Propriedades prebióticas e antimicrobianas de mel de abelha

Abstract

The prebiotics are non-digestible food components that improve host health by selectively stimulating, the growth and/or activity of desirable bacteria populations in the colon, such as bifidobacteria and lactobacilli. It is believed that honey bee may exert a prebiotic effect on the microbial population of the colon as it contains a series of oligosaccharides, which are well known prebiotic compounds. On the other hand, the honey presents inherent antimicrobial properties that limit the survival and the development of the great majority of the microorganisms, such as high osmotic pressure, low pH, among others factors. The aim of the work was to study the prebiotic and antimicrobial properties of honeys from Brazilian and European bees. The probiotics cultures employed were Lactobacillus acidophilus LA-5, Lactobacillus casei-01 e Bifidobacterium BB-12 (Christian Hansen®), Lactobacillus acidophilus e Bifidobacterium lactis (Sacco®), and L. casei Shirota. Growth and viability of the cultures along the storage, was determined in reconstituted nonfat dry milk, containing 3% (wt/vol) of Apis mellifera pasteurized honey. Controls without honey were prepared. At 23, 35 and 46 day interval, samples were collected for determination of the viable cell number, pH and titrable acidity. All cultures remained viable for up 46 days at 7ºC despite of being added of honey. The addition of honey to milk did not result in prebiotic effect for lactobacili. However, bifidobacteria strains produced more acid in the presence of honey (p<0,05) and shown an ability to adapt at low pH and high acidic conditions higher than that is normally accept as a limit for bifidobacteria growth, especially the strain B. lactis Sacco®. At the 46º day of storage, the higher cell counts was observed with L. casei-01 e L. casei Shirota (>9,0 log10 CFU/g) cultures in the presence of honey, whereas the lowest growth (6.11 log CFU/mL) and acidity (0,30%) was observed with B. BB-12 in the absence of honey. Probiotic resistance to bile salts, was evaluated using MRS broth added of 0,3% oxgall and 3% honey. Optical density was measured at 3, 6, 12, 24, 30 and 36 hours intervals. All probiotics were partially inhibited by bile salts during the first 6 hours of incubation. The honey did not contribute for a significant increase (p>0,05) on growth of probiotic bacteria in the presence of bile salts. The antimicrobial activity of different types of honey was determined by agar diffusion technique, using Apis and Melipona honeys (filter sterilized and pasteurized). Staphylococcus aureus ATCC 25923, enterotoxigenic Escherichia coli (ETEC) and Listeria inocua were resistant, whereas Salmonella Typhimurium and E. coli ATCC 25922 cultures were sensible. However the effect of Apis honey was due only the result of the increase of osmotic pressure, as the controls with glucose showed similar response.