title: Lactic acid as potential substitute of acetic acid for dissolution of chitosan: preharvest application to Butterhead lettuce.
abstract: Chitosan must be dissolved in acid solution to activate its antimicrobial properties. The objectives of present study were to determine whether acetic and lactic acids used to dissolve chitosan would influence its effectiveness to control the native microflora of Butterhead lettuce at harvest and during postharvest storage (7-8 °C, 5 days). Chitosan was applied as a SINGLE DOSE (14, 10, 7, 3 or 0 days previous to harvest) or in SUCCESSIVE DOSES (at 14 + 10 + 7+3 + 0 days prior to harvest). Although chitosan in acetic acid showed antimicrobial activity, treated plants showed dried brown stains which significantly reduced sensorial quality. Chitosan in lactic acid applied in a SINGLE DOSE at harvest or in SUCCESSIVE DOSES reduced microbial counts of all populations at harvest without affecting sensorial quality. After postharvest storage, lettuce treated with SUCCESSIVE APPLICATIONS of chitosan in lactic acid presented significant reductions in the microbial populations compared with untreated sample (-2.02 log in yeast and molds, -1.83 log in total coliforms, -1.4 log CFU g-1in mesophilic bacteria and -1.1 log in psychrophilic bacteria). In conclusion, replacement of acetic by lactic acid did not affect the antimicrobial activity of chitosan, reducing microbial counts at harvest and after postharvest storage without affecting sensorial quality.
authors.affiliation: Grupo de Investigación en Ingeniería de Alimentos, Facultad de Ingeniería, UNMdP, Juan B. Justo 4302, 7600 Mar del Plata, Argentina.|Consejo Nacional de Ciencia y Tecnología (CONICET), Ciudad Autónoma de Buenos Aires (CABA), Argentina.
authors.forename: María Gabriela
authors.initials: MG
authors.lastname: Goñi
authors.affiliation: Grupo de Investigación en Ingeniería de Alimentos, Facultad de Ingeniería, UNMdP, Juan B. Justo 4302, 7600 Mar del Plata, Argentina.|Consejo Nacional de Ciencia y Tecnología (CONICET), Idem, Argentina.
authors.forename: Bárbara
authors.initials: B
authors.lastname: Tomadoni
authors.affiliation: Grupo de Investigación en Ingeniería de Alimentos, Facultad de Ingeniería, UNMdP, Juan B. Justo 4302, 7600 Mar del Plata, Argentina.|Consejo Nacional de Ciencia y Tecnología (CONICET), Idem, Argentina.
authors.forename: Sara Inés
authors.initials: SI
authors.lastname: Roura
authors.affiliation: Grupo de Investigación en Ingeniería de Alimentos, Facultad de Ingeniería, UNMdP, Juan B. Justo 4302, 7600 Mar del Plata, Argentina.|Consejo Nacional de Ciencia y Tecnología (CONICET), Idem, Argentina.
authors.forename: María Del Rosario
authors.initials: MDR
authors.lastname: Moreira
keywords: Biopreservative; Greenhouse; Organic; Safety; Sensorial quality