不同烹调方法下马铃薯中部分维生素和矿物质保留因子的变化

目的研究马铃薯在不同烹调方法下各种维生素和矿物质元素的保留因子。方法将马铃薯去皮、洗涤、切割,以炒、烧、焯、炸、蒸等方法进行烹调,分别记录烹调前后的重量,采用相应的国标方法测定烹调前后马铃薯中几种维生素和矿物质元素的含量,并计算相应的保留因子。结果维生素C在烧马铃薯时保留率较高,在炒、焯、炸、蒸时损失较多;硫胺素、核黄素、维生素B6、烟酸在炒、烧、蒸时保留率较高,在焯和炸时有较大的损失;矿物质元素钾、钙、磷等在焯时损失较多,而在其它烹调方式下损失较少。结论马铃薯经烹调后各种维生素和矿物质元素都有不同程度的损失;同一种营养素在不同的烹调方法下保留因子也存在一定的差异。     

蔬菜中钙、磷、钾、钠烹调保留因子的研究

目的:研究蔬菜在不同烹调方法下钙、磷、钾、钠的保留因子,为进行膳食营养评价提供参考。方法:选择常用的11种蔬菜,以炒、炖、焯等方法进行烹调,记录烹调前后的重量,用国标方法测定烹调前后蔬菜中钙、磷、钾、钠的含量,计算相应的保留因子。结果:根菜类、鲜豆类、薯类、茄果类蔬菜炒后钙保留因子多在80%以上,叶菜炒后在60%～80%之间;焯后略低于其它烹调方法。鲜豆烹调后磷的保留因子依次为焯>炖>炒,其他蔬菜为炖>炒>焯。茄果类蔬菜钾的保留因子大于90%,经焯后叶菜、根菜类低于60%,其它蔬菜在60%～90%之间。钠的保留因子依次为炖>炒>焯,炖后在80%以上,焯后接近70%。结论:不同烹调方法处理后蔬菜中矿物质元素的损失程度差异很大,宜建立不同蔬菜的烹调后营养素保留因子库。进行膳食营养评价和选择烹调方法时,应考虑不同方法的烹调损失。     

10种野生食用鲜花维生素B1、B2、C含量测定

目前．我国自然界有可食用花卉虽然达百种以上，但常被食用的还不足总量的1／10，而目前发展较好的也只是菊花、金银花、茉莉花等数种，大量的鲜花资源有待开发。营养成分分析及评价是研究野生食用鲜花资源的基础和前提。本研究用标准方法荧光法测定鲜花中维生素B1、维生素B2及维生素C含量，同时探讨烹调加工方法对维生素的损失程度及影响。据此进行营养评价并提出具有较大开发利用和推广价值的野生食物资源。旨在填补云南野生食用鲜花营养成分空白，为花卉资源的开发和综合利用提供科学参考依据。     

烹调蔬菜如何减少维生素损失

蔬菜含丰富的维生素,但它所含是大量的水溶性维生素,遇光、遇热极易氧化分解。蔬菜不仅在烹调过程会损失许多维生素,在摘、洗、切过程也会丢失部分维生素。所以,加工蔬菜前应注意这几点:择菜结球叶菜不要剥掉未腐烂的外叶,葱蒜类蔬菜不要剥掉干的叶鞘外皮,豆类蔬菜不要剥荚。因为维生素C在常温条件下容易被氧化,保留外叶、外壳可延缓对维生素C的破坏。富含维生素A和维生素B2的蔬菜应避光保存,如胡萝卜等。去皮蔬菜在烹调前去皮,会增加维生素的损失。研究发现,根茎类蔬菜去皮后煮会损失40%的维生素C,不去皮则仅损失20%￣30%的维生素C。像…     

六种蔬菜生吃可以极速瘦身

蔬菜能生吃就尽量生吃,这样可以最大程度保留菜里的营养成分。凉拌菜越自然越好,能不焯的尽量不焯。维生素是水溶性物质,蔬菜一焯就易造成维生素的损失。专家提示,以下六种蔬菜生吃可以瘦身：     

烹调对蔬菜中类黄酮物质含量的影响

目的研究不同烹调方法对蔬菜类黄酮物质含量的影响,为开展类黄酮与健康关系的相关研究提供基础数据。方法以炒、焯、煮、微波四种方法烹调天津市售9种蔬菜,采用高效液相色谱法测定烹调前后以及汤汁中5种类黄酮物质含量。结果炒后类黄酮物质保存率较高,在54.6%~115.6%之间;焯为33.6%~107.8%;煮为31.7%~100.5%,微波保存率为43.1%~109.6%。汤汁中也有部分类黄酮物质存在,不同蔬菜经不同烹调后类黄酮转移率不尽相同,范围在1.4%~55.8%之间。结论烹调对各品种蔬菜类黄酮物质含量均有一定影响,不同烹调方法对不同蔬菜类黄酮物质含量影响不尽相同。     

食物烹调方法对含碘食盐中碘含量的影响

本实验研究了含碘食盐中碘在食物烹调中的保留率，以及食物对含碘食盐中碘的保留率的影响，选择市售的蔬菜，按民间常用的烹调方法烹调，并规定了各种烹调方法的详细步骤。采用碳酸钾固定碘，在５５０℃下硫酸锌助灰化，砷铈接触比色法测定碘含量。不同烹调方法对含碘食盐中碘的保留率影响不同。炖和蒸的烹调方式使碘的保留率一般大于炒的。烹调过程中不同蔬菜对碘盐中碘的保留率有一定的影响，茄果类、叶菜类、根茎类、豆类在炒的过程中碘保留率依次为８４．２％，５６．９％，４４．５％，３６．６％。茄果类、根茎类、豆类、畜肉类在炖的过程中碘保留率依次为６６．１％，５３．４％，４７．０％，４３．２％。食物中的有机碘稳定性高于含碘食盐中的无机碘     

烹调对食物中维生素含量的影响及保护措施的研究

本研究观察了不同烹调方法对米面食品、动物性食品和某些蔬菜中维生素含量的影响及某些保护性措施的效果。结果为:酵母发酵可以明显提高面食中核黄素的保存率。做米饭时,水洗使硫胺素和维生素PP损失20～50%;如果做捞米饭,汤中的水溶性维生素可占总量的30%;用碱煮稀饭,硫胺素几乎全被破坏,而核黄素和维生素PP不受影响。烹调动物性食品时,单纯炒(炸)使维生素损失10～30%,挂糊后再做炒(炸)则维生素的保存率接近100%;用水煮小肉块,汤中维生素的含量可占总量的30～40%。水焯蔬菜使水溶性维生素损失约30～40%,个别可达80%;炒菜时加醋,对维生素C的保护作用不明显;先切再水洗,个别切得细的菜维生素C损失比较严重,但多数菜切后水泡30min,维生素C的保存率仍大于90%。各种蔬菜烹调后β—胡萝卜素的保存率都在80%以上。     

烹调方式与维生素破坏

烹调方式大有讲究。大凡烹调方法合理、烹调时间得当,则维生素保存较多;而久焖久煮久炒后的菜肴,其维生素的损失则较多。长期摄食维生素含量不足的食物,容易发生维生素缺乏症。     

植物油食用方法对维生素E含量的影响

维生素Ｅ是人体内抗氧化作用、维持生殖功能和神经、免疫、上皮细胞正常反应的重要维生素。据1989年全国65个县调查结果,我国人群体内维生素Ｅ水平还是偏低的,有在食品中强化的必要,国家规定在植物油中强化维生素Ｅ。本实验研究了食用植物油中维生素Ｅ在食物烹调中的保留率,以及不同植物油对不同类型维生素Ｅ保留率的影响,为今后合理摄取维生素Ｅ这一人体必需的营养素提供科学的依据。1　材料和方法11　实验材料　市售的不同品牌花生油,核桃油,小磨香麻油。12　样品处理　每种食用植物油均按家庭常用方法,烹调采用了炒、炸、蒸等方式。本实…     

高效液相色谱法测定血清维生素B1和维生素B2含量

目的研究高效液相色谱测定血清中维生素B1(VB1)和维生素B2(VB2)的方法。方法采用C18反相色谱柱,以甲醇+磷酸盐缓冲溶液(pH3.5)作为流动相;二极管阵列检测器检测;采用Sep-park C18小柱吸附的样品前处理方法,考察了保留时间,洗脱液体积和比例对样品前处理效果的影响。结果方法的回收率82.67%～96.89%,变异系数<10%;线性相关系数分别为0.9985和0.9995,线性关系良好。测定正常人和肥胖人血清中VB1和VB2的含量,结果显示肥胖人血清中两种维生素的含量显著低于正常人。结论建立了HPLC测定血清中VB1和VB2的方法,肥胖人体内缺乏VB1和VB2。     

Nutrient retention in foods after earth-oven cooking compared to other forms of domestic cooking: 2. Vitamins

Effects of Pacific traditional style of cooking in an earth-oven¹ on vitamin content of chicken, lamb chops, fish, cassava, taro and palusami² were investigated. Retention of vitamins (retinol, β-carotenes, thiamin, riboflavin, niacin and ascorbic acid) in earth-oven cooked samples was compared with the retention in microwaved and oven-roasted chicken and lamb chops, microwave-cooked fish, boiled cassava and taro, and steamed cooked palusami, the nutrient analyses of all of which were conducted during the course of this study. Retention of retinol ranged from 20% to 91% for all cooked samples. Generally higher retention of this vitamin was observed in microwave cooked samples whereas the lowest retentions were characteristic of earth-oven cooked samples. Retention of more than 100% was observed for β-carotenes in cooked palusami. There was low retention of thiamin and riboflavin in most samples, with thiamin generally showing lower retention levels. Highest losses were usually observed with oven roasting, slightly more than the losses with earth-oven cooking. Microwave cooking caused the least loss of these two B vitamins. Niacin was quite stable to all the cooking methods with the retentions ranging from 63% to 95%. Retention values were comparable between similar samples cooked by different methods. Steam cooking was most detrimental to ascorbic acid in palusami. It caused a total loss of ascorbic acid from palusami upon cooking compared to earth-oven cooking after which 62% was retained in the palusami. Most ascorbic acid was retained in earth-oven cooked cassava (76%).     

Dietary sources of vitamin C, vitamin E and specific carotenoids in Spain

A cross-sectional study was conducted within the Spanish cohort of the European Prospective Investigation in Cancer and Nutrition to assess the principal food sources of vitamin C, vitamin E, alpha-carotene, beta-carotene, lycopene, lutein, beta-cryptoxanthin and zeaxanthin in an adult Spanish population. The study included 41446 healthy volunteers (25812 women and 15634 men), aged 29-69 years, from three Spanish regions in the north (Asturias, Navarra and Guipúzcoa) and two in the south (Murcia and Granada). Usual food intake was estimated by personal interview through a computerized version of a dietary history questionnaire. Foods that provided at least two-thirds of the studied nutrients were: fruits (mainly oranges) (51 %) and fruiting vegetables (mainly tomato and sweet pepper) (20 %) for vitamin C; vegetable oils (sunflower and olive) (40 %), non-citrus fruits (10 %), and nuts and seeds (8 %) for vitamin E; root vegetables (carrots) (82 %) for alpha-carotene; green leafy (28 %), root (24 %) and fruiting vegetables (22 %) for beta-carotene; fruiting vegetables (fresh tomato) (72 %) for lycopene; green leafy vegetables (64 %) for lutein; citrus fruits (68 %) for beta-cryptoxanthin; citrus fruits (43 %) and green leafy vegetables (20 %) for zeaxanthin. In conclusion, the main food sources of nutrients with redox properties have been identified in a Mediterranean country. This could provide an insight into the interpretation of epidemiological studies investigating the role of diet in health and disease.     

不同烹调方式对食物中花色苷稳定性的影响

目的研究不同烹调方式对植物性食物中花色苷稳定性的影响。方法以焯、煮、榨汁三种方法 ,处理豆、谷、薯、菜四类25种广州市售含花色苷的食物,采用超声波辅助提取,高效液相色谱法定性定量检测,比较烹调前后3种花色素检出量的变化。结果豆类和谷物中的花色素检出量,慢煮后损失率介于39.38%～93.72%之间;榨成豆浆/米糊,损失率介于16.84%～56.24%之间;慢煮豆粉/米粉,增加率介于5.58%～38.60%之间。蔬菜中的花色素检出量,榨汁后损失率介于12.65%～93.89%之间;焯后损失率介于12.00%～70.24%之间;煮后增加率介于37.48%～47.50%之间。薯类经烹调后,花色素检出量增加率介于16.00%～2320%之间。结论三种烹调方式,对豆类和谷物中花色苷稳定性的影响顺序为:慢煮>榨浆>快煮;对薯类和蔬菜食物中花色苷稳定性的影响顺序为:榨汁>煮>焯。食物中三种花色苷的稳定性顺序依次为:矢车菊素>芍药素>飞燕草素。     

Vitamin profile of cooked foods: how healthy is the practice of ready-to-eat foods?

During recent years importance of B complex vitamins, beta-carotene and vitamin C has been realised in terms of their antioxidative and anticarcinogenic properties. Fruits and vegetables are the rich sources of these vitamins. However, there are considerable cooking losses of vitamins, and information on vitamin contents of cooked foods is essential for assessing the adequacy of vitamin intakes. Secondly, there is a growing trend to consume ready-to-eat foods such as stuffed pancakes (samosa, patties), pastries, French fries; replacing traditional foods for lunch or dinner like roti, vegetable curry, bread, non-vegetarian items. Ready-to-eat foods are considered to give empty calories rather than a balanced diet. A study was undertaken to estimate ascorbic acid, folic acid, riboflavin, thiamine and beta-carotene of 263 cooked food samples and 260 meals representing dietary patterns of Asia, Africa, Europe, USA and Latin America by spectrophotometry and photoflurometry. A broad range of beta-carotene (84-2038 mcg%), riboflavin (0.01-0.48 mg%), thiamine (0.04-0.36 mg%), vitamin C (1-28 mg%) and folate (26-111 mcg%) was observed in individual foods. Bakery products and sweets were found to be poor sources and green leafy vegetables and fruits were good sources of these five vitamins. The differences between ready-to-eat foods and meals consumed during lunch or dinner were prominent for beta-carotene, ascorbic acid, riboflavin and folic acid (P < 0.05). The cooking losses were 34.6, 30, 52.2, 45.9 and 32.2% in case of ascorbic acid, thiamine, riboflavin, beta-carotene and folic acid respectively. Irrespective of whether it is ready-to-eat or a lunch/dinner food item, the contribution of vegetables in the preparations was found to make a marked impact on the vitamin profile. While results justify the concept of a food pyramid, emphasis needs to be given to types of fruits and vegetables rich in vitamins; preferably in their uncooked form, rather than considering their total consumption.     

Comparative dietary intake and sources of phylloquinone (vitamin K1) among British adults in 1986-7 and 2000-1

Using data from 7 d weighed dietary records, dietary intake and sources of phylloquinone (vitamin K1) were examined by socio-demographic and lifestyle factors in 1916 participants aged 16-64 years from the 1986-7 Dietary and Nutritional Survey of British Adults, and 1423 participants aged 19-64 years from the 2000-1 National Diet and Nutrition Survey. Using UK-specific food content data, geometric mean phylloquinone intakes were estimated as 72 (95% CI 70, 74) and 67 (95% CI 65, 69) microg/d in 1986-7 and 2000-1 respectively (P<0.001). In 1986-7, 47% of participants had phylloquinone intakes below the UK guideline for adequacy (> or =1 microg/kg body weight per d), compared with 59% in 2000-1 (P<0.001). In both surveys, daily phylloquinone intake was higher among men than women and increased significantly with age. Participants of manual occupational social class, or who were smokers, had lower phylloquinone intake than their counterparts. Participants living in Scotland and northern England had lower phylloquinone intake than those living elsewhere in mainland Britain, particularly in 1986-7 when the contribution from vegetables was also lower than elsewhere. However, by 2000-1 this regional difference was no longer significant. Overall, vegetables contributed 63% of phylloquinone intake in 1986-7 and 60% in 2000-1, with cooked leafy green vegetables (LGV) providing 23 and 19% respectively. In both surveys, the contribution of vegetables (cooked LGV in particular) was directly associated with age. These data show a decrease in phylloquinone intake from 1986-7 to 2000-1, mainly owing to lower consumption of cooked LGV.     

城乡婴幼儿维生素B_1、维生素B_2和烟酸机体营养状况分析

目的了解城市和农村地区婴幼儿维生素B1(VB1)、维生素B2(VB2)和烟酸的机体营养状况及其差异,为制定婴幼儿营养干预措施提供依据。方法抽取山东省某市0～3岁婴幼儿106名,农村0～3岁婴幼儿290名。取婴幼儿晨尿40ml,采用荧光法测定尿液中VB1、VB2和烟酸的含量。结果城市婴幼儿VB1、VB2和烟酸偏低和不足的百分比分别为1.9%、8.0%和9.1%,农村分别为4.5%、56.7%和27.1%。城乡婴幼儿机体VB1含量的中位数分别是495.00和420.56μg/g,其中12月～和24月～组城市高于农村(P<0.05)。城乡婴幼儿机体VB2含量的中位数为303.07和70.88μg/g,各年龄组婴幼儿VB2城市均高于农村(P<0.05)。城市及农村婴幼儿机体烟酸含量的中位数分别为6.31和4.22mg/g,其中6月～组、12月～组、18月～、24月～组婴幼儿烟酸含量存在城乡差异,城市高于农村(P<0.05)。结论城市和农村地区婴幼儿VB1、VB2和烟酸机体营养状况城乡差异显著,且城市均好于农村,农村地区VB2和烟酸缺乏比例较高。     

Beeswax and its unsaponifiable components as natural preservatives for butter and cottonseed oils

During recent years importance of B complex vitamins, beta-carotene and vitamin C has been realised in terms of their antioxidative and anticarcinogenic properties. Fruits and vegetables are the rich sources of these vitamins. However, there are considerable cooking losses of vitamins, and information on vitamin contents of cooked foods is essential for assessing the adequacy of vitamin intakes. Secondly, there is a growing trend to consume ready-to-eat foods such as stuffed pancakes (samosa, patties), pastries, French fries; replacing traditional foods for lunch or dinner like roti, vegetable curry, bread, non-vegetarian items. Ready-to-eat foods are considered to give empty calories rather than a balanced diet. A study was undertaken to estimate ascorbic acid, folic acid, riboflavin, thiamine and betacarotene of 263 cooked food samples and 260 meals representing dietary patterns of Asia, Africa, Europe, USA and Latin America by spectrophotometry and photoflurometry. A broad range of beta-carotene (84-2038 mcg%), riboflavin (0.01-0.48 mg%), thiamine (0.04-0.36 mg%), vitamin C (1-28 mg%) and folate (26-111mcg%) was observed in individual foods. Bakery products and sweets were found to be poor sources and green leafy vegetables and fruits were good sources of these five vitamins. The differences between ready-to-eat foods and meals consumed during lunch or dinner were prominent for beta-carotene, ascorbic acid, riboflavin and folic acid (P < 0.05). The cooking losses were 34.6, 30, 52.2, 45.9 and 32.2% in case of ascorbic acid, thiamine, riboflavin, beta-carotene and folic acid respectively. Irrespective of whether it is ready-to-eat or a lunch/dinner food item, the contribution of vegetables in the preparations was found to make a marked impact on the vitamin profile. While results justify the concept of a food pyramid, emphasis needs to be given to types of fruits and vegetables rich in vitamins; preferably in their uncooked form, rather than considering their total consumption.