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Title:Physicochemical and aroma characterization of Arbutus pavarii honey
Author(s):Hwisa, Nagiat Tayeb
Director of Research:Cadwallader, Keith R
Doctoral Committee Chair(s):Engeseth, Nicki J
Doctoral Committee Member(s):Pepino, Marta Yanina; Padua, Graciela W
Department / Program:Food Science & Human Nutrition
Discipline:Food Science & Human Nutrition
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Arbutus pavarii
honey
aroma
volatile compounds
norisoprenoids.
Abstract:Arbutus pavarii honey is a unique rare honey characterized by its bitter taste. It is produced by Apis mellifera bees from the nectar of the wild strawberry, Arbutus pavarii pamp., tree. Arbutus pavarii tree is an endemic, rare plant, native to the green mountain area located in the eastern part of Libya. This plant is endangered and vulnerable to extinction. Literature review showed that there is a scarcity of research on this honey. The few published studies demonstrated that it has antioxidant and antibacterial activity. Furthermore, there is a lack of research on the aroma composition of this honey. This research represents first to investigate the aroma characteristics of Arbutus pavarii honey. Three Arbutus pavarii samples obtained from local beekeepers in Derna city, harvested in 2015, 2016 and 2017, were analyzed in this research. The three samples were first subjected to melissopalynologics screening and investigated for their physicochemical characteristics. The physicochemical parameters investigated in this work showed agreement with previously published studies and satisfied the international standards, except for hydroxymethylfurfural (HMF) content of the two older samples which is justified by aging or possible thermal processing of these honeys. Pollen study revealed that melissopalynological analysis is not a reliable method and may not be useful to assess authenticity and to verify its botanical source. Volatile components of A. pavarii honey were isolated by continuous liquid-liquid extraction followed by solvent-assisted flavor evaporation (CLLE/SAFE) and by headspace-solid phase microextraction (HS-SPME). The volatile aroma components were identified by gas chromatography olfactometry (GC-O) and gas chromatography mass spectrometry (GC-MS) analytical methods and confirmed by authentic standards. The potent odorants of the honey were determined by aroma extract dilution analysis (AEDA) of the CLLE-SAFE extract using GC-O. Concentrations of certain selected volatile constituents were estimated by application of SIDA-HS-SPME-GC-(TOF)MS. The results indicated that A. pavarii honey has a complex matrix loaded with many volatile compounds; however, only some of its volatile components were detected as odor active. The predominant aroma components of this honey were norisoprenoids which explain its saffron-like odor, and the most important odorant that makes the major contribution to the overall aroma of this honey was 2-hydroxy-4,4,6-trimethylcyclohexa-2,5-dienone (lanierone) followed by 2-hydroxyisophorone and β-damascenone. Several other aroma components were found to impact the aroma of A. pavarii honey. These belong to diverse chemical classes such as acids, alcohols, aldehydes, esters, ketones, terpenes, etc. Both qualitative and quantitative analysis of A. pavarii honey ranked lanierone as the top odorant of this honey. Sensory analysis of the honey by sensory descriptive aroma profiling also ranked the saffron-like aroma as the predominant aroma attribute of this honey. This research provides a comprehensive characterization of aroma components of Arbutus pavarii honey which could be used as floral markers for verification of the botanical source of the honey nectar and a platform for useful authentication criteria.
Issue Date:2021-04-23
Type:Thesis
URI:http://hdl.handle.net/2142/110848
Rights Information:NA
Date Available in IDEALS:2021-09-17
Date Deposited:2021-05


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