Utjecaj uvjeta pripreme na senzorska svojstva zelenog čaja

undergraduate thesis

• Title (english): Influence of preparation on sensory properties of green tea
• Author: Ivana Španić
• Mentor: Draženka Komes (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Chemistry and Technology of Carbohydrates and Confectionery Products); Zagreb
• Defense date and country: 2014-07-10, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Nutrition

Abstract

Zeleni čaj, dobiven iz lišća biljke Camellia sinensis, jedno je od najkonzumiranijih pića na svijetu. Cilj ovoga rada bio je usporediti bioaktivni sastav (ukupni polifenoli, tanini i kafein) šest različitih vrsta zelenog čaja sa senzorskim profilom različito pripremljenih napitaka (3, 10, 20 i 30 minuta ekstrakcija). Udjeli ukupnih polifenola i tanina određeni su spektrofotometrijskim metodama, a udjel kafeina primjenom visokodjelotvorne tekućinske kromatografije (HPLC-PDA). Senzorsko ocjenjivanje zelenog čaja proveo je panel od šest educiranih ocjenjivača, a 10-bodovnom hedonističkom skalom ocjenjivala se gorčina, trpkost i općenita prihvatljivost. Najveći udjel ukupnih polifenola i tanina određen je u Darjeeling zelenom čaju, a najveći udjel kafeina određen je u zelenom čaju japanska Sencha. Zelene čajeve karakteriziraju miris po travi ili sijenu te gorak ili pomalo slatkast okus. Produljenjem ekstrakcije povećava se udjel ukupnih polifenola, tanina i kafeina što se odražava i na intenzitet gorčine i trpkosti te se smanjuje prihvatljivost konzumiranja takvih napitaka.

Abstract (english)

Green tea, made from leaves of Camellia sinensis, is one of the most consumed beverages in the world. The purpose of this study was to compare the bioactive composition (content of total polyphenols, tannins and caffeine) of six different types of green tea to the sensory profile of differently prepared drinks (3, 10, 20 and 30 minutes of extraxtion). The content of total polyphenols and tannins were determined using by spectrophotometric method, while the content of caffeine was detected using high performance liquid chromatography (HPLC–PDA). The panel of six sensory evaluators performed the sensory evaluation of green tea using 10-point hedonic scale in order to assess the bitterness, astringency and general acceptability. The highest content of total polyphenols and tannins was determined in Darjeeling green tea, and the highest content of caffeine was determined in Japanese Sencha green tea. Green tea is characterized by grass or stern aroma, and the bitter or slightly sweet taste. Content of total polyphenols, tannins and caffeine in green tea increased as the brewing time increased which is reflected in the intensity of bitterness and astringency and reduces the acceptability of consuming such beverages.

• Keywords: gorčina; senzorska analiza; trpkost; zeleni čaj
• Keywords (english): astringency; bitterness; green tea; sensory analysis
• Language: croatian
• URN:NBN: urn:nbn:hr:159:428071
• Study programme: Title: Nutrition; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) nutricionizma (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) nutricionizma)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-04-27 12:23:20