Effects of Weevil (Rhynchophorus palmarum), Teosinte (Dioon mejiae) and Caesar’s Mushroom (Amanita caesarea) on the Properties of Lactobacillus acidophilus LA-K

Abstract

Weevil (Rhynchophorus palmarum) powder, teosinte (Dioon mejiae) and Caesar’s mushroom (Amanita caesarea) flour have bioactive compounds with significant nutritional applications. This paper aimed to examine the influence of weevil, teosinte, and mushroom powders on the protease activity, acid tolerance, bile tolerance, lysozyme tolerance, and gastric juice resistance ability of Lactobacillus acidophilus LA-K. Acid tolerance was determined by adjusting the pH of MRS broth to 2.0 for L. acidophilus incubated under aerobic conditions at 37 °C. Bile tolerance was determined by incorporating 0.3% of oxgall. Protease activity was determined spectrophotometrically at 340 nm. Resistance to 100 mg/L of lysozyme in an electrolyte solution was also determined. All ingredients were incorporated at 2% (w/v), while the control had no added ingredients. Acid and lysozyme tolerance were examined at 0, 30, 60, 90, and 120 min of incubation, whereas bile tolerance was analyzed at 0, 4, and 8 h. Gastric juice tolerance was determined at pH 2, 3, 4, 5, and 7 during 0 and 30 min of incubation, while protease activity was evaluated at 0, 12, and 24 h. Use of weevil flour, and Caesar’s mushroom powder resulted in significantly (p < 0.05) lower counts for bile tolerance, acid tolerance, lysozyme resistance and simulated gastric juice tolerance characteristics. Protease activity increased with the use of teosinte flour. As such, this probiotic bacterium can be used alongside certain novel food sources at 2% concentration in the manufacture of fermented products such as yogurt.