Methanol and Major Volatile Compounds of Turkish Raki and Effect of Distillate Source

Abstract

Turkish Raki is the traditional anise flavoured distillate beverage produced mainly from a grape distillate called suma. Two types of Raki are produced in Turkey according to the distillate source. They are Type I — a fresh grape Raki produced only from suma and Type II — a Raki produced from a blended distillate of suma and alcohol of agricultural origin (mainly molasses). In this study the content of ethanol, methanol, distillate based major volatile compounds (aldehydes, esters, higher alcohols), aniseed based anethole and estragole, volatile acid and sugar values in two types of commercial Raki samples (40 samples) was determined and the effect of distillate source on the composition was examined. The distillate and the aniseed based major compounds of the Raki samples were analysed by direct injection with a GC‐MS‐FID according to the European Commission Reference Method. The results of variance analysis and PCA showed that there was a significant difference between the two types of Raki samples. Total volatiles (esters and higher alcohols), methanol, trans‐anethole, estragole and sugar values were higher in the samples made from suma alone. All of the analysed component levels of the Turkish Raki samples were in compliance with Turkish Distilled Beverage Regulations. The methanol levels ranged between 28.00–50.87 g/hL absolute alcohol (AA) in Type I samples and 22.03–41.06 g/hL AA in Type II samples. Distillate based total volatiles levels ranged between 136.12–147.88 g/hL AA, with a mean value of 142.88 g/hL AA, in Type I samples and 102.44–113.45 g/hL, with a mean value of 107.9 g/hL, in the Type II samples. The anise based compound trans‐anethole levels were significantly higher in the Type I samples (1,298–1,570 mg/L) than in the Type II samples (1,014–1,199 mg/L). According to distillate based volatiles, the Turkish Raki has a valuable content of volatile substances compared to other anise flavoured spirits.

Differentiation of Turkish Rakies through Headspace Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry Analysis

“…This may be attributable to the aniseed used for raki production, since the volatile composition of aniseed can change significantly amongst species 9 . Furthermore, in our previous work the aforementioned compounds were not observed, probably due to the direct injection of raki samples, which favours the detection of major volatile compounds 1 . A large part of the volatiles in raki samples are derived from aniseed 9 , except for some fermentative origin esters, such as ethyl octanoate and ethyl decanoate.…”

“…Suma is a distillate containing ca. 94.5% (v/v) alcohol originating from fermented fresh grapes or raisins 1 . Two types of raki are predominantly produced in Turkey, according to the distillate source for the second distillation; the raki produced from only suma and the raki produced from suma and agricultural originated ethyl alcohol 12 .…”

“…Little data is available on the volatile components of Turkish rakies 1,5,11,12 . Yavaş and Rapp 11 identified more than 80 volatile compounds in different raki brands from organic extracts obtained by liquid-liquid extraction.…”

Comparison of fermentation results and quality of the agricultural distillates obtained by application of commercial amylolytic preparations and cereal malts

“…This compound is produced in the process of hydrolysis of pectins by specific pectolytic enzymes, and in particular pectin methylesterase [72]. While methanol does not directly affect the flavor of the distillate, it is subjected to restrictive controls owing to its high toxicity [73]. Nevertheless, due to the fact that methanol arises as a result of de-esterification of pectins, which are naturally present in fruits, its presence at limited concentrations in fruit-derived distillates proves the identity of those products [74].…”

Characterization of Aroma Profile of Bogma, Traditional Homemade Turkish Spirit††

“…However, when used in Turkish raki, the most resembling spirit to Bogma, HS-SPME revealed the presence of 43 compounds, which were mainly composed of etheric oils from aniseed together with fermentation products (Anli et al, 2007;Yılmaztekin et al, 2011). It is concluded that the main source of volatile compounds are aniseed, fermentation, distillation and maturation (Erten and Canbaş, 2003;Cabaroglu and Yilmaztekin, 2011;Yılmaztekin et al, 2011).…”