Search

Namen dela je bil ugotoviti povezavo med fizikalno-kemijskimi lastnostmi medu, sladkornih sirupov in mešanic medu in sirupov. Želeli smo ugotoviti, kako se lastnosti spreminjajo v odvisnosti od deleža dodanega sirupa in vrste sirupa (glukozno-fruktozni in rižev sirup) na primeru treh vrst medu, to je akacijevega, cvetličnega in kostanjevega. Med je živilo, ki se uvršča med pogosteje potvorjena živila. Zaradi številnih nepoštenih praks pridelave medu smo želeli dobiti vpogled, katera metoda, poleg standardnih za preverjanje pristnosti, bi najhitreje pokazala morebitno potvorbo medu. Rezultati so pokazali, da se fizikalno-kemijske lastnosti spreminjajo glede na botanično poreklo medu in glede na delež in vrsto dodanega sirupa v med. Pri DSC analizi smo ugotovili, da se temperatura steklastega prehoda manjša z dodajanjem sirupa in večanjem njegovega deleža. Pri vsebnosti vode smo ugotovili, da le-ta narašča z večanjem vsebnosti sirupa, prav tako se veča tudi pH vrednost. Vrednosti električne prevodnosti z večanjem deleža sirupa padajo. Ugotovili smo tudi, da se vsebnosti prostih kislin manjšajo z dodajanjem sirupa in da se vsebnost laktonov povečuje z dodajanjem sirupa. Dodajanje sirupa igra pomembno vlogo tudi pri barvi medu, saj se vrednosti parametra L* povečujejo, parametra a* zmanjšujejo, pri parametru b* pa se pri akacijevem in cvetličnem medu zmanjšujejo, medtem ko se pri kostanjevem povečujejo. The aim of this thesis was to establish a correlation between different physicochemical properties of honey, sugar syrups, as well as honey and syrup mixtures. For that purpose, it was analysed how these properties vary across three different honey types, namely acacia, polyfloral and chestnut honeys, depending on their sugar syrup concentration or syrup type added (such as a glucose-fructose or rice syrup). Honey is classified among ten most often adulterated food products. Given numerous unfair practices occurring in the honey production, the thesis explored which alternative method would be the most feasible and robust one to detect any potential honey adulteration. The results obtained have shown that the physicochemical properties largely depend on the botanical origin of honey, as well as on the concentration and type of the syrup added. The DSC analysis demonstrated that the glass transition temperature decreases as the concentration of the syrup added increases. The water content in honey has been found to rise with the increase of syrup content. Similarly, as the syrup concentration increases the pH values observed rise, and those of the electrical conductivity diminish. It was also noticed that with the addition of syrup to honey, free acidity is reduced, and lactone content increased. The increase of syrup concentration also plays an important role in the colour of honey, with the L* parameter values increasing, and the a* parameter decreasing, or - in the case of the b* parameter - the values decreasing for both acacia and floral honeys, while increasing for chestnut honey.

Namen magistrske naloge je bil ugotoviti vpliv različnih vrst medu na potek alkoholne fermentacije in ovrednotiti fizikalno-kemijsko sestavo ter senzorične lastnosti pridelanih medic. V eksperimentalnem delu naloge smo pripravili šest vzorcev medenih raztopin s sladkorno stopnjo 20 °Brix, ki smo jim nato dodali hranila, kislino in kvasovke. S pomočjo gravimetrije smo spremljali alkoholno fermentacijo medenih raztopin, pripravljenih z različnimi vrstami medu. Alkoholna fermentacija je bila zaključena po 19 dneh. Vse pridelane medice so imele različno fermentacijsko kinetiko. Sestavo vzorcev pred in po fermentaciji smo analizirali s pomočjo WineScan␢. Medice so se kljub enaki začetni sladkorni stopnji razlikovale v vsebnostih alkohola, glukoze, fruktoze in kislin. Pri analizi vrednosti pH medene raztopine in medenega vina smo ugotovili, da se je ta med alkoholno fermentacijo pri vseh medicah znižala. Po zaključeni fermentaciji smo izvedli tudi senzorično analizo, s katero smo želeli preveriti všečnost in senzorične lastnosti pridelanih medic. Medice so se razlikovale v senzorični sprejemljivosti. Skoraj vse medice so bile senzorično sprejemljive, z izjemo medice pridelane iz kostanjevega medu. Najbolj všečni sta bili medici, pridelani iz gozdnega in smrekovega medu. Najslabše ocenjena je bila medica, pridelana iz kostanjevega medu, zaradi neprijetnega grenkega okusa. Z metodo hitrega profiliranja so preskuševalci sami izbrali opisnike, od katerih so prevladovali aroma po cvetlicah, aroma po bezgu in okus po grenkem. S statistično obdelavo podatkov smo dokazali, da se medice med seboj razlikujejo v vonju, okusu in aromi. The aim of the Master's thesis was to determine the influence of different types of honey on the alcoholic fermentation and to evaluate the physicochemical composition and sensory properties of the produced meads. In the experimental part we prepared six samples of honey solutions with a sugar level of 20 °Brix, to which we added nutrients, acid and yeast. With the help of gravimetry we monitored the alcoholic fermentation of honey solutions prepared with different types of honey. Alcoholic fermentation was completed after 19 days. All produced meads had different fermentation kinetics. The composition of the honey solutions before fermentation and the processed meads was analysed using WineScan␢. Despite having the same initial sugar content, the meads differed in contents of alcohol, glucose and fructose, and acidity. The pH value had decreased in all meads during alcoholic fermentation. Finally, we also performed sensory analysis to determine the sensory acceptability and sensory characteristics of the processed meads. Meads differed in sensory accepting. Almost all meads were sensory acceptable except for mead made from chestnut honey. The most acceptable meads were those made from forest and spruce honey. The least acceptable was mead made from chestnut honey because of its unpleasant bitter taste. Using the flash profiling method, the assessors selected descriptors for meads by themselves. Floral aroma, elderberry aroma and bitter taste were predominant descriptors. With the statistical analysis of obtained results, we were able to prove that meads differ in odour, taste and aroma.

V diplomskem delu smo ugotavljali zaznavo lastnosti arome in všečnost šestih različnih vzorcev kostanjevega medu slovenskega izvora s skupino 60 mladih potrošnikov. Preskuševalci so opisali vonj in aromo vzorcev kostanjevega medu s kvalitativno opisno metodo »Označi vse, kar ustreza« (CATA) in določili všečnost senzoričnih lastnosti (vonja, arome, sladkosti in grenkobe) na 7-točkovni in skupno všečnost na 9-točkovni hedonski lestvici. Določili smo še nekatere osnovne fizikalno-kemijske parametre povezane s senzorično značilnostjo oziroma kakovostjo medu, kot so vsebnost vode, električno prevodnost, vrednost pH ter parametre barve v sistemu CIE (L*, a*, b*). Dobljene podatke smo obdelali s statističnimi metodami in tako določili opisne statistike analiziranih parametrov. Pomembne senzorične značilnosti kostanjevega medu so močno intenziven vonj in aroma po kostanjevem cvetju, karamelu, in srednje do močno intenziven grenek okus. Izražene značilnosti vzorca se odražajo v višji oceni strokovnega panela, vendar pa to ne pomeni nujno tudi visoke hedonske ocene potrošnikov. Najvišjo hedonsko oceno sta dobila vzorca K2 in K8, ki sta imela šibko do srednje intenziven vonj in aromo ter srednje sladek in nežno grenek okus (metoda CATA). Najnižjo oceno všečnosti sta dobila vzorca K4 in K5, ki sta za senzorično kakovost prejela največ točk strokovnega panela. Zanju so potrošniki z metodo CATA najpogosteje navedli, da imata srednje intenziven oziroma intenziven vonj in aromo ter nežno oziroma srednje sladek in močno grenek okus. Opisnik arome »po karamelu« je v vseh vzorcih medu zaznalo 47 % in več potrošnikov. In the thesis we were checking the perception of aroma properties and the liking of six different samples of chestnut honey of Slovenian origin, with a panel of 60 young consumers. The assessors described the odor and aroma of samples with qualitative descriptive method »Check all that apply « (CATA) and determined the liking of sensory properties (odor, aroma, sweetness and bitterness) on a 7-point and overall liking on a 9-point hedonic scale. We have also determined some of the basic physico-chemical parameters associated with sensory characteristics or quality of the honey, like water content, electrical conductivity, pH value and color parameters in the CIE system (L*, a*, b*). The obtained data were processed by statistical methods and thus determined descriptive statistics of the analyzed parameters. The important sensory characteristics of chestnut honey are intense odor and aroma of chestnut flowers, caramel, and medium to intense bitter taste. The expressed characteristics of the sample are reflected in a higher rating of the expert panel, but this does not necessarily mean a high hedonic score from the consumers. The highest hedonic scores were given to the samples K2 and K8, which had a weak to medium intense odor and aroma, and a medium sweet and slightly bitter taste (CATA method). The lowest scores of liking received samples K4 and K5, which om the other hand received the highest number of points for the sensory quality from the expert panel. For these two samples consumers most often indicated, with the CATA method, a medium intense or intense odor and aroma, and a slightly or medium sweet and strongly bitter taste. The "caramel" aroma descriptor was checked by 47% and more consumers in all samples of honey.

Med je naravna sladka snov, ki jo čebele predelajo iz medičine ali mane z dodajanjem izločkov. Zaradi povečane bakterijske odpornosti proti antibiotikom in vedno boljšega poznavanja sestavin medu in njihovih interakcij, narašča potencial medu v boju proti boleznim povzročenih s strani bakterij. Ker ima med poznano protimikrobno in protiadhezivno aktivnost, smo predpostavili, da bi med lahko zaviral tvorbo biofilma v ustni votlini in tako preprečil naselitev in razrast patogenih bakterij in z njimi povezanih bolezni ustne votline. Proučevali smo vpliv kostanjevega medu na adhezijo bakterij vrste Streptococcus cristatus na zobno površino. Optimizirali smo metodiko določanja bakterijske adhezije na zobni površini (čiščenje zobnih površin pred bakterijsko adhezijo, način izpostavitve zobne površine bakterijam). Z optimizirano metodo smo ugotovili, da kostanjev med ni imel vpliva na adhezijo bakterij vrste Strept. cristatus na zobno površino. Da bi protiadhezivno aktivnost medu na zobni površini lahko podrobneje okarakterizirali, bi morali preizkusiti več koncentracij kostanjevega medu, spremljati kemijske lastnosti kostanjevega medu in ovrednotiti zobne površine ter pri vseh analizah uporabiti večje število le-teh. Honey is a natural sweet substance, which is produced by honey bees from nectar or honeydew by the addition of their own secretions. Due to the increased bacterial resistance to antibiotics and the increasing knowledge of honey's ingredients and their interactions, the potential of honey in the fight against bacterial-borne diseases is increasing. Since honey's antimicrobial and antiadhesive activity is well known, it has been assumed that honey will act as inhibitor in biofilm formation in oral cavity, thereby preventing attachment and spread of pathogenic bacteria and related diseases of oral cavity. We studied the impact of chestnut honey on Streptococcus cristatus adhesion on dental surface. We have optimized method for quantification of bacterial adhesion on dental surface (cleaning of tooth surfaces prior adhesion, the way of dental surface exposure to bacteria). Using the optimized method, we found that chestnut honey had no effect on Strept. cristatus adhesion to dental surface. In order to further characterize the antiadhesive activity of the honey on dental surface, several concentrations of chestnut honey should be tested, the chemical properties of chestnut honey should be analysed, dental surfaces should be evaluated and a greater number of them should be used in all analyses.