Displaying publications 1 - 20 of 95 in total

  1. Teh HF, Neoh BK, Wong YC, Kwong QB, Ooi TE, Ng TL, et al.
    J Agric Food Chem, 2014 Aug 13;62(32):8143-52.
    PMID: 25032485 DOI: 10.1021/jf500975h
    Oil palm is one of the most productive oil-producing crops and can store up to 90% oil in its fruit mesocarp. Oil palm fruit is a sessile drupe consisting of a fleshy mesocarp from which palm oil is extracted. Biochemical changes in the mesocarp cell walls, polyamines, and hormones at different ripening stages of oil palm fruits were studied, and the relationship between the structural and the biochemical metabolism of oil palm fruits during ripening is discussed. Time-course analysis of the changes in expression of polyamines, hormones, and cell-wall-related genes and metabolites provided insights into the complex processes and interactions involved in fruit development. Overall, a strong reduction in auxin-responsive gene expression was observed from 18 to 22 weeks after pollination. High polyamine concentrations coincided with fruit enlargement during lipid accumulation and latter stages of maturation. The trend of abscisic acid (ABA) concentration was concordant with GA₄ but opposite to the GA₃ profile such that as ABA levels increase the resulting elevated ABA/GA₃ ratio clearly coincides with maturation. Polygalacturonase, expansin, and actin gene expressions were also observed to increase during fruit maturation. The identification of the master regulators of these coordinated processes may allow screening for oil palm variants with altered ripening profiles.
  2. Sulaiman SF, Ooi KL
    J Agric Food Chem, 2014 Oct 1;62(39):9576-85.
    PMID: 25198055 DOI: 10.1021/jf502912t
    The present study compared pH, total soluble solids, vitamin C, and total phenolic contents, antioxidant activities, and α-glucosidase inhibitory activities of 40 fresh juices. The juice of Baccaurea polyneura showed the highest yield (74.17 ± 1.44%) and total soluble solids (32.83 ± 0.27 °Brix). The highest and lowest pH values were respectively measured from the juices of Dimocarpus longan (6.87 ± 0.01) and Averrhoa bilimbi (1.67 ± 0.67). The juice of Psidium guajava gave the highest total phenolic (857.24 ± 12.65 μg GAE/g sample) and vitamin C contents (590.31 ± 7.44 μg AAE/g sample). The juice of Phyllanthus acidus with moderate contents of total phenolics and vitamin C was found to exhibit the greatest scavenging (613.71 ± 2.59 μg VCEAC/g sample), reducing (2784.89 ± 3.93 μg TEAC/g sample), and α-glucosidase inhibitory activities (95.37 ± 0.15%). The juice of Barringtonia racemosa was ranked second in the activities and total phenolic content. Gallic and ellagic acids, which were quantified as the major phenolics of the respective juices, are suggested to be the main contributors to the antioxidant activities. The α-glucosidase inhibitory activity of the juices could be derived from myricetin and quercetin (that were previously reported as potent α-glucosidase inhibitors) in the hydrolyzed juice extracts. The juice of Syzygium samarangense, which was found to be highest in metal chelating activity (82.28 ± 0.10%), also was found to have these phenolics.
  3. Bukhari SN, Jantan I, Unsal Tan O, Sher M, Naeem-Ul-Hassan M, Qin HL
    J Agric Food Chem, 2014 Jun 18;62(24):5538-47.
    PMID: 24901506 DOI: 10.1021/jf501145b
    Hyperpigmentation in human skin and enzymatic browning in fruits, which are caused by tyrosinase enzyme, are not desirable. Investigations in the discovery of tyrosinase enzyme inhibitors and search for improved cytotoxic agents continue to be an important line in drug discovery and development. In present work, a new series of 30 compounds bearing α,β-unsaturated carbonyl moiety was designed and synthesized following curcumin as model. All compounds were evaluated for their effects on human cancer cell lines and mushroom tyrosinase enzyme. Moreover, the structure-activity relationships of these compounds are also explained. Molecular modeling studies of these new compounds were carried out to explore interactions with tyrosinase enzyme. Synthetic curcumin-like compounds (2a-b) were identified as potent anticancer agents with 81-82% cytotoxicity. Five of these newly synthesized compounds (1a, 8a-b, 10a-b) emerged to be the potent inhibitors of mushroom tyrosinase, providing further insight into designing compounds useful in fields of food, health, and agriculture.
  4. Ahmad Aufa Z, Hassan FA, Ismail A, Mohd Yusof BN, Hamid M
    J Agric Food Chem, 2014 Mar 5;62(9):2077-84.
    PMID: 24499380 DOI: 10.1021/jf403481p
    Underutilized vegetables are currently studied not only for their nutrient values but also for their health-promoting components for protection against chronic diseases. The present study was performed to evaluate chemical compositions and antioxidant properties of underutilized vegetable palm hearts, namely, lalis (Plectocomiopsis geminiflora) and pantu (Eugeissona insignis). Additionally, the vegetable extracts were evaluated for their activities in the inhibition of digestive enzymes and effects on insulin secretion using BRIN BD11 pancreatic cell lines. Both vegetables contain valuable sources of dietary fiber, potassium, and zinc. For the first time, the phenolic compounds of the vegetables were identified and quantified using HPLC-DAD and LC-ESI-MS. Appreciable amounts of chlorogenic acid were found in the studied vegetables. The sample extracts exhibited potential antioxidant capacities through chemical and biological in vitro assays. High inhibition of α-amylase activity (>50%) was found from the extracts. Thus, it was suggested the vegetable consumption could fulfill the nutrient requirements among local communities.
  5. Lim SL, Wu TY, Clarke C
    J Agric Food Chem, 2014 Jan 22;62(3):691-8.
    PMID: 24372356 DOI: 10.1021/jf404265f
    In this laboratory-scale study, earthworms were introduced as biodegraders of palm oil mill effluent (POME), which is a wastewater produced from the wet process of palm oil milling. POME was absorbed into amendments (soil or rice straw) in different ratios as feedstocks for the earthworm, Eudrilus eugeniae. The presence of earthworms led to significant increases in pH, electrical conductivity, and nutrient content but decreases in the C/N ratio (0.687-75.8%), soluble chemical oxygen demand (19.7-87.9%), and volatile solids (0.687-52.7%). However, earthworm growth was reduced in all treatments by the end of the treatment process. Rice straw was a better amendment/absorbent relative to soil, with a higher nutrient content and greater reduction in soluble chemical oxygen demand with a lower C/N ratio in the vermicompost. Among all treatments investigated, the treatment with 1 part rice straw and 3 parts POME (w/v) (RS1:3) produced the best quality vermicompost with high nutritional status.
  6. Sulaiman SF, Ooi KL, Supriatno
    J Agric Food Chem, 2013 Oct 23;61(42):10080-90.
    PMID: 24059845 DOI: 10.1021/jf4031037
    Antioxidant and α-glucosidase activities and total phenolic contents (TPC) in sequential extracts of dried pulps from seven cucurbit fruit vegetables were determined for the first time. The highest TPC and metal chelating activity were obtained from the chloroform extracts of Luffa acutangula (28.04 ± 0.37 mg GAE/g extract) and Benincasa hispida (EC50 = 0.44 ± 0.03 mg/mL), respectively. The ethyl acetate extract of Sechium edule showed the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity (951.73 ± 29.14 mM TE/g extract). The highest reducing and anti-α-glucosidase activities were shown by the methanol and ethyl acetate extracts of Momordica charantia (692.56 ± 43.38 mM AscAE/g extract; 66.64 ± 2.94%, respectively). The highest correlation (r = 0.99) was observed between the TPC and DPPH values of S. edule. Although caffeic acid was quantified as the major constituent in the methanol extract of Lagenaria siceraria , isoquercetin was found to be the main contributor to the activities. Gallic acid was identified as both the main and most active antioxidant constituent in the ethyl acetate extract of S. edule.
  7. Lau BF, Abdullah N, Aminudin N
    J Agric Food Chem, 2013 May 22;61(20):4890-7.
    PMID: 23597270 DOI: 10.1021/jf4002507
    The chemical composition of the tiger's milk mushroom (Lignosus rhinocerotis) from different developmental stages, i.e., the fruit body, sclerotium, and mycelium, was investigated for the first time. The fruit body and sclerotium of L. rhinocerotis were rich in carbohydrates and dietary fibers but low in fat. Protein levels in L. rhinocerotis were moderate, and all essential amino acids, except tryptophan, were present. The mycelium contained high levels of potassium, phosphorus, magnesium, riboflavin, and niacin and appreciable amounts of essential fatty acids. The results indicated that the sclerotium of L. rhinocerotis that was used in ethnomedicine was not superior to the fruit body and mycelium with regard to the nutritional content and bioactive constituents. Our findings provide some insights into the selection of appropriate mushroom part(s) of L. rhinocerotis and proper cultivation techniques for the development of new nutraceuticals or dietary supplements.
  8. Teoh CY, Ng WK
    J Agric Food Chem, 2013 Jun 26;61(25):6056-68.
    PMID: 23718861 DOI: 10.1021/jf400904j
    The present study aimed to investigate the potential role of dietary petroselinic acid (PSA) in enhancing the n-3 long-chain polyunsaturated fatty acid (LC-PUFA) content in fish tissues. Three isolipidic casein-based diets were formulated to comprise graded levels of PSA (0, 10, or 20% of total fatty acid) with the incremented inclusion of coriander seed oil. Fish growth and nutrient digestibility were not significantly (P > 0.05) influenced by dietary PSA level. In general, dietary PSA affected the fatty acid composition of tilapia tissues and whole-body, which reflected dietary fatty acid ratios. Dietary PSA significantly (P < 0.05) increased β-oxidation, particularly on α-linolenic acid (18:3n-3) and linoleic acid (18:2n-6). This study provided evidence that PSA, a pseudoproduct mimicking the structure of 18:3n-6, did reduce Δ-6 desaturation on 18:2n-6 but, contrary to popular speculation, did not stimulate more Δ-6 desaturase activity on 18:3n-3. The overall Δ-6 desaturase enzyme activity may be suppressed at high dietary levels of PSA. Nevertheless, the n-3 and n-6 LC-PUFA biosynthesis was not significantly inhibited by dietary PSA, indicating that the bioconversion efficiency is not modulated only by Δ-6 desaturase. The deposition of n-3 LC-PUFA in liver and fillet lipids was higher in fish fed PSA-supplemented diets.
  9. Hajeb P, Jinap S
    J Agric Food Chem, 2012 Jun 13;60(23):6069-76.
    PMID: 22515475 DOI: 10.1021/jf300582j
    An acidic solution containing mercury chelating agents to eliminate mercury in raw fish (mackerel) fillet was developed. The solution contained hydrochloric acid, sodium hydroxide, cysteine, EDTA, and NaCl. The optimum conditions for mercury reduction were achieved using response surface methodology (RSM) at cysteine concentration of 1.25%, EDTA of 275 mg/L, NaCl of 0.5%, pH of 3.75, and exposure time of 18 min. The optimized conditions produced a solution which can remove up to 91% mercury from raw fish fillet. Cysteine and EDTA were identified as potential chelating agents with the greatest potential for use. The solution can be employed in fish industries to reduce mercury in highly contaminated fish.
  10. Tahir NI, Shaari K, Abas F, Parveez GK, Ishak Z, Ramli US
    J Agric Food Chem, 2012 Nov 14;60(45):11201-10.
    PMID: 23116142 DOI: 10.1021/jf303267e
    The palm oil industry generates several byproducts, and more than half of the dry weight of the waste is of oil palm leaf whereby the tissue is underutilized. Recently, several research studies found promising potential of oil palm fronds as a source of nutraceutical due to its bioactive properties. However, the chemical composition of the tissue is still not deciphered. Using reversed-phase liquid chromatography (LC) electrospray mass spectrometry (ESI-MS), glycosylated apigenin and luteolin were separated and identified from oil palm (Elaeis guineensis Jacq.) leaf and structures of the constituents were elucidated by collision-induced dissociation (CID) tandem MS. From 28 derivatives of the flavones, 9 compounds were conjugated with hydroxymethylglutaric (HMG) acid. Improved knowledge on oil palm especially on bioactive component of the leaf tissue will allow correlation of its beneficial effects and further promotes efficient utilization of this agriculture byproduct.
  11. Feroz SR, Mohamad SB, Bujang N, Malek SN, Tayyab S
    J Agric Food Chem, 2012 Jun 13;60(23):5899-908.
    PMID: 22624666 DOI: 10.1021/jf301139h
    Interaction of flavokawain B (FB), a multitherapeutic flavonoid from Alpinia mutica with the major transport protein, human serum albumin (HSA), was investigated using different spectroscopic probes, i.e., intrinsic, synchronous, and three-dimensional (3-D) fluorescence, circular dichroism (CD), and molecular modeling studies. Values of binding parameters for FB-HSA interaction in terms of binding constant and stoichiometry of binding were determined from the fluorescence quench titration and were found to be 6.88 × 10(4) M(-1) and 1.0 mol of FB bound per mole of protein, respectively, at 25 °C. Thermodynamic analysis of the binding data obtained at different temperatures showed that the binding process was primarily mediated by hydrophobic interactions and hydrogen bonding, as the values of the enthalpy change (ΔH) and the entropy change (ΔS) were found to be -6.87 kJ mol(-1) and 69.50 J mol(-1) K(-1), respectively. FB binding to HSA led to both secondary and tertiary structural alterations in the protein as revealed by intrinsic, synchronous, and 3-D fluorescence results. Increased thermal stability of HSA in the presence of FB was also evident from the far-UV CD spectral results. The distance between the bound ligand and Trp-214 of HSA was determined as 3.03 nm based on the Förster resonance energy transfer mechanism. Displacement experiments using bilirubin and warfarin coupled with molecular modeling studies assigned the binding site of FB on HSA at domain IIA, i.e., Sudlow's site I.
  12. Sulaiman SF, Ooi KL
    J Agric Food Chem, 2012 Nov 28;60(47):11832-8.
    PMID: 23136968 DOI: 10.1021/jf303736h
    Mature-green and ripe fleshes from 12 samples of Mangifera were selected for this study. The mature-green fleshes were found to have higher vitamin C contents than the ripe fleshes. However, not all higher total or individual phenolic contents were measured from the mature-green fleshes. The highest contents of vitamin C and total phenolics were respectively measured from the aqueous extracts of mature-green (255.86 ± 12.98 μg AAE/g sample) and ripe (142.57 ± 0.38 μg GAE/g sample) fleshes of M. petandra cv. Pauh. Gallic acid and mangiferin were detected in all aqueous extracts. The extracts of the mature-green flesh of M. indica cv. Chokanan and the ripe flesh of M. indica cv. Siku Raja, respectively, exhibited the greatest 1,1-diphenyl-2-picrylhydrazyl radical (DPPH)-scavenging activity (408.21 ± 5.37 μg TE/g sample) and metal chelating activity (93.68 ± 0.74%). The combined or potentiation effects of the moderate vitamin C, gallic acid, and mangiferin contents in both extracts may be responsible for the activities. The highest mangiferin content (31.72 ± 2.57 μg/g sample) in the mature-green M. caesia (Binjai) could be the major contributor to its highest FRAP activity (868.29 ± 2.71 μg TE/g sample). This paper reports apparently the first comparative study highlighting the antioxidant activities of these fruit fleshes.
  13. H M, Khatib A, Shaari K, Abas F, Shitan M, Kneer R, et al.
    J Agric Food Chem, 2012 Jan 11;60(1):410-7.
    PMID: 22084897 DOI: 10.1021/jf200270y
    The metabolites of three species of Apiaceae, also known as Pegaga, were analyzed utilizing (1)H NMR spectroscopy and multivariate data analysis. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) resolved the species, Centella asiatica, Hydrocotyle bonariensis, and Hydrocotyle sibthorpioides, into three clusters. The saponins, asiaticoside and madecassoside, along with chlorogenic acids were the metabolites that contributed most to the separation. Furthermore, the effects of growth-lighting condition to metabolite contents were also investigated. The extracts of C. asiatica grown in full-day light exposure exhibited a stronger radical scavenging activity and contained more triterpenes (asiaticoside and madecassoside), flavonoids, and chlorogenic acids as compared to plants grown in 50% shade. This study established the potential of using a combination of (1)H NMR spectroscopy and multivariate data analyses in differentiating three closely related species and the effects of growth lighting, based on their metabolite contents and identification of the markers contributing to their differences.
  14. Mohd Esa N, Abdul Kadir KK, Amom Z, Azlan A
    J Agric Food Chem, 2011 Jul 27;59(14):7985-91.
    PMID: 21682316 DOI: 10.1021/jf201323x
    It is imperative that there be a diet designed specifically to improve lipid profile in order to impede the progress of atherosclerosis. Because rice is a staple food in Asia, it will be chosen as the diet of interest. This study sets out to discover whether consumption of different processed rice diets may result in a change of the lipid profile. The experiment was done on male New Zealand white rabbits after 10 weeks of treatment with diet containing 0.5% cholesterol. The experimental diets include white rice (WR), brown rice (BR), and germinated brown rice (GBR). Among them, rabbits fed a GBR diet demonstrated significantly lower levels of total cholesterol (TC), low-density lipoprotein (LDL), LDL/HDL, and atherogenic index (AI) and a higher level of high-density lipoprotein (HDL). Results from atherosclerotic plaque assessment further support the findings. The level of malondialdehyde (MDA), which acts as an indicator for oxidative stress, was also reduced by GBR diet. The positive change in lipid profile in the rabbits fed GBR appeared to correspond with the higher amounts of γ-oryzanol, tocopherol, and monounsaturated fatty acid (MUFA) content.
  15. Huang XD, Liang JB, Tan HY, Yahya R, Long R, Ho YW
    J Agric Food Chem, 2011 Oct 12;59(19):10677-82.
    PMID: 21899359 DOI: 10.1021/jf201925g
    Depending on their source, concentration, chemical structure, and molecular weight, condensed tannins (CTs) form insoluble complexes with protein, which could lead to ruminal bypass protein, benefiting animal production. In this study, CTs from Leuceana leucocephala hybrid were fractionated into five fractions by a size exclusion chromatography procedure. The molecular weights of the CT fractions were determined using Q-TOF LC-MS, and the protein-binding affinities of the respective CT fractions were determined using a protein precipitation assay with bovine serum albumin (BSA) as the standard protein. The calculated number-average molecular weights (M(n)) were 1348.6, 857.1, 730.1, 726.0, and 497.1, and b values (the b value represents the CT quantity that is needed to bind half of the maximum precipitable BSA) of the different molecular weight fractions were 0.381, 0.510, 0.580, 0.636, and 0.780 for fractions 1, 2, 3, 4, and 5, respectively. The results indicated that, in general, CTs of higher molecular weight fractions have stronger protein-binding affinity than those of lower molecular weights. However, the number of hydroxyl units within the structure of CT polymers also affects the protein-binding affinity.
  16. Hassan FA, Ismail A, Abdulhamid A, Azlan A
    J Agric Food Chem, 2011 Sep 14;59(17):9102-11.
    PMID: 21800901 DOI: 10.1021/jf201270n
    Phenolic compounds and antioxidant capacity of acidified methanolic extract prepared from fully ripe bambangan (Mangifera pajang K.) peel cultivated in Sarawak, Malaysia, were analyzed. The total phenolic content (98.3 mg GAE/g) of bambangan peel powder (BPP) was determined by the Folin-Ciocalteu method. BPP showed a strong potency of antioxidant activity and was consistent with that of BHT and vitamin C as confirmed by the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity and FRAP (ferric-reducing antioxidant power) assays. Gallic acid, p-coumaric acid, ellagic acid, protocatechuic acid, and mangiferin were the major compounds among the 16 phenolics that have been identified and quantified in M. pajang peels with 20.9, 12.7, 7.3, 5.4, and 4.8 mg/g BPP, respectively. Peak identities were confirmed by comparing their retention times, UV-vis absorption spectra, and mass spectra with authentic standards. The 16 phenolic compounds identified in M. pajang K. using HPLC-DAD and TSQ-ESI-MS are reported here for the first time.
  17. Anarjan N, Tan CP, Ling TC, Lye KL, Malmiri HJ, Nehdi IA, et al.
    J Agric Food Chem, 2011 Aug 24;59(16):8733-41.
    PMID: 21726079 DOI: 10.1021/jf201314u
    A simplex centroid mixture design was used to study the interactions between two chosen solvents, dichloromethane (DCM) and acetone (ACT), as organic-phase components in the formation and physicochemical characterization and cellular uptake of astaxanthin nanodispersions produced using precipitation and condensation processes. Full cubic or quadratic regression models with acceptable determination coefficients were obtained for all of the studied responses. Multiple-response optimization predicted that the organic phase with 38% (w/w) DCM and 62% (w/w) ACT yielded astaxanthin nanodispersions with the minimum particle size (106 nm), polydispersity index (0.191), and total astaxanthin loss (12.7%, w/w) and the maximum cellular uptake (2981 fmol/cell). Astaxanthin cellular uptake from the produced nanodispersions also showed a good correlation with their particle size distributions and astaxanthin trans/cis isomerization ratios. The absence of significant (p > 0.05) differences between the experimental and predicted values of the response variables confirmed the adequacy of the fitted models.
  18. Fung WY, Yuen KH, Liong MT
    J Agric Food Chem, 2011 Aug 10;59(15):8140-7.
    PMID: 21711050 DOI: 10.1021/jf2009342
    This study explored the potential of soluble dietary fiber (SDF) from agrowastes, okara (soybean solid waste), oil palm trunk (OPT), and oil palm frond (OPF) obtained via alkali treatment, in the nanoencapsulation of Lactobacillus acidophilus . SDF solutions were amended with 8% poly(vinyl alcohol) to produce nanofibers using electrospinning technology. The spinning solution made from okara had a higher pH value at 5.39 ± 0.01 and a higher viscosity at 578.00 ± 11.02 mPa·s (P < 0.05), which resulted in finer fibers. FTIR spectra of nanofibers showed the presence of hemicellulose material in the SDF. Thermal behavior of nanofibers suggested possible thermal protection of probiotics in heat-processed foods. L. acidophilus was incorporated into the spinning solution to produce nanofiber-encapsulated probiotic, measuring 229-703 nm, visible under fluorescence microscopy. Viability studies showed good bacterial survivability of 78.6-90% under electrospinning conditions and retained viability at refrigeration temperature during the 21 day storage study.
  19. Maqbool M, Ali A, Alderson PG, Zahid N, Siddiqui Y
    J Agric Food Chem, 2011 May 25;59(10):5474-82.
    PMID: 21476593 DOI: 10.1021/jf200623m
    The composite effects of gum arabic (GA) (5, 10, 15, and 20%) and chitosan (CH) (1.0%) on the biochemical and physiological characteristics of banana fruits stored at 13 ± 1 °C and 80 ± 3% relative humidity (RH) for 28 days and afterward for 5 days at simulated marketing conditions (25 °C, 60% RH) were investigated. Significant (P ≤ 0.05) differences were observed for the entire GA plus CH treatments as compared to the control. However, the results showed that after 33 days of storage, the weight loss and soluble solids concentration of fruits treated with 10% GA plus 1.0% CH composite coating were 24 and 54% lower, whereas fruit firmness, total carbohydrates, and reducing sugars were 31, 59, and 40% higher than the control, respectively. Furthermore, the composite edible coating of 10% GA plus 1.0% CH delayed color development and reduced the rate of respiration and ethylene evolution during storage as compared to the control. Similarly, sensory evaluation results also proved the effectiveness of 10% GA plus 1.0% CH composite coating by maintaining the overall quality of banana fruits. Consequently, the results of scanning electron microscopy also confirmed that the fruits coated with 10% GA plus 1.0% CH composite edible coating had very fewer cracks and showed a smooth surface. These findings suggest that 10% GA plus 1.0% CH as an edible composite coating can be used commercially for extending the storage life of banana fruits for up to 33 days.
  20. Zaidel DN, Arnous A, Holck J, Meyer AS
    J Agric Food Chem, 2011 Nov 9;59(21):11598-607.
    PMID: 21954887 DOI: 10.1021/jf203138u
    Ferulic acid (FA) groups esterified to the arabinan side chains of pectic polysaccharides can be oxidatively cross-linked in vitro by horseradish peroxidase (HRP) catalysis in the presence of hydrogen peroxide (H(2)O(2)) to form ferulic acid dehydrodimers (diFAs). The present work investigated whether the kinetics of HRP catalyzed cross-linking of FA esterified to α-(1,5)-linked arabinans are affected by the length of the arabinan chains carrying the feruloyl substitutions. The kinetics of the HRP-catalyzed cross-linking of four sets of arabinan samples from sugar beet pulp, having different molecular weights and hence different degrees of polymerization, were monitored by the disappearance of FA absorbance at 316 nm. MALDI-TOF/TOF-MS analysis confirmed that the sugar beet arabinans were feruloyl-substituted, and HPLC analysis verified that the amounts of diFAs increased when FA levels decreased as a result of the enzymatic oxidation treatment with HRP and H(2)O(2). At equimolar levels of FA (0.0025-0.05 mM) in the arabinan samples, the initial rates of the HRP-catalyzed cross-linking of the longer chain arabinans were slower than those of the shorter chain arabinans. The lower initial rates may be the result of the slower movement of larger molecules coupled with steric phenomena, making the required initial reaction of two FAs on longer chain arabinans slower than on shorter arabinans.
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