测定保健品中番茄红素的高效液相色谱法

目的 建立不同剂型保健品中(片剂样品、粉末状样品及油状样品)番茄红素的提取方法,同时采用高效液相色谱法进行测定.方法 样品用水溶解破膜,以三氯甲烷提取,处理过程中加入维生素C及焦性没食子酸抗氧化,用HPLC测定番茄红素的含量.结果 该法的线性范围为0.01 ～ 10.0 mg/L,相关系数为0.9997,检测限为0.005 mg/L,含微胶囊的片剂,粉状,油状样及不含微胶囊的油状样品平均加标回收率分别为91.4％、96.3％、89.8％和101.8％,平均相对标准偏差分别为3.59％、3.17％、4.87％和2.86％.结论 该法操作简单,提取效率高,能有效降低前处理过程中氧化损失,是一种测定保健品中的番茄红素的可靠方法.     

保健食品中大豆异黄酮测定方法研究

目的建立高效液相色谱法测定食品中D、G、De、Ge含量的方法,探讨样品测定的影响因素。方法样品用甲醇+水(80+20,v/v)超声提取30 m in,离心定容后过0.45μm滤膜,经200×4.6 mm,5μm的C18柱分离,以甲醇+水(60+40,v/v)作流动相,时间程序洗脱,紫外检测器以波长程序测定,测定时间只需15 m in,D、G、De、Ge分离良好。结果样品的加标回收率为90.2%-108.4%,RSD在0.93%-5.2%之间。结论该方法前处理简单,准确快速,可作为同时测定保健食品中四种大豆异黄酮含量的方法。     

保健食品中3种蒽醌衍生物含量的高效液相色谱法测定

目的:建立RP-HPLC法测定保健食品中3种蒽醌衍生物含量。方法:以XTerraTMRP18(3.9 mm×150 mm,5μm)为色谱柱,流动相:甲醇+含0.5%冰醋酸水溶液(75+25),检测波长:270 nm,流速:1 ml/min,柱温:25℃,外标法定量。结果:同时测定3种蒽醌衍生物大黄酸、大黄酚、大黄素的含量,其浓度分别在5.4~54、7.5~75和8.8~88μg/ml范围内呈良好的线性关系。方法的平均回收率分别为:107.3%、99.7%、101.1%,RSD为4.2%、6.8%、7.3%。结论:该方法简便、快速,测定结果准确可靠,重现性好,可用于保健食品中蒽醌含量的测定。     

Antioxidant activity of commonly consumed plant foods of India: contribution of their phenolic content

Antioxidants are important in protection against hypertension, diabetes, cardiovascular diseases and cancer. Polyphenols are potent antioxidants in plant foods, but their contribution to such protective effects is yet to be established. This study attempted to generate a database on the antioxidant activity (AOA) and phenolic content (PC) of some plant foods commonly consumed in India and to assess the contribution of the PC to their AOA. Plant foods belonging to different food groups such as cereals, legumes, oil seeds, oils, green leafy vegetables, other vegetables, spices, roots and tubers were analysed for AOA and PC. AOA was the highest in black pepper (0.43 mg food required for 50% inhibition of the coupled auto-oxidation of β-carotene and linoleic acid in a mixture in vitro) and it had the highest PC (191 mg gallic acid equivalent/100 g food). The AOA (18.4 mg) as well as the PC (not detectable) were the lowest in sunflower oil. PC in oil seeds was higher than that in the oil, which could be due to the hydrophilic nature of phenolics and suggests the need for greater use of oil seeds than oils. A significant correlation was observed between the AOA and PC of the plant foods studied in general (r=?0.465), but the coefficient of correlation and determination were high only in spices (r=?0.86 and r²=74%, respectively) and dehusked legumes (r=?0.65 and r²=42.2%, respectively). The results suggest that phenolics may contribute significantly to the AOA of some plant foods, such as spices and dehusked legumes.     

Comparison of proximate, mineral and vitamin composition of common Brazilian and US foods

Because food analysis is costly and laborious, analytical data are frequently borrowed from tables of developed countries and incorporated in tables of developing countries. Taking advantage of the new Brazilian table of food composition, which is based on representative national sampling and actual analyses, an attempt is made to gain an insight into the adequacy of this practice by comparing data from the Brazilian and US tables in terms of the proximate, mineral and vitamin composition of 19 selected foods, common to both countries. For proximate composition, data agreement is excellent for dry whole milk; good for condensed milk, dry nonfat instant milk and canned peas; and fairly good for black beans, milk chocolate, lentils, oats, long-grain white rice and wheat flour. Greater variation is seen with minerals and vitamins. In terms of minerals, agreement is very good only for dry whole milk, good for black beans and canned peas; fairly good with milk chocolate, lentils, wheat flour and natural yogurt. For vitamins, agreement can be considered good only for wheat crackers and yogurt and fairly good for condensed milk and dry whole milk. The comparison indicates that data may be borrowed for proximate composition provided the foods are equivalent. However, caution must be taken in borrowing data for micronutrients.     

食品中硼含量测定与居民硼摄入量评估

目的 检测广东省广州市市售常见食品中的硼含量并评估居民硼的膳食摄入量。方法 于2010—2012年在广州市采集113种共687份食品,采用姜黄素分光光度法测定硼含量,结合居民膳食调查数据计算居民硼膳食摄入量。结果 不同食品硼含量差异较大,豆类硼含量为(18.69±10.27)mg/kg,坚果为(10.95±7.49) mg/kg,水果为(1.34±7.26) mg/kg,蔬菜为(1.24±0.91) mg/kg,奶、鱼、肉以及大多数的谷物含硼较少;加工食品硼含量基本与其原料硼含量一致,但有2份肉丸硼含量高达58.12和66.92 mg/kg,1份碱水粽硼含量为2.65 mg/kg;全国及广州市居民膳食中硼的日均摄入量分别为1.32 和1.71 mg,主要食物来源分别为蔬菜及其制品,分别占25.76%及21.64%,禽畜肉类及其制品分别占22.73%及33.33%,大米及其制品分别占12.12%及13.45%,豆类及其制品分别占8.33%及12.92%。结论 各类食品硼含量顺序大概为:豆类>坚果类>水果类>蔬菜类>谷类>动物性食品;个别加工食品存在违法添加硼砂(硼酸)的可能;居民日硼摄入量在WHO推荐成人日摄入硼的安全范围内,但大量摄入违法添加硼的食物可增加危害风险。     

广州市预包装食品钠含量现状 及消费者低盐饮食认知调查

摘要:目的　了解广州市预包装食品钠含量现状及消费者低盐饮食认知情况。方法　抽取广州市4间连锁超市,记录783种预包装食品营养标签上的钠含量标示情况;随机抽取超市消费者271名,通过问卷调查其低盐饮食认知情况。结果　预包装食品钠含量总标示率为99.36%,各类预包装食品的钠含量范围和中位值均有较大的差异,榨菜、方便面和肉制品的钠含量中位数分别为2360 mg/100 g、1988 mg/100 g和1703 mg/100 g。关于低盐饮食,不同职业的消费者在接受低盐饮食的宣传渠道上有差异（χ2＝14.20,P＝0.048）,消费者教育接受率为41.7%,态度正向选择率为89.50%,行为选择率为56.28%,知识平均知晓率为49.31%。结论　随着GB28050-2011《食品安全国家标准-预包装食品营养标签通则》实施,预包装食品的钠含量标示率大幅度增加。然而,消费者的低盐饮食认知程度仍然较低,相关部门还应加强低盐饮食宣传教育。     

液质联用法同时检测动物源性食品中氯霉素和甲硝唑

目的 建立同时检测动物源性食品中氯霉素和甲硝唑的液相色谱-串联质谱法。方法 在试样中加入d5-氯霉素和d4-甲硝唑,经提取净化、浓缩、过滤后用液相色谱-串联质谱(LC-MS/MS)同时进行检测。结果 该方法线性范围均为0.25~5.0ng/ml,氯霉素和甲硝唑的检出限均为0.1μg/kg(S/N=3),定量限均为0.3μg/kg(S/N=10),线性范围均为0.25~5.0ng/ml,方法相对标准偏差(RSD)小于8%,样品加标回收率在85%~101%之间。240份畜肉样品中未检出氯霉素和甲硝唑;禽肉样品中氯霉素检出率为3.3%(2/60),甲硝唑检出率为1.7%(1/60)。水产品中氯霉素检出率为34.3%(24/70),未检测出甲硝唑,其中贝类样品中氯霉素检出率为43.3%(13/30)。结论 该方法快速、灵敏、准确,可用于动物源性食品中氯霉素和甲硝唑同时测定。     

HPLC法测定油浸食品中的苯甲酸、山梨酸含量

目的建立油浸食品中苯甲酸、山梨酸等防腐剂的高效液相色谱测定方法。方法采用10%的乙醇-磷酸盐混合溶液萃取,Eclipse XDB-C18柱分离,流动相:甲醇+乙酸铵(0.02 mol/L)溶液=6+94。结果苯甲酸的线性范围0～160μg/ml,r=0.999 8,最低检出浓度为0.90 mg/kg,加标回收率在96.9%～101.5%之间;山梨酸的线性范围0～160μg/ml,r=0.999 9,最低检出浓度为0.68 mg/kg,加标回收率在95.9%～100.8%之间。结论该方法样品处理简单、快速,试剂消耗少,线性范围宽,精密度和准确度较高,完全能够满足含油食品中的苯甲酸、山梨酸的检测。     

Diet and Refsum's disease. The determination of phytanic acid and phytol in certain foods and the application of this knowledge to the choice of suitable convenience foods for patients with Refsum's disease

One hundred and fifty-one foods were analysed for phytanic acid and 57 foods for free phytol. Foods analysed included examples from all major food groups, beverages and confectionery.
No significant amount of phytanic acid was found in any food of purely vegetable origin. The sources of phytanic acid in the UK diet were confirmed to be foods derived from ruminant animals and fish. They include beef, lamb and products containing the milk fats of cows, sheep and goats. All fish were found to contain phytanic acid roughly in proportion to their fat content. Domestic and commercial fat blends containing animal fats (chiefly hydrogenated fish oils) and baked goods made from these fats contained phytanic acid: pure vegetable fat blends and foods containing them did not.
Free phytol was found in small amounts in a variety of foods but not in sufficient quantity to warrant the exclusion of any one item from the diet of patients with Refsum's disease.     

Determination of the dietary fiber content of some foods using a biological method

The evaluation of a biological method for dietary fibre determination in food was the main purpose of this study. Three-week old Wistar rats were used in this experiments. The rats were administered during two weeks a diet containing 1% of crude fibre from bread, grits, green beans, white cabbage and carrot. It was found that the biological method gave results similar to those obtained by the enzymatic one.     

毛细管气相色谱法同时检测保健食品中的肌醇和葡萄糖

目的：建立毛细管气相色谱法同时测定保健食品中肌醇和葡萄糖的分析方法。方法：肌醇和葡萄糖能在无水乙酸钠催化下与乙酸酐反应,生成相应的酯。采用程序升温,经SPB-5毛细管色谱柱分离,火焰离子化检测器检测,根据保留时间定性,峰面积定量。结果：优化了衍生化反应和气相色谱的操作条件,肌醇和葡萄糖的线性范围为0．1～5mg／ml,肌醇的检出限为5．5μg／ml,葡萄糖为4．2μg/ml。日内精密度为3．45％～3．62％,加标回收率在87．7％～105．0％。结论：本方法采用的衍生化反应操作简便,所建立的检测方法的精密度和准确度均能满足食品分析的要求,对实际保健食品样品进行了测定,取得了满意的结果。     

Determination of the differences in 2-h plasma glucose values after ingestion of carbohydrate foods and oral glucose in Caribbean non-diabetic subjects

It has been reported that mixed meals are used in clinics in developing and developed countries in screening and diagnosis of diabetes. Thus, we aimed to determine the differences in 2-h plasma glucose values after non-diabetic subjects ingested 75?g pure glucose and its equivalent content in frequently consumed carbohydrate foods in Caribbean subjects. Twenty-seven apparently healthy non-diabetic subjects (nine males, 18 females) consumed 75?g pure glucose and its carbohydrate equivalent in three ethnic test foods (bread, rice and roti) at 7 days apart. Plasma glucose and insulin levels were determined in blood samples collected before and after 60, 90, 120 and 150?min of ingestion of these foods. In comparison with each of the test foods, the postprandial 1-h and 2-h plasma glucose values and the 60, 90, 120 and 150?min incremental glucose concentrations after oral glucose load were significantly higher than the corresponding values for each of the test foods (all P<0.01). In spite of these higher postprandial glucose concentrations, the postprandial insulin responses following the oral glucose load and the test foods did not significantly differ at any time point (all P>0.05). However, the test food, roti, tended to stimulate higher absolute and incremental insulin secretions than pure glucose or any other test food (all P>0.05). Generally, the correlation between 2-h plasma glucose value after the ingestion of the pure glucose and each of the test foods was significant (all correlation coefficients were greater than 0.70, P<0.01). In conclusion, different ethnic mixed meals could serve as an alternative to glucose in routine screening and diagnosis of diabetes if its available carbohydrate content is known and quantified.     

5种动物源食品中氟啶虫酰胺残留量的气相色谱法检测及液质联用方法确证

目的:建立5种动物源食品中氟啶虫酰胺残留量的气相色谱检测及液相色谱-质谱联用确证方法。方法:4种肉和水产品样品经乙酸乙酯均质提取,提取液经凝胶渗透色谱仪和氨基固相萃取柱净化,蜂蜜经CHROMABOND XTR固相萃取柱和氨基固相萃取柱净化,气相色谱仪带电子捕获(ECD)检测器和液相色谱-串联质谱仪带电喷雾(ESI源)进行氟啶虫酰胺残留量的分析和确证分析。结果:气相色谱法中氟啶虫酰胺在10μg/kg～500μg/kg呈线性关系(r≥0.999),5种动物源食品添加氟啶虫酰胺浓度为10μg/kg～200μg/kg时,回收率为74.5%～98.2%,相对标准偏差为1.02%～7.98%,检出限(LOD)为1.0μg/kg,定量限(LOQ)为5.0μg/kg。液质联用法作为氟啶虫酰胺的确证方法,检测低限为5.0μg/kg。结论:该方法简便、快速、准确。     

Mineral content of Pakistani foods: An update of food composition database of Pakistan through indirect method

Analysis of nutrients to develop new or update food composition database is costly and time consuming. An alternate approach is to add the data on nutrients from existing literature using guidelines set by International Network of Food Data Systems (INFOODS). The currently available database for food composition in Pakistan is fairly old (2001) and thus, needs to be updated. In the present study mineral content of various foods from Pakistan was collected from existing literature and scrutinized against a set of criteria for inclusion in updated food composition database of Pakistan. Data for 37 food items with eight minerals (calcium, iron, zinc, phosphorus, magnesium, potassium, sodium and copper) fits under the criteria therefore is included in updated database for foods of Pakistan. Additionally, chromium, cobalt, cadmium, lead, nickel and manganese were also updated for 16 food items. Further, selected mineral content (iron, zinc, phosphorus and calcium) was compared with food composition Table of Pakistan (published in 2001). Comparison results showed that mineral content for most of the foods vary among two databases. The present study demonstrates feasibility of updating food composition databases thorough scientific reports on food products of a particular country.     

Children's eating behavior: the importance of nutrition standards for foods in schools

BACKGROUND: To enhance the impact of school nutrition programs on children's health, more information is needed on the associations between healthy and unhealthy food offerings during school lunch periods and children's eating behavior. The purpose of this study is to evaluate the contributions of food offerings and participation in school lunch programs on children's overall (both in‐ and out‐of‐school) eating behavior. METHODS: A cross‐sectional observational study was conducted in which 2039 students in 12 elementary and 10 middle schools reported their eating behavior and the frequencies with which they purchased meals and à la carte items in the school cafeteria. Food service managers from each school provided information on the availability of foods and beverages during school lunch periods. Multilevel regression analyses were conducted to identify school‐ and student‐level predictors of children's eating behavior. RESULTS: The availability of nutritious foods during school lunch periods was associated with healthier eating behavior among students. However, this effect was observed only among children who infrequently purchased à la carte food items, and not among those who were frequent purchasers. CONCLUSION: Increased availability of fruits, vegetables, whole grains, and low‐fat dairy products as components of school meals may be an effective strategy to promote healthy eating behaviors among children. Improving the nutrition standards for foods offered in competition with federally reimbursable school meals may enhance the positive effects of school meal programs on student eating behavior.     

鱼、虾中己烯雌酚残留的高效液相色谱法测定研究

目的:建立了高效液相色谱分析方法对鱼、虾中乙烯雌酚残留进行测定的方法。方法:ODS-C18色谱柱,流动相为0.043 mol/L磷酸二氢钠(调pH5.0)∶甲醇(70∶30),检测波长λ为230 nm,外标法定量。结果:鱼类样品中己烯雌酚在0.03291μg/ml～0.1481μg/ml范围内线性良好,r=0.982164。虾类样品中己烯雌酚在0.03291μg/ml～0.1975μg/ml范围内线性良好r,=0.986136。回收率为99.7%～104.4%;重复进样RSD=0.81%(n=5);方法检出限为2.5μg/kg。结论:高效液相色谱法测定鱼、虾中乙烯雌酚残留,方法简单,回收率和重现性良好,结果准确可靠。     

HPLC法与香草醛比色法测定保健品中的人参皂甙

〔目的〕应用高效液相色谱法和分光光度法分别同时检测保健食品中人参总皂甙的含量。〔方法〕高效液相色谱法采用短色谱柱 ,低乙晴体积分数 ,非线性梯度洗脱对 6种主要人参皂甙Rg1,Rb1,Re,Rb2 、Rc、Rd进行分析。〔结果〕方法回收率 95 .6 %～ 97.7% ,检出限 2 .2ng ,RSD =1.30 %～ 6 .90 %。分光光度法用大孔吸附树脂吸附人参总皂甙 ,经梯度洗脱处理 ,香草醛显色后测定人参总皂甙含量。方法回收率 :95 .6 %～ 10 7.4 % ,检出限 :1.2 5 μg,RSD =3.5 1%～ 4 .17%。两种方法测定人参总皂甙结果有显著性差异 (t=4 .5 1>t( 0 .0 5) =1.895 )。〔结论〕HPLC法适用于单个皂甙的测定 ,比色法适用于总皂甙含量的测定