• Enrichment and Assessment of the Contributions of the Major Polyphenols to the Total Antioxidant Activity of Onion Extracts: A Fractionation by Flash Chromatography Approach

      Hossain, Mohammad Billal; Lebelle, Justine; Birsan, Rares; Rai, Dilip K.; Department of Agriculture, Food and the Marine; FIRM 06/NITAFRC/6 (MDPI AG, 2018-11-27)
      The present study extensively fractionated crude red onion extract in order to identify the polyphenols which contributed most in the total antioxidant capacity of the onion extract using a flash chromatography system. The flash separations produced 70 fractions which were tested for their total phenol content, total flavonoid content, and antioxidant capacities as measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Out of these 70 fractions, four fractions which were representatives of the four major peaks of the flash chromatograms, were further analysed for their constituent polyphenols using liquid chromatography tandem mass spectrometry (LC-MS/MS). The main contributor of onion antioxidant capacity is quercetin glycoside followed by quercetin aglycone although quercetin aglycone had higher antioxidant capacity than its glycosidic counterparts. High abundance of quercetin glycosides such as quercetin-3,4′-diglucoside and quercetin-4′-glucoside had compensated for their relatively low antioxidant capacities. A Higher degree of glycosylation resulted in lower antioxidant capacity. The fractionation approach also contributed in enrichment of the onion antioxidant polyphenols. A >9 folds enrichment was possible by discarding the early fractions (fractions 1–15) which contained the main bulk of the extracts, predominantly sugars.
    • Enrichment and Assessment of the Contributions of the Major Polyphenols to the Total Antioxidant Activity of Onion Extracts: A Fractionation by Flash Chromatography Approach

      Hossain, Mohammad Billal; Lebelle, Justine; Birsan, Rares; Rai, Dilip K.; Department of Agriculture, Food and the Marine; 06/NITAFRC/6 (MDPI, 2018-11-27)
      The present study extensively fractionated crude red onion extract in order to identify the polyphenols which contributed most in the total antioxidant capacity of the onion extract using a flash chromatography system. The flash separations produced 70 fractions which were tested for their total phenol content, total flavonoid content, and antioxidant capacities as measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Out of these 70 fractions, four fractions which were representatives of the four major peaks of the flash chromatograms, were further analysed for their constituent polyphenols using liquid chromatography tandem mass spectrometry (LC-MS/MS). The main contributor of onion antioxidant capacity is quercetin glycoside followed by quercetin aglycone although quercetin aglycone had higher antioxidant capacity than its glycosidic counterparts. High abundance of quercetin glycosides such as quercetin-3,4′-diglucoside and quercetin-4′-glucoside had compensated for their relatively low antioxidant capacities. A Higher degree of glycosylation resulted in lower antioxidant capacity. The fractionation approach also contributed in enrichment of the onion antioxidant polyphenols. A >9 folds enrichment was possible by discarding the early fractions (fractions 1–15) which contained the main bulk of the extracts, predominantly sugars.
    • Exploring the effects of pulsed electric field processing parameters on polyacetylene extraction from carrot slices

      Aguilo-Aguayo, Ingrid; Abreu, Corina; Hossain, Mohammad Billal; Altisent, Rosa; Brunton, Nigel; Viñas, Inmaculada; Rai, Dilip K.; Department of Agriculture, Food and the Marine; Generalitat of Catalonia; 06TNITAFRC6; et al. (MDPI, 2015-03-02)
      The effects of various pulsed electric field (PEF) parameters on the extraction of polyacetylenes from carrot slices were investigated. Optimised conditions with regard to electric field strength (1–4 kV/cm), number of pulses (100–1500), pulse frequency (10–200 Hz) and pulse width (10–30 μs) were identified using response surface methodology (RSM) to maximise the extraction of falcarinol (FaOH), falcarindiol (FaDOH) and falcarindiol-3-acetate (FaDOAc) from carrot slices. Data obtained from RSM and experiments fitted significantly (p < 0.0001) the proposed second-order response functions with high regression coefficients (R2) ranging from 0.82 to 0.75. Maximal FaOH (188%), FaDOH (164.9%) and FaDOAc (166.8%) levels relative to untreated samples were obtained from carrot slices after applying PEF treatments at 4 kV/cm with 100 number of pulses of 10 μs at 10 Hz. The predicted values from the developed quadratic polynomial equation were in close agreement with the actual experimental values with low average mean deviations (E%) ranging from 0.68% to 3.58%.
    • Optimisation and validation of ultra-high performance liquid chromatographic-tandem mass spectrometry method for qualitative and quantitative analysis of potato steroidal alkaloids

      Hossain, Mohammad Billal; Rai, Dilip K.; Brunton, Nigel; Department of Agriculture, Food and the Marine; 11/F/050 (Elsevier, 2015-06-09)
      An ultra-high performance liquid chromatographic-tandem mass spectrometry (UHPLC–MS/MS) method for quantification of potato steroidal alkaloids, namely α-solanine, α-chaconine, solanidine and demissidine was developed and validated. Three different column chemistries, i.e. ethylene bridged hybrid (BEH) C18, hydrophilic lipophilic interaction and amide columns, were assessed. The BEH C18 column showed best separation and sensitivity for the alkaloids. Validation data (inter-day and intra-day combined) for accuracy and recovery ranged from 94.3 to 107.7% and 97.0 to 103.5%, respectively. The accuracy data were within the acceptable range of 15% as outlined in the United States Food and Drug Administration (USFDA) guidelines. The recovery data were consistent and reproducible with a coefficient of variation (CV) ranging from 6.2 to 9.7%. In addition, precision of the method also met the criteria of the USFDA with CV values lower than 15% even at lower limit of quantification (LLOQ), while the permissible variation is considered acceptable below 20%. The limit of detection and LLOQ of the four alkaloids were in the range of 0.001–0.004 μg/mL whereas the linearities of the standard curves were between 0.980 and 0.995.
    • Profiling of Phytochemicals in Tissues from Sclerocarya birrea by HPLC-MS and Their Link with Antioxidant Activity

      Russo, Daniela; Kenny, Owen; Smyth, Thomas J.; Milella, Luigi; Diop, Moussoukhoye Sissokho; Rai, Dilip K.; Brunton, Nigel; Hossain, Mohammad Billal; Department of Agriculture, Food and the Marine (Hindawi, 2013-04-29)
      High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was employed to investigate the differences in phytochemicals in roots, bark, and leaf of Sclerocarya birrea (marula) for methanol and water extracts that exhibited the best antioxidant activities. As many as 36 compounds were observed in the extracts of these tissues of which 27 phenolic compounds were tentatively identified. The HPLC-MS/MS results showed flavonoid glycosides were prominent in leaf extracts while the galloylated tannins were largely in bark and root extracts. Four flavonoid glycosides that were reported for the first time in the marula leaf have been identified. The HPLC-MS/MS studies also illustrated different degrees (highest degree = 3) of oligomerisation and galloylation of tannins in the bark and root extracts.
    • Recovery of Steroidal Alkaloids from Potato Peels Using Pressurized Liquid Extraction

      Rawson, Ashish; Aguiló-Aguayo, Ingrid; Brunton, Nigel; Hossain, Mohammad Billal; Rai, Dilip K.; Department of Agriculture, Food and the Marine; 08/RD/AFRC/673 (MDPI, 2015-05-13)
      A higher yield of glycoalkaloids was recovered from potato peels using pressurized liquid extraction (1.92 mg/g dried potato peels) compared to conventional solid–liquid extraction (0.981 mg/g dried potato peels). Response surface methodology deduced the optimal temperature and extracting solvent (methanol) for the pressurized liquid extraction (PLE) of glycoalkaloids as 80 °C in 89% methanol. Using these two optimum PLE conditions, levels of individual steroidal alkaloids obtained were of 597, 873, 374 and 75 µg/g dried potato peel for α-solanine, α-chaconine, solanidine and demissidine respectively. Corresponding values for solid liquid extraction were 59%, 46%, 40% and 52% lower for α-solanine, α-chaconine, solanidine and demissidine respectively
    • A Review of Extraction and Analysis of Bioactives in Oat and Barley and Scope for Use of Novel Food Processing Technologies

      Gangopadhyay, Nirupama; Rai, Dilip K.; Brunton, Nigel; Hossain, Mohammad Billal; Department of Agriculture, Food and the Marine.; 11/SF/317 (MDPI, 2015-06-12)
      Oat and barely are cereal crops mainly used as animal feed and for the purposes of malting and brewing, respectively. Some studies have indicated that consumption of oat and barley rich foods may reduce the risk of some chronic diseases such as coronary heart disease, type II diabetes and cancer. Whilst there is no absolute consensus, some of these benefits may be linked to presence of compounds such as phenolics, vitamin E and β-glucan in these cereals. A number of benefits have also been linked to the lipid component (sterols, fatty acids) and the proteins and bioactive peptides in oats and barley. Since the available evidence is pointing toward the possible health benefits of oat and barley components, a number of authors have examined techniques for recovering them from their native sources. In the present review, we summarise and examine the range of conventional techniques that have been used for the purpose of extraction and detection of these bioactives. In addition, the recent advances in use of novel food processing technologies as a substitute to conventional processes for extraction of bioactives from oats and barley, has been discussed.
    • Ultrasound-assisted extraction of polyphenols from potato peels: profiling and kinetic modelling

      Kumari, Bibha; Tiwari, Brijesh K; Hossain, Mohammad Billal; Rai, Dilip K.; Brunton, Nigel; Department of Agriculture, Food and Marine; FIRM/11/F/050 (Wiley, 2017-02-14)
      Ultrasound‐assisted extraction (UAE) at 33 and 42 kHz has been investigated in the extraction of polyphenols from peels of two potato varieties, cream‐skinned Lady Claire (LC) and pink‐skinned Lady Rosetta (LR), commonly used in snack food production. Extraction efficacy between the UAE‐untreated (control) and the UAE‐treated extracts was assessed on the total phenolic content and antioxidant capacities (DPPH and FRAP). Application of UAE showed significantly higher recovery of phenolic compounds compared to solid–liquid extraction process alone. Lower ultrasonic frequency (33 kHz) was more effective in recovering polyphenols compared to 42 kHz ultrasonic treatment. The liquid chromatography‐tandem mass spectrometry revealed that chlorogenic acid and caffeic acid were the most prevalent phenolics in LR peels, whereas caffeic acid was dominant in LC peels. Peleg's equation showed a good correlation (R2 > 0.92) between the experimental values and the predicted values on the kinetics of UAE of phenolic compounds.