title: Influence of autochthonous lactic acid bacteria and enzymatic yeast extracts on the microbiological, biochemical and sensorial properties of Lben generic products.
abstract: In this study we identified Lactococcus lactis subsp. lactis, Lc. lactis subsp. lactis biovar diacetylactis, Kluyveromices lactis and Saccharomyces cerevisiae as the dominant microorganisms of traditional Moroccan acid-alcoholic fermented milk named Lben. The low pH (3·8±0·3), lactose (16·8±3·4 mg/l) and lactic acid (8·16±0·6 mg/l) content indicated that a strong fermentation occurred in the traditional product which was also characterised by the substantial presence of ethanol and typical volatile carbonyl compounds (i.e., acetoin, diacetyl and acetaldehyde). Microbiological analyses of experimental Lben manufactured with selected strains (isolated from the traditional product) of Lc. lactis subsp. lactis and Lc. lactis subsp. lactis biovar. diacetylactis alone (batch A) and in combination with enzymatic extract of a K. lactis strain (batch B) indicated a good effectiveness of the starters employed (∼1010 CFU/g of lactococci after 8 h of incubation) and a significant effect of the yeast enzyme extract on lactococci viability. Despite slight changes in the physicochemical characteristics of the two Lben during the 15 d storage period, volatile compounds (i.e. ethanol, acetaldehyde, diacetyl and acetoin) were consistently higher in batch B. Moreover, sensorial analysis performed after 15 d of storage, highlighted higher odour and flavour intensity, vegetable odour and viscosity in batch B while batch A displayed higher astringency.
authors.affiliation: Dipartimento di Agraria, University of Sassari, V.le Italia 39, 07100 Sassari, Italy.
authors.forename: Nicoletta P
authors.initials: NP
authors.lastname: Mangia
authors.affiliation: Dipartimento di Agraria, University of Sassari, V.le Italia 39, 07100 Sassari, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Garau
authors.affiliation: Dipartimento di Agraria, University of Sassari, V.le Italia 39, 07100 Sassari, Italy.
authors.forename: Marco A
authors.initials: MA
authors.lastname: Murgia
authors.affiliation: Office des Nations Unies Pour les Services, Rue Arabie Saoudite, 30000 Fès, Marocco.
authors.forename: Abdelmajid
authors.initials: A
authors.lastname: Bennani
authors.affiliation: Dipartimento di Agraria, University of Sassari, V.le Italia 39, 07100 Sassari, Italy.
authors.forename: Pietrino
authors.initials: P
authors.lastname: Deiana
mesh_terms: D000818:Animals; D055598:Chemical Phenomena; D043302:Cultured Milk Products / Q000737:chemistry* / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000032:analysis; D013294:Lactococcus lactis / Q000378:metabolism*; D007785:Lactose / Q000032:analysis; D009018:Morocco; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D012677:Sensation; D012903:Smell; D013649:Taste; D014783:Viscosity; D055549:Volatile Organic Compounds / Q000032:analysis
chemical_list: D055549:Volatile Organic Compounds; D019344:Lactic Acid; D007785:Lactose