الفهرس 
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Abstract
Nutraceuticals are natural substances, chemicals, or bioactive substances that exhibit biological activity and physiological benefits to elevate the body’s natural recovery. Microbial spoilage of nutraceutical raw materials can be caused by bacteria, yeasts or fungi which leads to the decomposition of the active ingredients in the products and affects the efficiency of the final product microcapsulation can be used as a method of preserving these compounds.
In the present study 22 bacterial isolates were isolated from four nutraceutical raw samples (Garlic, Ginger, Lactose monohydrate and Curcumin). The raw samples were obtained from pharmaceutical company to form microcapsules with chitosan.
Out of 22, 3 isolates showed thermal resistance after incubated at (60, 70 ,80 ℃) for (5, 10, 15 min). Garlic G2 lethal time was 10 min at 80oC, while isolates from ginger GI 3& GI 7 lethal time was 15 min at 80oC. All isolates were Gram positive cocci bacteria they were selected to further studies.
Ionizing radiation was used for bio-controlling the microbial contamination. The organisms were completely killed at 8.0 kGy and 9.0kGy for GI3 and for both GI7and G2
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respectively. Their D10 values were 0.67 kGy for GI3 while 1.03 kGy for GI7 and 0.9 kGy for G2.
Natural polymers (Chitosan, sodium alginate and arabic gum) antimicrobial activity against selected isolates was studied. Garlic isolate G2 showed high sensitivity to chitosan, sodium alginate and arabic gum, no inhibition zones were detected. Four antibiotics were used as positive control to determine the antibiotic resistant isolates and polymers efficiency. Chitosan concentration 4.0% had the most efficient killing ability (44mm) against GI7. Its inhibition zone was greater than the most powerful antibiotic (AMC: 42mm). The sensitivity of the selected isolates against sodium alginate and arabic gum was tested. All sodium alginate and arabic gum concentrations were lower than Cefuroxime (CXM) 30 μg/ml.
Combination treatments of arabic gum 50% or 3.0% sodium alginate were chosen to combine with chitosan conc. 4.0% decreased the chitosan efficiency.
GI3 and GI7 ginger isolates were identified morphologically as Gram positive, cocci. They showed biochemical characteristics of Enterococcus spp.
They were identified by partial amplification and 16S rRNA gene sequencing as Enterococcus facium & Enterococcus
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durans (99% sequence similarity) under accession number OK605881, OK605880, respectively.
Seven fungal isolates isolated from ginger and garlic were tested for aflatoxin production. Only 3 isolates could produce both B1and B2 aflatoxins.
They were identified by the basis of cultural and morphological characteristics as Aspergillus niger, Aspergillus flavus and Penicillium spp. Results showed that the Aspergillus flavus which isolated from ginger looked like the highly producer of aflatoxin.
Aspergillus flavus was exposed to different doses of gamma rays to reduce the fungal load. Doses of gamma ray 1.0, 2.0, 3.0, 3.5, 4.0, 4.5 and 5.0 kGy. The killing dose was at 5.0 kGy and the calculated D10 value for the organism was 0.7 kGy.
The sensitivity of A. flavus isolate was performed against various concentrations of natural polymers (chitosan, sodium alginate and arabic gum). Results showed that the chitosan concentration 2% inhibition zone was greater than ITC by 6mm and by 13 mm of KTC inhibition zone. While chitosan conc 1% had approximately the same KTC efficiency.
sodium alginate and arabic gum concentrations had no antifungal effect on Aspergillus flavus.
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Chitosan concentrations 2.0 %, 3.0 % & 4.0 % were chosen to form microcapsules. Maximum Chitosan/Ginger capsule yield was recorded when 4.0% chitosan concentration was mixed with 20 ml of GST. The produced capsule yield percentage was 92.5% while Chitosan /Garlic microcapsules yield was 87.5% at the same chitosan concentration and the same volume.
Scanning electron microscope (SEM) magnification 150x showed that all microcapsules had smooth and spherical shape except chitosan/ginger microcapsules had slightly smooth shape and chitosan/curcumin microcapsule had irregular shape, with rough surface and some pores.
The thermogravimetric analysis for the prepared microcapsules (TGA) was performed. Results indicated that Chitosan-garlic microcapsules less thermal stability than the other microcapsules.
Fourier-transform infrared spectroscopy (FTIR) showed some similarity of values of FTIR between raw materials powder and raw materials powder in all prepared microcapsule except the FTIR bands of the garlic microcapsules that were different from IR spectrogram of garlic and chitosan.