Interakcije medu z mikrovalovi

Arnšek, Pina (author), Šegatin, Nataša (mentor)

V diplomski nalogi nas je zanimalo, kako se v mikrovalovni pečici obnaša med, kako se spreminjajo njegove lastnosti in kakovost. V eksperimentalnem delu smo ugotavljali, kako se dielektrična konstanta medu v frekvenčnem območju mikrovalov spreminja v odvisnosti od vsebnosti in termodinamike aktivnosti vode. V petih različnih vzorcih medu (akacijevem, lipovem, cvetličnem, kostanjevem in gozdnem) smo v frekvenčnem območju od 200 MHz do 8,5 GHz izmerili dielektrične lastnosti. Iz rezultatov je razvidno, da ima gozdni med največjo vsebnost vode in vodno aktivnost, cvetlični med pa najnižjo vodno aktivnost, medtem ko ima lipov med najmanjšo vsebnost vode. Vsem vrstam medu se je dielektrična konstanta zniževala s frekvenco ne glede na vsebnost vode. Nižja kot je bila vsebnost vode in termodinamska aktivnost vode, nižja je bila dielektrična konstanta. Pri nižjih frekvencah se je dielektrična konstanta strmo znižala. Gozdni med ima največjo vsebnost vode in aktivnost vode, zato je posledično tudi dielektrična konstanta bila največja, medtem ko ima cvetlični med najnižjo vodno aktivnost in posledično nizko dielektrično konstanto. Vidno je, da je faktor izgub najvišji v vzorcu z največjo vodno aktivnostjo in vsebnostjo vode (v gozdnem medu) ne glede na frekvenco, medtem ko je ta najnižji v vzorcu z najmanjšo vsebnostjo in aktivnostjo vode. Najvišji faktor izgub je bil opazen pri najnižji frekvenci 200 MHz ne glede na vrsto medu, medtem ko je bil najnižji faktor izgub pri frekvenci 2,46 GHz, ki je dovoljena za gospodinjske mikrovalovne pečice.

• Language: Slovenian
• Keywords: med, vsebnost vode, termodinamska vodna aktivnost, mikrovalovi, dielektrične lastnosti
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [P. Arnšek]
• Year: 2020
• PID: 20.500.12556/RUL-127777
• UDC: 638.162:544.3:543.613.2:537.226.1
• COBISS.SI-ID: 67744515
• Publication date in RUL: 23.06.2021

Secondary language

• Language: English
• Title: Interactions of honey with microwaves

Abstract

In the diploma thesis we were interested in how honey behaves in the microwave oven, how it affects its properties and quality change. In the experimental part, we determined how the dielectric constant of honey in the frequency range of microwaves changes depending on the content and thermodynamics of water activity. Dielectric properties were measured in five samples of honey (acacia, linden, floral, chestnut and forest honey) in the frequency range from 200 MHz to 8.5 GHz. The results showed that forest honey has the highest water content and water activity, and flower honey has the lowest water activity, while linden honey has the lowest water content. For all types of honey, the dielectric constant decreased with frequency regardless of water content. The lower the water content and thermodynamic activity of the water is, the lower is the dielectric constant. At a lower frequency, the dielectric constant decreased sharply. Forest honey has the highest water content and water activity, so consequently the dielectric constant was also the highest; while the floral honey has the lowest water activity and consequently a low dielectric constant. It is seen that the loss factor is highest in the sample with the highest water activity and water content (in forest honey) regardless of frequency; while it is the lowest in the sample with the lowest water content and activity. The highest loss factor was observed at the lowest frequency of 200 MHz, regardless of the type of honey; while the lowest loss factor was at the frequency of 2.46 GHz, allowed for household microwave ovens.

• Keywords: honey, water content, thermodynamic water activity, microwaves, dielectric properties