The analysis of raw spirits – a review of methodology

Agricultural distillates (raw spirits) are alcoholic liquids obtained through distillation (preceded by alcoholic fermentation) of specific agricultural products that do not have the properties of ethyl alcohol or a spirit, but still retain the aroma and taste of the raw ingredients used. This review is a brief overview of agricultural distillates and of some methods commonly used (GC‐MS, GC‐FID, GC‐O, electronic nose) for performing quality assessments and for determining the composition and botanical origins of the raw spirits. Copyright © 2016 The Institute of Brewing & Distilling     

The impact of treatment of cereal mashes with hydrolases of non‐starch polysaccharides and pullulanase on the chemical composition of the obtained distillates

The distilling industry has been looking for more efficient technologies for spirit production. The pressureless starch liberation method (PLS) is an energy‐saving alternative to high‐pressure treatment of starch raw materials. Also, one of the promising solutions is the use of supportive enzymatic preparations during the mashing of starch raw materials. Rye and corn mashes obtained by the PLS method were treated with enzymes (pullulanase, xylanase, cellulases and cellobiase). The composition of volatile compounds in the distillates of the fermentation mashes was determined. Acetaldehyde was the dominant aliphatic carbonyl compound found in the raw distillates. Rye‐based fermentation distillates contained small amounts of propionaldehyde, isobutyraldehyde and isovaleraldehyde, which were not found in any of the corn distillates. The treatment of mashes with cellulolytic preparations caused an increase in the methanol content of the obtained distillates. All of the mashes treated with auxiliary enzymes yielded raw distillates with much higher levels of higher alcohols. The application of hydrolases of non‐starch polysaccharides, or pullulanase preparations, during the mashing of the starch raw materials affects the chemical composition of the distillates. Xylanase and pullulanase can be used in the processing of rye and corn mashes for subsequent use in distilled ethanol beverage production. Copyright © 2014 The Institute of Brewing & Distilling     

The nutritive value for ruminants of thin stillage and distillers' grains derived from wheat,rye, triticale and barley

A study was conducted to determine nutrient degradabilities of thin stillages and distillers' grains derived from wheat‐, rye‐, triticale‐ and barley‐based ethanol production. In vitro protein degradabilities of wheat, rye, triticale and barley thin stillages were determined using a protease enzyme assay. One ruminally fistulated cow was used to determine ruminal nutrient degradabilities for wheat, rye, triticale and barley distillers' grains. Results of the in vitro study showed that the soluble protein fraction was highest for rye thin stillage and lowest for barley thin stillage. The degradation rate of the slowly degradable protein fraction was higher for wheat and triticale thin stillage than rye thin stillage and was higher for rye than barley thin stillage. Effective degradability of crude protein followed the order rye (659 g kg⁻¹) > triticale (632 g kg⁻¹) > wheat (608 g kg⁻¹) > barley (482 g kg⁻¹) thin stillage. Ruminal degradability of dry matter was highest for rye and lowest for barley distillers' grains. Ruminal degradability of dry matter was also higher for wheat than triticale distillers' grains. Crude protein from barley distillers' grains had a lower ruminal degradability relative to crude protein from wheat and rye distillers' grains. Ruminal degradability of neutral detergent fibre was highest for rye distillers' grains (470 g kg⁻¹), intermediate for wheat and triticale distillers' grains (average 445 g kg⁻¹) and lowest for barley distillers' grains (342 g kg⁻¹). It was concluded that thin stillage and distillers' grains derived from barley had a lower nutritive value for ruminants compared with those derived from wheat, rye and triticale. © 2000 Society of Chemical Industry     

Differentiation of raw spirits of rye, corn and potato using chromatographic profiles of volatile compounds

BACKGROUND: The origin of the raw spirits influences the sensory quality of rectified spirits that are subsequently used for the production of vodka. The aim of this research was to evaluate the effectiveness of two methods based on the comparison of profiles of volatile compounds [solid phase microextraction–gas chromatography–mass spectrometry (SPME‐GC‐MS) and gas chromatography with flame ionisation detection (GC‐FID)] for the determination of origin of raw spirits obtained from rye, corn (maize) and potato. RESULTS: Profiles obtained for the volatile compounds by using these methods were different and were influenced by the sample introduction method. The main groups of volatiles obtained using SPME‐GC‐MS method were fatty acid ethyl esters, while in the case of GC‐FID fusel alcohols and ethyl acetate dominated. Data obtained from these methods were treated using principal component analysis and linear discriminant analysis to test the possibility of sample differentiation and classification. It was relatively easy to differentiate potato spirits from the remainder; however, it was not possible to fully distinguish the corn samples from rye samples. The classification ability of the SPME‐GC‐MS method was 95% but the prediction ability was 97.4%. For the GC‐FID method the classification ability was 90.1%, whereas the prediction ability was 94.27%. CONCLUSIONS: The methods presented can be used for reliable differentiation of potato spirits from corn and rye spirits. Copyright © 2012 Society of Chemical Industry     

Volatile metabolites in various cereal grains

To date, studies on volatile metabolites in cereal grain have focused mainly on a single species. In this paper, results are presented of the analysis of volatile compounds in five cereal grain species (spring wheat, durum wheat, triticale, rye, oats and barley) based on representative sampling of at least 15 cultivars of individual species. Profiles of volatile compounds were determined using solid phase microextraction (SPME) and GC–TOF (time of flight mass spectrometry). Many of the volatile compounds were only present in single samples; however, several dozen were found in over 50% of samples and 46 volatiles were found in all samples. Among them there were six alcohols, 10 aldehydes and ketones, six terpenes, seven hydrocarbons and 11 benzene derivatives. The highest concentrations of these compounds were found in durum wheat, while the lowest were observed in triticale and rye.     

Difference in volatile composition between the pericarp tissue and inner tissue of tomato (Solanum lycopersicum) fruit

Numerous studies have reported the volatile profiles in the whole fruit or pericarp tissue of tomato (Solanum lycopersicum) fruit; however, information is limited on the volatile composition in the inner tissue and its contribution to tomato aroma. For this, the pericarps and inner tissues of “Moneymaker,” “UglyRipe,” and “FL 47” fruits were separated before volatile analysis. Result showed that the volatile profiles were quite similar between the pericarp and inner tissue, suggesting the inner tissues also have a contribution to overall aroma quality. Besides the difference in volatile profile among cultivars, a higher concentration of alcohols was observed in the inner tissues of tomato fruit in comparison with that in the pericarp, which was associated with higher levels of 3‐methylbutanal, 2‐methylbutanal, 3‐methylbutanol, and 2‐methylbutanol in the inner tissue. These results also imply that different sampling methods might impact tomato aroma quality, which needs further verification via sensory penal.

Practical applications

The information on the volatile profile in the inner tissue and its contribution to tomato aroma is still rudimentary. In this study, the pericarp and inner tissue were separated from three tomato cultivars of different genetic background, and the volatile compositions were analyzed with HS‐SPME‐GC‐MS. Result showed that the volatile compositions were quite similar between the pericarp and inner tissue, suggesting that the inner tissues also have a contribution to overall aroma quality. Besides, a higher concentration of alcohols was observed in the inner tissues of tomato fruit in comparison with that in the pericarp, which was associated with higher levels of 3‐methylbutanal, 2‐methylbutanal, 3‐methylbutanol, and 2‐methylbutanol in the inner tissue. This study will provide the researchers and consumers some useful information on volatile composition in the inner tissue, its contribution to tomato aroma, and the impact of different sampling methods on the volatile profile.     

Use of wheat,triticale and rye flours in layer cake production

In this study, the capacity of obtaining high quality layer cakes from rye and triticale lines was analysed and compared to wheat lines. The samples were characterised considering grain hardness, flour composition and quality parameters as protein, pentosan, damaged starch, pasting viscosity and functional predictive test – solvent retention capacity test. Cakes were analysed in weight, symmetry, volume, volume index (VI) by measuring the height in different points of the cake, crust and crumb colour, crumb structure and texture. Wheat and triticale cakes showed similar characteristics. Rye cakes showed higher volume and lower weight than those with crumbs darker in colour, higher adhesiveness, springiness and resilience. The multiple regression analysis was used to develop an equation for cake volume index prediction. The best‐fit linear regression model was: VI = 14.75 – 0.14 × protein + 0.93 × water soluble pentosan – 0.27 × total pentosan. Despite the differences, high quality cakes can be elaborated with rye, triticale and soft wheat cultivars.     

TRI12 based quantitative real-time PCR assays reveal the distribution of trichothecene genotypes of F. graminearum and F. culmorum isolates in Danish small grain cereals

Quantitative real-time PCR assays, based on polymorphisms in the TRI12 gene of the trichothecene pathway, were developed to identify and quantify the trichothecene genotypes producing 3-acetyl-deoxynivalenol (3ADON), 15-acetyl-deoxynivalenol (15ADON) or nivalenol (NIV) in the Fusarium graminearum species complex, Fusarium culmorum, Fusarium cerealis and Fusarium pseudograminearum. These assays were applied on a total of 378 field samples of cereal grain of wheat, barley, triticale, rye and oats collected from 2003 to 2007 to study the trichothecene genotype composition in Danish cereals. The three genotypes, 3ADON, 15ADON and NIV were found in all five cereal species, great annual variation in the occurrence of the trichothecene genotypes was evident with considerable variation between the samples. 3ADON was the dominant genotype in barley, triticale, rye and oats while 15ADON was most dominant in wheat. The NIV genotype was found at low levels in most samples. Study of genotype composition within the Danish F. graminearum and F. culmorum population was based on principal component analysis (PCA). PCA revealed that the dominating genotype of F. graminearum in wheat is 15ADON. For barley, the PCA analysis indicated that the F. graminearum population consisted of all three genotypes, and in triticale, the F. graminearum population consisted mainly of 15ADON genotype. F. culmorum/F. cerealis showed correlation to the NIV genotype in wheat and triticale but not in barley. F. culmorum/F. cerealis also showed some correlation to 3ADON especially in wheat and triticale. Selected wheat and barley samples from 1957 to 2000 showed low amounts of F. graminearum and F. culmorum in general but with a dominance of the 3ADON genotype. 15ADON was not detected in these samples, except for very low amounts in the sample representing the years from 1997 to 2000. Detection of low amounts of the 15ADON genotype in these historical samples and the relatively high amounts of 15ADON genotype in 2003 and following years correspond well with the occurrence of F. graminearum and indicates that the 15ADON genotype was introduced along with F. graminearum around 2000. The amounts of the 3ADON and 15ADON genotypes correlated well with the total amount of DON whereas the amounts of NIV genotype correlated well with the amount of NIV in wheat and triticale but not in barley where the results indicate that Fusarium poae may also contribute to the NIV content.     

Identification of Volatile Compounds in Raw Spirits of Different Organoleptic Quality

The main purpose of the research was to determine the composition of the volatile fraction of raw spirits, as well as isolation of the aroma profiles for spirits differing in their sensory properties. Profiles were created using a headspace solid‐phase microextraction (HS‐SPME) and capillary gas chromatography‐mass spectrometry technique (GC‐MS). The results indicated the presence of over 200 compounds, of which significant numbers were identified. The most significant groups included esters, higher alcohols, aldehydes, acetals, as well as furans, sulphur compounds, terpenoids and benzene derivatives. Among the above‐mentioned compounds, over 50 were identified whose presence or high content could decrease the quality of the distillates. In particular, this pertains to higher quantities of compounds such as acetals and certain esters, as well as the two compounds, dimethyl trisulphide and geosmin. Aside from the dependence between volatile composition and the sensory quality, differences between distillates originating from different distilleries were observed.     

Characterisation of odour‐active compounds in papaya (Carica papaya L.) wine

The volatile compounds of papaya wine were isolated by continuous solvent extraction and analysed by gas chromatography‐flame ionization detector and gas chromatography‐mass spectrometry. A total of 118 volatile constituents were detected, and ninety‐seven were positively identified. The composition of papaya wine included fifty‐three esters, twenty‐two alcohols, nine acids, seven phenols and derivatives, seven sulphur compounds, five lactones, five terpenes, three ketones, two aldehydes and five miscellaneous compounds. The aroma‐active areas in the gas chromatogram were screened by application of the aroma extract dilution analysis and by odour activity values. Six odorants were considered as odour‐active volatiles: ethyl octanoate, (E)‐β‐damascenone, 3‐methylbutyl acetate, benzyl isohtiocyanate; ethyl hexanoate and ethyl butanoate.     

PHOSPHORUS AND PHOSPHATE LEVELS IN THE ALEURONE CELLS OF CEREAL GRAINS

The aleurone cells of barley, wheat, rice, rye, oats and triticale contained, comparatively, higher percentages of phosphorus than the aleurone cells of sorghum, maize or millet. The aleurone tissues of barley, wheat and rice had more phosphate than corresponding tissues of sorghum and maize. Phosphate was not detected in the aleurone tissue of maize but was found in trace amounts in the aleurone tissue of sorghum.     

Phytic acid concentration in selected raw materials and analysis of its hydrolysis rate with the use of microbial phytases during the mashing process

Phytic acid present in the raw materials can complex with many compounds and therefore limit their availability to the yeast during the alcoholic fermentation process. An effective utilization of biogenic compounds bound in phytates requires a detailed analysis of the raw materials for their phytic acid content. The aim of this study was to characterize the major technological parameters for selected raw materials used in the distilling industry (maize, rye, wheat and triticale grain) and to determine the phytic acid content and the IP6/total phosphorus ratio. The phytic acid hydrolysis rate during the mashing process, with the use of microbial phytases, was analysed. The highest phytic acid concentrations (2.30 ± 0.20 mg/g dry matter) and the highest IP6/total P (80.42 ± 6.99%) were observed in the maize grain samples. Therefore, further studies on the phytic acid hydrolysis rate with the use of various phytases were conducted for the maize grain. The highest hydrolytic activity was observed for the Phytase 10000L preparation. This was the preparation that hydrolysed the phytic acid completely in up to 90 min. The application of a highly effective phytase, in ethanol production from maize grain, could lead to a more effective utilization of the biogenic compounds during the fermentation process. Copyright © 2015 The Institute of Brewing & Distilling     

Cell wall composition of 1B/1R translocation wheat grains

The cell wall composition and total dietary fibre content of 12 different winter wheat cultivars both without and with 1B/1R gene were analysed. Translocation wheat (with 1B/1R gene) had higher contents of extractable xylose and unextractable mannose residues than standard wheat (without 1B/1R gene). Three sieved flours of standard wheat, translocation wheat and rye respectively were used for further detailed studies. Water‐extractable arabinoxylan was isolated and fractionated on a DEAE‐cellulose column. The water‐eluted fraction of translocation wheat had a higher proportion of monosubstituted xylose residues than the same fraction of standard wheat, which is a typical feature of rye arabinoxylan. Molecular weight determination showed that rye water‐eluted arabinoxylans were larger than those of wheat. The molecular weight of translocation wheat arabinoxylan was lower than that of standard wheat and had a high polydispersity. Xylanase‐resistant arabinoxylan was extracted from all three flours, and NMR studies showed that wheat xylanase‐resistant arabinoxylan had a lower amount of monosubstituted xylose residues, while the rye fraction was rich in consecutive disubstituted xylose residues. Translocation wheat xylanase‐resistant arabinoxylan resembled that of standard wheat. © 2002 Society of Chemical Industry     

Population growth of the khapra beetle,Trogoderma granarium Everts (Coleoptera: Dermestidae) on different commodities

We evaluated the population growth of the khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) on different grains, cracked wheat containment categories and amylaceous materials by conducting three series of laboratory bioassays. In the first series, peeled barley, whole (raw) barley, peeled oats, whole (raw) oats, peeled rice, rough rice, rye, triticale and hard wheat were tested. In the second series, six cracked wheat containment categories were tested: wheat containing intact kernels only (0% cracked kernels), wheat containing 5% cracked kernels and 95% intact kernels, wheat containing 10% cracked kernels and 90% intact kernels, wheat containing 25% cracked kernels and 75% intact kernels, wheat containing 50% cracked kernels and 50% intact kernels and wheat containing 100% cracked kernels. In the third series, the following amylaceous commodities were tested: hard wheat (intact kernels), whole oat flakes, maize flour, whole barley flour, pasta, white soft wheat flour, whole soft wheat flour, white hard wheat flour, whole hard wheat flour, whole rye flour and semolina. Significantly more dead adults were found on wheat than on peeled barley, maize, whole oats, rough rice and rye. Significantly more larvae alive were found on wheat and triticale, than on the other grains, with the exception of oats, both whole and peeled. The increase of the percentage of cracked wheat kernels increased population growth, except in the case of 10% cracked wheat kernels. In vials that contained 100% cracked wheat kernels, 584.1 individuals per vial were found, which was 3.7 times more than the respective number of larvae alive in vials with intact wheat kernels only. Significantly more dead adults were found on whole barley flour than on the other commodities. More than 1213 larvae per vial were recorded on whole barley flour, which was 1.3–15 times higher than the other commodities. The lowest number of larvae alive was found on pasta, followed by the white soft wheat flour. The findings of the present work show that some commodities are more prone to spread T. granarium than others, a fact which should be seriously taken into account in international trade of grains and related amylaceous products.     

The changes of the yield,composition and nutritive value of leaf protein extracted from vetch and cereal mixtures during three years cultivation

Three mixtures of vetch with cereals (rye, triticale and wheat) were grown during three consecutive seasons 1985/86, 1986/87 and 1987/88 and leaf protein concentrates (LPC) were prepared using the standard method. LPC were analysed for their gross composition and amino acid content. True digestibility (TD) and biological value (BV) of LPC proteins were estimated on rats using the Thomas-Mitchell balance method. There were no statistical differences in green matter and dry matter yield in the course of the whole experiment. However, in the first season (1986) the yield of vetch × rye mixture was apparently higher and that of the other two mixtures was lower than in the next two years. The protein content of LPC in 1986 was lowest, especially in the concentrates obtained from the triticale and wheat mixtures. There were only small differences in amino acid composition of proteins and these differences did not depend on the year of cultivation or species of cereal used. BV of protein extracted from the rye-containing mixtures was always lower than that of other preparations (means of three years: rye 40, triticale 46, wheat 49). Protein extracted in 1987 had the highest BV. It can be concluded that the season of cultivation affects the green and dry matter yield of legume x cereal mixtures though these differences are levelled off during long-term experiments. The LPC quality is affected both by the kind of cereal and year of cultivation.     

Evaluation of mycotoxin-contaminated cereals for their use in animal feeds in Hungary

In the period between December 5, 1991 and September 17, 1998, 760 maize, 367 wheat, 119 soybean, 222 barley, 85 bran, 32 triticale, 60 oat, 14 rye and 22 sunflower samples were investigated for the presence and concentration of seven fusariotoxins (T-2 toxin, zearalenone, deoxynivalenol, nivalenol, diacetoxyscirpenol, HT-2 toxin, fusarenone-X) and OTA. The comparison of analytical data with those of the relevant literature revealed that although the incidence rate and/ or concentration of Fusarium mycotoxins and OTA in Hungarian-grown cereals is occasionally considerable, the position of the country is not worse than the average of countries. Our findings indicate that soybean tends to be good substrate for trichothecene-producing fungi and the rate of contamination is regarded as substantial. The commodities were assorted into one of three quality categories. The proportion of objectionable samples was only 3.0, 2.2, 2.3 and 1.7% in maize, wheat, barley and soybean samples, respectively. However, this low rate of objection might still be a source of great economic loss. The proportion of objectionable samples was much higher in the case of bran, oat and triticale (7.1, 6.7, and 6.3%, respectively). The results of the present investigation indicate a need for regular screening for mycotoxins of importance and individual appraisal of each commodity from the point of their use in animal feeds.     

Effect of starter cultures on the quality of Suan yu,a Chinese traditional fermented freshwater fish

The generation of volatile compounds of four starter cultures composed of isolated microorganisms from traditional Suan yu was investigated. The cultures included two pure starters (PS1: Lactobacillus plantarum 120 and PS2: Pediococcus pentosaceus 220) and two mixed starters (MS1: L. plantarum 120, Staphylococcus xylosus 135 and Saccharomyces cerevisiae 31 at 1:1:1; MS2: P. pentosaceus 220, S. xylosus 135 and S. cerevisiae 31 at 1:1:1). Naturally fermented Suan yu was used as control. The volatile compounds were collected from the headspace of the samples by Solid‐phase microextraction and analysed by gas chromatography–mass spectrometry. The type and total content of volatile compounds in the mixed‐starter‐fermented fish were higher than those of the pure‐starter‐fermented samples and control. A total of seventy nine and eighty volatile compounds were detected in Suan yu fermented with MS1 and MS2, respectively, with ethanol as the predominant compound and hexanal, ethyl acetate, 3‐methylbutanol, 3‐hydroxy‐2‐butanone, hexanoic acid ethyl ester and 2,3‐butanedione as the other compounds. Furthermore, the sensorial acceptance of the different products with mixed starter cultures seemed to improve the quality of Suan yu products.     

Chemical Markers for Tracking the Sensory Contribution of Production Stages in Muscat Wine Distillates

The main sensory contribution of each post‐fermentation production stage of muscat wine distillates can be tracked by following the concentration of just 1 corresponding chemical marker. Matching sample clusters of sensory and chemical data by using principal components analysis (PCA) revealed potential chemical markers. The data used in this study correspond to 12 sensory attributes that showed significant differences among products (P < 0.05) and concentrations of 23 volatile compounds of 14 distillate fractions and 15 finished Piscos. Artificial fruit attribute, characteristic of the head fraction (FR1) can be tracked with esters. Linalool, main odor attribute of the 1st part of the heart (FR2) can be tracked with linalool molecule. The 2nd part of the heart (FR3) can be tracked with octanoic acid, decanoic acid, furfural and ethyl lactate, accounting for tails attribute. In blended and aged finished products, chemical markers accounting for the effects of distillate fractions were similar but not identical to the markers from samples obtained from the purely distilled samples. Chemical markers for FR1 are ethyl hexanoate, ethyl octanoate, ethyl decanoate. Differentiation between FR1 and FR2 is less evident than in the purely distilled samples due to the linalool and artificial fruit attribute correlation. Chemical markers for FR2, therefore, include linalool and esters ethyl hexanoate, ethyl octanoate, and ethyl decanoate. The blending of the 2nd part of the heart (FR3) can be tracked with 2‐phenylethanol, ethyl lactate, and decanoic acid. Oak aging was tracked with eugenol and whisky lactones, while 5‐hydroxy‐methyl‐2‐furfural accounted for added caramel.     

Fractional extraction of cereal flour proteins

Wheat (Wichita), rye, barley, oat and maize flours were successively extracted with 0.04 m sodium chloride solution (3 × ), water (3 × ), 70% ethanol (3 ×) and 0.1 N acetic acid. The fractions and residues were analysed for nitrogen and subjected to starch-gel electrophoresis. Saline extractions chiefly removed the albumins and globulins of all five cereals. The prolamins of wheat, rye and barley appeared mostly in the three aqueous extracts but also, particularly, those of very low mobility, occurred in the alcoholic solutions. The acetic acid-soluble fractions of wheat, rye and barley were shown by electrophoresis under reducing conditions to be crosslinked by S.S bonds; those of rye and barley showed some characteristic differences from glutenin. Oats and maize were practically devoid of this fraction. Most of the protein of oats and maize was insoluble. Electrophoresis patterns after reduction were obtained from insoluble fractions, though there were differences among the genera. Both overall protein solubility and the quantity of the acetic acid-soluble fraction were correlated with baking quality. The presence of covalent crosslinks other than S.S in glutelin fractions is suspected.