Effect of triple pot still distillation on the volatile compositions during the Rakı production

Abstract

Rakı is a traditional alcoholic spirit that distills from grapes/raisins distillate so‐called suma with aniseed (Pimpinella anisum) in the copper pot still distillers. During distillation, middle‐cut fractions are separated and used for Rakı productions. Lately, triple pot still distillations as a new process is also used for production. In this study, effect of distillation numbers on volatile compounds of middle‐cut fraction during the Rakı production was investigated. Minor volatiles were extracted with liquid–liquid extraction method and analyzed with GC‐MS/FID. Major volatiles were analyzed by direct injection with GC‐FID. Odor‐active compounds are also identified by GC‐O technique. While the number of distillations increased, the amount of volatiles from aniseed and suma decreased and the amount of higher alcohols, esters, and aldehydes of middle‐cut fractions are decreased. The highest amount of volatiles based on aniseed are determined as trans‐anethole, estragole, cis‐anethole, and γ‐himachalene. Odor‐active compounds were identified as anethole, estragole, linalool, ethyl‐2‐methyl‐butanote, γ‐himachalene, and p‐anisaldehyde. Practical applications Rakı is produced by distillation of “suma (grape distillate)” with aniseed (Pimpinella anisum) in traditional copper distillers (pot still) having volume of 5.000 liters. Suma is the distillate originating from grapes/raisin that is distilled up to 94.5% v/v alcohol by column still distillation with the purpose of keeping the flavor and smell of grapes. Rakı is a reach product in term of volatile compounds coming from grape distillate and aniseed. Despite of simple (traditional) pot still distillations, triple pot still distillations as a new process is also used in order to improve the quality for Rakı production. While the number of distillations increased, the amount of esters, terpenes, and aldehydes and volatile phenols are decreased. Off‐flavors coming from suma as like pungent, woody, fishy smells are separated with increasing the number of the distillations. So perceptions of odor‐active compounds that is desired become more powerful in triple distillation.

Sensory Lexicon and Major Volatiles of Rakı Using Descriptive Analysis and GC-FID/MS

“…The volatile components in Rakı determine the sensations of flavour and aroma experienced by the consumer. The general composition and volatile components of Rakı have been reported in previous studies [ 5 , 7 , 8 ]. These studies showed that Rakı is a rich product in terms of volatile compounds, and its aroma can be assigned to two different origins: Suma (grape distillate) and aniseed ( Pimpinella anisum L.).…”

“…Our results show that the addition of head and tail and agricultural ethyl alcohol reduced the number of aroma attributes and aroma consistency in Rakı samples. It has been reported in previous studies that Rakı is very rich in volatile compounds (propenylphenols, terpenes, higher alcohols, esters, carbonyl compounds), as identified by GC-MS, and that these compounds mostly come from aniseed ( Pimpinella anisum L.) and suma [ 5 , 7 , 8 , 42 ]. Darıcı et al [ 8 ] reported 51 identified aroma compounds and 19 odour active compounds in Rakı, and found that anethole, estragole, linalool, ethyl-2-methyl-butanote, gamma-himachalene, and p-anisaldehyde were the main contributors to the aroma of Rakı.…”

“…As major compounds, acetal, 2-methylbutan-1-ol (active amyl alcohol), 3-methylbutan-1-ol (isoamyl alcohol), methanol, ethyl acetate, butan-1-ol (n-butanol), butan-2-ol (secbutanol), 2-methylpropan-1-ol (isobutyl alcohol), propan-1-ol (n-propanol) and acetaldehyde were determined. GC-FID/MS condition, column, identification and validation parameters of the method were previously reported in detail by Darıcı, Bergama and Cabaroglu [ 8 ]. The GC equipment used was an Agilent 6890N, with FID.…”

“…Then 1 µL of the above mixture was injected into the GC. GC-FID/MS condition, column and identification and validation parameters of the method have previously been reported in detail by Darıcı, Bergama and Cabaroglu [ 8 ]. The GC equipment and the column were the same as described above.…”

“…The expert group came for eighteen sessions over five weeks in the sensory room. In the first five sessions, as a training period, the assessors smelled and tasted the prepared references that were considered to be related to the product flavour on the basis of previous research [ 5 , 7 , 8 , 20 , 21 ]. After the training sessions with the references, the formal panel took place over thirteen sessions, in which the Rakı samples were served.…”