Effect of refining processes on antioxidant capacity,total contents of phenolics and carotenoids in palm oils

Antioxidant capacity (AC), total phenolic content (TPC) and total carotenoid content (TCC) in palm oils at various stages of the refining process from two technological modes were determined. The obtained mean FRAP and DPPH values for the methanolic extracts of palm oils from mode 1 (19.5–102.8 μmol TE/100 g and 18.8–103.0 μmol TE/100 g) were lower than for oils from mode 2 (25.6–134.8 μmol TE/100 g and 25.4–135.4 μmol TE/100 g). The total phenolics (4.1–12.4 mg GA/100 g) and carotenoids (0.18–45.8 mg/100 g) in the studied oils were correlated with their antioxidant capacities determined by FRAP and DPPH methods (r = 0.6623–0.9878). During the refining process, for both technological modes resulted in a loss of AC by 80%, TPC by 26–55% and TCC by 99%. The bleaching step caused the highest losses of AC as determined by FRAP 41% and 46%, DPPH by 43% and 48%, while TPC loss was 45% and 23% and loss of carotenoids was 49% and 56%, in mode 1 and mode 2, respectively.     

Fatty acids and cholesterol oxidation in salted and dried shrimp

The aim of this work was to evaluate the occurrence of cholesterol oxidation products and to analyze the lipidic profile in salted–dried shrimp. Fifty samples of salted–dried shrimp were evaluated, and the cholesterol oxides (7β-OH, 7α-OH, 7-Keto and 25-OH) were quantified by high-performance liquid chromatography. The cholesterol oxides: 7β-OH (34.63–72.56 μg/g), 7α-OH (5.02–12.12μg/g), 7-Keto (7.44–32.68 μg/g) and 25-OH (2.37–22.88 μg/g) were determined in all samples analyzed. Regarding to the total cholesterol content and the average thiobarbituric acid reactive substances (TBARS) content, the results ranged from 73.88 to 247.69 mg/100 g, and 0.02 to 1.30 mgMA/kg, respectively. The fatty acids profile was: 27.48% saturated, 43.90% monounsaturated and 28.61% polyunsaturated. The presence of cholesterol oxidation products and the values of TBARS indicate the degree of oxidation of this product, which was probably initiated by inadequate conditions of processing and storage.     

Determination of aflatoxin levels in nuts and their products consumed in South Korea

A total of 85 nuts and their products marketed in South Korea were assessed for aflatoxins using a monitoring scheme consisting of enzyme-linked immunosorbent assay (ELISA) for rapid screening, high performance liquid chromatography (HPLC) for quantification and LC–mass spectrometry (MS) for confirmation. Thirty-one out of 85 samples gave ELISA readings above 0.06 and were screened as possible positive samples. Aflatoxin contents of possible positive samples were determined using HPLC with a detection limit of 0.08–1.25 μg/kg and a quantification limit of 0.15–2.50 μg/kg. Nine samples including 1 raw peanut, 4 roasted peanuts, 2 peanut butters, 1 pistachio and 1 seasoned assorted nut were contaminated with aflatoxins (10.6% of incidence), ranging in various levels up to 28.2 μg/kg. LC–MS analysis on contaminated samples revealed that peaks eluting at 4.4, 5.2, 9.1 and 11.9 min were confirmed as aflatoxin G₁, aflatoxin B₁, aflatoxin G₂ and aflatoxin B₂, respectively.     

Development of an HPLC–UV method for the simultaneous determination of tetracyclines in muscle and liver of porcine,chicken and bovine with accelerated solvent extraction

A simple and especially rapid method-using accelerated solvent extraction (ASE) and HPLC has been developed for the quantitative determination of oxytetracycline, tetracycline, chlortetracycline, minocycline, methacycline, demeclocycline and doxycycline in muscle and liver of porcine, chicken and bovine. Samples of muscle and liver were extracted with trichloracetic acid/acetonitrile using ASE instrument, parameters such as extraction temperature (40–80 °C) and pressure (45–85 bar) were investigated and the selected extraction (60 °C, 65 bar) was most effective. The limits of detection were lower than 10 μg/kg and limits of quantification no more than 15 μg/kg for all compounds in muscle and liver. The recoveries of tetracyclines spiked at levels of muscle 50–150 μg/kg, liver 150–450 μg/kg, averaged from 75.0% to 104.9% with the relative standard deviation values less than 10%. The method was applied to determine 30 real porcine livers. It is demonstrated that the new method is robust for detection and quantification of seven tetracycline residues in muscle and liver of porcine, chicken and bovine.     

Determination of trace element contents of baby foods from Turkey

The levels of trace elements in different types of baby foods consumed in Turkey were determined by flame and graphite furnace atomic absorption spectrometry. Dry, wet and microwave digestion procedures were compared and the microwave digestion method was found to be the best. The accuracy of the method was ensured by using a standard reference material (NIST-SRM 8418 Wheat Gluten). The levels of elements in analyzed samples were found to be under legal limits. The range of the investigated elements were 0.52–4.38 μg/g, 0.22–7.20 μg/g, 1.02–67.5 μg/g, 0.92–37.2 μg/g, 0.12–0.32 μg/g, 2.02–68.8 μg/kg, 10.7–66.8 μg/kg, 0.05–10.3 μg/g, 2.67–25.4 μg/kg for Cu, Mn, Fe, Zn, Se, Cr, Al, Ni and Co, respectively.     

Aflatoxin contents of stored and artificially inoculated cereals and nuts

Aflatoxin contents of cereals and nuts, collected from local markets of NWFP, were determined by thin layer chromatography (TLC). The seeds of these crops were also inoculated with Aspergillus flavus and the aflatoxin content and its relation with the proximate composition of seeds was studied. The effect of storage for different durations of time (2–3 and 12–18 months) on the aflatoxin content of seeds was also assessed. Aflatoxin content of cereals (wheat, maize and rice) ranged from 14 to 45 μg/kg, and that of nuts (almond, walnut and peanut) varied from 5 to 17 μg/kg. The aflatoxin content was within the safe limit (50 μg/kg) recommended by FAO. The aflatoxin content of inoculated seeds was significantly (p < 0.05) increased over control (un-inoculated seeds). This was positively related (r = 0.65) to moisture content of the seeds. However, negative correlation (r = −0.50) existed between aflatoxin and ash contents of the seeds. Protein, fat and total carbohydrate (NFE) contents were not much affected by inoculation. Prolonged storage for 18 months (1.5 years) significantly (p < 0.05) increased aflatoxin contents of seeds compared to short storage periods (2–3 months). It was concluded that aflatoxin content of food should be monitored to ensure food safety. Prolonged storage of cereal and nuts in warm humid condition should be avoided to minimize the risk of aflatoxin contamination.     

Liquid chromatography–tandem mass spectrometry for the determination of chrysoidine in yellow-fin tuna

A high performance liquid chromatography (HPLC) coupled to electrospray ionisation tandem mass spectrometry (MS/MS) method was described for the residue detection of chrysoidine in yellow-fin tuna in the present study. Samples were cleaned up with solid phase extraction (SPE) cartridge, and then injected into HPLC for separation. Multiple-reaction monitoring (MRM) was applied for quantitative determination. Results showed that the low limit of detection (LOD) of the method was 1.25 × 10⁻¹² g, and the low limit of quantification (LOQ) was 0.42 μg/L. The standard calibration curve was y = 2333.9x −845 (r² > 0.99) with the linear range of 0.63–100 μg/L. The average recoveries of chrysoidine ranged from 86.0% to 108.0% when the spiked concentration was from 0.5 μg/kg to 20 μg/kg. And the developed method also showed the good test precisions (RSD%: 4.38–14.27%).     

Composition and stability of phytochemicals in five varieties of black soybeans (Glycine max)

Phytochemical compositions of five varieties of black soybeans (Glycine max) and their stabilities at room temperature, 4 and −80 °C over 14 months were determined by HPLC systems with electrochemical (ECD) and UV detectors. Polyphenol profiling was carried out by a liquid chromatography–electrospray ionisation-mass spectrometry (LC–ESI-MS) with orbitrap as a mass analyser in both positive and negative ion modes, and polyphenols in aglycone forms were quantified by HPLC–ECD. Five different varieties of black soybeans (G. max) contained 249–405 μg/g dry wt of γ-tocopherol and 6.76–14.98 μg/g dry wt of lutein. Major polyphenols in black soybeans (G. max) were daidzein (193–288 μg/g dry wt) and genistein (145–223 μg/g dry wt), mainly present as glucosides and acetyl glucosides. No significant decrease was found in total phenols of black soybeans (G. max) stored at room temperature, 4 or −80 °C for 14 months. On the other hand, lutein and γ-tocopherol degraded significantly within a month of storage at room temperature (p < 0.01), whereas they remained stable up to 6 months at 4 °C and up to 14 months at −80 °C. The current study indicates that black soybeans (G. max) are rich source of γ-tocopherol and phenols (isoflavones, flavonols, flavan-3-ols, proanthocyanidins and anthocyanin) and that the levels vary depending upon varieties. In addition, storage at low temperature is recommended to reduce the loss of fat-soluble phytochemicals in black soybeans (G. max) over an extended period of time.     

Carotenoid contents of extruded and non-extruded sweetpotato flours from Papua New Guinea and Australia

Carotenoid contents of extruded and non-extruded flours of Papua New Guinean and Australian sweetpotato cultivars were studied, using spectrophotometry and high performance liquid chromatography (HPLC). The cultivars differed (p < 0.05) in their total carotenoid and β-carotene contents, and the Original Beauregard cultivar had the highest total carotenoid and β-carotene contents among the cultivars. The spectrophotometry (84–1720 μg/g solids) method generally over-estimated the total carotenoid content compared to the more specific HPLC (23–355 μg/g solids) method. Extrusion significantly (p < 0.05) decreased the ΔL^∗ Hunter colour values, while the Δa^∗, Δb^∗, total colour change (ΔE), chroma (CR), and browning indices (BI) increased. With the extruder and screw configuration used, extrusion at 40% moisture and 300 rpm screw speed retained carotenoid maximally at more than 80%. This study reports, for the first time, carotenoids of flours from south Pacific sweetpotato cultivars, and carotenoid retention during extrusion.     

Measurement of anthocyanins and other phytochemicals in purple wheat

The major anthocyanin composition of normal purple wheat and heat stressed purple wheat were measured using HPLC, LC–MS/MS and the pH differential method. The lignan secoisolariciresinol diglucoside (SDG) and melatonin content were also measured. Total anthocyanin profile of normal purple wheat (491.3 mg/kg) was significantly (P < 0.05) lower than that of the heat stressed purple wheat (522.7 mg/kg). Thirteen major anthocyanins were isolated and cyanidin 3-glucoside was the predominant anthocyanin in purple wheat. Using the pH differential method, the total anthocyanin content of normal (500.6 mg/kg) and heat stressed (526.0 mg/kg) purple wheat were similar to those observed using HPLC. The SDG content of normal and heat stressed purple wheat were 770 and 520 μg/kg, while melatonin content was 4 and 2 μg/kg, respectively. The presence of SDG and melatonin in addition to anthocyanins may contribute to the health benefits associated with consumption of coloured cereal grains.     

Stability and bioaccessibility of different forms of carotenoids and vitamin A during in vitro digestion

Vitamin A deficiency is a public health issue in developing countries and promoting dietary carotenoids as precursors is a promising strategy. However, carotenoids present in numerous fruits and vegetables are unstable and poorly bioaccessible. This study evaluated these two parameters during in vitro digestion of carotenoids and retinoids from carrot juice, raw and cooked spinach, micronutrient-fortified flour and standards without food matrix. Standards were unstable whereas vitamin A from fortified flour and native food carotenoids were generally better protected by the food matrix (30–100% remaining versus 7–30% for standards). Hydrothermal cooking did not influence spinach carotenoid digestive stability but decreased their contents, phenomenon compensated by a significantly better micellarisation from 15-fold for β-carotene to 72-fold for lutein. Finally, carrot juice provided the greatest amount of bioaccessible provitamin A with 1850 μg/100 g dry matter (DM) versus 790 and 80 μg/100 g DM in cooked and raw spinach, respectively.     

Aflatoxins contamination in spices and processed spice products commercialized in Korea

A survey for total aflatoxins (aflatoxins B₁, B₂, G₁, and G₂) was conducted on 88 spices and processed spice products commercialized in Korea. The presence of aflatoxins was determined by high-performance liquid chromatography (HPLC) with fluorescence detector using immunoaffinity column clean-up. Total aflatoxins (AFs) are detected in 12 samples (13.6% of incidence) including seven red pepper powder, two red pepper pastes (Kochujang), two curry and one ginger product. The contamination levels are 0.08–4.45 μg/kg as aflatoxin B₁ and 0.08–4.66 μg/kg as AFs. The liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis on contaminated samples was conducted for the confirmation of detected aflatoxins. The 12 samples which showed aflatoxins by HPLC/FLD were confirmed as aflatoxins by LC–MS/MS.     

Identification and analysis of isothiocyanates and new acylated anthocyanins in the juice of Raphanus sativus cv. Sango sprouts

The freeze-dried sprouts’ juice of Raphanus sativus (L.) cv. Sango was prepared and analysed for the first time. HPLC analysis of total isothiocyanates, after protein displacement, resulted in 77.8 ± 3.0 μmol/g of dry juice while GC–MS analysis of hexane and acetone extracts showed E- and Z-raphasatin (8.9 and 0.11 μmol/g, respectively) and sulforaphene (11.7 μmol/g), summing up to 20.7 ± 1.7 μmol/g of free isothiocyanates. Sprouts’ juice contained an unprecedented wealth of anthocyanins and a new fractionation methodology allowed us to isolate 34 mg/g of acylated anthocyanins (28.3 ± 1.9 μmol/g), belonging selectively to the cyanidin family. Analysis was performed by HPLC–PDA–ESI–MSⁿ and extended to deacylated anthocyanins and aglycones, obtained, respectively, by alkaline and acid hydrolysis. This study identified 70 anthocyanins, 19 of which have never been described before and 32 of which are reported here in R. sativus for the first time. Sango radish sprouts are exceptional dietary sources of heath-promoting micronutrients.     

Carotenoid compositions of coloured tomato cultivars and contribution to antioxidant activities and protection against H2O2-induced cell death in H9c2

The carotenoid compositions, antioxidant activities and the potential cardio-protective role of 13 tomato cultivars with distinct colour were studied. Colour coordinates were evaluated by colorimeter and the carotenoid compositions were analysed by UPLC. Red tomatoes had the highest total carotenoid contents (TCC) and antioxidant activities, followed by purple, orange, pink and yellow ones. The TCC were 120.5–278.0 μg/g DW, and the antioxidant activities were 21.32–40.07 μmol TE/g DW (PCL), 64.42–89.98% (DPPH) and 10.47–13.76 μmol TE/g DW (ORAC), respectively. The lipophilic extracts were also found to prevent cell death in a cell-based model system using cardiac H9c2 cells and H₂O₂, via attenuation of the caspase-3 and matrix metalloproteinase-2 activities. The extracts of different tomatoes showed strong but different antioxidant activities. Roles of total and individual carotenoids in the antioxidant activities were studied and lycopene showed the highest correlation. Results of this study can be used to guide the development of new tomato cultivars and functional foods, and benefit the consumers.     

Carotenoid composition and vitamin A activity of medicinally important green leafy vegetables

Carotenoid composition of green leafy vegetables (GLVs, n = 30) with medicinal value was analyzed by HPLC; vitamin A activity (as retinol equivalent, RE) of provitamin A carotenoids was calculated. Results show that among GLVs studied, the level of β-carotene (50–130 mg/100 g dry wt) was higher in nine GLVs than other carotenoids while lutein (50–187 mg/100 g dry wt) and zeaxanthin (1–5 mg/100 g dry wt) were higher in 12 GLVs than other xanthophylls. α-Carotene was detected only in nine GLVs, ranging from 1 to 37 mg/100 g dry wt. Interestingly, Chenopodium album, Commelina benghalensis and Solanum nigrum were found to contain higher levels of both lutein and β-carotene in the range of 84–187 and 50–115 mg/100 g dry wt, respectively. The values of retinol equivalents (RE) ranged from 641 to 19101 and were higher (>10,000) in six GLVs of the 30. The results demonstrate that GLVs studied contained higher levels of RE and lutein.     

Sacha inchi (Plukenetia volubilis): A seed source of polyunsaturated fatty acids,tocopherols, phytosterols,phenolic compounds and antioxidant capacity

Fatty acids (FA), phytosterols, tocopherols, phenolic compounds, total carotenoids and hydrophilic and lipophilic ORAC antioxidant capacities were evaluated in 16 cultivars of Sacha inchi (SI) seeds with the aim to valorise them and offer more information on the functional properties of SI seeds. A high α linolenic (α-Ln) fatty acid content was found in all cultivars (ω3, 12.8–16.0 g/100 g seed), followed by linoleic (L) fatty acid (ω6, 12.4–14.1 g/100 g seed). The ratio ω6/ω3 was within the 0.83–1.09 range. γ- and δ-tocopherols were the most important tocopherols, whereas the most representative phytosterols were β-sitosterol and stigmasterol. Contents of total phenolics, total carotenoids and hydrophilic and lipophilic antioxidant capacities ranged from 64.6 to 80 mg of gallic acid equivalent/100 g seed; from 0.07 to 0.09 mg of β-carotene equivalent/100 g of seed; from 4.3 to 7.3 and, from 1.0 to 2.8 μmol of Trolox equivalent/g of seed, respectively, among the evaluated SI cultivars. Results showed significant differences (p < 0.05) among the evaluated SI cultivars in the contents of ω3, ω6, antioxidant capacities and other evaluated phytochemicals. SI seeds should be considered as an important dietary source of health promoting phytochemicals.     

Quantitative determination of Zn protoporphyrin IX,heme and protoporphyrin IX in Parma ham by HPLC

We measured the contents of Zn protoporphyrin IX (ZPP), heme and protoporphyrin IX (PPIX) in Parma ham by simultaneous analysis using high-performance liquid chromatography (HPLC). Extraction with ethyl acetate–acetic acid (4:1) was suitable for the quantitative analysis of ZPP. The contents of heme, ZPP and PPIX in Parma ham were 15.0–29.9, 27.7–47.0 and 0.4–1.1 μg/g, respectively, and total content of porphyrin was 43.7–76.6 μg/g. The amount of ZPP in Parma ham was larger than that of heme, and ZPP accounted for 60–70% of all porphyrins.     

Distribution of fungi and aflatoxins in a stored peanut variety

The objective of the present study was to evaluate the mycoflora and occurrence of aflatoxins in stored peanut samples (hulls and kernels) from Tupã, State of São Paulo, Brazil. The samples were analyzed monthly over a period of one year. The results showed a predominance of Fusarium spp. (67.7% in hulls and 25.8% in kernels) and Aspergillus spp. (10.3% in hulls and 21.8% in kernels), and the presence of five other genera. The growth of Aspergillus flavus was mainly influenced by temperature and relative humidity. Analysis of hulls showed that 6.7% of the samples were contaminated with AFB₁ (mean levels = 15–23.9 μg/kg) and AFB₂ (mean levels = 3.3–5.6 μg/kg); in kernels, 33.3% of the samples were contaminated with AFB₁ (mean levels = 7.0–116 μg/kg) and 28.3% were contaminated with AFB₂ (mean levels = 3.3–45.5 μg/kg). Analysis of the toxigenic potential revealed that 93.8% of the A. flavus strains isolated were producers of AFB₁ and AFB₂.     

Antioxidant activity and phenolic content of 16 raisin grape (Vitis vinifera L.) cultivars and selections

Six raisin grape cultivars and 10 new raisin grape selections were analyzed for antioxidant activity (ABTS assay) and for total and individual phenolic compounds. Samples were freeze–dried and values are reported on a dry weight basis. Antioxidant activity across the 16 samples ranged from 7.7 to 60.9 μmol Trolox/g DW, with A95-27 exhibiting the greatest activity. Total phenolic content, determined in gallic acid equivalents using the Folin–Ciocalteau assay, ranged from 316.3 to 1141.3 mg gallic acid/100 g DW and was strongly correlated (r = 0.990) with antioxidant results. Concentrations of individual phenolics were determined by HPLC. trans-Caftaric acid was the predominant compound in all samples. A95-15 contained the lowest concentration (153.5 μg/g DW) of caftaric acid, while Fiesta contained the highest concentration (598.7 μg/g DW). Selections A56-66, A95-15, and A95-27 had much higher levels of catechin (86.5–209.1 μg/g DW) and epicatechin (126.5–365.7 μg/g DW) than the other samples.     

Fumonisin level in corn-based food and feed from Linxian County,a high-risk area for esophageal cancer in china

The level of mycotoxin fumonisins in corn-based food and feed collected from Linxian County, a high-risk area for esophageal cancer in China, has been analyzed using high-performance liquid chromatographic coupled with evaporative laser scattering detector (HPLC-ELSD). A total of 104 corn kernel samples were obtained from local households, granaries, wholesale markets (central markets), and retail markets (stores and supermarkets). Fumonisin B₁ (FB₁) was detected in the samples from households, granaries, central markets, and stores, with a positive rate of 61.5%, 50%, 33.3%, and 17%, respectively. No fumonisin was detected in samples from the supermarket. The highest FB₁ levels (0.30–3.20 μg/g; mean, 1.42 μg/g) were found in samples from the granary, followed by household (0.25–1.80 μg/g; mean, 0.73 μg/g), central market (0.25–1.10 μg/g; mean, 0.51 μg/g), and store (0.22–0.34 μg/g; mean, 0.28 μg/g). Among the 80 corn kernel samples collected from local households, 18 of 24 (75.0%) moldy samples contained high levels of FB₁ (0.28–3.30 μg/g; mean, 1.58 μg/g), and 20 of 56 (35.7%) apparently healthy samples contained low levels of FB₁ (0.21–0.82 μg/g; mean, 0.46 μg/g). As the central market plays an important role in trade of corn-based food and feed in China, a total of 115 corn-based food and feed samples were collected from the local central market. The highest FB₁ levels (0.30–3.13 μg/g; mean, 1.50 μg/g) were found in feed, followed by unprocessed food (0.31–0.63 μg/g; mean, 0.47 μg/g) and processed food (0.21–0.28 μg/g; mean, 0.25 μg/g). The positive incidence of FB₁ in feed, unprocessed, and processed food were 53.6%, 33.3% and 17.9%, respectively. In conclusion, the results showed that corn-based food and feed from Linxian County contained low level of FB₁ (<2 μg/g) in general, but efforts should be made to control the fumonisin contamination in corn kernels stored in granaries and households.