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:12/15/2016)... , Dec 15, 2016 ... Research and Markets has announced the addition ... offering. The report forecasts the global military biometrics market ... The report has been prepared based on an in-depth market ... and its growth prospects over the coming years. The report also includes ...
(Date:12/15/2016)... , Dec. 14, 2016 "Increase in ... biometrics market" The mobile biometrics market is expected to ... 49.33 billion by 2022, at a CAGR of 29.3% ... factors such as the growing demand for smart devices, ... transactions. "Software component is expected to grow ...
(Date:12/8/2016)... 2016  Singulex, Inc., the leader in Next Generation ... a license and supply agreement with Thermo Fisher Scientific, ... Singulex access to Thermo Scientific BRAHMS PCT (Procalcitonin), a ... used to diagnose systemic bacterial infection and sepsis and ... aid in assessing the risk of critically ill patients ...
Breaking Biology News(10 mins):
(Date:1/17/2017)... 17, 2017 The Global Implantable Biomaterials ... of around 7.5% over the next decade to ... the prominent trends that the market is witnessing ... & graft transplant surgeries and medical implants and ... is categorized into immunomodulatory biomaterials, natural, polymers, hydrogels ...
(Date:1/17/2017)... Ind. , Jan. 17, 2017  Zimmer Biomet ... fourth quarter and full-year 2016 sales and earnings conference ... Tuesday, January 31, 2017, at 8 a.m. Eastern Time.  ... will be made available at 7:30 a.m. Eastern Time ... live audio webcast can be accessed via Zimmer Biomet,s ...
(Date:1/17/2017)... , Jan. 17, 2017 Research ... report "Molecular Diagnostics - Technologies, Markets and Companies" ... ... diagnostics has increased remarkably during the past few years. More ... developing molecular diagnostics and 342 of these are profiled in ...
(Date:1/17/2017)... ... January 17, 2017 , ... ... 2016 annual meeting of the North American Spine Society (NASS)1 demonstrate high ... the majority of cases, when PEEK-OPTIMA™ HA Enhanced is used for interbody-fusion ...
Breaking Biology Technology: