不同烹调方法对蔬菜中总酸性物质含量和氨基态氮含量的影响

总酸性物质含量和氨基态氮含量是反映蔬菜品质的两项重要指标,蔬菜在不同的烹调方法下会发生一系列的生物化学变化,从而导致其中所含的营养成分的含量也随之发生改变。因此,采取适宜的烹调方法,在保证烹调出的菜肴具有良好的色、香、味等外观性状外,还要具有较高的营养价     

不同烹调方法对蔬菜中β—胡萝卜素含量的影响

用高效液相色谱法（HPLC）对不同烹调处理的蔬菜中的β-胡萝卜素含量变化进行了研究。结果表明：漂烫、气蒸、油炒对蔬菜中β-胡萝卜素的影响较小，其保存率依次为93．5±3．06％、88.7±1.45％、81.6±1.73％，变异系数依次为3.3％、1．6％、2．1％，而炖煮对蔬菜中β—胡萝卜素影响较大，其保存率为71．6±5．73％，变异系数为8．0％。     

烹调对蔬菜中硝态氮及Vc含量影响的研究

以菠菜、黄瓜、豇豆、胡萝卜4种有代表性的蔬菜为实验材料,研究了炒、炖、微波、蒸、焯、炸6种不同烹调方法对亚硝酸盐、硝酸盐及VC含量的影响.结果表明,不同烹调方法对4种蔬菜的亚硝酸盐含量影响显著,炒、炖、微波、蒸、焯制蔬菜亚硝酸盐下降率分别为44％～63％,58 ％～72％,46 ％～78％,31％～53％,65 ％～87％;而炸制却使菠菜和豇豆有所增加,其增长率分别为9.7％,23.1％.蔬菜中硝酸盐含量经烹调加工后都有不同程度的降低,焯、微波、炖制下降率明显,炸、炒、蒸制作用不明显.其中焯制硝酸盐的下降率最高,炸制下降率最低.大部分蔬菜中VC含量经烹调加工后都有不同程度的降低,特别是炸制VC损失率最高,为35 ％～79％,微波对蔬菜维生素损失率最低,为4 ％～18％,唯有焯制,使得叶菜菠菜VC反而增加4％.炒、炖、蒸制蔬菜VC损失率分别为11％～52％,10 ％～55％,12％～44％.综合蔬菜食用安全性和营养素保留率,可尽可能多的考虑微波、焯、炒制烹调蔬菜,少用炸、炖、蒸制法.     

不同烹调方法对野生蔬菜品质的影响

研究了漂烫、微波和油炒三种烹调方法对野生蔬菜蒲公英、荠菜一些品质的影响。结果表明，与对照相比，漂烫均导致蒲公英和荠菜的氨基态氮、总酸性物质、维生素C、可溶性糖、亚硝酸盐和硝酸盐含量降低。微波使总酸性物质、可溶性糖、硝酸盐含量增加，氨基态氮、维生素C、亚硝酸盐含量降低。油炒则使总酸性物质、硝酸盐含量增加，氨基态氮、维生素C、可溶性糖、亚硝酸盐含量降低。因此，从对人体健康的角度考虑，在食用蒲公英和荠菜时最好先经过漂烫处理以降低硝酸盐含量。     

贮藏、加工、烹调对十字花科蔬菜中硫苷物质含量的影响

十字花科芸薹属蔬菜在日常生活中极为普遍,其含有丰富的硫代葡萄糖苷物质。本文综述了不同贮藏条件、加工方法、烹调方式对不同种类十字花科蔬菜中的硫代葡萄糖苷物质的影响。     

家庭贮藏加工对蔬菜中亚硝酸盐含量的影响

采用比色法检测蔬菜中的亚硝酸盐含量。试验结果表明,不同蔬菜的亚硝酸盐含量在贮藏(常温和4℃冰箱)加工(不同煮沸时间)过程中变化明显,且有"亚硝化峰"现象。两种贮藏温度下,4℃冰箱贮藏可降低蔬菜中亚硝酸盐含量,并使亚硝化峰延迟出现;6种蔬菜中亚硝酸盐含量峰值比较为:菠菜、白菜芹菜、四季豆番茄、白萝卜;按蔬菜中亚硝酸盐限量值4.0mg/kg计,番茄和白萝卜中亚硝酸含量均未超标,而菠菜和白菜中亚硝酸含量均超标。煮沸时间在5 min~20 min内,6种蔬菜中亚硝盐含量均不超过3.5 mg/kg。以菠菜为例,煮熟后室温放置24 h~32 h期间,其亚硝酸盐含量和细菌总数迅速增加,放置至32 h,亚硝酸盐含量达到5.2 mg/kg。     

微波烹调蔬菜阻断N-亚硝胺形成的研究

研究了浙江省常见的12种蔬菜经微波烹调后阻断N-亚硝胺的形成情况.在体外模拟人体胃液的条件下,测定新鲜蔬菜、无盐无油、低盐低油及高盐高油微波烹调后蔬菜对N-亚硝胺的合成阻断率、对亚硝酸盐的清除率,并进行比较.结果表明,在元盐无油条件下蔬菜经微波烹调后,对N-亚硝胺合成阻断率、对亚硝酸清除率明显提高;低盐低油、高盐高油下蔬菜经微波烹调后,阻断率、清除率明显下降,其中,茄子、苦瓜和芹菜有促进亚硝胺形成的趋势;除胡萝卜、芦蒿外,其余蔬菜加盐、油烹调对N-亚硝胺的阻断低于新鲜蔬菜.微渡烹调蔬菜有利于阻断N-亚硝胺的形成,但应尽可能不加或少加盐、油.     

烹调对常见蔬菜抗氧化活性与成分的影响

对常见的21种蔬菜,以爆炒、炖煮、微波3种烹调方法处理,采用相关方法测定比较其烹调前后的抗氧化活性,以及VC、总多酚及总类黄酮含量,比较不同烹调方法对蔬菜抗氧化活性及相关物质含量的影响,为评价人群实际抗氧化物质摄入量及相关研究提供参考.结果表明:炖煮导致蔬菜抗氧化活性及相关物质损失较多,微波及爆炒损失较少,且有部分指标出现了增加现象.     

处置方法对菜品中亚硝酸盐含量的影响

为了减少亚硝酸盐对人体的伤害,本研究通过盐酸萘乙二胺法测定了经过不同加工方法及在4℃冰箱存放不同时间的芹菜、黄瓜和猪肉菜品中的亚硝酸盐的含量,发现在冰箱中存放的大部分菜品中的亚硝酸盐的含量前3天或前4天随着存放时间的延长而减少,从第4天或第5天开始增加或剧增,同时发现爆炒菜品在存放时间超过4d以后其中的亚硝酸盐含量往往是正常值的几倍甚至几十倍。建议人们食用新鲜菜品,冰箱存放食物的时间不要超过3d。     

食前处理方式对蔬菜中硝酸盐和亚硝酸盐含量的影响

如何降低蔬菜中的硝态氮含量受到人们日益广泛的关注。对蔬菜在贮存、漂烫、浸泡、加工等过枉中硝酸盐、亚硝酸盐含量的变化趋势及其影响因素进行了探讨,以期为人们的科学饮食提供帮助。     

不同烹调方式对蔬菜植物化学物及V_C的影响

目的:研究不同家庭烹调方法对紫薯、西兰花和青辣椒中的花色苷、硫苷、辣椒素和V C的影响。方法:三种蔬菜经过微波、蒸制、焯制和油炒等烹调后,以pH示差法测定花色苷,以高效液相色谱法测定硫苷和辣椒素,以2,6-二氯靛酚滴定法测定V C。结果:保存V C效果:蒸制>微波蒸制,焯制>油炒>微波煮制;保存花色苷效果:蒸制>微波蒸制,且蒸制使花色苷增加;保存总硫苷效果:油炒>焯制>微波煮制;保存辣椒素效果:微波煮制>焯制>油炒。结论:若控制烹调时间不过长,蒸制是最适宜保存蔬菜植物化学物及维生素的烹调方法。      

Effect of water cooking on free phytosterol levels in beans and vegetables

Plant sterols (phytosterols) are known to decrease plasma cholesterol, mainly the atherogenic LDL cholesterol. In an earlier study, the thermal stability of phytosterols in vegetable oils was reported. The aim of this present work was to investigate the potential effect of cooking (30 min in boiling water), for eight plant products (broad bean, celery, cabbage, courgette, carrot, cauliflower, onion, pepper), on the free phytosterol level. Sitosterol was the most abundant sterol, followed by campesterol. After cooking, the level of total sterols was higher in all vegetables than that before cooking, if dry matter is considered. Acid hydrolysis (active for glycosylated phytosterols) yielded a higher sterol value than alkaline hydrolysis alone (active for esterified phytosterols). This indicated that studied vegetables contained appreciable amounts of steryl glycosides. Their cooking induced higher values of free phytosterols. Cooked vegetables could give better protection against cardiovascular diseases thanks to higher phytosterol levels.     

发酵蔬菜中乳酸菌抑菌性的研究

乳酸菌(Lactic Acid Bacteria)是一类能发酵碳水化合物产生乳酸的细菌,他广泛应用于发酵食品中,是发酵蔬菜中的有益菌群。乳酸菌的抑菌功能是通过产生各种代谢产物包括酸性物质、二氧化碳、过氧化氢和细菌素等来实现的。通过分析发酵蔬菜中微生物菌群结构的组成,介绍了乳酸菌对病原菌和腐败菌的抑制作用特点及作用机理,旨在为乳酸菌制品的加工、储藏提供理论依据,更好地将乳酸菌这一益生菌应用于各类食品加工的实践操作中。     

Effect of cooking on the capsaicinoids and phenolics contents of Mexican peppers

Raw and cooked (boiled and grilled) Poblano, Bell, Chilaca, Caribe, Jalapeño, Serrano, Habanero, and Manzano peppers were evaluated for tristimulus colour, capsaicinoids (capsaicin, dihydrocapsaicin, nordihydrocapscapsaicin), and total phenolic contents. Boiling (96 °C) and grilling (210 °C) was performed under household conditions according to typical procedures of the Mexican cuisine. Contents of capsaicin (0.6–913.8 μg/g), dihydrocapsaicin (0–756.9 μg/g), nordihydrocapsaicin (0–68.2 μg/g), and total phenolics (1150.5–2190.0 μg of gallic acid equivalents/g) in raw peppers varied widely between types of peppers. Moderate losses (1.1–28.1%) in capsaicinoids were induced by boiling while grilling caused a significant increase (2.6–924.9%) in the content of these compounds. Proportion of individual capsaicinoids was similar in raw and cooked peppers. Boiling and grilling sequentially increased (7.4–137.0%) the total phenolic content in pungent peppers. Total phenolic content in non-pungent Bell peppers was reduced by cooking (1.6–26.9%). Boiling induced smaller changes in colour values (L*, a*, and b*) compared to grilling. The results demonstrated that Mexican raw peppers are rich in capsaicinoids and phenolic compounds. Household cooking can cause either decreases or increases in the content of such compounds in peppers.     

烹饪方式对猪肉品质及营养成分的影响

以猪背最长肌肉为研究对象,比较分析烹饪方式(蒸、煮、炸和烤)对其肉品质、常规营养成分、氨基酸和脂肪酸含量的影响。结果显示:与新鲜对照相比,烹饪加工后pH值、水分含量显著降低(P0.05);硬度、弹性、黏着性、灰分和粗蛋白、PUFA含量显著提高(P0.05);炸和微波的烹饪损失率显著高于蒸、煮和烘烤的(P0.05);煮的灰分含量无显著变化(P0.05),其它烹饪方式均显著升高(P0.05);炸的粗脂肪含量显著降低(P0.05),其它烹饪处理均显著升高(P0.05);烘烤显著降低了TAA含量(P0.05),其它烹饪方式均显著提高(P0.05);烘烤的DAA和EAA含量无显著变化(P0.05),其它烹饪方式均显著提高(P0.05);所有处理的EAA/TAA达到40.00%,EAA/NEAA67.00%;烹饪处理后必需氨基酸评分基本大于FAO/WHO计分模式,第一限制性氨基酸均为Val。说明烹饪处理对猪肉物理性质有不利影响,但可不同程度提高其营养价值。因此,日常生活中要根据实际需求选择适宜的烹饪方式,达到合理膳食的目的。     

发酵蔬菜中乳酸菌抑菌性的研究

乳酸菌（Lactic Acid Bacteria）是一类能发酵碳水化合物产生乳酸的细菌，他广泛应用于发酵食品中，是发酵蔬菜中的有益菌群。乳酸菌的抑菌功能是通过产生各种代谢产物包括酸性物质、二氧化碳、过氧化氢和细菌素等来实现的。通过分析发酵蔬菜中微生物菌群结构的组成，介绍了乳酸菌对病原菌和腐败菌的抑制作用特点及作用机理，旨在为乳酸菌制品的加工、储藏提供理论依据，更好地将乳酸菌这一益生菌应用于各类食品加工的实践操作中。     

Effect of different cooking methods on the antioxidant activity of some vegetables from Pakistan

The effects of different cooking methods (boiling, frying and microwave cooking) on the antioxidant activity of some selected vegetables (peas, carrot, spinach, cabbage, cauliflower, yellow turnip and white turnip) were assessed by measuring the total phenolic contents (TPC), reducing power and percentage inhibition in linoleic acid system. TPC (gallic acid equivalents g/100 g of dry weight) and reducing power of the methanolic extracts of raw‐, microwaved‐, boiled‐ and fried vegetables ranged 0.333–2.97, 0.52–2.68, 0.48–2.08, 1.00–2.02 and 0.391–2.24, 0.822–1.10, 0.547–1.16, 0.910–4.07, respectively. The level of inhibition of peroxidation ranged 71.4–89.0, 66.4–87.3, 73.2–89.2 and 77.4–91.3%, respectively. Antioxidant activity of the vegetables examined was appreciably affected because of varying cooking treatments. TPC of vegetables, generally, decreased by boiling, frying and microwave cooking. There was a significant (P < 0.05) increase in reducing power as a result of frying. However, boiling and microwave cooking did not affect reducing power. Inhibition of peroxidation increased by boiling and frying, whereas, in contrast it was decreased by microwave cooking. The results of the present investigation showed that all the cooking methods affected the antioxidant properties of the vegetables; however, microwave treatment exhibited more deleterious effects when compared with those of other treatments. Thus an appropriate method might be sought for the processing of such vegetables to retain their antioxidant components at maximum level.     

The effect of cooking on Brassica vegetables

Assessing antioxidant intake requires a food antioxidant database. However, cooking may affect antioxidant content due to antioxidant release, destruction or creation of redox-active metabolites. Here, effects of boiling, steaming and microwaving of broccoli, cauliflower, cabbage and choy-sum (Chinese cabbage) were explored by measuring antioxidant contents of raw and cooked vegetables. Cooking water was also tested. For all cooked vegetables, antioxidant content was highest in steamed > boiled > microwaved, and decreased with longer cooking time, regardless of method. All steamed vegetables had higher antioxidant contents than had matching raw vegetables. Effects were variable for boiling and microwaving. Microwaving caused greater antioxidant loss into cooking water than did boiling. Marked losses of anitoxidants occurred in microwaved cabbage and spinach. To assess food antioxidant content/intake accurately, cooking effects need detailed study. Steaming may be the cooking method of choice to release/conserve antioxidants. The cooking water is a potentially rich source of dietary antioxidants.