Navigation Links
Thesis analyzes factors responsible for the case of Basque natural cider turning bitter
Date:7/12/2010

Malolactic fermentation is a key part in the process of cider making, as it reduces acidity. Malic acid, a common component in fruit, undergoes a chemical transformation, turning into lactic acid. In the case of Basque natural cider (unlike with wine), after this process there is not normally any microbiological stabilisation treatment. This means that the lactic bacteria become the dominant microbiota. Some of these bacteria cause alterations that can affect the properties of the cider.

Biochemist, Mr Gaizka Garai investigated these bacteria, especially those that might make the cider bitter; this problem could affect the consumption of the drink. His PhD thesis is entitled Lactic bacteria of natural cider: involvement in alterations and probiotic potential of producer strains of (1,3)(1,2)--D-glucans.

Fructose, acidity and cold as factors

Some of the lactic bacteria that arise from fermentation metabolises glycerol and, as a consequence, produces the 3-HPA compound, which has a direct relation with an increase in bitterness. With this phenomenon in mind for his thesis, Mr Garai investigated what induced the presence of 3-HPA in Basque natural cider. As the researcher was able to clarify, the microbiota involved in the alteration of bitterness in natural cider is Lactobacillus collinoides. As regards other factors, the composition of the cider itself can cause this alteration. In fact, fructose (with a high concentration of sugar) facilitates the degradation of glycerol in the process of metabolism, in turn producing the accumulation of 3-HPA. Finally, the degree of acidity of the cider and the cold temperatures undergone in periods of maturing and storage can help the maintenance of 3-HPA.

Contains biogenic amines, but in small quantities

Lactic bacteria are not only a source of change in the bitterness; some of these are also producers of biogenic amines, which can produce toxic effects if ingested by persons with high sensitivity to them. Mr Garai studied for the first time the content of these amines in Basque natural cider. The quantities are not especially worrying. The most abundant biogenic amines that the researcher found were putrescine, tyramine and histamine, but in lower concentrations to what have been reported in drinks such as wine or beer. He also observed that there are a number of strains of biogenic amine-producing lactic bacteria, but that the most important was Lactobacillus diolivorans. This species is responsible in part for the production of histamine and tyramine. A strain of the previously mentioned Lactobacillus collinoides also produce biogenic amines; concretely, histamine.

Beneficial for the production of food

Lactic bacteria have certain beneficial properties and Mr Garai's thesis also deals with this aspect. Some of these produce exopolysaccharides, harmful for the production of drinks as they cause the product to turn oily. Nevertheless, this is not the case in food production. For example, certain lactic bacteria in natural cider are producers of the (1,3)(1,2)--D-glucan polysaccharide, which has been shown to be beneficial for both humans and animals, and valuable for the production of functional foods. Mr Garai has identified and analysed three strains amongst the lactic bacteria that produce this type of glucan in natural cider: P. parvulus CUPV1 and CUPV22 and L. suebicus CUPV221. Amongst other things, the researcher concluded that the last two show greater tolerance for gastric stress, and only L. suebicus CUPV221 can withstand the most extreme conditions of stress (pH 1,8).


'/>"/>

Contact: Amaia Portugal
a.portugal@elhuyar.com
34-943-363-040
Elhuyar Fundazioa
Source:Eurekalert

Related biology news :

1. JDRF funded study links hygiene hypothesis to diabetes prevention
2. Discovering the secret code behind photosynthesis
3. Research synthesis shines light on several management options after fires in diverse ecosystems
4. Pliable proteins keep photosynthesis on the light path
5. Advance in understanding cellulose synthesis
6. Facile synthesis of nanoparticles with multiple functions advanced in Singapore
7. Light, photosynthesis help bacteria invade fresh produce
8. Ancient remains put teeth into Barker hypothesis
9. Scientists find quantum mechanics at work in photosynthesis
10. High-throughput analysis of gene regulation, DNA synthesis in Cold Spring Harbor Protocols
11. Scripps Research team wins global race to achieve landmark synthesis of perplexing natural product
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/2/2016)... 2, 2016 Checkpoint Inhibitors for Cancer ... Are you interested in the future of ... checkpoint inhibitors. Visiongain,s report gives those predictions to ... national level. Avoid falling behind in data ... and revenues those emerging cancer therapies can achieve. ...
(Date:2/1/2016)... NEW YORK , Feb. 1, 2016  Today, ... Heart Association (AHA) announced plans to develop a first ... cognitive computing power of IBM Watson. In the first ... disease, AHA, IBM (NYSE: IBM ), and Welltok ... metrics and health assessments with cognitive analytics, delivered on ...
(Date:1/25/2016)... 2016  Glencoe Software, the world-leading supplier of image ... will provide the data management solution OMERO Plus for ... Photo - ... Phenotypic analysis measures the characteristics and behavior ... between states such as health and disease, the presence ...
Breaking Biology News(10 mins):
(Date:2/11/2016)... ATLANTA , Feb. 11, 2016  Wellcentive ... a Portland, Oregon -based community ... to provide population health analytics, quality reporting and ... help FamilyCare strengthen its team of quality managers, ... reporting to the provider groups serving FamilyCare members. ...
(Date:2/11/2016)... BioInformant announces the February 2016 release of its ... and Technologies – Market Size, Segments, Trends, and Projections ... The first and only market research firm ... more than a decade of historical information on all ... type. This powerful 175 page global strategic report contains ...
(Date:2/10/2016)... /PRNewswire/ - BioAmber Inc. (NYSE: BIOA ), a ... Mitsui & Co. Ltd., its partner in the ... investing an additional CDN$25 million in the joint venture ... 30% to 40%.  Mitsui will also play a stronger ... Sarnia , providing dedicated resources alongside ...
(Date:2/10/2016)... is introducing a hybrid membership model which will provide ... joining or renewing through an organizational purchasing model. For ... employee in any size association or AMC office can ... benefits.   John H. Graham, IV , ... organizations of any size and their employees to gain ...
Breaking Biology Technology: