**4. Glycinin**

Glycinin was isolated and characterized from soybeans stored under different ambient con‐ ditions (i) in 84% relative humidity at 30 o C (adverse conditions) for 9 months and (ii) in 57% relative humidity at 20 o C, (iii) in the cold (4 o C), and (iv) in an uncontrolled ambient garage for 18 months.. Glycinin purified from soybean exposed to the adverse conditions possessed a significant amount of sugar and demonstrated a decrease in hydrophobic interactions after 3 months; the total free sulfhydryl content in glycinin dropped, but the intramolecular disul‐ fide bonds increased; the alpha-helix content of secondary structure underwent a slight rise, but the beta-sheet content fell. The structure of glycinin purified from and subjected to the other three aforementioned conditions remained unaltered after 18 months of storage when compared to the control. The molecular mass of glycinin remained in the range of 313-340 kDa throughout the storage period for all four conditions [4].

Addition of 1% cholesterol and 0.5% cholic acid induced hypercholesterolemia in Male Wis‐ tar rats without altering weight gain. Daily administration (300 mg/kg/day) of glycinin (11S globulin) for 28 days led to a 2.8% increase of dietary protein intake and resulted in elevated HDL-C, reduced hepatic triglycerides and improved atherogenic index in hypercholestero‐ lemic animals [5].

Sitohy et al [6] isolated glycinin, basic subunit and β-conglycinin from soybean protein iso‐ late and tested them for antimicrobial activity against pathogenic and spoilage bacteria as compared to penicillin. All three of them demonstrated antibacterial activity identical to or higher than penicillin in the order; basic subunit > glycinin > β-conglycinin with minimal in‐ hibitory concentration (MIC) of 50, 100 and 1000 µg/ml, respectively. The half maximal in‐ hibitory concentration (IC50) values of the basic subunit, glycinin and β-conglycinin were 15, 16 and 695 µg/ml against *Listeria monocytogenes*; 17, 20, and 612 µg/ml against *Bacillus subti‐ lis*; and 18, 21 and 526 µg/ml against *S. enteritidis*, respectively. Transmission electron micro‐ scopy images of *L*. *monocytogenes* and *S. enteritidis* revealed larger sizes and separation of cell wall from cell membrane following treatment with glycinin or basic subunit. Scanning elec‐ tron microscopy of *B. subtilis* disclosed an irregular wrinkled external surface, fragmenta‐ tion, adhesion and aggregation of damaged cells or cellular debris following treatment with glycinin or the basic subunits but not with penicillin. All tested substances, especially the ba‐ sic subunit, manifested enhanced concentration-dependent cell permeation as indicated by crystal violet uptake. Glycinin and basic subunit demonstrated a more rapid antimicrobial action compared with penicillin. The cell killing efficiency was in the following descending order; basic subunit > glycinin > penicillin > β-conglycinin and the susceptibility of the bac‐ teria to the antimicrobial agents was in the order: *L. monocytogenes* > *B. subtilis* > *S. enteritidis.* Addition of glycinin and the basic subunit to pasteurized milk inoculated with the three bacteria; *L. monocytogenes, B. subtilis* and *S. enteritidis* (approximately 5 log CFU/ml) impeded their proliferation after storage at 4 °C for 16-20 days [6].
