Beverages, Volume 2, Issue 4 (December 2016) – 14 articles

Whisk(e)y is a major global distilled spirit beverage. Whiskies are produced from cereal starches that are saccharified, fermented and distilled prior to spirit maturation. The strain of Saccharomyces cerevisiae employed in whisky fermentations is crucially important not only in terms of ethanol yields, but also for production of minor yeast metabolites which collectively contribute to development of spirit flavour and aroma characteristics. Distillers must therefore pay very careful attention to the strain of yeast exploited to ensure consistency of fermentation performance and spirit congener profiles. In the Scotch whisky industry, initiatives to address sustainability issues facing the industry (for example, reduced energy and water usage) have resulted in a growing awareness regarding criteria for selecting new distilling yeasts with improved efficiency. For example, there is now a desire for Scotch whisky distilling yeasts to perform under more challenging conditions such as high gravity wort fermentations. This article highlights the important roles of S. cerevisiae strains in whisky production (with particular emphasis on Scotch) and describes key fermentation performance attributes sought in distiller’s yeast, such as high alcohol yields, stress tolerance and desirable congener profiles. We hope that the information herein will be useful for whisky producers and yeast suppliers in selecting new distilling strains of S. cerevisiae, and for the scientific community to stimulate further research in this area. Full article

This study aimed to evaluate the blueberry and carrot juice blend as a fermentable substrate for Lactobacillus reuteri LR92, in order to develop a fermented non-dairy functional beverage. Analysis of cell viability, pH, and acidity were performed during the fermentation process. The resistance of the microorganism in the blend, under simulated gastrointestinal conditions and in storage at 4 °C for 28 days, was evaluated at the same time as the antioxidant potential of the fermented juice. After 40 h of fermentation, the L. reuteri population presented a logarithmic growth of three cycles, reaching count records of 10.26 ± 0.23 log CFU/mL and after 28 days of storage at 4 °C, the bacterial population maintained elevated numbers of viable cell (8.96 ± 0.08 log CFU/mL), with increase in the antioxidant capacity of the fermented blend. However, in the test of gastric simulation, the L. reuteri population had a logarithmic reduction of five cycles. In the presence of bile salts, the viability was maintained even after 150 min of incubation. This way, the results suggested that the blueberry and carrot blend juice can be considered as a good medium for the growth of L. reuteri, providing microbiological stability during refrigerated storage with elevated antioxidant capacity, which allows for the development of a non-dairy probiotic beverage. Full article

A perfectly balanced wine can be said to create a symphony in the mouth. To achieve the sublime, both in wine and music, requires imagination and skilled orchestration of artistic craftmanship. For wine, inventiveness starts in the vineyard. Similar to a composer of music, the grapegrower produces grapes through a multitude of specifications to achieve a quality result. Different Vitis vinifera grape varieties allow the creation of wine of different genres. Akin to a conductor of music, the winemaker decides what genre to create and considers resources required to realise the grape’s potential. A primary consideration is the yeast: whether to inoculate the grape juice or leave it ‘wild’; whether to inoculate with a specific strain of Saccharomyces or a combination of Saccharomyces strains; or whether to proceed with a non-Saccharomyces species? Whilst the various Saccharomyces and non-Saccharomyces yeasts perform their role during fermentation, the performance is not over until the ‘fat lady’ (S. cerevisiae) has sung (i.e., the grape sugar has been fermented to specified dryness and alcoholic fermentation is complete). Is the wine harmonious or discordant? Will the consumer demand an encore and make a repeat purchase? Understanding consumer needs lets winemakers orchestrate different symphonies (i.e., wine styles) using single- or multi-species ferments. Some consumers will choose the sounds of a philharmonic orchestra comprising a great range of diverse instrumentalists (as is the case with wine created from spontaneous fermentation); some will prefer to listen to a smaller ensemble (analogous to wine produced by a selected group of non-Saccharomyces and Saccharomyces yeast); and others will favour the well-known and reliable superstar soprano (i.e., S. cerevisiae). But what if a digital music synthesizer—such as a synthetic yeast—becomes available that can produce any music genre with the purest of sounds by the touch of a few buttons? Will synthesisers spoil the character of the music and lead to the loss of the much-lauded romantic mystique? Or will music synthesisers support composers and conductors to create novel compositions and even higher quality performances that will thrill audiences? This article explores these and other relevant questions in the context of winemaking and the role that yeast and its genomics play in the betterment of wine quality. Full article

The production of the Ivorian sorghum beer known as tchapalo remains more or less an empirical process. The use of starter cultures was therefore suggested as the appropriate approach to alleviate the problems of variations in organoleptic quality and microbiological stability. In this study, we evaluated the capacity of S. cerevisiae and C. tropicalis to produce sorghum beer as freeze-dried starter in mixed or pure cultures. Beers produced with mixed freeze-dried cultures of S. cerevisiae F12-7 and C. tropicalis C0-7 showed residual sugars and ethanol contents similar to beers obtained with S. cerevisiae F12-7 pure culture, but the total sum of organic acids analyzed was the highest with the mixed culture (15.71 g/L). Higher alcohols were quantitatively the largest group of volatile compounds detected in beers. Among these compounds, 2-phenyl ethanol, a higher alcohol that plays an important role in beer flavor, was highly produced with the mixed culture (10,174.8 µg/L) than with the pure culture (8749.9 µg/L). Full article

The characteristic flavour and aroma of any beer is, in large part, determined by the yeast strain employed and the wort composition. In addition, properties such as flocculation, wort fermentation ability (including the uptake of wort sugars, amino acids, and peptides), ethanol and osmotic pressure tolerance together with oxygen requirements have a critical impact on fermentation performance. Yeast management between fermentations is also a critical brewing parameter. Brewer’s yeasts are mostly part of the genus Saccharomyces. Ale yeasts belong to the species Saccharomyces cerevisiae and lager yeasts to the species Saccharomyces pastorianus. The latter is an interspecies hybrid between S. cerevisiae and Saccharomyces eubayanus. Brewer’s yeast strains are facultative anaerobes—they are able to grow in the presence or absence of oxygen and this ability supports their property as an important industrial microorganism. This article covers important aspects of Saccharomyces molecular biology, physiology, and metabolism that is involved in wort fermentation and beer production. Full article

Mangiferin is present in various parts of Mangifera indica L. and has proven biological activities, such as antioxidant capabilities. The aim of this work was to evaluate the chemical composition of teas prepared from M. indica leaves, their potential use as a source of mangiferin and their total phenolic compounds. Teas were prepared with young and mature leaves of M. indica at three (medicinal plant: solvent) ratios utilizing three different preparation techniques. The mangiferin content was analyzed via high-performance liquid chromatography (HPLC). The tea with the highest mangiferin content was characterized for its total phenolic content and antioxidant activity. The oxidative stability was also evaluated by quantifying mangiferin, total phenolics and antioxidant activity using two preservation treatments for 0, 24 and 48 h. Sensory analysis was performed to measure the acceptance of the tea. The type of leaf, preparation technique and concentration influenced the mangiferin content in the teas. The highest concentration of mangiferin was obtained through decoction at a 5% (w/v) medicinal plant concentration. This tea exhibited stability up to 48 h after preparation under both preservation treatments and provided a positive sensory acceptance for consumers with flavors added. In conclusion, teas made from M. indica leaves have great potential as sources of mangiferin and phenolic compounds. Full article

Consumer wine preferences are not well understood. Anecdotally it is believed that preferences evolve over time, from sweet whites to full-bodied reds, as consumers become more experienced and familiar with wine. However, little is known about the change in wine preference or confidence with education and training. This research explored changes in consumers’ hedonic and confidence ratings for five commercial British Columbian (BC) wines (Ehrenfelser, Chardonnay, rosé, Pinot noir, Cabernet-Merlot) over a 12-week education/training period. Consumers (n = 133) completed a wine survey and evaluated the wines during the first and twelfth week of a university wine course, consisting of wine education and sensory training. Consumers provided hedonic (degree-of-liking) and confidence (degree-of-sureness) ratings for the visual, aroma and flavor characteristics of the wines, on 9-point and 5-point scales, respectively, before and after the 12-week wine course. Consumers were classified by gender (female, male), age and ethnicity. Kruskal Wallis, Mann-Whitney, Friedman, Wilcoxon Signed Rank and Chi-square tests and Spearman correlation coefficients were used to explore the effects of education/training on hedonic and confidence ratings. In general, consumers’ hedonic (visual, aroma, flavor) ratings increased significantly with education/training for the white and rosé wines (Ehrenfelser, Chardonnay, rosé) over the 12-week period. In contrast, consumer confidence increased substantially for all wine types. Surveys revealed, for the three largest subgroups of consumers (North American (NA), n = 38; European (EU), n = 31; Asian, n = 54), that NA and EU consumers had significantly higher frequency-of-purchase, frequency-of-purchase of Canadian wine, frequency-of-consumption and self-rated wine knowledge than Asian consumers. However, Asian consumers were willing to pay more for a bottle of wine compared to NA and EU consumers. This research provided insight into the millennial consumers and explored the nature and magnitude of changes in hedonic and confidence ratings with wine education/training. Full article

We report two experiments designed to assess the key sensory drivers underlying people’s association of a specific auditory pitch with Belgian beer. In particular, we assessed if people would rely mostly on the differences between beers in terms of their relative alcohol strength, or on the contrast between the most salient taste attributes of the different beers. In Experiment 1, the participants rated three bitter beers (differing in alcohol content), using a narrow range of pitch choices (50–500 Hz). The results revealed that the beers were all rated around the same pitch (Mean = 232 Hz, SD = 136 Hz). In Experiment 2, a wider range of pitch choices (50–1500 Hz), along with the addition of a much sweeter beer, revealed that people mostly tend to match beers with bitter-range profiles at significantly lower pitch ranges when compared to the average pitch of a much sweeter beer. These results therefore demonstrate that clear differences in taste attributes lead to distinctly different matches in terms of pitch. Having demonstrated the robustness of the basic crossmodal matching, future research should aim to uncover the basis for such matches and better understand the perceptual effects of matching/non-matching tones on the multisensory drinking experience. Full article

Alcoholic beverages are produced following the fermentation of sugars by yeasts, mainly (but not exclusively) strains of the species, Saccharomyces cerevisiae. The sugary starting materials may emanate from cereal starches (which require enzymatic pre-hydrolysis) in the case of beers and whiskies, sucrose-rich plants (molasses or sugar juice from sugarcane) in the case of rums, or from fruits (which do not require pre-hydrolysis) in the case of wines and brandies. In the presence of sugars, together with other essential nutrients such as amino acids, minerals and vitamins, S. cerevisiae will conduct fermentative metabolism to ethanol and carbon dioxide (as the primary fermentation metabolites) as the cells strive to make energy and regenerate the coenzyme NAD⁺ under anaerobic conditions. Yeasts will also produce numerous secondary metabolites which act as important beverage flavour congeners, including higher alcohols, esters, carbonyls and sulphur compounds. These are very important in dictating the final flavour and aroma characteristics of beverages such as beer and wine, but also in distilled beverages such as whisky, rum and brandy. Therefore, yeasts are of vital importance in providing the alcohol content and the sensory profiles of such beverages. This Introductory Chapter reviews, in general, the growth, physiology and metabolism of S. cerevisiae in alcoholic beverage fermentations. Full article

Consumers’ food quality perception and sensorial experience are important in food consumption behavior and food choice. Red fruit juices are appreciated fruit juices for almost all consumers, due to their flavor and intense red color. Studies have also shown that their phytochemical composition, which is associated with their antioxidant activity, shows a protective effect against many chronic diseases. Nevertheless, the profile and concentration of anthocyanins are different in function of the fruit used; therefore, the color and health benefits of the juices also show differences. Some red fruit juices have lower concentrations of anthocyanins, for example strawberry, and others have higher concentrations, such as elderberry and black currant juices. High correlation was observed between antioxidant activity and red fruit juices’ total anthocyanins concentration. Therefore, this review will addresses red fruit juices phenolic composition, with a special focus on the challenges for future, and some ideas on the sensory impact. Full article

Cachaça is a sugar cane spirit produced in Brazil. Ethyl carbamate (EC), a potential carcinogenic compound, may be present in cachaça above the limit established by law. The purpose of this study was to determine the concentration of ethyl carbamate in cachaças recently produced in Brazil in order to verify their compliance with the law. The concentration of ethyl carbamate was determined in 376 samples of cachaça through gas chromatography coupled to a mass spectrometer (GC-MS). The mean value of ethyl carbamate in the cachaças analyzed was 145 µg/L, and 24% of them were not in compliancy with the law (EC < 210 µg/L). However, compared to previous studies, advances have been observed regarding the adjustment of cachaças to the legal limit. Cachaças produced in large distilleries through continuous column distillation presented a mean value of 200 µg/L of ethyl carbamate. Cachaças produced in small distilleries using pot still distillation presented a mean content of 74 µg/L. Small producers have been more engaged in using good manufacturing practices to guarantee the quality of cachaças. Full article

Probiotic features and the ability of two oenological lactic acid bacteria strains (Pediococcus pentosaceus CIAL‐86 and Lactobacillus plantarum CIAL‐121) and a reference probiotic strain (Lactobacillus plantarum CLC 17) to metabolize wine polyphenols are examined. After summarizing previous results regarding their resistance to lysozyme, gastric juice and bile salts, the three strains were assessed for their ability to release phenolic metabolites after their incubation with a wine phenolic extract. Neither of the two bacteria were able to metabolize wine polyphenols, at least in the conditions used in this study, although a certain stimulatory effect on bacterial growth was observed in the presence of a wine‐derived phenolic metabolite (i.e., 3,4‐dihydroxyphenylacetic acid) and a wine phenolic compound (i.e., (+) ‐catechin). Bacteria cell‐free supernatants from the three strains delayed and inhibited almost completely the growth of the pathogen E. coli CIAL‐153, probably due to the presence of organic acids derived from the bacterial metabolism of carbohydrates. Lastly, the three strains showed a high percentage of adhesion to intestinal cells, and pre‐incubation of Caco‐2 cells with bacteria strains prior to the addition of E. coli CIAL‐153 produced a notable inhibition of the adhesion of E. coli to the intestinal cells. Full article

It is not uncommon for research and quality control samples, including carbonated beverage samples, to be refrigerated or frozen during peak periods of production and/or sampling, when analytical demand exceeds instrumental capacity. However, the effect of sub‐ambient temperatures on carbonated beverage composition during storage has not been well characterized. Mid‐infrared (MIR) spectroscopy combined with principal component analysis (PCA) and traditional chemical analyses were used to evaluate the effects of refrigeration (for 1 week) and freezing (for 1 or 6 weeks) on the composition of carbonated beverages, including sparkling water, sparkling wine, beer, and cider. Carbonated beverages were generally resistant to changes in pH, titratable acidity, alcohol, total phenolics, sugar, and color, during short‐term (1 week) storage. However, long‐term (6 week) freezing resulted in decreased total phenolics, with acidity also affected, albeit to a lesser extent. MIR spectroscopy combined with PCA enabled discrimination of carbonated beverages based on composition, with alcohol content having a significant influence. Examination of the MIR ‘fingerprint’ region indicated subtle compositional changes occurred in carbonated beverages following prolonged freezing. Full article

People often say that beer tastes better from a bottle than from a can. However, one can ask how reliable this perceived difference is across consumers. And, if reliable, one can further ask whether it is a purely psychological phenomenon (associated with the influence of packaging on taste perception), or whether instead it reflects some more mundane physico-chemical interaction between the packaging material (or packing procedure/process) and the contents. Two experiments were conducted in order to address these questions. In the main experiment, 151 participants at the 2016 Edinburgh Science Festival were served a special ‘craft beer’ in a plastic cup. The beer was either poured from a bottle or can (a between-participants experimental design was used). The participants were encouraged to pick up the packaging in order to inspect the label before tasting the beer. The participants rated the perceived taste, quality, and freshness of the beer, as well as their likelihood of purchase, and estimated the price. All of the beer came from the same batch (specifically a Session IPA from Barney’s Brewery in Edinburgh). None of the participants were familiar with this particular craft brew. Nevertheless, those who evaluated the beer from the bottle rated it as tasting better than those who rated the beer served from the can. Having demonstrated such a perceptual difference (in terms of taste), we then went on to investigate whether people would prefer one packaging format over the other when the beer from bottle and can was served blind to a new group of participants (i.e., when the participants did not know the packaging material). The participants in this control study (n = 29) were asked which beer they preferred. Alternatively, they could state that the two samples tasted the same. No sign of a consistent preference was obtained under such blind tasting conditions. Explanations for the psychological impact of the packaging format, in terms of differences in packaging weight (between tin and glass), and/or prior associations of quality with specific packaging materials/formats (what some have chosen to call ‘image molds’), are discussed. Full article