Retinol and carotene content of foods consumed in East Africa determined by high performance liquid chromatography

The vitamin A activity of a number of fresh and dried foods important in the diet of people in East Africa was determined by high performance liquid chromatography. The analytical results obtained were combined with data from the literature for inclusion in a comprehensive food table which has been used in a study on xerophthalmia in the United Republic of Tanzania. The importance of adopting standard procedures for reporting retinol and carotenoid values is discussed.     

Malonaldehyde content of indigenous and imported foods and foodstuffs in Nigeria

Several types of imported and locally available foods and foodstuffs in Nigeria were analysed for their malonaldehyde concentrations. The malonaldehyde levels of imported canned fish products ranged from 0·32 to 3·32 mg/kg. Thermal treatment of mackerel (Scomber scombus) reduced its malonaldehyde level but increased the oncogenic substance of other fish samples. Freezing beef for 4 days increased the malonaldehyde level with a mean of 0·48 mg/kg. The extract from boiled liver had a higher malonaldehyde level than that from raw liver. Milk and milk products did not contain any detectable quantity of malonaldehyde. The need to determine the cumulative effect(s) of ingesting small quantities of malonaldehyde for long periods and further appraisal of all food items for this oncogene are discussed.     

Determination of dyes sudans in of raw foods

The number of cases using of forbidden dyes (such as Sudan-I and Para Red) in European foodstuff (including foodstuff from Russia) were increased last time. In this case it was required to adapt existing analytical methods for the control of dyes Sudan I-IV and Para Red. It was used for this purpose high performance liquid chromatography with detectings on diode-array and MS detector. Sudan I and Para Red were detected in 3 foodstuffs from examined 49 products. Concentration levels of these dyes were varied from 3 up to 500 mg/kg. Limits of determination of the methods is: HPLC-diode-array--0.1 mg/kg and HPLC-MS--0.5 mg/kg.     

Listeria species in raw and ready-to-eat foods from restaurants

From September 1999 to March 2000, meat (pork, beef, and chicken), fish (salmon, hake, and sole), vegetable (lettuce and spinach), and Spanish potato omelette samples obtained at restaurants were collected and tested for the occurrence of Listeria spp. Listeria monocytogenes was isolated from 3 (2.9%) out of 103 studied samples. Other species isolated were Listeria grayi (13.6%), Listeria innocua (1.9%), Listeria ivanovii (5.8%), Listeria seeligeri (3.9%), and Listeria welshimeri (1.9%). Listeria was neither isolated from beef nor any type of fish.     

Total phenolic content,antioxidant and antidiabetic properties of methanolic extract of raw and traditionally processed Kenyan indigenous food ingredients

Certain indigenous foods commonly consumed by Kenyan vulnerable groups (the malnourished; children under 5 years of age; pregnant and lactating women; malnourished adults in cases of vitamin or mineral deficiencies, TB, diabetes, cancer, AIDS; refugees; orphans the elderly and the disabled) are not yet evaluated for phenolic content and health relevant functionality. The present study was therefore designed to analyze the phenolic content, antioxidant and antidiabetic properties of methanolic extract of raw and traditionally processed food ingredients. The total phenolic contents of the cereals, legumes, oil seeds and vegetables were ranged from 0.41 to 3.00 g/100 g DM. Amaranth grain (Amaranthus cruentus) and drumstick leaves (Moringa oleifera) exhibited significantly higher phenolic content than the other samples. The methanolic extract of the investigated samples showed promising levels of DPPH radical scavenging activity (81–89%); ferric reducing/antioxidant power (FRAP, 44–744 mmolL^?1 Fe[II]/g extract DM); α-amylase (10–45%) and α-glucosidase (13–80%) inhibition activities. The food ingredients with high phenolic content exhibited relatively higher antioxidant and antidiabetic activities. The results indicate that soaking + cooking is the mild processing method to preserve the phenolic compounds and their health relevant functionality in the presently investigated cereal, legume and oil grains, while cooking is suitable treatment for vegetables.     

食品中甲醛的含量与控制

在食品加工过程中,可以通过采取不使用甲醛作为添加剂或甲醛含量高的物质做原料;采用合理的加工工艺;不使用甲醛为材料制造的树脂作为食品包装材料等措施,来有效地控制食品中的甲醛含量。      

Aluminium content of foods and diets

Literature data on the aluminium content of individual foods have been compiled, summarized and presented by food groups. The contribution of aluminium from food preparation and cooking utensils and from food additives is discussed. Literature data on the daily intake of aluminium are summarized, and the contribution of food groups to daily aluminium intake is estimated. The major sources of dietary aluminium include several with aluminium additives (grain products, processed cheese and salt) and several that are naturally high in aluminium (tea, herbs and spices). The aluminium that may migrate from aluminium utensils is probably not a major or consistent source of this element. Daily intakes of aluminium, as reported prior to 1980, were 18-36 mg per day. More recent data, which are probably more accurate, indicate intakes of 9 mg per day for teenage and adult females and 12-14 mg per day for teenage and adult males.     

功能食品和功能性食品配料发展新动向

功能食品是世界食品工业新的增长点,功能性食品配料也成为国内外竟相开发的热点.文章介绍了功能食品的发展概况以及功能性食品配料的发展新动向.重点介绍了功能明显、原料广泛、安全可靠、国内外较流行的几个品种的发展新动向.     

Variation in the xanthophyll and carotene content of lucerne,clovers and grasses

The xanthophyll and carotene contents of eleven lucerne clones were found to be higher during September and November than during June and July. Both carotenoids reached a maximum at or before first flowering and then declined as blossoming progressed. Lutein decreased in November while violaxanthin increased. Six grasses and four legumes were analysed for the principal leaf xanthophylls, lutein, violaxanthin and neoxanthin, as well as total xanthophyll and carotene.     

基于拉曼光谱的胡萝卜中β-胡萝卜素的快速无损检测

目的利用实验室自行搭建的拉曼点扫描系统,以市售新鲜胡萝卜为研究对象,建立一种快速无损检测胡萝卜中的β-胡萝卜素的预测模型。方法在胡萝卜长度方向每隔1 cm进行点扫描,样品点扫描拉曼光谱曲线均先采用Savizky-Golay 5点平滑法去噪后再用Baseline方法进行去除荧光背景预处理,最后取平均值作为样品的拉曼光谱。胡萝卜中的β-胡萝卜素标准理化值按照国家标准GB/T 5009.83-2003法进行测定,理化值与1521 cm~(-1)和1156 cm~(-1)处β-胡萝卜素的拉曼特征峰强建立了多元线性回归模型。结果模型校正集的相关系数(R_C)和均方根误差(RMSEC)分别为0.9249和12.04 mg/kg,验证集的相关系数(RP)和均方根误差(RMSEP)分别为0.9155和1 1.47 mg/kg。结论基于拉曼光谱完全可以实现新鲜胡萝卜中β-胡萝卜素含量的检测,为新鲜果蔬中β-胡萝卜素含量的定量检测提供技术支撑。     

原料淀粉中铝残留量的调查分析

目的了解我国原料淀粉中铝含量,为制定和完善淀粉制品的铝限量标准提供科学依据。方法随机抽取6类229份原料淀粉样品,按GB/T 5009.182—2003《面制食品中铝的测定》处理样品,检测铝含量并进行分析。结果原料淀粉中铝含量范围为ND~190.43 mg/kg,中位数为18.14 mg/kg,平均含量达到36.04 mg/kg,多数处于较低水平。不同种类的原料淀粉中铝含量差异有统计学意义(P0.05),其中甘薯淀粉中的铝含量远高于其他原料淀粉,其含量平均值达到69.52 mg/kg,其中最大值为190.43 mg/kg。结论甘薯是富铝作物,建议加强对甘薯类淀粉制品的特殊监管。本研究初步了解了6类原料淀粉中的铝残留量,为制定和完善铝本底含量值标准提供依据。     

面食及淀粉类食品中铝含量调查

检测分析本地区面食(馒头、包子、花卷)、油条、煎饺、淀粉制品(凉皮、粉皮、粉丝)共110份食品中铝污染状况,了解明矾的使用情况,为食品安全监管提供依据。方法 按GB/T 5009.182—2003《面制食品中铝的测定》进行铝含量检测,按GB/T 2760—2011《食品安全国家标准 食品添加剂使用标准》进行评价,铝含量>100 mg/kg判为超标。因粉丝粉条无铝限量标准,不做超标判定。结果 发酵面食超标率25.7%,油条超标率为53.7%,凉皮超标率为100%。煎饺、粉皮未发现超标。发酵面食中铝污染情况有所改善,油条中铝超标情况近几年有所改善。凉皮超标情况严重。结论 发酵面食(馒头、包子、花卷)、油条、淀粉制品(凉皮、粉丝)中存在铝污染现象,易引起健康损害,应引起食品安全部门重视。粉丝中铝的形态检测与评价有待探讨。     

Changes in lycopene and beta carotene contents in aril and oil of gac fruit during storage

Gac fruits were physically measured and stored under ambient conditions for up to 2 weeks to observe changes in carotenoid contents (lycopene and beta carotene) in its aril. Initial concentrations in the aril of lycopene were from 2.378 mg/g fresh weight (FW) to 3.728 mg/g FW and those of beta carotene were from 0.257 to 0.379 mg/g FW. Carotenoid concentrations in the aril remained stable after 1 week but sharply declined after 2 weeks of storage. Gac oil, pressed from gac aril, has similar concentrations of lycopene and beta carotene (2.436 and 2.592 mg/g, respectively). Oil was treated with 0.02% of butylated hydroxytoluene, or with a stream of nitrogen or untreated then stored in the dark for up to 15 or 19 weeks under different temperatures (5 °C, ambient, 45 and 60 °C). Lycopene and beta carotene in control gac oil degraded following the first-order kinetic model. The degradation rate of lycopene and beta carotene in the treated oil samples were lower than that in the control oil but the first-order kinetic was not always followed. However, both lycopene and beta carotene degraded quickly in gac oil with the first-order kinetic under high temperature conditions (45 and 60 °C) regardless of the treatments used.     

Folate content of various Nigerian foods

Various raw and processed food items commonly consumed in three selected communities around Zaria, in northern Nigeria, have been examined for their folate contents using Lactobacillus casei. The folate levels of most of the foodstuffs were low. The estimated folate intake by individuals consuming these foodstuffs, calculated on a normal three-meals-a-day basis, was less than recommended daily intake levels.     

Saponin content of some Nigerian foods

Saponins have been extracted and purified from millet (Pennisetum typhoideum), beans (Phaseolus vulgaris), guinea-corn (Sorghum vulgare) and groundnut (Arachis hypogaea). Beans were found to contain a considerable amount of saponin—245.0 mg kg^?1, while millet, guinea-corn and groundnut contained 194.7, 72.7 and 48.8 mg kg^?1 dry weight basis respectively.     

测定食品中硝酸盐含量方法的改进

对镉还原测定食品中硝酸盐的方法进行了改进,研究了影响镉柱还原效率的因素.结果表明,当镉柱高度为5 cm,氨缓冲溶液pH 9.15～9.78,水洗脱液2～3倍于镉柱容积时,还原效率及回收率都较高.