ABSTRACT
Lactic acid bacteria (LAB) strains were assayed for the conservation of fresh sardine "Sardina pilchardus". Lactobacillus delbrueckii subsp. delbrueckii was used for inoculation of sardine fillets in a solution of NaCl (5%, w/w) and glucose (4%, w/w) concentration in water. Microbial counts including Standard Plate Count (SPC), LAB, yeasts, coliforms, Salmonella, staphylococci and Clostridium were followed during two weeks of storage at 30 degrees C. Determinations of chemical parameters including pH, dry matter, fat, ash, total nitrogen (NT), total volatile basic nitrogen (TVBN) and trimethylamine (TMA) were carried out under the same conditions. Chemical determinations showed a net pH decrease from an initial value of 6.05 in raw sardine fillets to 4.3 after 16 days of fermentation. Increases in TMA content and TBVN were observed. Microbiological control showed that LAB counts reached a level up to 3.10(9) cfu/g after 4 days of fermentation. After two weeks, fermented fish was free of coliforms and Salmonella. The inhibition of pathogenic microflora including staphylococci and Clostridium was also observed. The results indicated that controlled LAB fermentation could be used as a successful process for biopreservation of sardines produced in huge quantities in Morocco.
Subject(s)
Anti-Bacterial Agents/metabolism , Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Fishes/microbiology , Lactic Acid/metabolism , Lactic Acid/pharmacology , Lactobacillus delbrueckii/metabolism , Animals , Bacteria/growth & development , Colony Count, Microbial , Fats/analysis , Fermentation , Food Preservation/methods , Fungi/drug effects , Fungi/growth & development , Hydrogen-Ion Concentration , Nitrogen/analysis , TemperatureABSTRACT
The apiculture industry is more and more interested in finding typical markers to authenticate floral origin of honeys. With this aim, some reliable volatile compounds were proposed to identify origin of lime tree and chestnut samples. A dichloromethane extraction followed by a Likens-Nickerson simultaneous steam distillation/solvent extraction led to representative honey extracts. About 400 volatile compounds were separated by gas chromatography, but only a few authenticated the floral origin of honeys. Chestnut honeys are distinguishable from other origins by high concentrations of acetophenone, 1-phenylethanol (>88 ppb), and 2-aminoacetophenone (>154 ppb). Lime tree honeys are characterized by enhanced amounts of shikimate pathway derivatives (ethylmethylphenol isomer (>31 ppb), 4-tert-butylphenol, estragole (>51 ppb), and p-methylacetophenone but also by high concentrations of monoterpene-derived compounds (menthol, thymol, 8-p-menthene-1,2-diol, and carvacrol (>76 ppb)) and methyl(1-methylethenyl)benzene.
