Analysis and Formation of Key Sulfur Aroma Compounds in Wine

Abstract

Identification and measurement of sulfur aroma compounds to better describe wine quality and style has been of significant importance to researchers and wine producers for many years. This necessarily requires the development of analytical methods to robustly quantify labile sulfur compounds at trace concentrations. With the ever-growing importance of screwcaps and other alternatives to cork closures, additional focus is on characterizing and minimizing 'reduced characters' during bottle storage. There is also a need to better understand the roles of must composition, yeast nutrients, yeast sulfur metabolism and copper fining in controlling sulfur aroma compounds. This paper explores how static headspace GC analysis of volatile sulfur compounds with cool-on-column injection and SCD detection has been optimized and applied for studies requiring direct analysis of fermentation-derived sulfur aroma compounds, such as H 2 S, DMS, CS 2 and methanethiol.

Development of stable isotope dilution assays for the quantitation of the food odorants hydrogen sulphide, methanethiol, ethanethiol, and propane-1-thiol and application to durian (Durio zibethinus L.) pulp

“…In particular, hydrogen sulphide occurs in a wide variety of foods [1] and exhibits a characteristic smell usually referred to as rotten egg-like [1][2][3][4][5][6][7] and an odour detection threshold of 10 µg/L [8]. In food, hydrogen sulphide may be formed either enzymatically or thermally from cysteine or cysteine-containing peptides.…”

“…The thermal formation of hydrogen sulphide from cysteine follows the Strecker degradation path [14][15][16][17]. Yeast metabolism is another source of hydrogen sulphide in fermented foods such as beer [18] or wine [4,5], where it is held responsible for specific offflavours. Though, particularly in higher amounts, hydrogen sulphide is often detrimental to food flavours [5], in small amounts it is known to contribute to the characteristic aroma of foods such as eggs [7], fish [3], and chicken meat [19,20].…”

“…Methanethiol is also a very common food volatile [1,21] and described as having a rotten and cabbage-like smell [5,6,22,23]. With 0.59 µg/L its odour detection threshold in water is even lower than that of hydrogen sulphide [8].…”

“…In some foods, e.g. wine [2,5], it adds to off-flavours and in high amounts it may indicate microbial food spoilage [11,12].…”

“…Ethanethiol and propane-1-thiol show pronounced rotten odours, with some reminiscence of onions [1,5,6]. Their odour thresholds in water amount to 0.095 µg/L (ethanethiol) and 0.49 µg/L (propane-1-thiol), respectively [8].…”