Repository logo
 

Understanding the Marketability of Korean Rice Wine (Makgeolli) in New Zealand Using Sensory and Physicochemical Methods

Files

Thesis(2.95 MB)

Date

2025

Authors

Supervisor

Kam, Rothman
Phillips, Megan

Item type

Thesis

Degree name

Doctor of Philosophy

Journal Title

Journal ISSN

Volume Title

Publisher

Auckland University of Technology

Abstract

Physicochemical and sensory information is critical to understanding the physical properties of food products. When this information is not available, then it would be difficult to establish a market opportunity for the food product as manufacturers and researchers cannot predict whether the food product will be accepted or rejected from the marketplace. In this thesis, physicochemical principles and sensory evaluations were used to understand the properties of makgeolli and their different processing methods. Makgeolli is a traditional rice alcoholic beverage that originated in Korea. Four methods of preparing makgeolli were investigated in this thesis, as their material e.g., fermentation starter (nuruk, traditional Korean fermentation starter), rice (either glutinous rice and/or non-glutinous rice) and time of fermentation varied. Interestingly, makgeolli uses simultaneous saccharification and fermentation for the brewing process meaning starch hydrolysis and alcoholic fermentation occur concurrently within the same vessel. The four methods of producing makgeolli include (1) single-stage simultaneous saccharification and fermentation of glutinous rice with nuruk – a Korean starter culture (1SF-N), single-stage fermentation with nuruk and yeast (1SF-YN), two-stage fermentation (2SF) and three-stage fermentation (3SF). Study 1, physicochemical properties such as alcohol content, pH, colour, mineral content, proximate composition, antioxidant activity, total phenolic content, sugar, free amino acid, and organic acid profile were used to examine the four different makgeolli processing methods. Results indicate 1SF-N makgeolli sample had the highest alcohol, crude protein, antioxidant activity, total phenolic and free amino acids content while the 2SF makgeolli sample had the highest concentration of glucose and maltose. In addition to chemical analysis, sensory evaluation using polarised projective mapping (PPM) with sweetness (using sucrose), sourness (using citric acid), and bitterness (using quinine) as references or ‘poles’ that participants can compare the makgeolli samples against when placing the makgeolli samples on the A3 piece of paper. Although 1SF-N makgeolli sample had the most physicochemical features such as high concentrations of antioxidants, total phenolic content and free amino acids, it was the least liked makgeolli sample. In comparison, 2SF makgeolli sample was the most overall liked likely due to the higher sugar content compared to the other makgeolli samples. In study 2, chemical analysis using solid-phase microextraction coupled with gas chromatography-mass spectrometry (SPME-GC-MS) to identify the different volatile compounds present in the four makgeolli samples. In total, 45 volatile compounds were identified and the majority of compounds found of interest in the makgeolli samples were esters (25 compounds) and alcohol (10 compounds). Principle component analysis (PCA) was employed to determine the interactions of volatile compounds in the makgeolli samples. In terms of volatile compounds that are well represented in the PCA graph, limonene (citrus-like flavour), ethyl pentanoate, and hexanal (green/grass-like flavour) contributed the most for Dimension 1. For Dimension 2 on the PCA graph, 2-ethoxy-2-methyl-propane, 2-methyl-1-propanol, and isobutyl acetate were the three highest volatile compounds that contributed the most. Two sensory experiments were carried out simultaneously using Check-All-That-Apply (CATA) and Just-About-Right (JAR) were also included in this study. One hundred and twenty-nine participants (n = 68 female participants) took part in the study. Twenty terms were used for CATA, and among the 20 terms, 14 terms reached statistical significance between the four makgeolli samples. For JAR, seven attributes were evaluated and a high proportion of participants indicated that sourness was too much in three of the four makgeolli samples. In study 3, product categorisation of makgeolli was investigated and characterised among beer and wine samples. Two separate sensory studies were conducted with projective mapping with ultra-flash profiling (PM with UFP) completed first then polarised sensory positioning (PSP). A collective total of 159 participants took part in the study with 68 participants in PM with UFP and 91 in PSP. Previous research indicates that makgeolli shared similar traits to semi-sweet white or rose wine, however, results from both sensory experiments indicate makgeolli had unique sensory traits and attributes, therefore, makgeolli should be categorised or marketed differently. In study 4, two sensory experiments were conducted to understand how the environment affects the participant’s attitudes, behaviour, and perception while consuming makgeolli in New Zealand. Experiment 1 (n = 60) was carried out in a laboratory setting using the evoked context method to simulate a context scenario while Experiment 2 (n = 113) was carried out in physical environments including a laboratory, an Asian restaurant, and participant’s home. Both experiments indicate that context appropriateness was an important factor while consuming the makgeolli beverage and different context scenarios or physical environments did not change participant’s overall liking of makgeolli. In summary, context appropriateness may be an important factor to consider in the consumer’s decision-making process and should be considered as part of hedonic testing or acceptance testing on food products. Overall, this thesis provides insightful information regarding to physicochemical and sensory information on the different processing methods of makgeolli. In terms of the practicality of the research, manufacturers and researchers have basic physicochemical information about the different makgeolli samples. Further experimentation should be considered such as shelf-life and packaging, and additional research on microbial diversity and growth would be beneficial. For sensory analysis and evaluation, makgeolli was examined in different environments which provides a comprehensive view into how makgeolli is perceived among participants (e.g., home, laboratory, and restaurant environments). Considering the current economic environment and consumer behaviour changes, large-scale production and commercialisation of makgeolli in New Zealand is not advisable.

Description

Keywords

Source

DOI

Publisher's version

Rights statement

Permanent link

http://hdl.handle.net/10292/19264

Collections

Doctoral Theses