Chemical and sensory profiles of makgeolli, Korean commercial rice wine, from descriptive, chemical, and volatile compound analyses Heeyong Jung a , Seung-Joo Lee b , Jeong Ho Lim a , Bum Keun Kim a , Kee Jai Park a,⇑ a Korea Food Research Institute, 1201-62 Anyangpangyo-ro, Songnam-si, Gyeonggi-do 463-746, Republic of Korea b Department of Culinary and Food Service Management, Sejong University, Seoul 143-747, Republic of Korea article info Article history: Received 6 March 2013 Received in revised form 16 October 2013 Accepted 23 November 2013 Available online 7 December 2013 Keywords: Makgeolli Rice wine Volatile SPME GC–MS Sensory analysis abstract The chemical and sensory profiles of 12 commercial samples of makgeolli, a Korean rice wine, were deter- mined using descriptive sensory, chemical, and volatile components analyses. The sample wines were analysed for their titratable acidity, ethanol content, pH, Hunter colour value and total reducing sugars. The chemical compositions of the makgeolli samples were found to be significantly different. The volatile compounds were extracted with solid-phase microextraction and analysed by gas chromatography time- of-flight mass spectrometry. In all, 45 major volatile compounds, consisting of 33 esters, 8 alcohols, 1 aldehyde, 1 acid, 1 phenol and 1 terpene, were identified; each makgeolli sample included 28–35 volatile compounds. Based on principal component analysis of the sensory data, samples RW1, RW2, RW5, RW8 and RW12 were associated with roasted cereal, mouldy, bubbles, sweet and sour attributes; the other samples were associated with sensory attributes of yellowness, yeast, full body, turbidity, continuation, swallow, alcohol, fruit aroma and whiteness. Ó 2014 Published by Elsevier Ltd. 1. Introduction Makgeolli is a traditional Korean rice wine that has been con- sumed by Koreans for many centuries. The wine is also known by historical names such as takju, dongdongju, and nongju. Tradi- tionally, makgeolli is brewed by fermenting nuruk (the source of the microorganism) by using yeast in a 2-step process involving saccharification and alcohol fermentation. The raw material rice is prepared by washing and soaking for 1–3 h, followed by steam- ing and cooling down of the steamed rice to room temperature. After cooling, the rice is thoroughly mixed with nuruk and yeast, and water is added for the parallel processes of saccharification and alcohol fermentation. Nuruk is a traditional starter culture made from wheat or grits, which allows the growth of various nat- ural types of microorganisms such as fungi, yeast and lactic acid bacteria that saccharify the rice starch during fermentation (Kim et al., 2011). Moreover, several microorganisms from nuruk remain alive in the final products after bottling and during distribution. Makgeolli is also considered to have health benefits, because it con- tains various ingredients such as proteins, sugars, vitamins, bioac- tive compounds and organic acids (Jeong, Nam, Lee, & Lee, 2011; Kim, Kim, Bae, & Ahn, 2010). The wine is characterised by flavours of bitterness, sourness, sweetness, saltiness and umami (a savoury taste) (Lee, 1986). Furthermore, makgeolli has distinctive characteristics owing to its astringency, pungency, and full body, in addition to its unusual taste that results from the live yeast still present during fermentation and distribution (Lee, Kim, & Lee, 2009). The addition of various wild-type yeasts and raw materials dur- ing fermentation was found to affect the chemical characteristics and volatile compounds profiles in the Korean traditional rice wine yakju, which is similar to makgeolli (Kim, Kim, Bae, & Ahn, 2010). Among the volatile compounds produced, short- and long-chain esters were affected, depending on the yeast strains present. The types of yeast strains from nuruk and the degrees of milling of the rice greatly affected the chemical and volatile compounds of the glutinous rice wines (Kim et al., 2010). An increase in the de- gree of milling decreases the alcohol, amino acid and organic acid contents, but increases the soluble solids, degree of colour, ultravi- olet absorbance and reducing sugar and free sugar contents. Recently, solid-phase microextraction (SPME), especially head- space (HS)-SPME sampling, has been widely used for the analysis of the volatile compounds in foods and beverages such as fruit juice beverage, vegetable oils, beers, wines and coffees because of its ease of use and sensitivity (Jung & Ebeler, 2003; Song, Gardner, Holland, & Beaudry, 1997). Furthermore, the combination of gas chromatog- raphy and time-of-flight mass spectrometry (GC–TOF/MS) can shorten the quantitative and qualitative analyses time, in addition to providing full mass spectra with a mass accuracy above 0.002 Da, even at very low sample concentrations (Song et al., 1997). The studies on makgeolli were weighted towards the enhance- ment of the fermentation process associated with microorganisms, by varying the addition of raw materials. Sensory evaluations of 0308-8146/$ - see front matter Ó 2014 Published by Elsevier Ltd. http://dx.doi.org/10.1016/j.foodchem.2013.11.127 ⇑ Corresponding author. Tel.: +82 31 780 9157; fax: +82 31 780 9343. E-mail addresses: jake@kfri.re.kr, jake68@naver.com (K.J. Park). Food Chemistry 152 (2014) 624–632 Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem