinc in the polenta prepared from lpa1-1 maize and the wild-type maize were 17:1 and 36:1, respectively. The corresponding fractional absorptions of zinc were 0.30 +/- 0.13 and 0.17 +/- 0.11, respectively (P < 0.005). CONCLUSION: Substitution of a low-phytic acid grain in a maize-based diet is associated with a substantial increase in zinc absorption.     

Zinc absorption in humans from meals based on rye, barley, oatmeal, triticale and whole wheat

The absorption of zinc from meals based on 60 g of rye, barley, oatmeal, triticale or whole wheat was studied by use of extrinsic labelling with 65Zn and measurement of the whole-body retention of the radionuclide. The cereals were prepared in the form of bread or porridge and were served with 200 mL of milk. The oatmeal flakes were also served without further preparation. The absorption of zinc was negatively correlated to the phytic acid content of the meal with the highest absorption, 26.8 +/- 7.4%, from the rye bread meal containing 100 mumol of phytic acid and the lowest, 8.4 +/- 1.0%, from oatmeal porridge with a phytic acid content of 600 mumol. It is concluded that food preparation that decreases the phytic acid content improves zinc absorption.     

Effect of phytic acid and microbial phytase on the flow and amino acid composition of endogenous protein at the terminal ileum of growing broiler chickens

The effects of phytic acid and microbial phytase on the flow and composition of endogenous protein at the terminal ileum of broiler chickens were investigated using the peptide alimentation method. Phytic acid (fed as the sodium salt) was included in a synthetic diet at 8.5, 11.5 and 14.5 g/kg (or 2.4, 3.2 and 4.0 g/kg phytate-phosphorus) and each diet was fed without or with an Escherichia coli-derived microbial phytase at 500 phytase units/kg diet. A control containing no phytate was fed as a comparison to estimate basal endogenous flows. Ingestion of phytic acid increased (P < 0.05) the flow of endogenous amino acids and N by an average of 47 % at the lowest phytic acid concentration and 87 % at the highest. The addition of microbial phytase reduced (P < 0.05) the inimical effects of phytic acid on endogenous amino acid flow at all dietary phytic acid levels. The composition of endogenous protein was also influenced (P < 0.10-0.001) by increasing phytic acid concentrations and phytase addition. The effects of phytic acid and phytase on endogenous flow and composition of endogenous protein, however, varied depending on the amino acid. It is concluded that the effects of phytase on amino acid digestibility may be mediated, in part, through a route of reduced endogenous loss.     

Iron absorption from experimental infant formulas based on pea (Pisum sativum)-protein isolate: the effect of phytic acid and ascorbic acid

Infant formula based on pea (Pisum sativum)-protein isolate has been suggested as an alternative to soybean formula in countries where soybean is not a native crop, or when soybean protein cannot be used due to allergic reactions or intolerances. In the present study, Fe absorption from experimental infant formulas based on pea-protein isolate was measured in healthy non-anaemic young women. The influence of phytic acid and ascorbic acid on Fe absorption was evaluated, using a stable-isotope technique based on incorporation of Fe stable-isotope labels into erythrocytes 14 d after administration. Geometric mean Fe absorption increased from 20.7 (+1 SD 41.6, -1 SD 10.3) % to 33.1 (+1 SD 58.6, -1 SD 18.7) %; (P < 0.0001; n 10) after enzymic degradation of virtually all phytic acid. Doubling the molar ratio Fe:ascorbic acid from 1:2.1 to 1:4.2 in the infant formula with native phytic acid content also increased Fe absorption significantly (P < 0.0001; n 10); geometric mean Fe absorption increased from 14.8 (+1 SD 32.1, -1 SD 6.8) % to 22.1 (+1 SD 47.2, -1 SD 10.4) %. These results confirm the inhibitory and enhancing effects of phytic acid and ascorbic acid respectively on Fe absorption, but also indicate relatively high fractional Fe absorption from the pea-protein-based formulas. After adjusting for differences in Fe status, our data indicate that Fe absorption from dephytinised pea protein might be less inhibitory than dephytinised soybean protein as measured in a previous study (Hurrell et al. 1998).     

学前儿童膳食植酸摄入量及对锌生物利用率的影响

用改良的离子交换法测定了学龄前儿童膳食植酸的摄入量,并用植酸/锌摩尔比值及人体代谢平衡实验评价和观察植酸抑制锌吸收利用的程度。 膳食植酸平均摄入499mg/d,植酸/锌摩尔比值平均为6.66。当摄取植酸含量高的食物时,植酸/锌摩尔比值也仅达到10.6。而抑制锌吸收的临界比值范围为10～20。代谢平衡实验未观察到锌的生物利用率受到抑制。 因此,在我国目前的膳食条件下,锌缺乏与植酸关系不大。     

Antioxidant and Type 2 Diabetes Related Functional Properties of Phytic Acid Extract from Kenyan Local Food Ingredients: Effects of Traditional Processing Methods

Emerging scientific evidences reveal that phytic acid has several positive effects on human health. The antioxidant and type 2 diabetes related enzyme inhibition properties of phytic acid extract prepared from raw and traditionally processed local grains and vegetables collected from Kenya were evaluated. Phytic acid content of raw grains and vegetables ranged between 2.81–3.01 and 0.29–3.23 g/100 g DM, respectively. The phytic acid extract from raw samples revealed 59%–89% of DPPH radical scavenging capacity, 27–3,526 mmol Fe(II)/g extract of reducing power, 20%–72% of α-amylase inhibition activity and 8%–91% of α-glucosidase inhibition activity. Cooking and roasting improved the antioxidant and health relevant functionality of phytic acid extracts obtained from Kenyan local vegetables and grains, respectively.