Nitrate in leafy vegetables,culinary herbs,and cucumber grown under cover in Estonia: content and intake

The content of nitrate in leafy vegetables, culinary herbs, and cucumber was determined during the years 2006–2008. All samples of Estonian origin, except white cabbage, were grown under cover. Seasonal differences in nitrate concentrations were observed in lettuce and spinach. Nitrate concentrations in lettuce were 22% and those in spinach were 24% higher in winter crops compared with samples collected in summer. The mean nitrate level was 3023 mg kg^–1 for fresh lettuce and 2337 mg kg^–1 for spinach. On average, 11.6% of fresh lettuce and spinach samples nitrate concentration exceeded the maximum level specified in European Commission Regulation No. 1881/2006. The mean levels were 999 mg kg^–1 for imported iceberg lettuce and 1287 mg kg^–1 for frozen spinach, which are below the maximum European Commission limits. Parsley, dill, basil, thyme, and rucola contained high concentrations of nitrate from mean levels of 2134 mg kg^–1 for parsley up to 8150 mg kg^–1 for rucola. Mean nitrate concentrations ranged from 382 to 1115 mg kg^–1 for white cabbage and Chinese cabbage, respectively. The per capita mean daily intake of nitrates related to the consumption of leafy vegetables, culinary herbs, and cucumber for the whole Estonian population was 31.3 mg day^–1, which comprised 14.2% of the acceptable daily intake (ADI).     

Distribution pattern of a flavonoid extract in the gastrointestinal lumen and wall of rats

Purified flavonoid extract from illuminated parsley (Petroselinum crispum (Mill.) Nym.) cell culture was administered by gavage to Wistar rats. The dose corresponded to 6.9 mg flavonoids on aglycone base/kg body mass. Segments of the gastrointestinal wall from stomach to colon, their luminal contents, and liver and kidneys were collected at time intervals between 1 and 12 h and investigated by HPLC of the respective extracts for flavonoids. The spreading of the flavonoids was accompanied by partial deglycosylation that began already in the stomach where at first quercetin and later apigenin, chrysoeriol and isorhamnetin aglycones were detected. We got evidence of flavonoid absorption by the stomach that does not require the liberation of aglycones. Due to obvious differences in metabolization and absorption rates the composition and the content of flavonoids changes in the gastrointestinal segments and their contents with time. Flavonoids could be detected neither within the gastrointestinal lumen after 12 h nor in the kidneys at any time. But traces of flavonoids were found in the livers at 1.5 and 12 h.     

Fresh-cut aromatic herbs: Nutritional quality stability during shelf-life

Fresh-cut vegetables are a successful convenient healthy food. Nowadays, the presence of new varieties of minimally processed vegetables in the market is common in response to the consumers demand for new flavours and high quality products. Within the most recent fresh-cut products are the aromatic herbs. In this work, the objective was to evaluate the nutritional quality and stability of four fresh-cut aromatic herbs. Several physicochemical quality characteristics (colour, pH, total soluble solids, and total titratable acidity) were monitored in fresh-cut chives, coriander, spearmint and parsley leaves, stored under refrigeration (3 ± 1 °C) during 10 days. Their nutritional composition was determined, including mineral composition (phosphorous, potassium, sodium, calcium, magnesium, iron, zinc, manganese and copper) and fat- and water-soluble vitamin contents. Total soluble phenolics, flavonoids and the antioxidant capacity were determined by spectrophotometric methods. The aromatic herbs kept their fresh appearance during the storage, maintaining their colour throughout shelf-life. Their macronutrient composition and mineral content were stable during storage. Coriander had the highest mineral and fat-soluble vitamin content, while spearmint showed the best scores in the phenolic, flavonoid and antioxidant capacity assays. Vitamins and antioxidant capacity showed some variation during storage, with a differential behaviour of each compound according to the sample.     

Relative antioxidant and cytoprotective activities of common herbs

Many studies have been carried out on bioactivities of individual herbs, however, no collective study on their comparative antioxidant and cytoprotective activities against oxidative damage has been reported. We selected 17 common commercial herbs and studied their relative phenolic contents, antioxidant activities, and cytoprotective activities on gap–junction intercellular communication and antioxidative enzymes in vitro under the same conditions. Total polyphenol content ranged from 464 to 870 gallic acid equivalents (GAE) mg/100 g and total flavonoid content from 212 to 494 catechin equivalents (CE) mg/100 g. Among the samples, chamomile, rosehip, hawthorn, lemon verbena, and green tea contained relatively high total phenolics (769–844 mg GAE/100 g) and flavonoids (400–4 mg CE/100 g). Chamomile also showed the highest antioxidant activity with 960 mg/100 g of vitamin C equivalent (VCE), followed by hawthorn (929 mg VCE/100 g) and black tea (916 mg VCE/100 g). Total phenolic and total flavonoids showed a higher correlation with antioxidant activity. Most of herbs enhanced cell viability and showed protective effects against oxidative stress induced by hydrogen peroxide in Chinese hamster lung fibroblast (V79-4) cells. Furthermore, herbs used in this study showed higher protective effect on gap–junction intercellular communication (GJIC) as compared to gallic acid and catechin, and also enhanced activity of the antioxidative enzymes such as superoxide dismutase (SOD) and catalase (CAT) in a dose-dependent manner.     

Quantitative variation in Brazilian vegetable sources of flavonols and flavones

Reliable data on the levels of flavonoids in foods are necessary to identify sources and establish better the association between consumption and incidence of diseases. The objective of this work was to determine the flavonols and flavones of major vegetable sources in Brazil, compare with data obtained in different countries and evaluate possible seasonal and processing effects. Quercetin was the most widely distributed flavonol in the vegetables analysed, onions, kale and rucula being the richest sources. Kaempferol had the highest level in rucula. Apigenin was found only in parsley, at high concentration. The flavonoid contents tended to be higher in the summer, but the difference was statistically significant only for quercetin in curly lettuce and kale. Dehydrated onion had widely varying within-brand and between-brand quercetin contents, indicating lack of quality control in the processing plants. Dehydrated parsley, on the other hand, did not have significant difference in the apigenin content among four brands.     

北京市售30种蔬菜中类黄酮物质含量分析

目的测定北京地区30种蔬菜中5种类黄酮物质的含量。方法采用高效液相色谱法检测槲皮素、山奈酚、杨梅黄酮、木犀草素、芹菜配基类黄酮物质的含量,蔬菜样品均购自北京当地菜市场。结果30种蔬菜中全部检出了槲皮素,含量在2.1～85.9mg/kg鲜重,9种蔬菜检出杨梅黄酮,8种蔬菜检出芹菜配基,8种蔬菜检出木犀草素,仅在胡萝卜和西红柿中检出山奈酚。紫洋葱、白洋葱、胡萝卜、甜椒和苦瓜等蔬菜类黄酮含量较高。结论不同蔬菜类黄酮物质的组成和含量差别较大,槲皮素为蔬菜中主要的类黄酮物质。     

Flavonols and flavones of parsley cell suspension culture change the antioxidative capacity of plasma in rats

The flavonoid aglycones from an illuminated parsley (Petroselinum crispum (Mill.) Nym.) cell suspension culture were identified and quantified as the flavones apigenin, luteolin and chrysoeriol and the flavonols kaempferol, quercetin and isorhamnetin. Flavonoid extracts from these cultures were purified by solid phase extraction from RP C-18 phase and given by gavage to rats. Only extract from illuminated culture increased the antioxidative capacity (AOC) of blood plasma temporarily with maximum values after 1 h. It is concluded that the course of AOC reflects changes in the plasma content of flavonoids.     

荞麦叶黄酮的提取工艺优化及其抗氧化性

为了对荞麦叶黄酮的提取和抗氧化性进行研究,采用响应面法对超声波法辅助提取荞麦叶黄酮的工艺进行了优化,高效液相色谱（HPLC）法分析了荞麦叶黄酮成分,并对荞麦叶黄酮的抗氧化性进行了测定。结果表明:当超声频率45 kHz、超声功率100 W、液料比30:1 mL:g、超声时间22 min,超声温度为28 ℃,乙醇体积分数为51%时,荞麦叶黄酮的提取量为80.311 mg/g,与预测值81.414 mg/g相对误差为1.35%,表明该模型预测值与实际值拟合效果良好。HPLC检测表明,荞麦叶黄酮的主要成分为芦丁和槲皮素,其含量分别为66.5%和13.9%。抗氧化试验表明,荞麦叶黄酮对DPPH自由基（DPPH·）、ABTS自由基（ABTS+·）和羟基自由基（·OH）的半清除浓度（IC₅₀）分别为0.012、0.044、0.344 mg/mL,表明其具有较强的抗氧化能力。本试验为荞麦叶的综合利用提供了理论依据。     

Flavonoid pattern of sage (Salvia officinalis L.) unifloral honey

The aim of the present paper was to determine the flavonoids in monofloral sage (Salvia officinalis L.) honey which is characteristic and specific for the area of Croatian coast and islands. For that purpose 38 sage honey samples from two production seasons were analysed. After specific pollen content determination, and analyses of selected physicochemical parameters which confirmed that samples are in compliance with national and international regulations and can be regarded as unifloral sage honeys, flavonoid fraction was isolated and analysed using RP-HPLC/DAD method. The HPLC analysis showed that all examined sage honey samples contain quercetin (3,3′,4′,5,7-pentahydroxyflavone), luteolin (3′,4′,5,7-tetrahydroxyflavone), kaempferol (3,4′,5,7-tetrahydroxyflavone), apigenin (4′,5,7-trihydroxyflavone), chrysin (5,7-dihydroxyflavone) and galangin (3,5,7-trihydroxyflavone), as well as p-coumaric (trans-4-hydroxycinnamic acid) and caffeic acid (3,4-dihydroxycinnamic acid). Total amount of identified flavonoids varied from 109.4 μg/100 g of honey to 589.9 μg/100 g of honey, with the average of 288.5 μg/100 g of honey. All analysed honey samples showed common and specific flavonoid profile which could be the basis for differentiating sage from other monofloral honeys.     

Characterization of Flavonoids in Different Cultivars of Onion (Allium cepa L.)

ABSTRACT: :
Twelve cultivars of different colored onions (white, golden, and red) were evaluated for fresh bulb yields and for flavonoid contents. The fresh bulb yields ranged from 3.1 to 6.7 kg m⁻² as found in golden cultivars "Santana" and "Castillo" respectively. The flavonoids, extracted with methanol/water/acetic acid (50:42:8, v:v:v) from fresh bulbs and characterized by HPLC with a DAD detector, were mainly made up of quercetin and isorhamnetin in the form of aglycones and glycosides. The highest amount of free quercetin was detected in the fresh bulbs of "Tropea rossa tonda" (557.8 mgkg⁻¹) whereas that of total flavonoids was found in "Dorata Density" (979.1 mgkg⁻¹). The golden cultivar "Castillo" resulted in the highest bulb and flavonoid yields (6.7 kg m⁻² and 5.2 g m⁻² respectively)     

Flavonoids,phenolic acids and abscisic acid in Australian and New Zealand Leptospermum honeys

Flavonoids, phenolic acids and abscisic acid of Australian and New Zealand Leptospermum honeys were analyzed by HPLC. Fifteen flavonoids were isolated in Australian jelly bush honey (Leptospermum polygalifolium), with an average content of 2.22 mg/100 g honey. Myricetin (3,5,7,3′,4′,5′-hexahydroxyflavone), luteolin (5,7,3′,4′-tetrahydroxyflavone) and tricetin (5,7,3′,4′,5′-pentahydroxyflavone) were the main flavonoids identified. The mean content of total phenolic acids in jelly bush honey was 5.14 mg/100 g honey, with gallic and coumaric acids as the potential phenolic acids. Abscisic acid was quantified as twice the amount (11.6 mg/100 g honey) of the phenolic acids in this honey. The flavonoid profile mainly consisted of quercetin (3,5,7,3′,4′-pentahydroxyflavone), isorhamnetin (3,5,7,4′-tetrahydroxyflavone 3′-methyl ethyl), chrysin (5,7-dihydroxyflavone), luteolin and an unknown flavanone in New Zealand manuka (Leptospermum scoparium) honey with an average content of total flavonoids of 3.06 mg/100 g honey. The content of total phenolic acids was up to 14.0 mg/100 g honey, with gallic acid as the main component. A substantial quantity (32.8 mg/100 g honey) of abscisic acid was present in manuka honey. These results showed that flavonoids and phenolic acids could be used for authenticating honey floral origins, and abscisic acid may aid in this authentication.     

纤维素酶-超声联合提取菠菜中总黄酮及其成分分析

本研究采用纤维素酶联合超声提取法提取菠菜中总黄酮,通过单因素实验考察了甲醇浓度、酶添加量、料液比、提取温度、酶解pH和提取时间对总黄酮得率影响,并通过正交试验对总黄酮的提取条件进行了优化。利用高效液相色谱法对纯化后的菠菜总黄酮成分进行分析。结果表明,菠菜总黄酮提取的最适条件为:用70%的甲醇溶液作为提取剂,酶添加量1.2%、料液比1:30 g/mL,在提取温度60℃、酶解pH5.0、提取时间45 min的提取条件下提取得到菠菜总黄酮得率为15.56%。利用高效液相色谱同时分离7种黄酮类化合物成分:没食子酸、绿原酸、儿茶素、芦丁、芹菜素、山奈酚、槲皮素,测出含量分别为:0.83、1.37、0.64、1.46、2.12、1.25、1.87 mg/g。经方法学验证,各种黄酮类化合物单体的线性关系良好,加样回收率准确度较高,相对标准偏差良好,可用于菠菜黄酮的定性定量检测。     

Flavonoid content and antioxidant activity of vegetables from Indonesia

Extracts from 11 vegetables of Indonesian origin were screened for flavonoid content, total phenolics, and antioxidant activity. The flavonols myricetin, quercetin, and kaempferol and flavones luteolin and apigenin were quantified by HPLC. Flavonoid content in mg/100 g fresh weight (fw) was apparently initially reported for Cosmos caudatus H.B.K. (52.19), Polyscias pinnata (52.19), Pluchea indica Less. (6.39), Nothopanax scutellarius (Burm.f.) Merr (5.43), Talinum triangulare (Jacq.) Willd. (3.93), Pilea melastomoides (Poir.) Bl. (2.27), and Etlingera elatior (Jack) R.M.Sm (1.18). The flavonoid content of the vegetables studied were mainly quercetin and kaempferol and ranged from 0.3 to 143 mg/100 g fw, with the highest level found in Sauropus androgynus (L) Merr. C. caudatus H.B.K. had the greatest total phenols among the vegetables analysed, with 1.52 mg GAE/100 g fw. P. indica Less. and C. caudatus H.B.K. had the highest antioxidant activity as measured by ferric cyanide reducing power, DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) scavenging, and inhibition of linoleic acid oxidation. Therefore, S. androgynus (L) Merr, C. caudatus H.B.K., and P. pinnata were identified as potentially rich sources of dietary flavonoids and antioxidants.     

离子液体辅助超声萃取-高效液相色谱同时测定半边莲中6 种黄酮类化合物

目的：通过单因素试验和正交试验对离子液体辅助萃取半边莲中黄酮类化合物的条件进行优化,建立高效液相色谱法同时分离测定半边莲中芦丁、槲皮素、柚皮素、橙皮素、山柰酚和芹菜素的方法。方法：采用InertSustain C18色谱柱（150 mm×4.6 mm,5 μm）进行分离;流动相为甲醇（B）-乙酸溶液（A,pH 3.0）,梯度洗脱;流速1.0 mL/min;紫外检测波长285 nm;柱温35 ℃。结果：以黄酮类化合物的提取量为指标,最佳提取条件为甲醇体积分数80%、固液比1∶80（g/mL）、萃取时间30 min、离子液体浓度0.6 mol/L。在优化的色谱条件下,芦丁、槲皮素、柚皮素、橙皮素、山柰酚和芹菜素分离效果良好;定性检出限（RSN = 3）依次为0.001 2、0.002 3、0.002 6、0.000 2、0.001 0、0.000 6 μg/mL;样品回收率为91.77%～102.53%。结论：该萃取方法操作简单快速,为半边莲中黄酮类化合物的提取分离及检测提供了有效的方法。     

Polyphenol content and antiradical activity of Cichorium intybus L. from biodynamic and conventional farming

Conventionally- and biodynamically-grown chicory (Cichorium intybus L.) was compared for its polyphenol content and antiradical activity. Two growing periods were analysed: in the first, the plants were subjected to severe water stress; in the second the stress was absent. The polyphenol content (Folin–Ciocalteu test) was higher in samples from the former than in the latter (about 650 and 420mg of gallic acid/100g fresh sample, respectively), and in any case did not differ between the two growing systems; antiradical activity for the second sampling was higher in the case of the biodynamic system. HPLC/DAD/MS analysis identified five hydroxycinnamic acids and eight flavonoids (quercetin, kaempferol, luteolin and apigenin glycosides) and indicated changes in hydroxycinnamic content in the four samplings which were greatest in the case of conventional farming. Biodynamic farming, like organic farming, allows the achievement of good results, with particular attention to environmental conditions.     

The phenolic compounds and the antioxidant potential of infusion of herbs from the Brazilian Amazonian region

The consumption of tea increased significantly in the past few years as a result of its health benefits as potent antioxidants in the diet. However, studies on the antioxidant compounds from Brazilian tea are scarce. Thus, the aim of this work was to evaluate the total phenolic compounds (TPC) and total flavonoids (TF) contents and the antioxidant capacity (DPPH and β-carotene/linoleic acid system) of nine herb infusions from the Amazonian region, namely agirú (Chrysobalanus icaco), açoita-cavalo (Luehea speciosa), capim-santo (Cymbopogon citratus), erva-cidreira (Lippia alba), graviola (Annona muricata L.), jucá (Libidibia ferrea), pata-de-vaca (Bauhinia ungulata), parirí (Fridericia chica) and sacaca comum (Croton spp.). These herbs were chosen based on popular knowledge and consumption. C. ferrea (68.13 mg GAE/g), L. speciosa (47.54 mg GAE/g) and C. icaco (51.30 mg GAE/g) presented the highest TPC contents, while L. speciosa (12.85 mg CE/g) and L. alba (15.42 mg CE/g) showed the highest TF contents. The highest antioxidant capacity, using both assays, was shown by L. ferrea. The three herbs with the highest TPC contents were selected to be analyzed by high performance liquid chromatography (HPLC) coupled to a diode array detector (DAD). A commercial green tea (Camellia sinensis) was also analyzed as a reference. The main compounds tentatively identified were gallic acid (0.45 mg/g), myricetin (0.78 mg/g) and quercetin (0.14 mg/g) in C. icaco; (+)-catechin (1.20 mg/g) and quercetin (0.14 mg/g) in L. speciosa; gallic acid (0.59 mg/g) and quercetin (0.13 mg/g) in C. ferrea; and gallic acid (0.24 mg/g), (−)-epicatechin (2.44 mg/g), (+)-catechin (0.68 mg/g) and quercetin (0.66 mg/g) in green tea. Among the nine studied herbs, the importance of L. ferrea should be pointed out since it presented the highest TPC content and antioxidant capacity and its gallic acid content was much higher than that of green tea.     

紫外可见分光光度法和高效液相色谱法法测定酒神菊属蜂胶和国产蜂胶中黄酮含量对比研究

目的对比采用紫外可见分光光度法(ultraviolet-visible spectrophotometry,UV-VIS)和高效液相色谱法(high performance liquid chromatography,HPLC)测定国产和酒神菊属蜂胶样品中的黄酮类化合物含量差异。方法以芦丁作为对照品,参考《2003版保健食品中总黄酮的含量测定》和GB/T 20574-2006《蜂胶中总黄酮含量的测定方法分光光度比色法》,采用UV-VIS和HPLC分析技术检测酒神菊属蜂胶和国产蜂胶中的黄酮类化合物含量。结果采用UV-VIS法测得酒神菊属蜂胶总黄酮含量为3.11%～8.03%(均值为6.04%),低于国产蜂胶总黄酮含量为3.00%～16.30%(均值为9.97%);采用HPLC法测定杨梅素、槲皮素、山奈酚、芹菜素、乔松素和高良姜素等黄酮类成份,酒神菊属蜂胶中黄酮类化合物总含量范围为1.562%～6.432%,国产蜂胶黄酮类化合物总含量范围为2.238%～13.621%。结论 UV-VIS和HPLC法下测得的总黄酮含量相近,但蜂胶中的黄酮类化合物含量上百种,所以以芦丁计检测蜂胶中总黄酮含量值得深究,同时有必要建立更合理的方法评价蜂胶的质量。     

Quercetin,luteolin, apigenin and kaempferol contents of some foods

Quercetin, luteolin, apigenin and kaempferol contents of Urtica sp., Rosa cannina (rosehip), Salvia officinalis (sage), Tilia platyphyllos (linden flower), black tea, Daucus carota L. spp sativus (violet carrot juice), grape molasses, honey and tarhana were determined by HPLC with UV detection. Consumption of the samples was assessed using a food frequency questionnaire method. One hundred healthy volunteers were asked to state the number of times on average per day, week or month they consumed each item over the last 6 months. Quercetin was determined in all samples except honey, whereas luteolin was determined only in sage. Kaempferol was determined in black tea, linden flower and honey samples, and apigenin was determined in honey and Urtica sp. Quercetin intake by the consumption of tea, linden flower, sage rosehip, violet carrot juice, grape molasses, tarhana and juice of Urtica sp. were estimated as 4.2–25, 2.6, 3.3, and 2.0 μg/day, 1.67 mg/day, 1.70 mg/day, 1.78 mg/month and 21.75–65.25 μg/month, respectively. Luteolin intake by the consumption of sage was estimated as 1.32 μg/day. Apigenin intakes by the consumption of honey and juice of Urtica sp. were estimated as 2.34 mg/day and 3.58–10.73 mg/month, respectively. Kaempferol intakes of the participants from tea, linden flower and honey were estimated as 13.2–79.2, 13.56 and 190 μg/day respectively. ©     

Flavonoid content of commercial capers (Capparis spinosa, C. sicula and C. orientalis) produced in mediterranean countries

 The flavonol content of commercial capers (pickled flower buds of Capparis spinosa L., C. sicula Veill. in Duham. and C. orientalis Veill. in Duham.) produced in different Mediterranean countries (Spain, Italy, Greece, Turkey and Morocco) has been analysed. The content of quercetin 3-rutinoside, kaempferol 3-rutinoside; and kaempferol 3-rhamnosyl-rutinoside as well as the aglycones (quercetin and kaempferol) were evaluated by HPLC coupled with a diode-array detector. The free aglycones were not detected in the original flower buds, indicating that they were produced during the brining process. In addition, brining extracted most of the kaempferol 3-rhamnosyl rutinoside present in the original buds, this being a minor constituent in pickled capers. The average content of flavonoid glycosides in commercial capers was 5.18 mg/g fresh weight. When this value is converted to the corresponding aglycones (quercetin and kaempferol), capers provide an average of 3.86 mg/g fresh weight. A serving of capers (10 g) will provide 65 mg of flavonoid glycosides or the equivalent 40 mg of quercetin as aglycone. Received: 3 March 2000     

Chemical characterization and functional properties of selected leafy vegetables for innovative mixed salads

The content of bioactive compounds and antioxidant capacity of nine vegetables of conventional and unconventional utilization in salad mixtures were studied. The total phenolic and flavonoid contents ranged between 39.6–148.5 mg GAE/100g FW and 76.3–217.4 mg QE/100g FW, respectively. Ascorbic acid content ranged between 16.4 and 198.8 mg AAE/100g FW. Antioxidant capacity was assessed using DPPH, FRAP, and ORAC methods; values were in the range of 48.9–245.8 mg TE/100g FW, 67.7–335.8 mg TE/100g FW, and 104.86–833.9 mg TE/100g FW, respectively. Red cabbage, beet greens, parsley, and rocket exhibited the highest antioxidant capacities. Catechin was the most abundant phenolic compound identified in the free fraction, and p‐coumaric acid, quercetin, and caffeic acid in the hydrolyzed fraction. Results suggested that the presence of these phenolics could be of great importance in preventing some chronic and degenerative diseases when regularly consumed. Nonconventional vegetables showed high antioxidant properties, therefore, it is important to promote their consumption.

Practical applications

Not all vegetables have the same phenolic composition, and not all phenolics have the same antioxidant capacity. Knowledge of the bioactive content and antioxidant capacity profile in each vegetable could be of interest to consumers and the food industry for selecting the more suitable leaves to make salad mixtures with high nutritional and functional values. These compounds can prevent some chronic‐degenerative diseases related to oxidative stress, so it is important introduce them regularly into the diet. Moreover, the evaluation of nontraditional vegetables is intended to bring consumers toward a new source of bioactive compounds, prompting their consumption, and providing added value to certain plant parts that are sometimes considered as waste products.