Summary
Yams (the tubers of Dioscorea spp.) are widely consumed but are also regarded as a medicinal food in China. Traditional Chinese herbal medicines using yams are only available on a seasonal ...basis, as yams quickly deteriorate during winter storage. Yam (Dioscorea purpurea, a major variety of yams in Taiwan) was freeze‐dried and ground to obtain yam flour. Bread was made by replacing up to 25% of wheat flour with yam flour. Although the loaf volume decreased with the addition of yam flour, the results showed that up to 20% of yam flour could be included in bread formulation without altering the sensory acceptance of the blended bread. The incorporation of yam flour in bread markedly increased the antioxidant capacity of the bread as tested by both DPPH free radical scavenging and total antioxidation tests. Breads containing yam flour can broaden the utilization of yams and may be regarded as possible health‐promoting foods.
A technique of combining poly(ethylene-co-methacrylic acid), PEMA, with benzoic acid and sorbic acid to form antimicrobial food packaging material was developed. Heat-pressed film was first modified ...with NaOH (1 mol/L) or HCl (1 mol/L) and then incorporated with benzoic acid and sorbic acid, respectively, by using acetone as a swelling agent. The incorporation of preservatives into fabricated antimicrobial films was confirmed by characterization of the specific vibrational stretching shown on the IR spectra of the resulting films. Sodium hydroxide and preservative-treated films exhibited dominantly antimicrobial properties in fungal growth inhibition tests, presumably due to the higher amount of preservatives released from the films (75 mg benzoic acid or 55 mg sorbic acid per g of film) than other types of films. Based on the results, we demonstrated that the combination technique with acetone as swelling agent was feasible to manufacture antimicrobial food packaging films.
Age-related cataracts is a pressing health issue with the increase in elderly populations. This creates an imminent demand for the development of an early, noninvasive method of cataracts diagnosis. ...Early detection of cataracts will improve quality of life and may prevent morbidity associated with advanced cataracts and surgery. Raman spectrum of proteins provides characteristic information regarding molecular interactions of peptide residues. Hence Raman spectroscopy is a promising tool for the study of protein-related diseases, such as cataracts. We surveyed the literature to assess the use of Raman technology in the studies of human lens and animal models. These studies included analysis of amino acids (i.e., cysteine, tryptophan, and tyrosine, etc.) and secondary protein structures (i.e., α-helix and β-sheet) in various Raman profiles. Other studies used Raman spectroscopy to analyze and monitor the development of cataracts in lens. Technological advances in the instrumentation of laser Raman spectroscopy, including Fourier transform Raman spectroscopy, Raman microspectroscopy, and confocal Raman microspectroscopy have improved the performance of Raman spectroscopic analysis. How to take advantage of these developments and make it closer to reality using Raman spectroscopic methods to diagnose cataracts in a timely manner is a key challenge for the scientific community of Raman spectroscopy.
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Methods to obtain pure proteins in large amounts are indispensible in protein research. We report here a large-scale/simultaneous isolation of taxon-specific crystallins (ɛ- and ...δ-crystallin) from the eye lenses of Mule duck. We also investigate the compositions, enzymatic activities, and structures of these purified taxon-specific proteins. A relatively mild method of ion-exchange chromatography was developed to fractionate ɛ-crystallin and δ-crystallin in large amount, ca. ∼6.60mg/g-lens and ∼41.0mg/g-lens, respectively. Both crystallins were identified by electrophoresis, HPLC, and MALDI-TOF-MS. ɛ-Crystallin, with native composition of Mr 142kDa, consisted of two subunits of 35kDa and 36kDa, while δ-Crystallin, with native molecular mass of 200kDa, comprised single subunit of Mr ∼50kDa. Both ɛ- and δ-crystallin were tetramers. The former showed lactate dehydrogenase (LDH) activity, while the latter appeared slightly active in an argininosuccinate lyase (ASL) assay. Raman spectroscopic results indicated that the secondary structures of ɛ- and δ-crystallin were predominantly α-helix as evidenced by the vibrational stretching of amide III over 1260cm−1 and amide I at 1255cm−1, in greatly contrast to the anti-parallel β-sheet of α- and β-crystallin as demonstrated by amide III at 1238cm−1 and amide I at 1672cm−1. The microenvironments of aromatic amino acids and the status of thiol groups also vary in different crystallins. The compositions, enzyme activities, and structures of the ɛ- and δ-crystalline of Mule duck are different from those of Muscovy duck (Cairina moschata) or Kaiya duck (Anas Platyrhynchos var. domestica), which reflect faithfully species specificity.
Health benefits of soy isoflavones have attracted the concern of the public and the interest of health-care professionals. In this study, two trials were conducted in characterizing bone-related ...traits and lens proteins as affected by supplementation of soy aglycon isoflavones (SAI). In trial 1, an in vivo study, 20 Sprague−Dawley rats were ovariectomized (OVX) and randomly distributed into OVX and OVX+SAI (135 mg of SAI/kg of feed; 8.33 mg/kg body weight; 2.5 mg/day) groups. Another group containing 10 rats with a sham operation was control (Sham). The experiment period was 3 months, and the rats were subjected to bone-related traits and lens protein characterization. In trial 2, an in vitro study, osteoprogenitor cells (UMR-106) were divided into SAI-supplemented (0.5 mg of SAI/mL of medium) and unsupplemented groups. Results of the in vivo study indicated that daily BW gains in the OVX and OVX+SAI groups were greater than that of the Sham group (p < 0.05). Bone ash and Ca contents of the Sham and OVX+SAI groups were higher than those of the OVX group (p < 0.05), while bone density, strength, and phosphorus contents among groups varied insignificantly (p > 0.05). When the lens proteins were extracted and analyzed with size-exclusion HPLC, the contents of β- and γ-crystallins were lowest in the OVX group and the protein solubility decrease could be recovered by dietary SAI supplementation (shown by OVX+SAI group). Based on Raman spectra of the isolated lens proteins, disulfide bonds were observed more in OVX lens than in the Sham and OVX+SAI lens. Results of in vitro study with osteoprogenitor cells revealed that cell viability, alkaline phosphatase activity, osteocalcin, and Ca contents of the SAI-supplemented group were higher than those of the unsupplemented group (p < 0.05). The likely potency to enhance bone and lens health by SAI supplementation is worth pointing out. Keywords: Soy aglycon isoflavones; bone-related traits; lens proteins; osteoprogenitor cells; osteocalcin; bone calcium
Raman spectroscopy has been accepted as a useful tool for the characterization of natural products. However, to identify a specific compound in a mixture sample of natural products using Raman ...spectra alone is highly challenging if not impossible. We demonstrated an effective solution to such issues using a method combining statistical Raman spectroscopy and Mass spectrometry. The method was validated with a successful application to the identification of the major anthocyanin components in a purple yam (Dioscorea purpurea) extract. Of particular interest is that statistical grouping of the bioflavonoid standards that formed the database of this study was found to correspond closely to the conventional chemical classification. An initial theory on the chemical aspects of Raman spectroscopy pertaining to the connectivity of Raman-active functional groups in bioflavonoids was developed based on the statistical correlation between chemical classification and Raman spectroscopy.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Each of four conserved glutamate residues of Bacillus stearothermophilus leucine aminopeptidase II (BsLAPII) was replaced with aspartate, lysine, and leucine respectively by site-directed ...mutagenesis. The over-expressed wild-type and mutant enzymes were purified to homogeneity by nickel-chelate chromatography and the molecular mass of the subunit was determined to be 44.5 kDa by SDS-PAGE. The specific activity for the Glu-316 and Glu-340 mutants was completely abolished, while Glu-249 mutants showed comparable activity to that of the wild-type BsLAPII. Compared with the wild-type enzyme, the E250D and E250L mutant enzymes retained less than 18% of the enzyme activity and exhibited a dramatic decrease in the value of k (cat)/K (m). These observations indicate that Glu-250, Glu-316, and Glu-340 residues are critical for the catalytic activity of BsLAPII.
We have studied the adsorption of silver nanoparticles (AgNPs) and catechin on readily available commercial zeolite beads. Both adsorbates became available on the zeolite and were several fold more ...concentrated after a simple adsorption process, contributing to a 10-times overall increase in the collision probability between the two adsorbates. We were further able to detect AgNP-induced Surface Enhanced Raman Scattering (SERS) of catechin on the zeolite after sequential depositions of AgNPs and catechin on the zeolite using this process. To demonstrate high reproducibility, 93% of the zeolite sensors assembled this way were tested and proved satisfactory, and gave a distinctive catechin SERS signature. Preparation of the zeolite sensor was extremely easy with a nearly 90% yield.
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