美卓收购美国Wyesco of Louisiana L.L.C.公司服务业务

日前,美卓公司收购Wyesco of Louisiana L.L.C.公司服务业务,该公司位于美国路易斯安那州Slaughter市。自2010年7月19日起,这家有30名雇员的服务机构,将被并入美卓造纸与制浆技术,并更名为美卓Weyesco服务中心。     

Comparison of the Baird–Parker agar and 3MTMPetrifilmTMrapid S. aureus count plate methods for detection and enumeration of Staphylococcus aureus

This study compared Baird–Parker (B–P) agar plating with the 3M^TMPetrifilm^TMrapid S. aureus count plate method (PFRSA) for detection and enumeration ofStaphylococcus aureus . Sampling of deli-sliced meats (n=11) and cheeses (n=39), meat sandwiches (n=7) and raw bovine milk (n=14) revealed B–P to be insufficiently selective. Even with narrow identification criteria for presumptive S. aureus, 73% of 84 isolates from B–P were not S. aureus. None of the meat, cheese or sandwich samples tested positive using the PFRSA method. All 14 raw bovine milk samples tested positive for S. aureus using the PFRSA method and confirmed S. aureus isolates were recovered from 12 samples on B–P plates. Results of two storage studies using inoculated Swiss and mozzarella cheeses showed that the two enumeration methods were essentially equivalent and that increases in S. aureus numbers of more than 2 log cfu are unlikely on Swiss and mozzarella cheeses stored at ≤25°C for ≤20 h. Despite a high-temperature incubation step that prevented isolate confirmation, the PFRSA method was found to be a suitable alternative to B–P for detecting and enumerating S. aureus. Because of the relative speed of the PFRSA method, analysts may consider using it as an initial screen with positive samples re-tested using the B–P method, with subsequent testing, e.g. coagulase, of isolates.     

Activity and bioavailability of food protein-derived angiotensin-I-converting enzyme–inhibitory peptides

Angiotensin-I-converting enzyme (ACE) inhibitory peptides are able to inhibit the activity of ACE, which is the key enzymatic factor mediating systemic hypertension. ACE-inhibitory peptides can be obtained from edible proteins and have the function of antihypertension. The amino acid sequences and the secondary structures of ACE-inhibitory peptides determine the inhibitory activities and stability. The resistance of ACE-inhibitory peptides to digestive enzymes and peptidase affect their antihypertensive bioactivity in vivo. In this paper, the mechanism of ACE-inhibition, sources of the inhibitory peptides, structure–activity relationships, stability during digestion, absorption and transportation of ACE-inhibitory peptides, and consumption of ACE-inhibitory peptides are reviewed, which provide guidance to the development of new functional foods and production of antihypertensive nutraceuticals and pharmaceuticals.     

Comparative Analysis of Antioxidative Activity of Flavonoids Using HPLC–ED and Photometric Assays

The present investigation reports on the application of a new antioxidant activity assay for the examination of flavonoids. It has been shown that the high-performance liquid chromatography with electrochemical detection (HPLC–ED) measurements allow to obtain additional information about the antioxidative properties of pure compounds by measuring their half-wave potential, the chromatographic peak height, and the product of the peak height and exponent of potential. In comparison to the classical electrochemical measurements, the HPLC–ED is characterized by a much smaller detection limit. The results were compared with the standard photometric measurement based on 1,1-diphenyl-2-picrylhydrazyl radicals. The possible antioxidant activity forecasting is also discussed.     

In Vitro Hypoglycemic Activity of the Phenolic Compounds in Longan Fruit (Dimocarpus longan var. Fen Ke) Shell Against α-Glucosidase and β-Galactosidase

The in vitro hypoglycemic effect of longan fruit (Dimocarpus longan var. Fen Ke) shell extracts was evaluated by inhibiting α-glucosidase and β-galactosidase activities. The IC₅₀ values of hot water and 50% ethanol ultrasonic extracts against the α-glucosidase were 9.2 and 13.4 mg/mL, and those against the β-galactosidase were 12.9 and 19.7 mg/mL, respectively. The hot water extracts (20 mg/mL) with aid of ultrasound-assisted extraction may enhance the inhibitory rates of α-glucosidase and β-galactosidase by 10.6 and 12.0% as compared with conventional extraction, respectively. Two phenolic compounds, gallic acid and ellagic acid, were identified as the major phenolic in hot water extracts from longan fruit shell against α-glucosidase and β-galactosidase. Inhibition of α-glucosidase and β-galactosidase were proven to be as a therapeutic approach for decreasing postprandial hyperglycemia. As a result, the longan fruit shell extracts may develop to be as a potential strategy for early treatment of postprandial hyperglycemia.     

Analysis of phenolic compounds in cork from Quercus suber L. by HPLC–DAD/ESI–MS

The aim of the present work was to identify the extractable phenolic compounds present in cork from Quercus suber L. The structures of thirty three compounds were tentatively identified by liquid chromatography coupled to electrospray ionisation mass spectrometry (HPLC–DAD/ESI–MS). The majority of those compounds were gallic acid derivatives, in the form of either galloyl esters of glucose (gallotannins), combinations of galloyl and hexahydroxydiphenoyl esters of glucose (ellagitannins), dehydrated tergallic-C-glucosides or ellagic acid derivatives. Others were found to correspond to low molecular weight phenolic compounds, like acids and aldehydes. Mongolicain, a flavanoellagitannin in which hydrolysable tannin and flavan-3-ol moieties are connected through a carbon–carbon linkage, was also detected in cork from Q. suber L. The results illustrate the rich array of phenolic compounds present in cork.     

Physiological aspects of host specificity in the Bruchidae—V. Varietal differences in the resistance of Vicia faba L. to Callosobruchus chinensis L.

The relative resistance of some varieties of broad beans (Vicia faba L.) to Callosobruchus chinensis L. is solely due to difficulties encountered by the hatching larvae and by the emerging adult in penetrating through the seed-coat. No differences in development are noticeable on decorticated seeds of the different varieties. The thickness of the seed-coat seems to be the only limiting factor, and Vicia faba seed-coats are apparently non-toxic to larvae. This is demonstrated by the high survival of larvae penetrating V. faba seed-coats. We wish to suggest that selection of broad bean varieties with thicker seed-coats would significantly reduce infestation by Callosobruchus chinensis during storage.     

A Review on Structure–Activity Relationship of Dietary Polyphenols Inhibiting α-Amylase

The inhibitory effects of dietary polyphenols against α-amylase have attracted great interest among researchers. The aim of this review is to give an overview of the research reports on the structure–activity relationship of polyphenols inhibiting α-amylase. The molecular structures that influence the inhibition are the following: (1) The hydroxylation of flavonoids improved the inhibitory effect on α-amylase; (2) Presence of an unsaturated 2,3-bond in conjugation with a 4-carbonyl group has been associated with stronger inhibition; (3) The glycosylation of flavonoids decreased the inhibitory effect on α-amylase depending on the conjugation site and the class of sugar moiety; (4) The methylation and methoxylation of flavonoids obviously weakened the inhibitory effect; (5) The galloylated catechins have higher inhibition than nongalloylated catechins; the catechol-type catechins were stronger than the pyrogallol-type catechins; the inhibition activities of the catechins with 2,3-trans structure were higher than those of the catechins with 2,3-cis structure; (6) Cyanidin-3-glucoside showed higher inhibition against than cyanidin and cyanidin-3-galactoside and cyanidin-3,5-diglucoside had no inhibitory activity; (7) Ellagitannins with β-galloyl groups at glucose C-1 positions have higher inhibitory effect than the α-galloyl and nongalloyl compounds and the molecular weight of ellagitannins is not an important element.     

Effect of heat processing on oxazolidine of Capparis masaikai LévI.

Capparis masaikai, as a Chinese local plant, its mature seeds are used in traditional Chinese medicine and commonly chewed for their sweet taste. However, the seeds also contain 2-hydroxyethylglucosinolate (2-Hydr GLS), which can be hydrolyzed by the myrosinase enzyme to product bitterness and harmful substance 1,3-oxazolidine-2-thione (OZT). In this study, heat processing has been used to reduce the OZT in C. masaikai seeds. The effect of heat processing on myrosinase enzymatic activity, 2-Hydr GLS content and water content has been investigated by incubation under different temperatures (30–90°C). Further experiments using mice model showed that feeding of heat processed C. masaikai seeds eliminated the content of OZT in mice blood. Thus, our study indicated that heat processing could be used as an effective method to reduce the harmful OZT and improve the taste of C. masaikai seeds.     

Influence of Homogenization Conditions on Physical Properties and Antioxidant Activity of Fully Biodegradable Pea Protein–Alpha-Tocopherol Films

In this study, antioxidant biodegradable films based on pea protein and alpha-tocopherol were successfully developed by solution casting. The effect of both the homogenization conditions (rotor–stator and microfluidizer) and the relative humidity (RH) on the microstructure and physical properties (transparency, tensile, oxygen and water vapour barrier properties) of pea protein/alpha-tocopherol-based films was evaluated. The addition of alpha-tocopherol produced minimal changes in the films’ transparency, while providing them with antioxidant properties and improved water vapour and oxygen barrier properties (up to 30 % in both water vapour and oxygen permeability) when films were at low and intermediate RH. The addition of alpha-tocopherol in microfluidized films gave rise to an increase in their resistance to break and extensibility (up to 27 % in E values) at intermediate and high RH. These results add a new insight into the potential of employing pea protein and alpha-tocopherol in the development of fully biodegradable antioxidant films which are of interest in food packaging.     

Structure–activity relationships of acetylated flavone glycosides from Galeopsis ladanum L. (Lamiaceae)

Antioxidant activity, neuroprotective effect and acetylcholinesterase inhibitor activity were studied in acetylated flavones from Galeopsis ladanum L. (Lamiaceae), previously isolated and identified by UV-spectra, UPLC–MS/MS and ¹H-NMR spectroscopy. Structure–activity relationships of flavonoids have been determined in many antioxidant assays, generally focused on hydroxyl groups. In this study we have detected new interesting structure–activity relationships for the isolated flavonoids due to the acetylation of sugar moiety of these flavonoids. Methylation at 4′-OH and monoacetylation is beneficial to inhibiting AChE and shows a neouroprotective effect.     

NMR-based quantification of rosmarinic and carnosic acids,GC–MS profile and bioactivity relevant to neurodegenerative disorders of Rosmarinus officinalis L. extracts

A comparative study of phytochemicals content and biological properties of eight Rosmarinus officinalis (rosemary) populations (RO1–RO8) collected in different areas of Tunisia was carried out. Two of the main rosemary constituents, rosmarinic and carnosic acids, were quantified by an NMR technique. Carnosic acid content was higher than that of rosmarinic acid. The non-polar constituents were examined by GC and GC–MS. Total phenols and flavonoids content were also determined in order to discuss the possible correlation between these phytochemicals and bioactivity. Antioxidant activity was investigated through different in vitro assays. Sample RO3 from a sub-humid area showed the highest potency in 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay (IC₅₀ of 6.74 μg/mL) while RO5 from arid area exhibited the highest radical 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) scavenging activity (IC₅₀ of 5.92 μg/mL). The most active sample in Ferric Reducing Antioxidant Power (FRAP) assay was RO4 (62.21 μM Fe(II)/g), followed by RO1–RO3 and RO8 harvested in sub-humid areas with values in the range 49.61–58.72 μM Fe(II)/g. Extracts were able to inhibit acethylcholinesterase (AChE) and butyrylcholinesterase (BChE). Sample RO5 exhibited a promising AChE inhibitory activity (IC₅₀ of 4.47 μg/mL). Thus, we suggest rosemary extracts as a functional food ingredient for preventing AD.     

Characterisation by SPME–GC–MS of the volatile profile of a Spanish soft cheese P.D.O. Torta del Casar during ripening

The volatile profile of the Spanish soft cheese of the Protected Designation of Origin (PDO) Torta del Casar, made from raw ewes’ milk, was studied in four different stages of ripening (1, 30, 60 and 90 days) by the method of SPME–GC–MS. A total of 46 compounds were detected: 13 acids, 9 esters, 4 ketones, 7 alcohols, 3 aldehydes, 7 aromatic compounds and 3 compounds which could not be classified into those groups. Carboxylic acids were the most abundant group isolated; their levels significantly increased during ripening and comprised 61.5% of the total aroma extract at the end of ripening. At day 90, acids of microbial origin were the most abundant, followed by acids derived from amino acids while acids from lipolysis of triglycerides were the least abundant. Esters were the next most important group and their amount also increased significantly during maturation, as did ketones, while alcohols content slightly decreased at the end of the ripening. At day 90, the compounds at highest levels were acetic acid, 3-methylbutanoic acid, butanoic acid propyl ester and 2-butan-one; so these compounds, due to their high levels and their low threshold value could play an important role in the final aromatic profile of this cheese.     

Determination of Free Radical Scavenging Activity of Plant Extracts Through DPPH Assay: An EPR and UV–Vis Study

Several methods have been developed to assess the radical scavenging activity. Among them, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) spectrophotometric method is one of the most widely applied and is appreciated for its reliability. In this study, a comparison of two spectroscopic methods (electron paramagnetic resonance (EPR) and ultraviolet–visible (UV–Vis) spectroscopy) was performed analysing the spectroscopic features of DPPH in mixed ethanol/water solution and the free radical scavenging properties of myrtle leaves extracts and citrus juices. When DPPH was dissolved in mixed solvents, EPR enabled to identify the aggregation phenomena that occur when high amounts of water were employed. On the contrary, UV–Vis revealed only small differences in the absorption maximum among solutions with increasing water contents, without detecting aggregation. EC₅₀ values of myrtle leaf extracts and citrus juices calculated from UV–Vis data were lower than those calculated with EPR. In myrtle extracts, the DPPH depletion measured by UV–Vis was not concentration dependent, revealing the interference in the analysis of the decomposition products of the antioxidants, which absorb at 517 nm. EPR spectroscopy was proven to be most reliable with all types of matrix since it is not dependent on the chemical composition of the extract.     

Inhibitory effect of Zanthoxylum bungeanum maxim. and Capsicum annuum L. on the activities of pancreatic lipase and α-amylase

Zanthoxylum bungeanum maxim. (ZBM) and Capsicum annuum L. (CAL) are popular condiments in China. In this study, the inhibition of pancreatic lipase and α-amylase by ZBM and CAL extracts, as well as catechin, rutin, hydroxy-α-sanshool (from ZBM extract) and capsaicin (from CAL extract), was determined. The half maximal inhibitory concentration (IC₅₀) values of ZBM extract, CAL extract, rutin, hydroxy-α-sanshool and capsaicin against pancreatic lipase were 82.1, 533.5, 583.8, 565.7 and 62.4 μg mL⁻¹, respectively, while that against α-amylase were 125.6, 1167.2, 213.2195.6 and 163.2 μg mL⁻¹, respectively. Catechin had no detectible inhibition on the two enzymes even at 4 mg mL⁻¹. The combination of hydroxy-α-sanshool and capsaicin against the two enzymes showed similar inhibition trends to that of ZBM and CAL extracts (synergism at low concentrations but antagonism at high concentrations), suggesting the two compounds were closely associated with the functions of the crude extracts. The results obtained from the in vitro digestion were similar but with a lower inhibition rate. Kinetic studies revealed that ZBM extract, hydroxy-α-sanshool and capsaicin showed mixed-type inhibition for pancreatic lipase and α-amylase. Molecular modelling suggested capsaicin had a higher affinity to the two enzymes, with glide scores of −8.18 and −7.87 kcal mol⁻¹, respectively.