title: Combined effects of high pressure homogenization treatment and citral on microbiological quality of apricot juice.
abstract: High pressure homogenization (HPH) technique is able to significantly reduce spoilage microbiota in fruit juice. On the other hand, aroma compounds and essential oils can have a key role in the microbial stability of these products. For this reason, the aim of this work was to evaluate the combined effects of an aroma compound (citral, used at a concentration of 50 mg/l) and HPH treatments (performed at 100 MPa for 1-8 successive passes) on the inactivation dynamics of Saccharomyces cerevisiae SPA strain inoculated in apricot juices at level of about 4.5 log CFU/ml. Moreover, growth of surviving yeast cells was measured during the storage of the treated juice at 10°C and pH, water activity, viscosity and volatile molecule profile of apricot juice were studied. Since citral had been diluted in ethanol before the addition to juice, also samples with only ethanol added at the same volume used to dissolve citral were considered. The results showed that yeast cell viability decreased with the increases of passes at 100 MPa and the relationship between yeast cell loads and number of passes at 100 MPa followed a linear trend. In addition, the effect of HPH treatment can be notably potentiated throughout the presence of citral and ethanol, increasing the time necessary to reach a spoilage threshold during storage. The volatile profiles of the juices added with citral showed a substitution by yeast metabolism of this aldehyde with molecule characterized by a lower antimicrobial activity such as alcohols. The HPH treatments had also a significant effect on pH and viscosity of apricot juices while did not affect a(w).
authors.affiliation: Dipartimento di Scienze degli Alimenti, Università degli Studi di Bologna, Cesena, Piazza Goidanich 60, Cesena (FC), Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Patrignani
authors.forename: Giulia
authors.initials: G
authors.lastname: Tabanelli
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Siroli
authors.forename: Fausto
authors.initials: F
authors.lastname: Gardini
authors.forename: Rosalba
authors.initials: R
authors.lastname: Lanciotti
mesh_terms: D000080462:Acyclic Monoterpenes; D000935:Antifungal Agents / Q000494:pharmacology; D001628:Beverages / Q000032:analysis / Q000382:microbiology*; D015169:Colony Count, Microbial; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods* / Q000592:standards; D008401:Gas Chromatography-Mass Spectrometry; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D050296:Microbial Viability / Q000187:drug effects; D039821:Monoterpenes / Q000494:pharmacology*; D011312:Pressure; D027861:Prunus; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000502:physiology*; D013997:Time Factors; D014783:Viscosity
chemical_list: D000080462:Acyclic Monoterpenes; D000935:Antifungal Agents; D039821:Monoterpenes; C007076:citral