Effects of acetic acid/acetic anhydride ratios on the properties of corn starch acetates.

Corn starch was pre-treated with acetic acid and then acetylated by acetic anhydride under microwave irradiation. The effects of molar ratios of these two reagents on the acetylation of starch were investigated. Starch acetate with a high degree of substitution (DS, 2.93) was obtained at a molar ratio (acetic acid/acetic anhydride) of 1:1. However, the DS should tend to decrease with a change of this ratio. The FT-IR analysis indicated characteristic absorption peaks, with increasing DS materialised by an increase of the carbonyl CO group and a decrease of the hydroxyl O-H group, at about 1750cm(-1) and 3450cm(-1), respectively. The X-ray diffraction patterns of acetylated starch showed an amorphous structure. Degree of crystallinity, surface morphology, water solubility and water absorption index of corn starch were also affected by the changes in reagent ratios. The glass transition (Tg) and melting (Tm) temperatures of acetylated starches also decreased after acetylation.

Rapid preparation of procyanidins B2 and C1 from Granny Smith apples by using low pressure column chromatography and identification of their oligomeric procyanidins.

Research in the field of procyanidins is always hindered by the lack of procyanidin standards, and the preparation of procyanidins, especially in large scale, remains difficult and time-consuming. Commercial sources of procyanidin standards are scarce. In this study, a rapid preparation method of procyanidins by using low-pressure column chromatography was developed. Procyanidins in Granny Smith apples were extracted with boiled water and purified on an ADS-17 macroporous resin column to obtain a Granny Smith apple procyanidin extract (GSE). GSE was fractionated according to its degree of polymerization on a Toyopearl TSK HW-40s column. Procyanidins B2 (epicatechin-(4beta-8)-epicatechin) and C1 (epicatechin-(4beta-8)-epicatechin-(4beta-8)-epicatechin) were prepared without HPLC separation. Oligomeric procyanidins from Granny Smith apples were also identified by liquid chromatography-electrospray ionization-mass spectrometry.

Role of secondary structures in the gelation of porcine myosin at different pH values.

Secondary structures, gelation properties and their relationships in porcine myosin were studied by circular dichroism, dynamic rheological measurement and scanning electron microscopy. Gelling of porcine myosin involved a change in myosin conformation with protein-protein and protein-water interactions. The gelation properties were strongly pH and temperature dependent. Near the pI (pH 5.5 and 6.0), porcine myosin could spontaneously coagulate at 15°C resulting partially from the presence of more ß-sheets. Myosin at pH6.5-9.0 began to form a gel at temperatures greater than 38°C. Heating caused α-helices to partially turn into ß-sheets and random coils. Subsequently, myosin aggregated and formed a gel network. The gel strength decreased and the water-holding capacity (WHC) increased with increasing pH. Correlation analysis indicated that both the unfolding of α-helices and the formation of ß-sheets favored the gelation of porcine myosin. A high ß-sheet fraction prior to heating resulted in a low WHC of resultant gel. A compact and uniform gel was also obtained at pH6.5.

Characterization of aroma active compounds in fruit juice and peel oil of Jinchen sweet orange fruit (Citrus sinensis (L.) Osbeck) by GC-MS and GC-O.

Gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O) were used to determine the aromatic composition and aroma active compounds of fruit juice and peel oil of Jinchen sweet orange fruit. Totals of 49 and 32 compounds were identified in fruit juice and peel oil, respectively. GC-O was performed to study the aromatic profile of Jinchen fruit juice and peel oil. A total of 41 components appeared to contribute to the aroma of fruit juice and peel oil. Twelve components were the odorants perceived in both samples. The aromatic compositions of fruit juice were more complex than that of peel oil. Ethyl butanoate, beta-myrcene, octanal, linalool, alpha-pinene, and decanal were found to be responsible for the aromatic notes in fruit juice and peel oil. Nineteen components have been perceived only in the juice and ten compounds were described as aromatic components of only the peel oil by the panelists. These differences lead to the different overall aroma between fruit juice and peel oil.

[Concentrations of heavy metals and safe assessments of fishes in main lakes from Wuhan City].

The concentrations of Zn, Cu, Pb, Cr and Cd have been measured by ICP-OES in clays, water and fishes from representative lake, including South Lake, East Lake and Yezhi Lake in Wuhan City. The results were obtained as follow: the concentration of Cu from Yezhi Lake and the concentration of Cd from East Lake are respectively 0.010mg/L and 0.0054mg/L, and higher than the standard of water quality in fresh water cultivation. The concentrations of cadmium from three lakes sediments are 0.95mg/L, 1.07mg/L and 1.13mg/L, and also higher than the surroundings requirement of environmentally harmless aquatic products. The variety of concentrations of heavy metals have been observed in different tissues and different families. Heavy metals are mainly accumulated in scales and gills. The concentrations of heavy metals of mussels are much lower than the health standard of consumptions.

Ameliorative effect of lotus seedpod proanthocyanidins on cognitive impairment and brain aging induced by D-galactose.

This study mainly investigated the ameliorative effect of lotus seedpod proanthocyanidins (LSPC) and the mechanism underlying such effect on cognitive impairment and brain aging induced by d-galactose. Aging mice induced by d-galactose (150 mg/kg, sc injection daily for 6 weeks) were chosen for the experiment. LSPCs (30, 60, and 90 mg/kg, ig) were provided after d-galactose injection. Learning and memory functions were detected by Y-maze and step-down avoidance tests. Then, some biochemical indexes related to cognitive ability and aging were measured. Histopathological feature and P53 protein expression in the hippocampus were observed. Results showed that the three different doses of LSPC could significantly ameliorate the learning and memory abilities impaired by d-galactose. LSPC significantly reduced the levels of malondialdehyde and nitric oxide (i.e. 90 mg/kg LSPC group vs. model group, P=0.008), reduced the content of ß-amyloid peptide 1-42 (i.e. 90 mg/kg LSPC group vs. model group, P=0.009), decreased the activities of acetylcholinesterase, monoamine oxidase B, total nitric oxide synthase (i.e. 90 mg/kg LSPC group vs. model group, P=0.006), and neuronal nitric oxide synthase and synchronously increased the activities of superoxide dismutase and glutathione peroxidase in the brain. Furthermore, LSPC could prevent neuron damage and could lessen the expression of P53 protein in the hippocampus. These findings demonstrated that LSPC effectively attenuated cognitive damage and improved parameters related to brain aging in senescent mice induced by d-galactose, and may be used to treat Alzheimer's disease.

Isolation, characterization, and determination of antioxidative activity of oligomeric procyanidins from the seedpod of Nelumbo nucifera Gaertn.

The procyanidins of nonedible parts of lotus (Nelumbo nucifera Gaertn.) were determined for the first time. The procyanidins of lotus seedpod were extracted with Me(2)CO/H(2)O and purified by Sephadex LH-20 column chromatography, with a purity of >98%. ESI-MS analysis showed that the main molecular weight distribution of procyanidins ranged from 291 to 1155, with M + H peak values of 291.1, 579.2, 731.2, 867.2, 1019.4, and 1155.3, respectively. This indicates that the extract contains monomers, dimers, and tetramers of procyanidins, in which the amounts of dimers are greatest, and catechin and epicatechin are the base units. (1)H NMR and (13)C NMR spectra confirmed that two to four monomers are linked through C(4)-C(8) (or C(6)) bonds. The effects of the procyanidins on lipid autoxidation, lipoxygenase activities, and free radical scavenging were also studied. The results showed that 0.1% procyanidins have a strong antioxidant activity in a soybean oil system, better than BHT at the same concentration; inhibited lipoxygenase activity by >90% at a concentration of 62.5 mug/mL, with an IC(50) value of 21.6 mug/mL; and had IC(50) inhibitory values rate to (*)OH of 10.5 mg/L and a scavenging effect on O(2)(*)(-) of 17.6 mg/L.

Novel antioxidant peptides from fermented mushroom Ganoderma lucidum.

Oxidative stress has been linked with the pathogenesis of many human diseases including cancer, aging, and atherosclerosis. The present study investigates the antioxidant activities of peptides isolated from the medicinal mushroom, Ganoderma lucidum. G. lucidum has been shown to possess potent antioxidant activity with little or no side effects. Polysaccharide, polysaccharide-peptide complex, and phenolic components of G. lucidum have been proposed to be responsible for this antioxidant effect. However, research has shown that the G. lucidum peptide (GLP) is the major antioxidant component of G. lucidum. The objective of this study was to evaluate the antioxidant activity of this peptide using different oxidation systems. GLP showed potent antioxidant activities in both lightproof soybean oil and lard systems, assessed by lipid peroxidant value. Compared to butylated hydroxytoluene, GLP showed a higher antioxidant activity in the soybean oil system. Soybean lipoxygenase activity was blocked by GLP in a dose-dependent manner with an IC50 value of 27.1 microg/mL. GLP showed scavenging activity toward hydroxyl radicals produced in a deoxyribose system with an IC50 value of 25 microg/mL, and GLP effectively quenched superoxide radical anion produced by pyrogallol autoxidation in a dose-dependent manner. Malondialdehyde level has been used as the oxidation index in many biological systems. GLP showed substantial antioxidant activity in the rat liver tissue homogenates and mitochondrial membrane peroxidation systems. The auto-hemolysis of rat red blood cells was also blocked by GLP in a dose-dependent manner. On the basis of these results, it is concluded that GLP is the major constituent responsible for the antioxidant activity of G. lucidum. GLP could play an important role in the inhibition of lipid peroxidation in biological systems through its antioxidant, metal chelating, and free radical scavenging activities.

[Study on molecular chain morphology and chain parameters of konjac glucomannan].

AIM: To study the molecular chain morphology and chain parameters of konjac glucomannan (KGM). METHODS: Solution behavior was studied by using light scattering(LS), gel permeation chromatograph (GPC) and method of viscosity. The molecular morphology was observed directly by atom force microscope (AFM) and transmission electron microscope (TEM). RESULTS: The average molecular weight (Mw), root-mean-square ratio of gyration(1/2), second Viral coefficients (A2) and multi-disperse coefficients (Mw/Mn) are 1.04 x 10(6), 105.0 +/- 0.9 nm, (-1.59 +/- 0.28) x 10(-3) mol.mL.g-2 and (1.020 +/- 0.003) respectively; Mark-Houwink equation was established as [eta] = 5.96 x 10(-2) Mw0.73, the molecular chain parameters were as follows: ML = 982.82 nm-1, q = 27.93 nm, d = 0.74 nm, h = 0.26 nm, L = 1,054.11 nm. CONCLUSION: Both the result showed by direct observation and the deduction drawn by solution behavior confirmed that the KGM molecular is stentering semi-flexible linear chain without branch.

Characterization of oligomeric procyanidins and identification of quercetin glucuronide from lotus ( Nelumbo nucifera Gaertn.) seedpod.

Procyanidins are a class of polyphenols in the plant kingdom. Lotus ( Nelumbo nucifera Gaertn.) seedpods, the inedible part of lotus and a byproduct during the production of lotus seeds, were found to be a new source rich in procyanidins. Detailed information about oligomeric procyanidins in lotus seedpods remains unknown. In this study, lotus seedpods were extracted using 60% aqueous methanol and characterized with phloroglucinolysis and liquid chromatography (mass spectrometry with an electrospray ionization source). The results indicate that the oligomeric and polymeric fraction had a mean degree of polymerization of 3.2 and 15.4, respectively, and consisted of (+)-catechin (m/z 289), gallocatechin or epigallocatechin (m/z 305), quercetin glycoside (m/z 463), quercetin glucuronide (m/z 477), procyanidin dimers (m/z 577.1), proanthocyanidin dimer gallate (m/z 593.3), prodelphinidin dimers (m/z 609.1), procyanidin trimers (m/z 865.1), etc. Quercetin glucuronide was further purified using flash chromatography and identified as quercetin-3-O-ß-glucuronide by determining its exact mass using ion-trap time-of-flight mass spectrometry and ¹H and ¹³C nuclear magnetic resonance, ¹H-detected heteronuclear single-quantum coherence, and ¹H-detected heteronuclear multiple-bond correlation analyses.

Comparative study on the stability of fish actomyosin and pork actomyosin.

Effects of temperature, pH and ionic strength on the stability of actomyosin (AM) from fish and pork were studied using UV spectra, solubility, turbidity, and sulfhydryl group content measurement for comparison. Pork AM exhibited higher stability to cold storage and heating than fish AM. The unfolding rate of AM increased with increasing temperature. Intense aggregation occurred over 30 °C for fish AM and 40 °C for pork AM. New disulfide bonds mainly formed over 40 °C for fish AM and 60 °C for pork AM. Pork AM exhibited the higher turbidity than fish AM in the range of 50-90 °C, suggesting the higher extent of aggregation of pork AM. Ionic strength mainly influenced solubility of AM, but there was no effect on cleavage and formation of disulfide bond. The lowest solubility of both AM was at pH 5.42. Additionally, fish AM was more sensitive to pH changes than pork AM.

Inhibitory effect of lotus seedpod oligomeric procyanidins on advanced glycation end product formation in a lactose-lysine model system

Background Industrial food processing induces protein glycation modifications and toxic advanced glycation end products (AGEs) which affect human health. Therefore, it is of interest to monitor AGEs in food processing. The present study was carried out to investigate the influence of lotus seedpod oligomeric procyanidin (LSOPC) concentrations, solution pH value and metal ions on AGE formation by heat treatment of lactose-lysine model solutions. Ne-(carboxymethyl) lysine (CML), as one of the common AGEs was also determined by HPLC-MS/MS in this experiment. Results The results showed that LSOPC can inhibit the formation of AGEs effectively at higher concentrations, lower temperature, and it can reverse the promotion function of metal ions because of its high inhibition activity. Also, LSOPC can inhibit CML formation in the Maillard reaction as well. Conclusion These results indicated that LSOPC could be used as functional food ingredients to inhibit AGE formation.

The mixture of procyanidins extracted from the lotus seed pod and bilobalide ameliorates scopolamine-induced memory impairment in mice.

OBJECTIVE: To study the co-effect of procyanidins extracted from the lotus seed pod (LSPC) and bilobalide (BIL) on ameliorating scopolamine-induced learning and memory impairment in young mice. METHODS: Fifty male Kunming mice with similar learning and memory capabilities were selected by Morris water maze test and were randomized into 5 groups (n=10 in each group): control group, scopolamine group, L-(LSPC+BIL) group (50 mg/kg LSPC+10 mg/kg BIL), M-(LSPC+BIL) group (100 mg/kg LSPC+20 mg/kg BIL), H-(LSPC+BIL) group (150 mg/kg LSPC+30 mg/kg BIL). Scopolamine model with impaired learning and memory was established by scopolamine treatment (1 mg/kg), and after 10 min mice were tested. In L-, M-, and H-(LSPC+BIL) groups, mice were treated with LSPC and BIL ig. for 30 days, while mice in the other 2 groups were treated with normal saline ig. instead. After the 30-day's treatment, the co-effect of LSPC and BIL on learning and memory was tested by Morris water maze and the step-down avoidance tests. RESULTS: The memory impairment caused by scopolamine in young mice could be ameliorated by co-treatment of LSPC and BIL, as indicated by significantly shorter escape latency and swimming distance in the Morris water maze test, when compared with those in the scopolamine group. In the step-down avoidance test, mice in all the 3 dose groups showed significantly smaller number of errors and longer latency than mice in the scopolamine group did. CONCLUSION: Co-treatment of LSPE and BIL can ameliorate scopolamine-induced learning and memory impairment in young mice.

Mogrosides extract from Siraitia grosvenori scavenges free radicals in vitro and lowers oxidative stress, serum glucose, and lipid levels in alloxan-induced diabetic mice.

This study evaluated the supplementation of a mogrosides extract (MG) from fruits of Siraitia grosvenori on reducing oxidative stress, hyperglycemia, and hyperlipidemia in alloxan-induced diabetic mice. The oxygen free radical scavenging activity of MG was also assessed in vitro. After induction of diabetes, a significant increase in the levels of serum glucose, total cholesterol (TC), triacylglycerol (TG), and hepatic malondialdehyde (MDA) as well as a reduction in the level of hepatic high-density lipoprotein cholesterol (HDL-C) associated with diminution of the corresponding antioxidant enzymes, such as glutathione peroxidase (GSH-Px) and superoxide dismutase, were observed in all diabetic mice. Treatment of diabetic mice with MG (100, 300, and 500 mg/kg ) for 4 weeks significantly decreased serum glucose, TC, TG, and hepatic MDA levels (P < .05), whereas it increased serum HDL-C level and reactivated the hepatic antioxidant enzymes (P < .05) in alloxan-induced diabetic mice (P < .05). The hypoglycemic, hypolipidemic, and antioxidative activities of MG (100 mg/kg treatment) were all higher compared with all other diabetic groups and were similar to that observed for XiaoKeWan-pill (894 mg/kg; Guangzhou Zhongyi Pharmaceutical Co., Ltd., Guangzhou, China), a Chinese traditional antidiabetic drug. Antioxidant capacity evaluated in vitro showed that MG and mogroside V, which was the main component of MG, possessed strong oxygen free radical scavenging activities. These results demonstrate that the extract may have capacity to inhibiting hyperglycemia induced by diabetes, and the data suggest that administration of the extract may be helpful in the prevention of diabetic complications associated with oxidative stress and hyperlipidemia. We conclude that the extract should be evaluated as a candidate for future studies on diabetes mellitus.