Influence of harvest time on the composition and quality of Rosinjola cultivar virgin olive oils

Autor: Olivera Koprivnjak, Barbara Sladonja, Dubravka Škevin, Ivana Belobrajić, Karolina Brkić Bubola
Jazyk: angličtina
Rok vydání: 2012
Předmět:
Zdroj: Croatian journal of food science and technology
Volume 4
Issue 1
Croatian Journal of Food Science and Technology, Vol 4, Iss 1, Pp 9-18 (2012)
ISSN: 1848-9923
1847-3466
Popis: Cilj ovog istraživanja bio je utvrditi utjecaj roka berbe maslina autohtone istarske sorte Rosinjola na udio ulja u tijestu maslina te na sastav i kvalitetu dobivenih ulja. U kasnom roku berbe utvrđena je viša vrijednost udjela ulja u suhoj tvari tijesta maslina nego u ranom roku berbe, ali je kasna berba negativno utjecala na tržišne parametre kvalitete dobivenog ulja. Udio oleinske kiseline lagano se smanjio u kasnom roku berbe, a udio linolne kiseline je porastao. Omjer oleinska/linolna kiselina, koncentracije ukupnih fenola i orto-difenola, te vrijednosti indeksa gorčine i antioksidacijski kapacitet smanjili su se u ulju dobivenom u kasnom roku berbe. Kasni rok berbe utjecao je i na opadanje koncentracije klorofila i karotenoida te vrijednosti parametara boje (a*, b* i C) u dobivenim uljima, a svjetlina ulja (L*) se povećala. U uljima iz kasnog roka berbe koncentracije većine hlapivih tvari koje utječu na pozitivna mirisna svojstva sorte Rosinjola su opale, osim aldehida kojima je koncentracija blago narasla. Senzorska ocjena ulja iz kasnog roka berbe se smanjila, kao i intenziteti svojstava maslina, jabuka, trava, gorko i pikantno u tom ulju, dok su se intenziteti svojstava slatko i ostalo zrelo voće povećali. Ulja dobivena u ranom roku berbe opisana su kao skladna i trpka s izraženim zelenim mirisnim notama, a u ulja dobivena u kasnom roku berbe kao prezrela i bez svježine. Dobiveni rezultati izuzetno su važni zbog određivanje optimalnog trenutka berbe kao i razumijevanja potencijala sorte Rosinjola za proizvodnju visoko kvalitetnih djevičanskih maslinovih ulja s ciljanim i posebnim karakteristikama.
The aim of this investigation was to determine the influence of Rosinjola cultivar fruits harvest time on oil content in olive pastes and on composition and quality of obtained oils. In the late harvest time the higher value of oil in the dry matter of olive paste was determined than in the early harvest time, but the late harvest negatively affected oil quality parameters. The proportion of oleic acid decreased slightly in the late harvest time and linoleic acid increased. The ratio of oleic/linoleic acid, total phenols and ortho-diphenols, as well as bitterness index and antioxidant capacity decreased in the oil obtained from black fruit. Late harvest time influenced the decrease in chlorophyll and carotenoid content and color parameter values (a*, b* and C) in obtained oils, but lightness (L*) increased. The concentration of volatiles responsible for positive odour of Rosinjola oils decreased, except for aldehydes which increased slightly. Sensory score of oil obtained from the late harvest time decreased, as well as intensities of sensory characteristics olive fruity, apple, green grass, bitter and pungent, while the intensities of characteristics sweet and ripe fruits increased. Oils obtained in the early harvest time were described as harmonious and astringent with pronounced green odour notes, and oils obtained in the late harvest time as overripe and without freshness. The obtained results are important for optimal harvest time determination and understanding the potential of Rosinjola cultivar for production of high quality virgin olive oil with targeted and specific characteristics.
Databáze: OpenAIRE
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