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05
Mai
Date Maio 5, 2019
Categories Drinks Research, Food & Drinks, Innovation

YEASTories and BACTheories 3: Kombucha, the rising star of fermented beverages

Kombuchawhaaat? If you have never heard about this beverage, do not be afraid! The pronunciation is easier than it looks and it is tastier than it sounds! Kombucha is a beverage that results from the fermentation of black or green tea leaves and cane sugar with several bacterial and yeast species – a Symbiotic Culture Of Bacteria and Yeast (SCOBY). Kombucha is one of the rising stars in the revival of specialty fermented beverages that has been taking place in the market over the last recent years.

The rise of fermented beverages, both in variety and production volume, has been defined as one of the most important trends in 2019 within the food beverage sector. To give you a more objective picture, the global fermented beverages market is expected to increase steadily until 2023, reaching 935 billion euros (in 2015 it was valued at 600 billion euros). The beverage consumers and the millennials generation in particular have a high interest on experiencing novel and unusual flavors together with different textures and the fermentation process can strongly influence those characteristics.

What makes kombucha unique

But why is Kombucha so special within the large variety of fermented beverages? Kombucha is a low-sugar tea-based fermented beverage with considerable levels of organic acids, vitamins and polyphenols, known for their health benefits. By adding fruit, herbs or flavors into this mixture you get a quite unique and refreshing beverage that is, most often, sparkling and non-/low-alcoholic. Kombucha can have a drier and/or tarter character like the traditional ciders or the “Brett” beers and the production of alcohol can also be boosted by adjusting the fermentation conditions (if alcohol is higher than 4.5% it is referred as Hard Kombucha). The explosion of flavors present in Kombucha can be quite overwhelming in the start due to its high acidity but quite addictive afterwards. The definition of Kombucha is quite broad and there is a great variety of flavors and profiles in the market at the moment, going from soft-drink like beverages with low sugar and high drinkability to more dry and acidic beverages that can be in the direction of sour beers or dry cider.

Tea and sugar are two central ingredients for the production of kombucha

One of the best parts about Kombucha is that you can produce it at home with a very limited amount of kitchen gear, no fancy equipment being needed.

There are several dedicated websites with infographics and videos that can be very helpful before you do your first Kombucha brew, where more detailed explanations about the gear required as well as recipes and how to find and get the SCOBY. In a simplistic way, the production process of kombucha requires two fermentation steps:

  • Primary fermentation:the mixture of yeast and bacterial species converts the sugar into ethanol and organic acids. At the start of the process, oxygen is present (aerobic conditions), which promotes the cell division of the yeast species and later conversion of sugar into ethanol and carbon dioxide (CO2). The type and proportion of yeast species varies from SCOBY to SCOBY but Saccharomyces, Brettanomyces, Pichia and Hanseniaspora are some of the most common ones. When sugar is depleted, ethanol becomes the most abundant carbon source, which promotes the activity of the different bacterial species that will convert it into organic acids. Species belonging to the genus Acetobacter, Gluconobacter and Lactobacillus are the major responsible for the production of acetic acid, gluconic acid and glucuronic acid. Acetic acid, that gives vinegar aroma and taste, is normally the most abundant organic acid when the primary fermentation is finished. At the beginning of the process the SCOBY will be at the top of the flask and during the fermentation it starts to sink, forming a new SCOBY at the top. Thus, at the end of the primary fermentation you will have two SCOBYs that can be used for two new batches of Kombucha.
SCOBY – The Symbiotic Culture Of Bacteria and Yeast that is responsible for the formation of unique flavors and aromas in Kombucha (Image from BUCHI, www.buchi.com.au/)
  • Secondary fermentation: the Kombucha from the primary fermentation is filtered to remove the major particles and then flavored by adding fruit, juices, herbs, spices and/or others. The sugar addition from the flavoring step will promote the anaerobic fermentation of yeast, resulting in the formation of carbon dioxide (CO2) which naturally carbonates the final beverage. When this step is made directly in the bottle – bottle fermentation – it can be tricky since you need to calculate how much CO2 will be produced from the sugar added during flavoring. The first time you may get an over-carbonated beverage with too much fizz.

Even though there are many reports regarding the positive impact of Kombucha on the digestive system and gut health together with its action as anticarcinogenic, antihypertensive, antidiabetic, and hepatoprotective, it is important to note that currently, Kombucha cannot be granted with any official health claims. I believe that in a near future some concrete results from clinical studies will give a more accurate information regarding the active functionalities of Kombucha.

Kombucha flavoring step (image from ifoodreal, https:// ifoodreal.com/)

The Kombucha presence in the European market is still limited when comparing with the United States, where this fermented beverage can be found throughout the whole country. The implementation of Kombucha in Europe requires some more consumer education since it is a beverage with a unique and acquired taste, but it is clear that more and more people are becoming aware of its existence and benefits. Next time you see some Kombucha in a shop or pub, go for it and give it a try! Soon after there is a high chance that you will be planning your first brew of Kombucha at home.

Sources

https://www.globenewswire.com/news-release/2017/04/17/961353/0/en/Global-Fermented-Beverages-Market-2014-2016-2023-Launches-of-New-Products-are-Stimulating-the-Market-Growth.html
https://www.foodnavigator.com/Article/2018/05/04/There-is-a-mega-trend-around-fermentation-The-rising-star-of-fermented-foods
Coton, Monika, et al. “Unraveling microbial ecology of industrial-scale Kombucha fermentations by metabarcoding and culture-based methods.” FEMS microbiology ecology 93.5 (2017).
Professional Kombucha Brewers Workshop, Barcelona (2019).
Jayabalan, Rasu, et al. “A review on kombucha tea—microbiology, composition, fermentation, beneficial effects, toxicity, and tea fungus.” Comprehensive Reviews in Food Science and Food Safety 13.4 (2014): 538-550.
Dutta, Himjyoti, and Sanjib Kr Paul. “Kombucha Drink: Production, Quality, and Safety Aspects.” Production and Management of Beverages. Woodhead Publishing, 2019. 259-288.

CFER Labs is your partner in food and drinks R&D. Obtain your free of charge workplan by clicking here.

0 Comments Author Diogo Portugal-Nunes
03
Mar
Date Março 3, 2019
Categories Drinks Research

Grape maturation: more than just a change of colour

While Portugal is now seeing some signs of Spring with longer and warmer sunny days, Australia is well through Summer and with the 40 plus degree days behind us Autumn is just around the corner. In a wine production country this means that the busiest time of the year has arrived and it is vintage time! For us winemakers the long vintage days are the most exciting time of the year, when we finally get the grapes in the winery and eventually manage to turn them into (good) wine. But it is also one of the most critical stages of the whole winemaking process when the decision of what and when to harvest needs to be taken. In this review we will focus on what happen during the late stage of the grape development (maturation) and its relation with the harvest timing.

I work in the Clare Valley (Australia) mainly with ‘international varieties’, such as Riesling, Pinot Gris, Shiraz or Cabernet Sauvignon, which all grow in the same region and pretty much under the same conditions, but that ripen at different time in the season (in some cases up to 1-2 months apart). By the time that you read this article we should have harvested all our Pinot Gris but the Cabernet will be hanging on the vines for a few more weeks, so how do we decide what and when to pick?

The biological cycle of the grapevine is a set of physiological and biochemical changes triggered by temperature, sun exposure, hormones, water availability, etc, that starts early in the Spring with bud burst and finishes late in the Autumn with leaves fall, just before the vine goes through a period of dormancy during Winter.

What happens during each stage of the grapevine life cycle can potentially influence the quality of the wine, but it is the late stage of the berry development or maturation (ripening) that deserves more attention from a winemaking point of view.

Maturation is a growth phase that lasts from 35 to 55 days that follows the herbaceous growth and véraison and is characterized by some of the most noticeable changes in the grapes: pronounced berry growth, sugar accumulation, decrease of acidity/raise of pH and accumulation/changes in phenolic compounds and aromatic. We are able to look at these changes and use that information as a precious tool to predict maturity dates and establish the picking dates.

In the ripening stage the berries accumulate sugar and lower their organic acid concentration, with dramatic changes in the profile of the phenolic compounds and aromatics.

Sugars

The sugar content of the grapes is an important physiological parameter to access maturity and harvest timing as it defines the potential alcohol of the wine. During the herbaceous growth its concentration is similar to the leaves, but from véraison onwards there is a massive transport and accumulation of these carbohydrates in the berries. The sugar synthesis occurs in the leaves as a product of photosynthesis and migrates to the berries in the form of sucrose where it is hydrolyzed to glucose and fructose. The last two are the main sugars in grapes and as the season progresses their concentration gets to a point where they become the predominant total soluble solids in the juice, reason why sugar accumulation/ripening traceability is often based on density measurements (density, Baumé or Oechsle). It is not commonly used, but the glucose/fructose ratio can be a maturity indicative as it markedly decreases during the grape development until it remains almost constant at maturity (about 1:1).

White grapes generally ripen at lower sugar levels than red grapes and consequently the alcohol content of white wines is lower than reds once fermentation is completed by yeast (conversion rate of approximately 17g/L of glucose/fructose for 1% alcohol).

Acids and pH

Tartaric and malic acid are the two major acids present in grapes and responsible for the biggest fraction of the total acidity. The tartaric is rapidly accumulated in the berries during the herbaceous growth and remains almost constant during maturation; on the other hand, malic acid concentration declines during the ripening period and the ratio tartaric/malic varies drastically. The rate as the malic acid is metabolized depends on the variety and climate, but it is one of the main reasons why cool climate regions tend to deliver fruit with higher total acidity comparing to warmer regions. As the total acidity drops and some cations accumulate in the berries, the pH raises. The pH plays a crucial role in the microbiological and chemical stability of juice and wine it is also taken into account. At maturity the pH of white grapes is normally under 3.3 and 3.6 for the reds, and the total acidity between 5.0-8.0g/L of tartaric acid equivalents.

If you add a few drops of vinegar or lemon juice to your salads (acidification), this seasoning will make it taste better. The same could be thought for the importance of the acidity in wine. When in the balance, the acidity is the backbone of the wine, bringing brightness and freshness and lifting up other flavors.

Phenolic compounds and aromatic substances

The synthesis and accumulation of anthocyanins in the skins is the most visible expression of grape maturation in red grapes; behind the scenes, another phenols play a crucial role on the phenolic ripeness: the tannins. Tannins are present both in the skin and seeds and as season progresses they become less extractable and less astringent, more ‘round’ and pleasant. A potential good wine starts with a good assessment of the phenolic ripeness of the grapes, as it impacts the structure, mouthfeel, astringency, aromatics and ageing potential of the wine.

It is also during the maturation stage that the aromatic potential of the grapes develops and accumulates, mainly in the skins. These molecules can be free volatile aromatic compounds or non-aromatic precursors that will later be released by yeast during fermentation. Sometimes it may be hard to access the aromatic potential of the grapes at a given time, but we know how it can change during maturation. A good base wine for sparkling is produced with grapes harvested earlier in the season, not only to retain a higher natural acidity/low alcohol, but also because the aromatic profile is more neutral. Riesling or Touriga Nacional harvested later in the season originate wines with more floral expression.

Generalized graphical representation of grape berry compositional changes during development and ripening (from Watson, 2003)

The maturity point of the grapes is directly related to the style of the finished wine and can potentially limit its quality. Monitoring the parameters mentioned above as the grapes ripening progresses is a fundamental procedure to define a desired maturity point and decide the harvest date. Variety, soil, vineyard practices and growing conditions all influence the life cycle of the grapevine, so defining an exact maturation point is in reality difficult and quite subjective. However, if we can get the maturation to a point where all the parameters are in balance to a desired style then we are potentially in a good position to make a good wine!

CFER Labs is your partner in food and drinks R&D. Obtain your free of charge workplan by clicking here.

0 Comments Author Joel Santos
14
Fev
Date Fevereiro 14, 2019
Categories Drinks Research, Innovation

The antithesis of energetic drinks – a scientific review of relaxation and sleeping drinks

Energetic drinks are, without a question, one of the hottest topics in the food industry right now. However, in a time where a considerable fraction of the population shows stress symptoms, energy drinks might not be the answer your customer is looking for.

A relaxation drink is defined as a non-alcoholic beverage that contains calming ingredients. These drinks are growing in popularity and rely on the use of nutrients and herbs to reduce anxiety and promote relaxation. Sleeping drinks are also a growing trend in consumption, relying on slightly different natural components to induce the consumer a sensation of sleepiness and promoting a longer and more relaxed sleeping. Both types of drinks act by regulating a complex hormonal response in the consumer.

Stress, anxiety and sleep

Stress and anxiety are two major factors affecting the population. Stress is a condition arising from external physical or mental overload. It can make a person feel embattled, nervous, anxious or otherwise less capable of full and normal response to environmental demands.
Anxiety is a generalized mood of fear, worry and or uneasiness. It can be stimulated from environment factors, or result from bad habits or social situations. In developed countries, anxiety disorder rates range from 13.6% to 28.8% of the population. [1] The growing
urbanization, lack of exercise and stressful quotidian are bringing stress and anxiety to historical levels. Anxiety and stress may lead to insomnia, depression or even suicide.

Sleep plays a vital role in brain function and systemic physiology across many body systems. Problems with sleep are widely prevalent and include deficits in quantity and quality of sleep; sleep problems that impact the continuity of sleep are collectively referred to as sleep
disruptions. Disruption of sleep is widespread.

A 2014 survey conducted by the National Sleep Foundation reported that 35% of American adults rated their sleep quality as “poor” or “only fair”.

Trouble falling asleep at least one night per week was reported by 45% of respondents. In addition, 53% of respondents had trouble staying asleep on at least one night of the previous week, and 23% of respondents had trouble staying asleep on five or more nights. [2]

The hormonal regulation and possible ingredients for relaxation and improved sleep

Adaptogens are herbs that improve an individual’s ability to cope with stress and anxiety. These herbs normalize the physiological process of the body and help the body adapt to changes in times of increased stress, normally by reducing the serum cortisol levels, the stress hormone. A recent study discovered that Ashwagandha root extract safely improves an individual’s resistance towards stress and improves self-assessed quality of life by substantially lowering cortisol levels. [3] Other herbs, such as linden, hops or chamomille are also considered to be adaptogens in this regard. Chamomile is widely regarded as a mild tranquillizer and sleep inducer. Sedative effects may be due to the flavonoid apigenin that binds to benzodiazepine receptors in the brain. Studies in preclinical models have shown anticonvulsant and central
nervous system (CNS) depressant effects respectively. Clinical trials are notable for their absence, although 10 cardiac patients are reported to have immediately fallen into a deep sleep lasting for 90 minutes after drinking chamomile tea. [4]

According to American researchers [1], there are different types of anxiety that could be mild or sever depending on the level of the disorders. Using drugs is a common but harsh way to treat anxiety disorders. More natural treatments including amino acid, minerals, and fatty acids
ingestion can reduce anxiety and induce relaxation. Further, herbs and botanical medicine, such as St. John’s wort (Hypericum perforatum), Ginkgo biloba, Kava Kava, which have different roles to reduce many psychiatric disorders, also reduce anxiety.

In this regard, anxiety may be managed without the harsh side effects of pharmaceuticals using nutritional and botanical treatment as well as life-style changes.

Vitamins C, D, and E, omega-3 fatty acids, and the green tea amino acid L-theanine are dietary supplements known to increase the production of dopamine. Japanese researchers have found that the ingestion of 50 to 200mg of theanine promotes the generation of α-wavesin the brain some minutes after being ingested. α-waves have been studied as a relaxation index state in humans [5]. Theanine also lowers body temperature and blood pressure, two important factors in the relaxation process absent from drowsiness.

Drugs that alter serotonin levels are used in treating depression, generalized anxiety disorder and social phobia. Monoamine oxidase inhibitors (MAOIs) prevent the breakdown of monoamine neurotransmitters (including serotonin), increasing concentrations of the
neurotransmitter in the brain and promoting a sensation of relaxation and happiness. MAOI’s may be synthesized or natural. Herbs, spices and nutrients can inhibit MAO enzymes without the unpleasant side effects of antidepressants, examples being the nutmeg extract, the
passionflower, curcumin or black pepper extract. [6]

Herbs, spices and nutrients can inhibit MAO enzymes without the unpleasant side effects of antidepressants.

The sleep-wake cycle and its modulation

Both dopamine and serotonin play a non straightforward role in mammals’sleep-wake cycle and wakefulness/relaxation sensations. Dopamine can inhibit norepinephrine, causing the subject to feel more alert. Serotonin is involved in wakefulness, sleep onset, and preventing REM sleep.

Serotonin is required to produce melatonin, a hormone that plays a major role in sleep. The production and release of melatonin in the brain is connected to the time of day, increasing when it’s dark and decreasing when it’s light. Melatonin production declines with age.
Consumers use melatonin for sleep disorders, such as insomnia and jet lag. Unlike with many sleep medications, it does not promote dependency, habituation or experience a hangover effect. It is available as an ingredient for food and drink fortification. Melatonin can be used to treat delayed sleep phase and circadian rhythm sleep disorders in the blind and provide some insomnia relief. Valerian root extract is also a major sleep promoter, safely administered in food and pill forms.

Further, supplementation with the amino acid L-tryptophan and its precursor, 5-HTP, and the B vitamins, vitamin D, selenium, and omega-3 fats increases serotonin production. Tryptophan may increase agreeableness, decrease quarrelsomeness and improve mood. Although purified tryptophan increases brain serotonin, foods containing tryptophan do not. This is because tryptophan is transported into the brain by a transport system that is active towards all the large neutral amino acids and tryptophan is the least abundant amino acid in protein. α-Lactalbumin, a minor constituent of milk, is one protein that contains relatively more tryptophan than most proteins, and milk brands are taking advantage of this situation to incorrectly claim that milk promotes a better sleep through tryptophan ingestion.

α-Lactalbumin, a minor constituent of milk, is a protein that contains relatively more tryptophan than most proteins, and milk brands are taking advantage of this situation to incorrectly claim that milk promotes a better sleep through tryptophan ingestion.

Gamma-aminobutryric acid (GABA) is a major chemical signalling molecule in the process of relaxation/sleepiness and is becoming a trendy ingredient in the food industry. A randomized, single-blind, placebo-controlled crossover-designed study was conducted to evaluate the effect of GABA on sleep. Sleep was evaluated by electroencephalography (EEG) after oral GABA administration. GABA significantly shortened sleep latency and increased the total non-rapid eye movement (non-REM) sleep time. Questionnaires showed that subjects receiving GABA realized its effects on sleep. [7] Dietary GABA supplement in clinical studies relieves anxiety and increases alpha brain waves, which are associated with relaxation.

The bottom line

The sensation of relaxation and sleeping promotion are interconnected. However, some ingredients, whether natural or synthetic, may be more adequate for a specific application, and regulatory laws may soon be imposed in incipient markets. In a further piece we will explore how regulatory laws may be applied to this sector and the market size for this type of innovative drinks.

CFER Labs is your partner in food and drinks R&D. Obtain your free of charge workplan by clicking here.

Sources

[1] E. Alramadhan, M. S. Hanna, M. S. Hanna, T. G. Goldstein, S. M. Avila, and B. S. Weeks, “Dietary and botanical anxiolytics,” Med. Sci. Monit., vol. 18, no. 4, p. RA40-RA48, 2012.
[2] G. Medic, M. Wille, and M. E. H. Hemels, “Short- and long-term health consequences of sleep disruption,” Nat. Sci. Sleep, vol. 9, pp. 151–161, 2017.
[3] and S. A. K. Chandrasekhar, Jyoti Kapoor, “A Prospective, Randomized Double-Blind,  Placebo-Controlled Study of Safety and Efficacy of a High-Concentration Full-Spectrum Extract of Ashwagandha Root in Reducing Stress and Anxiety in Adults,” Indian J.
Psychol. Med., vol. 34, no. 3, pp. 255–262, 2012.
[4] J. M. Hodgson and K. D. Croft, Tea flavonoids and cardiovascular health, vol. 31, no. 6. 2010.
[5] D. C. Chu, T. Okubo, Y. Nagato, and H. Yokogoshi, “L-theanine – A unique amino acid of green tea and its relaxation effect in humans,” Trends Food Sci. Technol., vol. 10, no. 6–7, pp. 199–204, 1999.
[6] R. Article, “Available online through www.jpronline.info Natural Monoamine oxidase inhibitors : A Review,” vol. 3, no. 3, pp. 482–485, 2010.
[7] A. Y. Y. P. M. Kim, “Effect of oral γ-aminobutyric acid (GABA) administration on sleep and its absorption in humans,” Food Sci. Biotechnol., vol. 25, no. 2, pp. 547–551, 2016.

 

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