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Isolation, purification and characterisation of transglutaminase from rosemary (Rosemarinus officinalis L.) leaves

100%

El-Hofi M. , Ismail A. , Nour M. , Ibrahim O.

Acta Scientiarum Polonorum. Technologia Alimentaria

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2014

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tom 13

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nr 3

EN

Background. Rosemary (Rosmarinus officinalis L.) is a spice and medicinal herb widely used around the world of the natural antioxidants, and it has been widely accepted as one of the spices with the highest antioxidant activity. Transglutaminase (EC 2.3.2.13; TGase) is an enzyme capable of catalysing acyl transfer reactions by introducing covalent cross-links between proteins, as well as peptides and various primary amines. TGase activity in plants was first observed in pea seedlings, and subsequently found in organs of both lower and higher plants. Recently, TGase has captured researchers’ interest due to its attractive potential application in food industries. Therefore, the objectives of this study are isolation and purification of TGase from new plant source rosemary (Rosmarinus officinalis L.) leaves at the laboratory scale. Moreover, investigation of the biochemical properties of the purified TGase to provide a suitable TGase enzyme for food industry applications are in focus. Material and methods. Rosemary {Rosmarinus officinalis L.) leaves was used as a new plant source to TGase. The biochemical characteristics of the crude and purified enzyme were determined. Results. Rosemary {Rosmarinus officinalis L.) TGase was purified to homogeneity by successive three purification steps including ammonium sulfate precipitatation, ion exchange chromatography on DEAE-Sephad- ex A-50 column and Size exclusion column chromatography on Sephadex G-100 column. Under experimental conditions, 20-30% of ammonium sulfate saturation in the enzyme solution had a high yield of enzyme activity could be obtained. The purified enzyme from the Sephadex G-100 column had 21.35% yield with increased about 7.31 in purification fold. Rosemary TGase exhibited optimum activity at pH 7.0 and 55°C for the catalytic reaction of hydroxylamine and Z-Gln-Gly. The purified TGase almost maintained fuli activity after incubation for 15 min up to 60°C and it was completely inactivated at 85°C. The rosemary TGase was stimulated at 2-6 mM CaCl2 concentrations while it lost about 5-20% from its activity by increasing CaCl2 concentration. Sodium chloride (2-14%) shows no noticeable inhibition of the purified TGase activity. Mg+2, Ba+2 were acivited by the purified TGase while it was strongly inhibited by Fe+2, moderately by Cu+2 and Mn+2. Conclusion. This paper reports on the purification and characterisation of TGase from newly isolated plant, rosemary {Rosmarinus officinalis L.) leaves. Finding results of the TGase properties make this enzyme a good candidate for application in the food industry. However, additional work is required to increase activity yield during extraction and purification for commercial scale of TGase from this plant.

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Preparation and characterization of low density polyethylene nanocomposites with modified montmorillonite clay

100%

Nour M. , Elgazery M. , Awad W. , Amer M.

Polimery

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2009

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tom T. 54, nr 7-8

536-540

EN

Organically modified montmorillonite clay (OMC) and its iron complex (OMC-Fe) were prepared using 1-acetylpyridinium chloride salicylhydrazone. Low density polyethylene (PE-LD) was compounded with either OMC or OMC-Fe (in amount of 3 or 7 wt. %) using ultrasonic radiation. The morphology of polyethylene composites was characterized by atomic force microscopy (AFM). The thermal stability and flammability properties of polyethylene composites were evaluated using thermogravimetric analysis and cone calorimetry, respectively. The resultant composites exhibited improved flammability relative to the pure polyethylene.

PL

Montmorylonit (MMT) modyfikowano za pomocą surfaktantu (H2ACSH). Z części uzyskanej organicznie modyfikowanej glinki montmorylonitoej (OMC) otrzymywano jej kompleks z kationami żelaza (III) (OMC-Fe). Następnie używając fal ultradźwiękowych przygotowano nanokompozyty polietylenu małej gęstości (PE-LD) z OMC lub OMC-Fe w ilości 3 lub 7 % mas. Metodą mikroskopii sił atomowych (AEM) wykonano charakterystykę morfologiczną próbek nanokompozytów. Stabilność termiczną tych próbek zbadano metodą analizy termograwimetrycznej, a palność za pomocą kalorymetru stożkowego. Stwierdzono, że dodatek OMC lub OMC-Fe do PE-LD praktycznie nie wpływa na stabilność termiczną nanokompozytów w porównaniu z czystym PE-LD, ale zmniejsza ich palność.

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Effect of rosemary transglutaminase on yoghurt fortified with whey protein isolate

75%

Ibrahim O. , Glibowski P. , Nour M. , El-Hofi M. , El-Tanboly E.-S. , Abd-Rabou N.

Polish Journal of Food and Nutrition Sciences

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2017

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tom 67

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nr 4

EN

Rosemary (Rosmarinus officinalis L.) transglutaminase (RTGase) was used to cross-link whey protein isolate (WPI) and its ability to induce gelation was investigated. The rheological and textural properties of WPI were improved with RTGase treatment. Set-type yoghurts fortifi ed with 1% WPI powder treated with RTGase at the level of 2.5 and 10 unit/g protein were studied. Chemical, rheological, textural and organoleptic properties of the yoghurt treated with RTGase were better than these of the control yoghurt.