Effects of some processing methods on nitrate and nitrite changes in cruciferous vegetables

Changes in nitrate and nitrite content in selected cruciferous vegetables, resulting from blanching, boiling, freezing, frozen storage and boiling after previous freezing, were analyzed. The highest level of nitrate was detected in curly kale (302.0 mg/kg) and the lowest in green cauliflower (61.0 mg/kg). As for nitrite, the respective levels were found in white cauliflower (3.49 mg/kg) and green cauliflower (1.47 mg/kg). Both blanching and boiling of the cruciferous vegetables caused a considerable decrease in the total nitrate content, but at the same time no explicit changes were noted regarding the level of nitrite. In the vegetables stored frozen for 48 h, previously blanched, either an increase or no change was observed in the nitrate level, with the changes in the nitrite level being irregular. In the vegetables stored frozen for 4 months, previously blanched, generally a decrease was noted in the nitrate, and an increase in the nitrite level compared to the levels in the blanched vegetables. Boiling of the frozen vegetables (stored frozen for 48 h) most frequently caused a considerable reduction of the nitrate level in comparison to the content in the raw frozen vegetables. No changes were observed resulting from the boiling of the vegetables previously stored frozen for 4 months. Simultaneously, no explicit changes were found regarding the nitrite level in the frozen vegetable after boiling.     

哈尔滨市售蔬菜中阿维菌素和吡虫啉农药残留检测

目的了解哈尔滨市售蔬菜中阿维菌素和吡虫啉农药的残留现状。方法于2007-05／10,从哈尔滨市10个主要农贸市场和5个超市采集的大辣椒、小辣椒、黄瓜、西红柿、豆角、菠菜、油菜、大头菜、花菜和白菜菜样各15件,采用高效液相色谱法检测其农药残留情况。结果阿维菌素农药的检出率41．33％,超标率38．00％;吡虫啉农药的检出率为20．67％,均未超出吡虫啉的最高残留限量标准。10种蔬菜样品中白菜、油菜、大头菜和菠菜的阿维菌素农药检出率较高,在40％～53．33％之间,白菜的超标率最高,为53．33％;菠菜、大头菜和西红柿吡虫啉农药的检出率较高,在26．67％～33．33％之间。结论调查的蔬菜中普遍存在阿维菌素、吡虫啉农药残留,需要引起有关方面的关注。     

Values of nitrate and nitrite in selected vegetables and potatoes cultivated in the region of Pu?aw]

Nitrate and nitrite contents were determined in selected vegetables and potatoes from plantations of individuals farmers, situated either in the vicinity of the Nitrogen Plant in Pu?awy or at a distance from this plant (control). Vegetables and potatoes both newly harvested and stored for 4 months in cellars were analysed. From farms selected by lot, samples of lettuce, cabbage, sauerkraut, beets, carrots and potatoes (all harvested in 1986 and 1987) were collected. Nitrate and nitrite contents were determined in 1215 plant samples. Nitrates were reduced on a cadmium column to nitrites, whereupon they were determined colorimetrically using sulphanilic acid and N-1-naphthylethylenediamine. This results showed that the nitrate contents are higher in the vegetables and potatoes cultivated in the region of the Nitrogen Plant, as compared with those from the Janowiec village distant from this plant (control). Differences in mean nitrate contents per 100 g dry matter were in years 1986 and 1987 for: lettuce 73%, 36%; cabbage 54%, 39%; beets 16%, 20%; carrots 51%, 29%; potatoes 77%, 36%, respectively. Moreover, the vegetables and potatoes grown in the region of the Nitrogen Plant, as compared with the control vegetables from the village located at a distance from this plant, displayed a greater percentage of samples with plants characterized by higher nitrate contents. The greater percentage of samples containing high nitrate levels, as well as the higher mean nitrate contents in vegetables and potatoes testify to the effect of the Nitrogen Plant on nitrate concentrations in the crops. In vegetables from both regions, the nitrite contents did not exceed 1 mg NaNO2/kg.(ABSTRACT TRUNCATED AT 250 WORDS)     

Quantitative analysis of nitrate and nitrite contents in vegetables commonly consumed in Delta State, Nigeria

Plasma thiocyanate has been reported to be high among cassava-eating populations such as that in Nigeria because of the cyanide content of cassava. Thiocyanate, which is secreted into the stomach contents of animals, has been demonstrated to catalyse the formation of nitrosamines (potent carcinogens) in the stomach from secondary amines and nitrite. The main source of the nitrite precursor in this environment is vegetables, primarily eaten as the chief supplier of proteins. The present study attempts to analyse the levels of nitrate and nitrite in vegetables commonly grown and consumed in Delta State, Nigeria. The nitrate and nitrite contents in green vegetable (Amaranthus spp.), bitter leaf (Vernonia amygdalina), pumpkin (Telfaria occidentalis) and water leaf (Talinum triangulare) grown in different localities of the state were determined by standard analytical procedures. The results show that those vegetables grown in the industrialised urban centres of the state had higher nitrate (223 (SD 71) mg/kg dry weight; P<0.05) and nitrite (12.6 (SD 1.7) mg/kg dry weight; P>0.05) levels when compared with the same species (188 (SD 77) mg nitrate/kg dry weight and 10.9 (SD 1.1) mg nitrite/kg dry weight) cultivated in less industrialised suburbs. We conclude that frequent consumption of such vegetables whose nitrate and nitrite contents are high by cassava-eating individuals might put them at risk of developing stomach cancer and other possible results of nitrate and/or nitrite toxicity. In order to avoid an outbreak in our communities, appropriate agencies should monitor and regulate the release of chemicals into the environment. In the meantime, the cultivation and consumption of vegetables grown in industrialised areas of the state should be discouraged.     

Occurrence of patulin in fruit and vegetables

In different varieties of apples and pears suffering from brown rot, patulin was found in about 50 p. 100 of samples investigated (about 120). Patulin levels as high as 1 g/kg rotten material were found 2-3 days after the fruit was removed from the cold store where it had been stored for 5 months. A significant diffusion into the healthy plant tissue was not observed in apples, but in peaches, tomatoes and pears. Vegetable products with natural patulin content: apples, pears, peaches, apricots, bananas, pine apples, grapes. After inoculation with Penicillium expansum, P. urticae or Byssochlamys nivea, patulin was also found in greengages, strawberries, honeydew melons, red and green paprika, tomatoes, cucumbers and carrots. The artificial infection failed in celeriac, kohlrabi, cauliflower, red cabbage, radish, horseradish, onions, squash (zuccini), potatoes and egg plants. The author further investigated the patulin synthesis as a function of the temperature as well as its oxygen requirement in various mold species and strains.     

高氮施肥区蔬菜硝酸盐及亚硝酸盐调查

目的了解高氮施肥区蔬菜硝酸盐及亚硝酸盐污染情况。方法于2011年7—10月选择沙颍河上游地区每月采样,共采集27种、136个蔬菜样品检测硝酸盐、亚硝酸盐含量并进行初步的健康风险评估。结果 8—9月蔬菜硝酸盐含量较高,10月最低;9月蔬菜亚硝酸盐含量最高,7—8月较低,10月最低;7—10月份6类蔬菜亚硝酸盐含量超标(4.00mg/kg)率为41.67%,10月均达标。蔬菜硝酸盐健康风险指数除10月外均1;亚硝酸盐健康风险指数均1。结论该区域蔬菜硝酸盐和亚硝酸盐蓄积水平较高,且硝酸盐存在一定的健康风险。     

南京市市售蔬菜硝酸盐和亚硝酸盐污染状况分析

目的:掌握南京市市售蔬菜中硝酸盐和亚硝酸盐的污染情况,为蔬菜供应安全及安全生产管理提供理论依据.方法:在南京市农贸市场和蔬菜批发市场共11个采集点采集44种蔬菜样品980份,用国标法(GB/T5009.33)分析蔬菜中的硝酸盐和亚硝酸盐含量.结果:不同种类蔬菜中硝酸盐含量差别较大,硝酸盐的含量依次为特菜类＞叶菜类＞茎类＞块根类＞瓜菜类＞甘蓝类＞果菜类＞豆类＞鳞茎类＞菌类;同一类别不同品种蔬菜中硝酸盐含量差别亦较大,从几倍至几十倍;检测的样品中,硝酸盐处于严重污染状态的占28.16％.蔬菜中亚硝酸盐含量相对较低,其含量与蔬菜的新鲜程度有关.结论:南京市市售蔬菜中硝酸盐污染较为严重,应引起足够重视,加强监督管理.     

Mineral profile of raw and cooked leafy vegetables consumed in Southern Brazil

Butterhead lettuce, rucola, watercress, kale, chicory, cabbage, Chinese cabbage, and a spinach substitute (Tetragonia expansa) are widely consumed in Southern Brazil. Samples were collected five times during a year in food markets and analyzed for total potassium, sodium, calcium, magnesium, iron, manganese, copper, and zinc by flame atomic absorption spectrometry and for moisture content. All vegetables can contribute to diet in terms of potassium, calcium and magnesium. Kale offers the highest amounts of calcium (283±43 mg Ca/100 g) and Chinese cabbage, cabbage, and butterhead lettuce the lowest, with values from 33 to 58 mg Ca/100 g. The highest concentrations of magnesium were found in kale and in the spinach substitute and they were 52±4 and 55±16 mg Ca/100 g, respectively. Moisture content varied less among samples of the same vegetable than minerals did. Four of the vegetables (kale, chicory, Chinese cabbage, and cabbage) were cooked briefly during 3 min and analyzed for the same elements. The brief cooking did not cause appreciable losses for any of the minerals.     

Carrot Consumption Frequency Associated with Reduced BMI and Obesity through the SNP Intermediary rs4445711

It is unclear whether genetic interactions are involved in the association between vegetable intake and reduced body mass index (BMI) or obesity. We conducted a comprehensive search for single nucleotide polymorphisms (SNPs) which are associated with the interaction between vegetable intake frequency and BMI or obesity. We performed a genome-wide association analysis to evaluate the genetic interactions between self-reported intake of vegetables such as carrot, broccoli, spinach, other green vegetables (green pepper and green beans), pumpkin, and cabbage with BMI and obesity, which is defined as a BMI ≥ 25.0 kg/m² in the Japanese population (n = 12,225). The mean BMI and prevalence of obesity was 23.9 ± 3.4 kg/m² and 32.3% in men and 22.1 ± 3.8 kg/m² and 17.3% in in women, respectively. A significant interaction was observed between rs4445711 and frequency of carrot intake on BMI (p = 4.5 × 10⁻⁸). This interaction was slightly attenuated after adjustment for age, sex, alcohol intake, smoking, physical activity and the frequency of total vegetable intake (p = 2.1 × 10⁻⁷). A significant interaction was also observed between rs4445711 and frequency of carrot intake on obesity (p = 2.5 × 10⁻⁸). No significant interactions that were the same as the interaction between frequency of carrot intake and rs4445711 were observed between the intake frequency of broccoli, spinach, other green vegetables, pumpkin or cabbage and BMI or obesity. The frequency of carrot consumption is implicated in reducing BMI by the intermediary of rs4445711. This novel genetic association may provide new clues to clarify the association between vegetable intake and BMI or obesity.     

Effect of Vitamin C and Protein Supplementation on Plasma Nitrate and Nitrite Response following Consumption of Beetroot Juice

Beetroot juice is a food high in nitrate and is associated with cardiometabolic health benefits and enhanced exercise performance through the production of nitric oxide in the nitrate–nitrite–nitric oxide pathway. Since various food components influence this pathway, the aim of this trial was to study the effect of beetroot juice alone and in conjunction with vitamin C or protein on the acute response to plasma nitrate and nitrite levels in healthy middle- to older-aged adults. In this cross-over trial, each participant received, in a randomized order, a single dose of Beet It Sport^® alone; Beet It Sport^®, plus a 200 mg vitamin C supplement; and Beet It Sport^® plus 15 g of whey protein. Plasma levels of nitrate and nitrite were determined prior to and at 1 and 3 h after intervention. Log plasma nitrate and nitrite was calculated to obtain data that were normally distributed, and these data were analyzed using two-way within-factors ANOVA, with time and treatment as the independent factors. There were no statistically significant differences for log plasma nitrate (p = 0.308) or log plasma nitrite (p = 0.391) values across treatments. Log plasma nitrate increased significantly from pre-consumption levels after 1 h (p < 0.001) and 3 h (p < 0.001), but plasma nitrate was lower at 3 h than 1 h (p < 0.001). Log plasma nitrite increased from pre to 1 h (p < 0.001) and 3 h (p < 0.001) with log values at 3 h higher than at 1 h (p = 0.003). In this cohort, we observed no differences in log plasma nitrate and nitrite at 1 h and 3 h after co-ingesting beetroot juice with vitamin C or a whey protein supplement compared to beetroot juice alone. Further research needs to be undertaken to expand the blood-sampling time-frame and to examine factors that may influence the kinetics of the plasma nitrate to nitrite efficacy, such as differences in fluid volume and osmolarity between treatments employed.     

A Nitrate-Rich Vegetable Intervention Elevates Plasma Nitrate and Nitrite Concentrations and Reduces Blood Pressure in Healthy Young Adults

BackgroundEmerging evidence suggests that increasing dietary nitrate intake may be an effective approach to reduce blood pressure. Beetroot juice is often used to supplement dietary nitrate, whereas nitrate intake levels from habitual diet are low. An increase in the habitual intake of nitrate-rich vegetables may represent an alternative to nitrate supplementation. However, the effectiveness and acceptability of a nitrate–rich-vegetables diet remain to be established.ObjectiveThe aim was to investigate the effect and feasibility of two different intervention strategies to increase dietary nitrate intake, on plasma nitrate/nitrite concentrations and blood pressure.DesignA randomized, crossover trial was used.ParticipantsParticipants were healthy men and women (both n=15; age: 24±6 years) from the Netherlands.InterventionParticipants were instructed to consume ∼400 mg nitrate at lunch, provided through nitrate-rich vegetables and dietary counseling, or beetroot juice supplementation. Both interventions lasted 1 week, with 1-week washout (January to April 2017).Main outcomePlasma nitrate and nitrite concentrations and resting systolic and diastolic blood pressure were measured in an overnight fasted state (before and after intervention) and ∼2.5 hours after lunch (before and throughout intervention on day 1, 4, and 7).Statistical analysisTwo-factor (time × treatment) repeated-measures analyses of variance were performed.ResultsMean plasma nitrate concentrations increased with both interventions, with a larger increase in beetroot juice vs nitrate-rich vegetables, both in a fasted state and ∼2.5 hours after lunch (day 1, beetroot juice: 2.31±0.56 mg/dL [373±90 μmol/L] vs nitrate-rich vegetables: 1.71±0.83 mg/dL [277±134 μmol/L]; P<0.001). Likewise, mean plasma nitrite concentrations increased with both interventions, but were higher after lunch in beetroot juice than in nitrate-rich vegetables (day 1: 2.58±1.52 μg/dL [560±331 nmol/L] vs 2.15±1.21 μg/dL [468±263 nmol/L]; P=0.020). Fasting mean systolic and diastolic blood pressure did not change, but mean systolic and diastolic blood pressure assessed ∼2.5 hours after lunch were significantly reduced throughout both intervention periods (P<0.05), with no differences between beetroot juice and nitrate-rich vegetables (day 1, systolic blood pressure: –5.1±9.5 mm Hg and diastolic blood pressure: –5.3±8.9 mm Hg).ConclusionShort-term consumption of dietary nitrate in the form of nitrate-rich vegetables represents an effective means to increase plasma nitrate and nitrite concentrations, and reduces blood pressure to the same extent as beetroot juice supplementation.     

An unusual combination in papaya (Carica papaya): The good (glucosinolates) and the bad (cyanogenic glycosides)

Glucosinolates are a group of sulphur-containing glycosides found in the plant order Brassicales which includes the Brassica vegetables such as broccoli, cabbage and cauliflower. When brought into contact with the plant enzymes, myrosinases, the glucosinolates break down releasing glucose and other products which serve principally in plant defence against herbivores. The most important of the products from a human nutritional viewpoint, are the isothiocyanates. These potent inducers of detoxifying enzymes bestow the distinct anti-cancer properties on these plants. Unique among tropical fruits, papaya is known to contain an abundance of one particular glucosinolate, glucotropaeolin. Other compounds that play a pivotal role in the chemical defence system of many plants are the cyanogenic glycosides. Cyanogenic glycosides are activated by plant enzymes in the event of pest attack, releasing the deterrent: toxic hydrogen cyanide. Papaya, in addition to glucosinolates, also contains low levels of cyanogenic glycosides, an unusual occurrence because it was assumed that the two classes of metabolites were mutually exclusive. Studies measuring the levels of both in the edible parts of the papaya fruit and other utilised tissues are discussed and considered in the context of potential human health ramifications.     

Short-Term Effects of a High Nitrate Diet on Nitrate Metabolism in Healthy Individuals

Dietary nitrate, through the enterosalivary nitrate-nitrite-NO pathway, can improve blood pressure and arterial stiffness. How long systemic nitrate and nitrite remain elevated following cessation of high nitrate intake is unknown. In 19 healthy men and women, the time for salivary and plasma nitrate and nitrite to return to baseline after 7 days increased nitrate intake from green leafy vegetables was determined. Salivary and plasma nitrate and nitrite was measured at baseline [D0], end of high nitrate diet [D7], day 9 [+2D], day 14 [+7D] and day 21 [+14D]. Urinary nitrite and nitrate was assessed at D7 and +14D. Increased dietary nitrate for 7 days resulted in a more than fourfold increase in saliva and plasma nitrate and nitrite (p < 0.001) measured at [D7]. At [+2D] plasma nitrite and nitrate had returned to baseline while saliva nitrate and nitrite were more than 1.5 times higher than at baseline levels. By [+7D] all metabolites had returned to baseline levels. The pattern of response was similar between men and women. Urinary nitrate and nitrate was sevenfold higher at D7 compared to +14D. These results suggest that daily ingestion of nitrate may be required to maintain the physiological changes associated with high nitrate intake.     

Assessment of Iprovalicarb, a Systemic Fungicide in/on Cabbage (Brassica oleracea var. capitata)

Iprovalicarb is a systemic fungicide and has high biological activity with particular efficacy against downy mildew. Iprovalicarb has an excellent toxicological and ecotoxicological profile. It has excellent fungicidal activity against Plasmopara viticola, Peronospora vicia, Phytophthora sp, Alternaria sp in grapes, potatoes, tomatoes, tobacco and vegetables. Iprovalicarb (Melody 50 W) was applied as a foliar spray on cabbage at the recommended dose, 300 g a.i ha⁻¹ and double the recommended dose, 600 g a.i ha⁻¹ at 50% head formation stage. Two application of each dose was made after an interval of 15 days. Residues of iprovalicarb in cabbage samples were analyzed by high performance liquid chromatography. It was detectable up to 15 days in both cabbage head and leaves at both the doses of application, after first and second applications. The dissipation model yielded rate constants 0.1157, 0.1121, 0.1170, 0.1114 day⁻¹ on cabbage heads after first and second applications at the recommended and double the recommended dose of application, respectively. The residual half-lives on cabbage heads and leaves were varied between 2.6–2.7 and 2.5–2.8 days, respectively. This suggested that dissipation was independent of initial doses and followed first order kinetics. The projected Theoretical Maximum Residue Contribution of iprovalicarb after first and second application was found to be lower than calculated Maximum Permissible Intake.     

哈尔滨市售蔬菜中有机磷和拟除虫菊酯农药的残留量

目的了解哈尔滨市蔬菜中有机磷农药、拟除虫菊酯类农药的残留情况,为政府相关部门制订政策提供依据。方法于2007年5—10月,从哈尔滨市10个主要农贸市场和5个超市采集大辣椒、小辣椒、黄瓜、西红柿、豆角、菠菜、油菜、大头菜、花菜和白菜菜样各15件,采用气相色谱法检测其农药的残留情况。结果共检测出4种有机磷农药(甲胺磷:0.003 1～0.048 8mg/kg;敌敌畏:0.001 5～0.052 7mg/kg;氧化乐果:0.003 9～0.3449mg/kg;水胺硫磷:0.0026～0.0869mg/kg)和3种拟除虫菊酯类农药(氯氰菊酯:0.018 1～0.324 5 m/kg;氰戊菊酯:0.024 7～0.024 8 mg/kg;溴氰菊酯:0.039 4～0.044 1 mg/kg)残留,甲拌磷、乐果、甲基对硫磷均未检出残留。农药残留超标率由高至低依次为氧化乐果(24.00%)>甲胺磷(20.67%)>水胺硫磷(4.67%)。氧化乐果在10种蔬菜中均有检出,氯氰菊酯在9种蔬菜中检出,敌敌畏和甲胺磷分别在7种蔬菜中检出。结论本次调查的蔬菜中普遍存在有机磷、拟除虫菊酯类农药的残留。     

Antioxidant capacity and phenolic content of selected commercially available cruciferous vegetables

Antioxidant activity, free radical scavenging activity and phenolic content of red cabbage (Brassica oleracea var. capitata rubra), Chinese cabbage (Brassica rapa pekinensis var cylindrica), green cabbage (Brassica oleracea var capitata), mustard cabbage (Brassica juncea var rugosa) and Chinese white cabbage (Brassica rapa var chinensis), grown in Malaysia, were evaluated. Red cabbage had the highest antioxidant activity and phenolic content compared to the other cruciferous vegetables studied (p < 0.05). The contributions of all cruciferous vegetables to the antioxidant activity was >79%. The radical scavenging activity was in the order of Chinese white cabbage > red cabbage > mustard cabbage > Chinese cabbage > green cabbage. There was a significant difference (p < 0.05) in the means of scavenging activity observed between cabbage, Chinese cabbage and Chinese mustard. Phenolic content was significantly different (p < 0.05) among all the cruciferous vegetables studied, and was in the order of red cabbage > Chinese white cabbage > green cabbage > Chinese cabbage >mustard cabbage. The study indicated that red cabbage possessed the highest antioxidant capacity and phenolic compounds concentration among all the cruciferous vegetables studied.     

Determination of Vitamin C, b-carotene and Riboflavin Contents in Five Green Vegetables Organically and Conventionally Grown

As consumer interest in organically grown vegetables is increasing in Malaysia, there is a need to answer whether the vegetables are more nutritious than those conventionally grown. This study investigates commercially available vegetables grown organically and conventionally, purchased from retailers to analyse β-carotene, vitamin C and riboflavin contents. Five types of green vegetables were selected, namely Chinese mustard (sawi) (Brassica juncea), Chinese kale (kai-lan) (Brassica alboglabra), lettuce (daun salad) (Lactuca sativa), spinach (bayam putih) (Amaranthus viridis) and swamp cabbage (kangkung) (Ipomoea aquatica). For vitamin analysis, a reverse-phase high performance liquid chromatography was used to identify and quantify β -carotene, vitamin C and riboflavin. The findings showed that not all of the organically grown vegetables were higher in vitamins than that conventionally grown. This study found that only swamp cabbage grown organically was highest in β -carotene, vitamin C and riboflavin contents among the entire samples studied. The various nutrients in organically grown vegetables need to be analysed for the generation of a database on nutritional value which is important for future research.     

Decontamination of Chlorantraniliprole Residues on Cabbage and Cauliflower through Household Processing Methods

A supervised field trial was conducted to study the residues of chlorantraniliprole on cabbage and cauliflower. Three applications of chlorantraniliprole at 10 days interval were made @ 9.25 and 18.50 g a.i. ha⁻¹. The samples of marketable size heads and curds of cabbage and cauliflower were collected at 0 and 1 day after the last application. QuEChERS sample preparation was used for the determination of chlorantraniliprole residues on cabbage heads and cauliflower curds. The residues of chlorantraniliprole were quantified by high performance liquid chromatography (HPLC) with photo diode array (PDA) detector and confirmed by high performance thin layer chromatography (HPTLC). Washing of cabbage and cauliflower with tap water removed about 17%–40% of chlorantraniliprole residues. However, boiling removed 100% of chlorantraniliprole residues on cabbage and cauliflower in both the cases.     

Plasma nitrate and nitrite are increased by a high-nitrate supplement but not by high-nitrate foods in older adults

Little is known about the effect of dietary nitrate on the nitrate/nitrite/nitric oxide cycle in older adults. We examined the effect of a 3-day control diet vs high-nitrate diet, with and without a high-nitrate supplement (beetroot juice), on plasma nitrate and nitrite kinetics and blood pressure using a randomized 4-period crossover controlled design. We hypothesized that the high-nitrate diet would show higher levels of plasma nitrate/nitrite and lower blood pressure compared with the control diet, which would be potentiated by the supplement. Participants were 8 normotensive older men and women (5 female, 3 male, 72.5 ± 4.7 years old) with no overt disease or medications that affect nitric oxide metabolism. Plasma nitrate and nitrite levels and blood pressure were measured before and hourly for 3 hours after each meal. The mean daily changes in plasma nitrate and nitrite were significantly different from baseline for both control diet + supplement (P < .001 and P = .017 for nitrate and nitrite, respectively) and high-nitrate diet + supplement (P = .001 and P = .002), but not for control diet (P = .713 and P = .741) or high-nitrate diet (P = .852 and P = .500). Blood pressure decreased from the morning baseline measure to the three 2-hour postmeal follow-up time points for all treatments, but there was no main effect for treatment. In healthy older adults, a high-nitrate supplement consumed at breakfast elevated plasma nitrate and nitrite levels throughout the day. This observation may have practical utility for the timing of intake of a nitrate supplement with physical activity for older adults with vascular dysfunction.     

Effects of cooking on in vitro sinigrin bioaccessibility,total phenols,antioxidant and antimutagenic activity of cauliflower (Brassica oleraceae L. var. Botrytis)

Cauliflower (Brassica oleraceae L. var. Botrytis) is a good source of bioactive compounds, such as glucosinolates, phenolic compounds and vitamins. In this study, the effects of some processes (i.e. boiling, steaming) on the sinigrin bioaccessibility as a major glucosinolate found in cruciferous vegetables after in vitro digestion, also in vitro antimutagenic activities, total phenols and total antioxidant capacities of cauliflower were determined. The sinigrin content was reduced by approximately 9.6% and 29.1% in steamed and boiled cauliflower (p > 0.05), respectively. After in vitro simulated digestion, sinigrin content was decreased by 26.4% in raw samples, increased by 29.5% and 114.7% in steamed and boiled samples, respectively. In all samples, mutagenic effect to Salmonella typhimurium TA 100 was not seen. When samples were steamed, phenol content was increased by 14.83%. After boiling total phenol content of cauliflower was decreased by 1.8%. Total antioxidant capacities (TAC) measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3 ethylbenzothiazoline-6-sulfonic acid) (ABTS) methods were increased by 47% and 39%, respectively (p < 0.05) in steamed samples and decreased by 8% and 7% with boiling, respectively (p > 0.05). TAC in raw sample of cauliflower, which was investigated in phosphomolybdenum assays, was determined as 18.7 mg ascorbic acid equivalents (AAE)/100 g. In all cases, the highest antioxidant activity was determined in the steamed samples, while the lowest antioxidant activity was in boiled samples.