Title Nutritivni sastav svježeg lista koprive pakiranog u uvjetima modificirane atmosfere Title (english) Nutritional composition of fresh nettle leaf packaged in modified atmosphere conditions Author Petra Pišonić Mentor Jana Šic Žlabur (mentor)Committee member Jana Šic Žlabur (predsjednik povjerenstva)Committee member Mia Kurek (član povjerenstva)Committee member Sanja Radman (član povjerenstva)Committee member Sandra Voća (član povjerenstva)Granter University of Zagreb Defense date and country 2023-09-25, Croatia Scientific / art field, BIOTECHNICAL SCIENCES Abstract Svježi list koprive bogatog je nutritivnog sastava te obiluje brojnim fitokemikalijama visokog antioksidacijskog kapaciteta, a zbog čega je to zeleno lisnato povrće vrlo značajnih funkcionalnih vrijednosti. S obzirom na visoku stopu respiracije, očuvanje nutritivnih i senzorskih svojstava svježeg lista koprive kroz određeno razdoblje čuvanja izuzetno je zahtjevan proces, a posebice u svrhu konzumacije u svježem stanju. Stoga je i cilj ovoga istraživanja bio utvrditi promjenu sadržaja specijaliziranih metabolita (SM) svježeg lista kultivirane koprive pakiranog u uvjetima modificirane atmosfere tijekom razdoblja čuvanja od 9 dana. Kopriva korištena u istraživanju uzgojena je u hidroponskom sustavu dotjecanja i otjecanja. Za potrebe pakiranja varirana su dva ambalažna materijala, biaksijalno orijentirani polipropilen (BOPP) i polietilen niske gustoće (PE-LD) koje karakteriziraju različita barijerna svojstva (propusnost na plinove, vodenu paru itd.), a za potrebe pakiranja u uvjetima modificirane atmosfere kombiniran je sljedeći sastav plinova: atmosfera A: 5 % O2 i 10 % CO2; atmosfera B: 5 % O2 i 5 % CO2. Kontrolni uzorak predstavljao je zapakirani svježi list koprive u spomenuta dva tipa ambalažnog materijala u normalnoj atmosferi (zrak). Zapakirani svježi listovi koprive skladišteni su u razdoblju od 9 dana na temperaturi 4 ± 2 °C prosječne vlažnosti zraka od 60 %. Tijekom navedenog razdoblja analizirao se sadržaj: vitamina C, ukupnih fenola (flavonoida i neflavonoida), ukupnih klorofila (klorofila a i b), ukupnih karotenoida te antioksidacijski kapacitet. Nakon 9 dana skladištenja, uzorci lista koprive pakiranog u BOPP ambalažnom materijalu imali su viši sadržaj vitamina C, ukupnih polifenola, ukupnih klorofila te sukladno navedenom viši antioksidacijski kapacitet, dok su pak uzorci pakirani u PE-LD materijal imali značajno veći sadržaj ukupnih karotenoida. Atmosfera sastava 5 % O2 i 10 % CO2 prilikom pakiranja u modificiranoj atmosferi utjecala je na održavanje visokog udjela vitamina C, ukupnih polifenola, ukupnih klorofila te antioksidacijskog kapaciteta, dok je atmosfera sastava 5 % O2 i 5 % CO2 pogodovala višoj koncentraciju karotenoida u svježem zapakiranom listu koprive. Temeljem rezultata istraživanja može se zaključiti kako ambalažni materijal BOPP, kao i atmosfera plinskog sastava: 5 % O2 i 10 % CO2 pridonose ne samo očuvanju specijaliziranih metabolita, nego dolazi i do porasta u koncentracijama specijaliziranih metabolita tijekom razdoblja skladištenja (9 dana) u odnosu na svježi list koprive.
Abstract (english) The fresh nettle leaf has a rich nutritional composition and is rich in numerous phytochemicals with high antioxidant capacity, which is why it is a green leafy vegetable with very significant functional values. Considering the high respiration rate, maintaining the nutritional and sensory properties of a fresh nettle leaf over a storage period is an extremely demanding process, especially for fresh consumption. Therefore, the aim of this study was to determine changes in the content of specific metabolites (SM) in fresh nettle leaves packed under modified atmosphere during a storage period of 9 days. The nettle used in this study was grown in a hydroponic system with inflow and outflow. Two packaging materials, biaxially oriented polypropylene (BOPP) and low-density polyethylene (PE-LD), characterized by different barrier properties (permeability to gases, water vapor, etc.) were used for packaging. For modified atmosphere packaging, the following gas composition was combined: Atmosphere A: 5 % O2 and 10 % CO2; Atmosphere B: 5 % O2 and 5 % CO2. The control sample was a fresh nettle leaf packed in the above two different types of packing material under normal atmosphere (air). The packed fresh nettle leaves were stored for 9 days at a temperature of 4 ± 2 °C and an average humidity of 60 %. During this period, the content of: Vitamin C, total phenols (flavonoids and non-flavonoids), total chlorophyll (chlorophyll a and b), total carotenoids and antioxidant capacity were analysed. After 9 days of storage, the nettle leaf samples packed in BOPP packaging material showed higher content of vitamin C, total polyphenols, total chlorophyll and, accordingly, higher antioxidant capacity, while the samples packed in PE-LD showed significantly higher content of total carotenoids. The atmosphere with the composition of 5 % O2 and 10 % CO2 during packaging in a modified atmosphere influenced the maintenance of high levels of vitamin C, total polyphenols, total chlorophyll and antioxidant capacity, while the atmosphere with the composition of 5 % O2 and 5 % CO2 favoured a higher concentration of carotenoids in freshly packaged nettle leaves. From the research results, it can be concluded that both the packaging material BOPP and the gas composition of the atmosphere: 5 % O2 and 10 % CO2 not only contributed to the preservation of specialized metabolites, but also to an increase in the concentrations of specialized metabolites during the storage period (9 days) compared to fresh nettle leaf.
Keywords
kopriva
modificirana atmosfera
polimerna ambalaža
specijalizirani metaboliti
skladištenje
Keywords (english)
nettle
modified atmosphere
polymer packaging
specialized metabolites
storage
Language croatian URN:NBN urn:nbn:hr:204:271714 Study programme Title: Organic Agriculture with Agrotourism Type of resource Text File origin Born digital Access conditions Access restricted to authenticated users Terms of use Created on 2023-10-26 12:30:19
