Composition and availability of soluble and insoluble oxalates in raw and cooked taro (Colocasia esculenta var. Schott) leaves

Taro (Colocasia esculenta var. Schott) is a major staple food crop in parts of Asia and the Pacific Islands and is grown as a minor crop in New Zealand. Soluble, insoluble and total oxalate content of young and older leaves were determined by HPLC following hot water (80 °C) and hot (80 °C) acid (0.2 mol/L HCL) extractions. Young taro leaves contained 589 ± 35.8 mg total oxalates/100 g fresh weight (FW) while older taro leaves contained (443 ± 15.0 mg total oxalates/100 g FW). Soluble oxalates were 74% of the total oxalate content of the young and old leaves.     

Effects of phytate and minerals on the bioavailability of oxalate from food

Phytate and mineral cations are both considered as important dietary factors for inhibiting the crystallisation of calcium oxalate kidney stones in susceptible individuals. In this paper, the phytate and mineral composition of whole bran cereals (wheat, barley and oat) and legumes were determined together with their soluble and insoluble oxalate concentrations in order to investigate the effects on oxalate solubility. The oat bran sample had the highest soluble oxalate concentration at 79 ± 1.3 mg/100 g, while total and soluble oxalate concentrations in the food samples studied range from 33 to 199 mg/100 g and 14 to 79 mg/100 g, respectively. The phytate concentration was in the range from 227 to 4393 mg/100 g and the concentrations of cations were in the range 54–70 mg/100 g for calcium, 75–398 mg/100 g for magnesium, 244–1529 mg/100 g for potassium and 4–11 mg/100 g for iron. Soluble oxalate concentration did not increase in proportion to total oxalate, and the phytate concentration in all foods was sufficient to contribute to an increase in soluble oxalate concentration by binding calcium.     

Tocopherols and total phenolics in 10 different nut types

The study was conducted to assess the content of tocopherols (α-, β-, γ- and δ-) and carotenoids (α- and β-carotene, zeaxanthin, lutein, cryptoxanthin and lycopene) in the unsaponifiable matter as well as the amount of total phenols of 10 different types of nuts. Tocopherols and carotenoids were analysed with HPLC, total phenols photometrically. The mean value of α-tocopherol equivalents ranged from non-detectable (macadamias) to 33.1 mg/100 g extracted oil (hazelnuts). Among all nuts, almonds and hazelnuts had the highest mean α-tocopherol content (24.2 and 31.4 mg/100 g extracted oil, respectively). β- and γ-tocopherols were prevalent in Brazil nuts, cashews, peanuts, pecans, pines, pistachios and walnuts. Mean values oscillated between 5.1 (cashews) and 29.3 (pistachios). Traces of δ-tocopherol (<4 mg/100 g extracted oil) were analysed in cashews, hazelnuts, peanuts, pecans, pines, pistachios and walnuts. There were no carotenoids detected in the tested nuts with the exception of pistachios. The mean content of total phenolics varied between 32 mg gallic acid equivalents/100 g (pines) and 1625 mg (walnuts). The results show the heterogenic amounts of antioxidants in nuts, which emphasises the recommendation of a mixed nuts intake.     

Variation in contents of phenolic compounds during growth and post-harvest storage of pigeon pea seedlings

The variation in contents of seven phenolic compounds in pigeon pea seedlings during growth and storage was investigated. Maximum contents of vitexin, isovitexin and orientin were found in leaves growing 40 days, which were 0.99 ± 0.06, 6.63 ± 0.35 and 30.89 ± 1.92 mg/g DW. Apigenin and luteolin were extensively distributed in leaves, stems and roots. Pinostrobin and cajaninstilbene acid were mainly accumulated in leaves, the peak values 3.53 ± 0.18 and 2.49 ± 0.13 mg/g DW appeared at the 60th day. Slight and steady increases of seven phenolic compounds were found in room temperature (25 °C) stored pigeon pea leaves up to 120 days. The highest accumulation of seven phenolic compounds at chilling temperature (4 °C) was observed at the 45th day, after which the contents decreased sharply. The stems extracts exhibited more efficient DPPH radical-scavenging ability while the roots extracts demonstrated the strongest lipid peroxidation inhibitory activity.     

Effect of food matrix on amandin, almond (Prunus dulcis L.) major protein, immunorecognition and recovery

Amandin, the primary storage protein in almonds, contains key polypeptides recognized by almond-allergic patients. A variety of food matrices representing diverse categories of foods were analyzed to assess the effect of food matrix on amandin recognition and recovery using rabbit polyclonal antibody based immunoassays. Food matrices from dairy, nuts, and vegetables typically resulted in over-estimation of amandin. Some foods representing legumes and cereals resulted in over-estimation while others in under-estimation of amandin. The amandin recovery range was 116-198 μg/100μg (dairy) 110-292 μg/100μg (tree nuts), 43-304 μg/100μg (legumes), 106-183 μg/100μg (most cereals- with the exception of barley, whole-wheat flour, wild rice and raisin bran whole mix). Amandin recovery from spices was typically low (2-85 μg/100μg) with a few exceptions where higher recoveries were observed (121-334 μg/100μg). Salt (black and white), tea, confectionery (sugar, cocoa, dark chocolate), and fruits (1-83 μg/100μg) generally resulted in lower recoveries. Tested food matrices did not adversely affect amandin immunorecognition in Western blots. The pH and the extraction buffer type affected amandin recovery. The results suggest that food matrix effects as well as extraction conditions need to be carefully evaluated when developing immunoassays for amandin detection and quantification.     

Folate contents of some selected Fijian foods using tri-enzyme extraction method

Folic acid and total folate contents of 18 common foods in the Fijian diet were assayed. Foods were purchased from the central and eastern parts of Viti Levu in Fiji. Tri-enzyme treatment was performed to release bound folates using protease and α-amylase, with chicken pancreas as the conjugase. The highest total folate content was recorded for egg yolk (Gallus domesticus) at 256 μg/100 g, followed by long beans (Vigna sesquipedalis) which contained 130 μg/100 g of total folate (fresh weight basis). The local leafy vegetable called Bele (Abelmoschus manihot) and the Drumstick leaves (Moringa oleifera) available in Fiji also had high total folate contents, above 100 μg/100 g (fresh weight basis). For the 18 foods studied, the content of folic acid ranged from 3 to 189 μg/100 g and the total folate content was in the range of 3–256 μg/100 g, indicating a very wide range of folate content in the foods studied.     

UPLC and HPLC of caffeoyl esters in wild and cultivated Arctium lappa L.

Analytical methods including ultra-performance liquid chromatography (UPLC) and high-performance liquid chromatography (HPLC) with photodiode array (PDA) detector were developed for the analysis of caffeoylquinic acid derivatives in seeds, leaves and roots of Arctium lappa L. Separation was performed on C₁₈ column utilising 5% (v/v) acetic acid in water and acetonitrile at 330 nm. Both methodologies were validated in terms of linearity, precision, and recovery. The results showed that the major advantages of UPLC, over HPLC were the fast analysis, narrow peaks, high sensitivity, and reduction of solvent consumption. Subsequently the methods were applied for the identification and quantification of chlorogenic acid (5-CQA) and 1,5-dicaffeoylquinic acid (1,5-DCQA) as main compounds in samples. The total phenolic content of samples ranged from 3.93 to 14.13 g of 5-CQA equivalent/100 g dry weight (DW). There was a significant variability from 89 to 571 mg/100 g for 5-CQA and 48 to 486 mg/100 g for 1,5-DCQA in dry material.     

Antioxidant and antiproliferative activities of common edible nut seeds

Frequent consumption of nuts has been linked to a lowered risk of cardiovascular disease. Phytochemicals, especially phenolics, in nuts may be considered to be the major bioactive compounds for health benefits. Nine types of tree nuts and peanuts commonly available in the United States were evaluated for total phenolic and flavonoid contents, antioxidant, and antiproliferative activities. The profiles of total phenolics and flavonoids, including both soluble free and bound forms, were investigated by utilizing solvent extraction, base digestion, and solid-phase extraction methods. Walnuts had the highest total phenolic and flavonoid contents (1580.5 ± 58.0 mg/100 g, 744.8 ± 93.3 mg/100 g, respectively). Walnuts also possessed the highest total antioxidant activity (458.1 ± 14.0 μmol of vitamin C equiv/g of nut). Both soluble phenolic and flavonoid contents were positively correlated with total antioxidant activity (R² = 0.9901, p < 0.05; and R² = 0.9749, p < 0.05, respectively). The proliferation of HepG₂ and Caco-2 cells was significantly inhibited in a dose-dependent pattern after exposure to the extracts of nuts, with walnuts and pecans exhibiting the highest antiproliferative activity. These results provide new knowledge about health functions of nuts and may influence consumers toward purchasing nuts exhibiting greater potential health benefits.     

Simultaneous determination of polymethoxyflavones in Citrus species,Kiyomi tangor and Satsuma mandarin,by high performance liquid chromatography

The content of polymethoxyflavones (PMFs) in Kiyomi tangor (Citrus unshiu Marcov. forma miyagawa-wase × C. sinensis) and Satsuma mandarin (C. unshiu Marcov. forma miyagawa-wase) was determined by HPLC/UV. The major PMFs of Kiyomi tangor were determined as 3,6,7,4′-tetramethoxyflavone in the peels (10.1 mg/g) and leaves (9.2 mg/g), and 3-hydroxy-5,6,7,4′-tetramethoxyflavone in the stems (1.5 mg/g). The major PMFs of Satsuma mandarin were determined as 5,6,7,8,4′-pentamethoxyflavone in the peels (2.2 mg/g) and leaves (1.6 mg/g), and 5,6,7,3′,4′-pentamethoxyflavone in the stems (1.4 mg/g). Large amounts of Citrus by-products can ultimately provide a cheap and convenient source of PMFs.     

Sodium content in retail Cheddar, Mozzarella, and process cheeses varies considerably in the United States

Reducing the sodium content in cheese is expected to contribute to reducing the overall intake of sodium by US consumers. The purpose of this study was to measure the sodium levels in cheeses that are most commonly purchased by US consumers in the retail market, including brand and private label. A secondary purpose of the study was to generate data that can enable the dairy industry to adopt best practices regarding sodium levels in cheeses. The sodium content of a total of 1,665 samples of Cheddar (650 samples), low moisture part skim (LMPS) Mozzarella (746 samples), and process cheese singles (269 samples) from 4 geographical regions were collected over a period of 3 wk, and were analyzed over a 1-mo period. Process cheese contained the highest mean level of sodium (1,242 mg/100 g), followed by string cheese (724 mg/100 g). Across Cheddar cheese forms and brands, the mean analytical sodium was 615 mg/100 g, with 95% between 474 and 731 mg/100 g; label sodium ranged from 600 to 800 mg/100 g (mean 648 mg). Across all LMPS Mozzarella forms and brands, the mean analytical sodium was 666 mg/100 g, with 95% between 452 and 876 mg/100g; label sodium ranged from 526 to 893 mg/100 g (mean 685 mg). Across all process cheese forms and brands, the mean analytical sodium was 1,242 mg/100 g, with 95% between 936 and 1,590 mg/100 g; label sodium ranged from 1,185 to 1,740 mg/100 g (mean 1,313 mg/100 g). These findings demonstrate that manufacturers tended to be conservative with their reporting of sodium on labels. Manufacturers need to reduce variability to better target desired sodium levels, which is an opportunity for better process control, and will enable them to label sodium more accurately.     

Chromium content in selected convenience and fast foods in Poland

The chromium content in selected convenience and fast foods was determined. Samples were wet digested with HNO₃ (69%) in a microwave digestion system. Chromium was determined by graphite furnace atomic absorption spectroscopy (GF-AAS). The chromium content in convenience food ranged on average from 2.22 to 18.2 μg/100 g, in fast food from 3.76 to 28.6 μg/100 g, and in instant food from 0.34 to 4.75 μg/100 g.     

Antioxidant Potential and Polyphenol Content of Beverages,Chocolates, Nuts,and Seeds

Polyphenols present in plant foods as natural antioxidants may inhibit the pathogenesis of many diseases, which involve oxidative reactions. This study aimed to measure the total antioxidant potential with the ferric reducing antioxidant power method and the total polyphenol contents of 15 kinds of beverages, 4 types of chocolates, and 6 sorts of nuts and seeds commonly consumed. The antioxidant potential and polyphenol content ranged (respectively): in beverages 0.216–2.940 mmol/100 ml and 31–241 mg/100 ml, in chocolates 0.550–14.67 mmol/100 g and 222–1617 mg/100 g, in nuts and seeds 0.851–55.91 mmol/100 g and 125–3521 mg/100 g. The antioxidant potential of the foods tested was related to the total polyphenol contents.     

Composition and bioavailability of oxalates in baked taro (Colocasia esculenta var. Schott) leaves eaten with cows milk and cows milk and coconut milk

Taro leaves are an important food in the Pacific Islands but the overall oxalate composition and its nutritional effect has not been investigated. The oxalate contents of taro leaves were determined using chemical and in vitro extraction methods. Maori‐type taro leaves contained 524.2 ± 21.3 mg total oxalates 100 g^?1 fresh weight (FW) and 241.1 ± 20.9 mg soluble oxalates 100 g^?1 FW while the Japanese‐type leaves contained 525.6 ± 19.9 mg total oxalates 100 g^?1 FW and 330.4 ± 28.3 mg soluble oxalates 100 g^?1 FW. Maori‐type taro leaves contained 416.4 ± 1.5 mg gastric soluble oxalates 100 g^?1 FW and 212.4 ± 34.8 mg intestinal soluble oxalates 100 g^?1 FW while the Japanese‐type leaves contained 433.3 ± 9.7 mg gastric soluble oxalates 100 g^?1 FW and 224.2 ± 38.7 mg intestinal soluble oxalates 100 g^?1 FW). Human feeding experiments were conducted to determine the availability of the oxalates in the baked leaves following additions of cows milk and coconut milk. The consumption of a test meal of baked taro leaves resulted in a significant increase (P < 0.001) in the output of urinary oxalate in the following 6 h when compared to the output of oxalate during a reference collection. When the leaves were baked with cows milk or cows milk and coconut milk combined and consumed there was a small non‐significant reduction in urinary oxalate output which suggests that less soluble oxalate was absorbed from these mixtures.     

Folate content in foods commonly consumed in Egypt

The folate content in some Egyptian foods was determined using RP-HPLC-FL. Trienzyme treatment was used for legumes, dienzyme treatment for cereals and starchy vegetables, and monoenzyme treatment for vegetables and fruits. The highest folate content (633 μg/100 g) was found in dried Jew’s mellow due to low water content, followed by legumes (e.g. 150 μg/100 g for chick peas) and leafy vegetables (100 μg/100 g). For other foods, folate content ranged from 10–90 μg/100 g. In all foods, the predominant folate form was 5-CH₃–H₄folate, except for dried Jew’s mellow, which contained more than 80% 10-HCO–PteGlu. Using folate data from our own analyses and food tables and food consumption data, the dietary folate intake per capita in Egypt was estimated. However, representative and validated food composition data for folate in Egyptian foods are needed for estimating and evaluating the adequacy of the population’s folate intake.     

Effect of preliminary processing and method of preservation on the content of selected antioxidative compounds in kale (Brassica oleracea L. var. acephala) leaves

Vitamin C and polyphenol content as well as total antioxidative activity were investigated in fresh leaves of kale; in leaves after blanching or cooking; and in frozen and canned leaves. In 100 g fresh matter, kale leaves contained 384.9 mg polyphenols and 112.1 mg vitamin C, with a Trolox equivalent antioxidant capacity (TEAC) level of 1175 μM Trolox. Of the polyphenols identified in kale leaves, ferulic acid occurred in the highest amount (240.44 mg/100 g, constituting 62% of total polyphenols). Freezing was a better method of preserving kale leaves since the loss of nutritive constituents was lower than in the case of canning. Depending on preliminary processing and storage temperature, after one-year storage frozen leaves contained 82.9–171.3 mg polyphenols and 39.3–65.4 mg vitamin C, with TEAC at the level of 501–681 μM Trolox in 100 g. In canned leaves these values were: 91.3–94.1 mg polyphenols, 16.1–19.3 mg vitamin C and 268–293 μM Trolox.     

Effect of storage conditions on furosine formation in milk–cereal based baby foods

The effect of storage during 9 months at 25, 30 and 37 °C on furosine formation in three milk–cereal based baby foods was studied to evaluate development of the Maillard reaction. Furosine was measured by HPLC-UV. Immediately after the manufacturing process, furosine contents were 310–340 mg/100 g protein and at the 9th storage month were 426–603 mg/100 g protein. Storage time and temperature have a significant increase (p < 0.05) of furosine content during storage. Furosine contents were higher in sample containing honey than in those without honey. Interactions (p < 0.05) between storage time and temperature or type of sample were found. A predictive model equation of the evolution of furosine during storage explaining 80% of the variability in furosine content was obtained. The blockage of lysine through storage calculated using the furosine and total lysine provided values ranged from 9.5% to 18.1% for analysed baby foods.     

The effects of gender,age and region on macro- and micronutrient contents and fatty acid profiles in the muscles of roe deer and wild boar in Mecklenburg-Western Pomerania (Germany)

Samples of M. longissimus were collected from a total of 203 feral roe deer (n = 118) and wild boar (n = 85) in two regions of Mecklenburg-Western Pomerania (Germany). The muscle lipid saturated fatty acid proportions of roe deer and wild boar ranged between 33 and 49 g/100 g total fatty acids and 31 and 35 g/100 g total fatty acids, respectively. The total n − 3 PUFA proportions in roe deer muscle varied between 8.0 and 14 g/100 g fatty acids, and in wild boar muscle between 2.6 and 6.0 g/100 g fatty acids. The major vitamin E homologue, α-tocopherol, was determined to be between 5.8 and 13.1 mg/kg in roe deer muscles. Lower levels between 1.2 and 4.7 mg/kg were measured in wild boar muscles. The iron and zinc concentrations in roe deer and wild boar muscle ranged from 26.3 to 33.9 mg/kg and from 17.0 to 21.7 mg/kg, and from 13.6 to 39.3 mg/kg and 18.1 to 31.9 mg/kg, respectively.     

Identification and characterisation of low-molecular-weight phenolic compounds in bayberry (Myrica rubra Sieb. et Zucc.) leaves by HPLC-DAD and HPLC-UV-ESIMS

Leaves of each of two bayberry cultivars, Biqi and Dongkui, were divided into three categories by age, namely immature, intermediate, and mature. Phenolic compounds were analysed by the methods of HPLC-DAD and HPLC-UV-ESIMS. Gallic acid and EGCG were identified positively, and 13 other compounds (flavan-3-ol monomers, prodelphinidin oligomers, and flavonol glycosides) were partially identified. Gallic acid (7.5–87.8 mg/100 g) was the only phenolic acid detected and flavan-3-ols were abundant. Myricetin deoxyhexoside (535.4–853.0 mg/100 g) was the major flavonol glycoside. Among the three categories, immature leaves of both cultivars recorded the highest level of total phenolics, irrespective of whether they were measured by the Folin–Ciocalteu method (19404.0 mg/100 g in Biqi and 19626.0 mg/100 g in Dongkui) or as the sum of individual phenolic compounds (2255.9 mg/100 g in Biqi and 1797.1 mg/100 g in Dongkui). The results showed that bayberry leaves are a potentially rich source of beneficial phenolics.     

Cell wall phenolics and polysaccharides in different tissues of quinoa (Chenopodium quinoa Willd)

Quinoa (Chenopodium quinoa Willd) is an Andean pseudo-cereal, of the Chenopodiaceae family, which is currently being studied for introduction in Northern Europe as an alternative to industrial crops. The aim of this work was to verify existence in quinoa of the distinctive cell wall features identified in other Chenopodiaceae, ie presence of pectin-bound ferulic acid and dehydrodiferulic acids. Alcohol-insoluble solids (AIS) were prepared from leaves, stems and roots of mature quinoa plants, representing 0.10, 0.20 and 0.47 g g⁻¹ respectively of the fresh weight. Ferulic acid and dehydrodiferulic acid derivatives were present in all the organs, with the highest concentrations in the leaves with 2.1 and 0.5 mg g⁻¹ AIS respectively. The ratio of dehydrodiferulic acid to ferulic acid was highest in the roots. Pectins extracted by hot HCl from AIS of leaves were rich in ferulic acid (3.4 mg g⁻¹), but also highly acetylated (DAc 20), and rich in rhamnose, two characteristics encountered in other Chenopodiaceae. © 1999 Society of Chemical Industry     

An evaluation of carotenoid levels and composition of glabrous canaryseed

Nineteen glabrous canaryseeds comprising brown- and yellow-coloured varieties were investigated to determine carotenoid content and their properties. Total carotenoid content of canaryseeds ranged from 7.57 to 11.69 mg/kg. β-Carotene, lutein, and zeaxanthin were the major carotenoids of glabrous canaryseed. β-Carotene ranged from 5291 to 6273, 4564 to 5352, and 3651 to 4428 μg/kg while lutein ranged from 2667 to 3370, 1532 to 3007, and 2042 to 2299 μg/kg, respectively in canaryseed flour, wholemeal and bran. Zeaxanthin was relatively low (?650 μg/kg). High β-carotene levels distinguished glabrous canaryseeds from other cereal crops as potential ingredients for carotenoid-enriched functional foods.