الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
In the present study 7S, 11S globulins and basic subunits were isolated from defatted sesame protein, fractionated by SDS-PAGE and tested for their biological activities. Sesame protein was isolated and acetylated with acetic anhydride at different concentrations (0.1, 0.2, 0.4, 1.0 ml of anhydride/g protein) in the presence of sodium acetate for 1h at room temperature to give acetylated proteins. Acetylation decreased the iso-electric point of sesame protein isolate from pH 4.5 for the SPI to pH 4 in the case of acetylated sesame protein isolate (ASPI). The SDS–PAGE of acetylated proteins showed slight increments in the molecular weight distribution
Sesame protein isolates (SPI) and native albumin (NA) were hydrazinated with hydrazine (50 mol hydrazine/mole carboxylic group) in the presence of methanol for 10 h at 4˚C to give yields of 91.8% and 91.6%, respectively. The SDS–PAGE molecular weight distribution of proteins showed slight increments after hydrazination. Urea-PAGE of native and hydrazinated proteins represented exchanges in charge between native and modified proteins. Hydrazination raised the pIs (iso-electric points) of proteins from pH 4.5 and 5 for the native proteins to pH 8 and pH 9 for hydrazinated sesame protein (HSPI) and hydrazinated albumin (HA), respectively. Native, acetylated and hydrazinated proteins (SPI, NA, ASPI, HSPI, HA) were applied to Petri dishes containing nutrient agar infected with pathogenic Gram-positive bacteria (Bacillus subtilis), Gram-negative bacteria (Pseudomonas aeruginosa) and two fungi (Aspergillus flavus and Candida albicans), for testing their action on these two bacteria, it was observed that either native or acetylated samples did not produce any inhibition zones. On other hand, the antibacterial activity of hydrazinated sesame protein isolate (HSPI) was observed against Pseudomonas aeruginosa (G-) with 12 mm zone. Using agar well diffusion assay the tested modified proteins induced inhibition zones against two tested bacteria (Staphylococcus aureus (G+) and Escherichia coli (G-)), and against one tested bacteria (Escherichia coli) for hydrazinated sesame protein isolates (HSPI), hydrazinated albumin (HA), respectively. The minimum inhibitory concentration (MIC) for two tested proteins against the Escherichia coli was 150μg/mLASPI, HSPI and HA were tested for their potential toxicity when administrated to Wistar Albino mice as one single dose (5, 50, 300, 2000 and 5000 mg/kg body weight). Single acute administration of very high doses (2000, and 5000 mg/kg body weight) of ASPI, HSPI and HA did not produce any death indicating that the NOAEL (Not Observed Adverse Effect Level) of ASPI, HSPI and HA is more than 10,000 mg/kg body weight/day.
Sesame protein isolate, ethanol extract and methanol extract from sesame seeds were isolated and investigated their in-vitro antioxidant activities (using DPPH assay) as well as their antimicrobial activities. Antioxidant activities were measured in the seed extracts and compared with synthetic antioxidants as tert-butyl hydroquinone (TBHQ). The antioxidant activities of methanol extract (SM), ethanol extract (SE), sesame protein isolate (SPI) and TBHQ recorded 85.2±0.77, 79.6±0.35, 11.2±0.65 and 92.5±1.82%, respectively. Additionally, the antibacterial activity of SE and SPI has been checked in terms of zone of inhibition by disc diffusion method against E.coli, B.subtilis, P. aeruginosa and S. aureus and compared with the antibiotic ampicillin. Ethanolic seed extract of S. indicum at concentration 500 mg/ml showed a diameter of inhibition zone at range of 14-15 mm against S. aureus, B. subtilis, P. aeruginosa and E.coli. SPI did not show any inhibition zone. These results suggest that alcoholic seed extract of sesame contained different types of pharmacologically active compounds with antioxidant and antimicrobial activities. Different amounts of defatted sesame meal (DSM) as a natural antioxidant and protein source were added to raw beef burger to study its effects on total volatile basic nitrogen (TVBN) and thiobarbituric acid (TBA) as well as microbial loader. Besides, the direct addition of defatted sesame meal (DSM) to beef burger may be useful for obtaining a new product enriched in bioactive compound and protein and providing new use for this by-product from sesame oil industry. Keywords: Defatted sesame meal , Sesame protein isolate , 11S, 7S, FTIR, Acetylation, Hydrazination, Urea-PAGE , SDS-PAGE, Antioxidant activity, Antimicrobial activity, Burger.