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At least 937 records · Page 52Linked to original sources
PubMed2007

Enzyme-catalyzed change of antioxidants content and antioxidant activity of asparagus juice.

A pectolytic enzyme preparation from Aspergillus niger (pectinase AN) decreased most rutin content and antioxidant activity of asparagus juice. To investigate the mechanism of such loss, we analyzed several possible related enzyme activities in pectinase AN. We found that the activity of pectinase AN to oxidize guaiacol had no significant difference with or without the presence of H2O2; thus it was laccase activity, not peroxidase (PO) activity, that pectinase AN contained. We did not find any polyphenol oxidase (PPO) activity in pectinase AN. Laccase in pectinase AN could be the major cause of loss of rutin and antioxidant activity of asparagus juice. When most laccase activity of pectinase AN was inactivated after heating at 70 degrees C for 1.5 min and incubated with asparagus juice, the loss rate of rutin was only 9% of that treated with unheated pectinase AN, and the antioxidant activity was even increased. Rhamnosidase activity was detected in pectinase AN and can change rutin in asparagus juice to quercetin-3-glucoside, which has higher antioxidant activity than rutin. This may explain the increase of antioxidant activity of asparagus juice treated with heated pectinase AN that still contained some rhamnosidase activity. The discovery of our research is helpful to produce juice with high antioxidant activity and high health benefits in the juice industry.

Antioxidants↗
PubMed2003

New dimeric morphine from opium poppy (Papaver somuniferum) and its physiological function.

Together with bismorphine A (1), a new compound bismorphine B (2) was identified in the wounded capsules of Papaver somniferum. On the basis of analyses of the various spectral data, bismorphine B (2) was determined as a novel morphinan alkaloid, in which two morphine units are coupled through a biphenyl ether bond. When the physiological function of bismorphine B (2) in opium poppy was investigated, it was evident that this alkaloid more effectively cross-links cell wall polysaccharide pectins than bismorphine A (1) and that such cross-linking reaction leads to resistance against hydrolysis by pectinase.

Alkaloids↗
PubMed2000

High-speed pectic enzyme fractionation by immobilised metal ion affinity membranes.

Immobilised metal ion affinity polysulfone hollow-fibre membranes, with a high capacity for protein adsorption, were prepared and their utilisation for commercial pectic enzyme fractionation was studied. The pass-through fraction containing pectinlyase is useful for fruit-juice clarification without methanol production on account of pectinesterase being retained by the IDA-Cu2+ membrane.

Chromatography, Affinity↗
PubMed1999

Evaluation of an enzyme-containing capsular shaped pulsatile drug delivery system.

PURPOSE: To develop an enzymatically-controlled pulsatile drug release system based on an impermeable capsule body, which contains the drug and is closed by an erodible pectin/pectinase-plug. METHODS: The plug was prepared by direct compression of pectin and pectinase in different ratios. In addition to the disintegration times of the plugs, the lag times and the release profiles of the pulsatile system were determined as a function of pectin:enzyme ratio, the pH of the surrounding medium, and the addition of buffering or chelating agents. RESULTS: The disintegration time of the plug, respectively the lag time prior to the drug release was controlled by the pectin:enzyme ratio and the plug weight. The inclusion of a buffering agent within the plug lead to a plug disintegration independent of the surrounding pH. The addition of N(alpha)-EDTA hindered the formation of non-soluble calcium pectinate in the presence of calcium ions in the environment. The addition of effervescent agents to the capsule content resulted in a rapid emptying of the capsule content after plug degradation. CONCLUSIONS: A pulsatile drug delivery system based on an erodible pectin plug containing a pectinolytic enzyme was developed. The drug release was controlled by the enzymatic degradation and dissolution of pectin.

Administration, Oral↗
PubMed2003

Enzyme production by the nematode-trapping fungus, Duddingtonia flagrans.

Duddingtonia flagrans degrades peptides, proteins, starch, pectin, lipase, lecithin and oils when grown on agar medium. Serine proteases with optimal activity at pH 8.5 to 10.5 were produced when it was grown in submerged culture. It also produced phospholipase C with optimal activity at pH 8.5, lipases with high activity at pH 3.5 and at 7.5 to 8.5 and pectin-degrading enzymes with pH optima of 3 and 8. The pH of the culture medium affected the types of lipases and pectin degrading enzymes produced but not the proteases or phospholipase C.

Ascomycota↗
PubMed2003

Isolation and characterisation of resistant-to-fermentation carbohydrate polymers from cultures of Rhizopus nigricans grown on agrofood waste materials.

Rhizopus nigricans was cultivated in a liquid medium using lemon, mandarin, orange, pear and melon peel or artichoke bracts as the carbon source. In all cultures, a carbohydrate polymer fraction remained resistant to fermentation. These fractions were isolated in gram amounts and characterised. The molecular weight distribution of the fractions and its sugar composition resembles those of the hairy-regions of the pectins. In the fractions, four main carbohydrates were found: 4-7 mol% Rha, 42-59 mol% Ara, 7-14 mol% Gal, 17-33 mol% GalA.

Agriculture↗
PubMed2004

Expression of pectinase activity among Aspergillus flavus isolates from southwestern and southeastern United States.

Aspergillus flavus is a widely distributed filamentous fungus that contaminates crops with the potent carcinogen aflatoxin. This species can be divided into S and L strains on the basis of sclerotial morphology. During crop infection, A. flavus can secrete a large array of hydrolytic enzymes. These include pectinase, which aids fungal spread through plant tissues. A survey of pectinase expression by soil isolates derived from different regions of the United States revealed geographic polymorphisms. Strain L isolates from Arizona produced moderate to high levels of a specific pectinase P2c, while S strain isolates produced variable amounts of P2c. In contrast, L strain isolates from southeastern U.S. yielded variable P2c production, while S strain isolates consistently expressed high P2c levels. These results were corroborated by pectinase surveys of additional collections of A. flavus from soil and cottonseed. Expression patterns for P2c and pectinmethylesterase were evaluated for a select number of isolates using an isoelectric focusing technique. Clear zone reactions from the pectinase plate assay corresponded to the presence of P2c, while red ring reactions corresponded to the lack of P2c. Commercial cottonseed infected by S strain isolates frequently contained aflatoxin, even when infected by S strain isolates that did not produce pectinase P2c. Thus, although P2c-lacking isolates have reduced invasiveness, these isolates still have sufficient pathogenicity to cause aflatoxin contamination.

Aflatoxins↗
PubMed2001

Exopectinases produced by Aspergillus niger in solid-state and submerged fermentation: a comparative study.

Exopectinase production by Aspergillus niger was compared in submerged fermentation (SmF) and solid-state fermentation (SSF). SSF was carried out using polyurethane foam (PUF) as the solid support. The purpose was to study the effect of sucrose addition (0 or 40 g/l) and water activity level (A(w)=0.99 or 0.96) on the level of enzyme activity induced by 15 g/l of pectin. Mycelial growth, as well as extracellular protease production, was also monitored. Sucrose addition in SmF resulted in catabolite repression of exopectinase activity. However, in SSF, an enhancement of enzyme activity was observed. Protease levels were minimal in SSF experiments with sucrose and maximal in SmF without sucrose. Exopectinase yields (IU/g X) were negligible in SmF with sucrose. The high levels of exopectinase with sucrose and high A(w) in SSF can be explained by a much higher level of biomass production without catabolite repression and with lower protease contamination.

Aspergillus niger↗
PubMed1998

Occupational asthma in fruit salad processing.

BACKGROUND: Three subjects employed in the preparation of fruit for fruit salads reported work-related respiratory symptoms. Their work entailed removing the peel from citrus fruits, primarily oranges, following soaking of the fruits in a bath of enzymes including fungal derived pectinase and glucanase. Objectives To investigate the respiratory symptoms reported by these workers and determine their causes. METHODS: The three workers were investigated by a respiratory physician, including spirometry and serial peak flow measurements. Blood was taken for the measurement of IgE and IgG antibody responses against the enzyme solution. RESULTS: Predominant symptoms in these workers were shortness of breath, chest tightness and wheezing which were all alleviated at weekends and holidays only to occur when returning to work. Serial peak flow measurements showed a clear work-related pattern. All three had strong IgE responses to the enzyme solution used at the workplace and showed distinct patterns of binding in immunoblots. All three improved immensely following withdrawal from the workplace environment. CONCLUSION: Enzymes appear to be widely used in the preparation of fruit and although they are used in liquid form, exposure can occur to induce immunological sensitization and asthma.

Adult↗