Cabbage cooking, aroma

The impact of MOX upon reductive aromas is being exanained in a further research project at the University of Auckland, using SPME GC-MS (Nguyen et ah, 2010). The wines subject to MOX, or stored in an 02-permeable Flextank, recorded lower concentrations of compoimds such as methanethiol (aroma of cooked cabbage, with a perception threshold of 0.3 pg/L Mestres et al., 2000), and 3-(methylthio)-l-propanol... 

Sensory properties were presented in the same publication. The aroma strength of this mercaptan is very far from that of prenyl mercaptan (Q.10) which is also formed under roasting conditions. The pure substance has a sweet, soup-like odor, which is perceived as cooked meat and spicy when diluted in water to ca 0.1 ppm. Odor and taste thresholds, 2-6 and 8-10 ppb respectively, are relatively high compared to those of Q.10 and Q.20. The use of this alcohol and of its formate (see below) for artificial aromatizing of various foods has been patented (DE Patent 23.16465, 1973). At a concentration of 0.1 ppm it is characterized by a meaty, sulfury, skunky, cabbage flavor (Chemisis, 1999). 

Methanethiol (MeSH) is one of the simplest sulfur compounds and plays a decisive role in reduction defects related to wine aromas (Ribereau-Gayon et al., 2006b). The perception threshold of methanethiol in a hydroalcoholic solution is just 0.3 ig/L (ppb) and the compound can generate an odour reminiscent of cooked cabbage (Mestres et al., 2000). 

Like the acquisition of a taste for bitter or sour foods, a taste for foods with what would seem at first to be an unpleasant aroma or flavour can also be acquired. Here things become more complex - a pleasant smell to one person may be repulsive to another. Some people enjoy the smell of cooked cabbage and sprouts, whereas others can hardly bear to be in the same room. The durian fruit is a highly prized delicacy in South-East Asia, yet to the uninitiated it smells of sewage or faeces — hardly an appetizing aroma. 

The components of cooked cauUflower Brassica oleracea var. botrytis) and broccoH B. 0 var. italica) aroma are similar to the aroma components of cabbage. Another important compound is the aldehyde nonanaL The typical odour of cauliflower comes from 3-(methylthio)propyl isothiocyanate (8-192), which is produced from glucosinolate glucoibervirin. The typical odour of broccoli is also due to the presence of 3-(methylsulfinyl)propyl isothiocyanate (8-193), which develops from glucosinolate glucoiberin. 

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