Določanje vsebnosti antioksidantov v kakavu in temni čokoladi

Gotal, Veronika (avtor), Pogačnik, Lea (mentor)

Kakav in kakavovi izdelki spadajo med živila, ki so izjemno bogata z antioksidanti. S pojavom novih trendov zdravega načina življenja ljudje iščejo alternativne vire prehranjevanja z visoko vsebnostjo antioksidantov. Zato smo se v okviru diplomskega dela odločili, da bomo v temnih čokoladah (temna čokolada “Choceur” s 85 % kakava in temna čokolada “Lindt” s 70 % kakava), mlečnih čokoladah (mlečna čokolada “Fina” in mlečna čokolada “Lindt”), beli čokoladi (bela čokolada “Lindt”) in v presnem kakavu (presni kakav “Criollo”) določali in primerjali vsebnost skupnih fenolnih spojin (SFS) ter troloksu ekvivalentno antioksidativno učinkovitost (TEAC). Iz razmaščenih vzorcev čokolad in kakava smo pripravili ekstrakte z mešanico acetona in 2 % raztopine ocetne kisline v razmerju 70 : 30 (v/v). Zaradi nizkih vsebnosti antioksidantov v beli čokoladi smo pripravili tudi ekstrakt samo z 2 % raztopino ocetne kisline. SFS smo določali spektrofotometrično z uporabo Folin-Ciocalteujeve metode, rezultate pa podali kot ekvivalent galne kisline. Najvišjo vsebnost SFS smo določili v presnemu kakavu (124,9 µmol/g), najnižjo vsebnost pa smo določili v beli čokoladi (1,0 µmol/g). TEAC smo določili s pomočjo metode lovljenja radikala DPPH•, rezultate pa podali kot ekvivalent troloksa. Največjo TEAC je pokazal presni kakav (207 µmol/g), medtem ko je bila TEAC ekstrakta bele čokolad izjemno nizka, in sicer 0,2 µmol/g. Iz naše raziskave lahko tudi sklepamo, da različna vsebnost kakava v izdelkih močno vpliva na vsebnost SFS in na TEAC.

• Jezik: Slovenski jezik
• Ključne besede: živila, kakav, čokolada, antioksidanti, fenolne spojine, antioksidativna učinkovitost
• Vrsta gradiva: Diplomsko delo/naloga
• Tipologija: 2.11 - Diplomsko delo
• Organizacija: BF - Biotehniška fakulteta
• Založnik: [V. Gotal]
• Leto izida: 2018
• PID: 20.500.12556/RUL-101850
• UDK: 663.91:547.56:66.094.3.097.8
• COBISS.SI-ID: 4927864
• Datum objave v RUL: 08.07.2018

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Determination of antioxidants in cocoa and dark chocolate

Izvleček

Cocoa and cocoa products are among the foods that are extremely rich with antioxidants. With the emergence of new trends in a healthy lifestyle, people are looking for alternative sources of nutrition with a high content of antioxidants. And for this reason, we have decided to determine and compare the content of total phenolic compounds (TPC) and trolox equivalent antioxidant capacity (TEAC) in the dark chocolate (dark chocolate “Choceur” with 85 % cocoa and dark chocolate “Lindt” with 70 % cocoa), milk chocolate (milk chocolate “Fina” and milk chocolate “Lindt”), white chocolate (white chocolate “Lindt”) and in the raw cocoa (raw cocoa “Criollo”). From the defatted samples of chocolate and cocoa, extracts were prepared with a mixture of acetone and 2 % acetic acid solution in a ratio of 70 : 30 (v/v). Because of the low content of antioxidants in the samples of white chocolate, we decided to prepare extracts also with 2 % acetic acid solution. TPC was determined spectrophotometrically using the Folin-Ciocalteu method and the results were given as the equivalent of gallic acid. The highest content of TPC was determined in the raw cocoa (124.9 μmol/g) and the lowest content was determined in the white chocolate (1.0 μmol/g). The TEAC was determined using the DPPH• radical scavenging method. The largest TEAC showed raw cocoa (207 μmol/g), whereas the white chocolate showed an extremely low TEAC (0.2 μmol/g). From our research we can also conclude that the content of cocoa in chocolate products strongly influences the content of TPC and TEAC.

• Ključne besede: foods, cocoa, chocolate, antioxidants, phenolic compounds, antioxidant efficacy