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Inhibiting malate metabolism in L. plantarum 299v by introducing lactic acid in ProViva apple drinks

Göransson, Madeleine LU (2016) KLG820 20162
Food Technology and Nutrition (M.Sc.)
Abstract
This master thesis aimed to evaluate the possibilities of inhibition of Lactobacillus plantarum 299v metabolism of malate by introduction of lactic acid in ProViva apple drinks. The malate metabolism of L. plantarum have been found to promote an overproduction of carbon dioxide in ProViva apple drinks and thereby the metabolism was tried to be inhibited. The experiment included three different concentration of apple juice in combination with three different concentrations of lactic acid. This lead to a total of nine different apple drinks to examine and the drinks were evaluated with respect to carbon dioxide production, pH changes and organic acids alternations. Besides this, the amount of live probiotics and the absence/presence of molds... (More)
This master thesis aimed to evaluate the possibilities of inhibition of Lactobacillus plantarum 299v metabolism of malate by introduction of lactic acid in ProViva apple drinks. The malate metabolism of L. plantarum have been found to promote an overproduction of carbon dioxide in ProViva apple drinks and thereby the metabolism was tried to be inhibited. The experiment included three different concentration of apple juice in combination with three different concentrations of lactic acid. This lead to a total of nine different apple drinks to examine and the drinks were evaluated with respect to carbon dioxide production, pH changes and organic acids alternations. Besides this, the amount of live probiotics and the absence/presence of molds and yeast were documented. The analyses were performed specific days from the drinks had been produced until the drinks had been stored in 8oC for 36 days. Sensorial analysis were performed to highlight possible flavor differences during storage and also to grade the different drinks with respect to how tasty they were.

It was found that the concentration of lactic acid does affect the L. plantarum and its metabolism. The bacterium was inhibited in growth due to the addition of lactic acid and the gas formation was decreased. It was also found that with a lactic acid concentration equal to or above 7g/l the L. plantarum started to die. At the same time a lactic acid concentration of 4g/l seemed to be a promising concentration for a future ProViva apple drink. The sensory analysis showed that no significant difference in organoleptic properties could be found during the storage of the drinks. The amount of added lactic acid to the apple juices did not significantly matter for the shelf life of the drinks since the yeast and mold present in the analysis appeared to occur randomly. (Less)
Popular Abstract
ProViva Apple drink – Might soon be the drink to consume for promoting a healthy stomach!


An increasing awareness of health leads to an increasing awareness of probiotics. Probiotics are live microorganisms which promote health benefits to its host when ingested. Probiotics have in the recent years become popular as ingredients in food products, such as in fruit drinks – which ProViva AB produce. Apple juice is a popular drink to consume in Sweden, however, it has so far in the production of ProViva drinks been impossible to produce a ProViva drink with apple. This is because the probiotics love apples – just like we do – which leads to an overproduction of carbon dioxide in the drinks. Though, after research, it has now been found... (More)
ProViva Apple drink – Might soon be the drink to consume for promoting a healthy stomach!


An increasing awareness of health leads to an increasing awareness of probiotics. Probiotics are live microorganisms which promote health benefits to its host when ingested. Probiotics have in the recent years become popular as ingredients in food products, such as in fruit drinks – which ProViva AB produce. Apple juice is a popular drink to consume in Sweden, however, it has so far in the production of ProViva drinks been impossible to produce a ProViva drink with apple. This is because the probiotics love apples – just like we do – which leads to an overproduction of carbon dioxide in the drinks. Though, after research, it has now been found that the over production of carbon dioxide can be inhibited which open up doors for a production of a ProViva apple drink!

A lot of people are having stomach problems and diseases such as irritated bowel disease gets more and more familiar for us. In the same time the awareness for healthiness and healthy food increases in society. More and more people tend to care about what they are eating and thereby the market of healthy food alternatives increases. The ProViva fruit drinks provide the body with two positive factors. First of all they contain fruits which are an important part of the diet and should, together with vegetables as a recommendation from the Swedish National Food Agency, be consumed in at least five portions every day (for an adult equal to approximately 500 grams). Secondly, they contain the probiotic bacterium Lactobacillus plantarum 299v (L. plantarum 299v) which has been seen to promote a healthy gut microbiota in different ways. For example L. plantarum have been found to modulate the immune system to produce more antibodies. The bacterium has also been seen to compete pathogenic bacteria and also to strengthen the epithelial layer and thereby inhibit the invasion of pathogenic bacteria to the blood stream. The fruit content of ProViva, and the presence of L. plantarum, make ProViva drinks a good choice when preferring a healthy lifestyle.

L. plantarum is a non-spore forming, gram positive bacterium that grows anaerobically. L. plantarum has a high tolerance to low pH and can grow in pH below four. Due to its high tolerance to low pH it can survive throughout the acidic environment in the stomach and start to colonize in the gastrointestinal tract of humans. L. plantarum is commonly present in a lot of different fermented food products thereby the bacterium is usually a resident in the human body, from the mouth to the column.

Apple juice is a widespread popular drink to consume all over the world. China is the country that produces the most apple juice concentrate in the world, this with a production of 1 million tons year 2007/2008. In Sweden apples also have been seen to be a popular choice and apples are the second most popular fruit to consume after bananas. An apple consists of a lot of different nutrient, as for example vitamin C and different minerals. It also consists of dietary fibers and is rich in different phenolic compounds. Apples also contains organic acids, and the most common organic acid in apples is the malic acid.

So far, in the ProViva drink catalog, there are a lot of different fruit and berry drinks. However, never has a ProViva drink with apple been able to be produced. This due to that an overproduction of carbon dioxide occurs when apple is combined with L. plantarum. The presence of malic acid in apple makes the L. plantarum ferment this organic acid in what is called the malolactic fermentation. L. plantarum uses the malic acid as a substrate and forms lactic acid and carbon dioxide as products. The carbon dioxide production due to the malolactic fermentation explains the overproduction of carbon dioxide that has been seen. This overproduction of carbon dioxide does affect the flavor of the drinks, as well as the shelf-life and also limits the possibility of packaging the drinks. The packages get all filled with gas- to that point that they even blow up and burst!

An additional problem that also has been noticed when combining apple and L. plantarum is that formation of off-flavors occurs. The upcoming off-flavors are known to taste as medical, glove or smoked.

Research has now found that it soon might be possible to buy a ProViva Apple drink nearby in your store. It has been found that the addition of lactic acid to a ProViva apple drink inhibit the over production of carbon dioxide. The L. plantarum and the metabolism are affected/modified in different ways when lactic acid is introduced. It has also been noticed that the appearance of off-flavors are avoided after introduction of lactic acid. In figure 1 it can be seen how a package of pure apple drink looks after 6 storage days in 25oC compared to a package with a ProViva apple drink (without lactic acid). The package of the drink with ProViva apple drink has lost its structure due to carbon dioxide formation, and can not stand straight up anymore. This picture gives an understanding of the problems with the malolactic fermentation. However, after addition of lactic acid to the ProViva apple drink it has been found that the package will keep its original structure due to the inhibition of malolactic fermentation.

The addition of lactic acid to the ProViva apple drinks is believed to affect the cells of L. plantarum in different ways. As for example it is hypothesized that the lactic acid interacts with the cell membrane which disrupt its function. The entrance of lactic acid into the cells does also promote a decrease in the intracellular pH. This pH decrease is believed to cause inactivation of enzymes that are important for a proper function of the bacterium. However, at the same time as an inhibition of the malolactic fermentation has been noticed it should be said that L. plantarum still survive and live in the ProViva apple drinks. The probiotic properties of the drink are thereby preserved.

What more influences does the addition of lactic acid have to the ProViva apple drink? Since it is an acid that is added the taste of the drink off course gets a bit sour. However, the sweetness from the apple is still noticeable and who does not like the thought of a fresh drink with taste of the late summer’s first new Swedish sour apples. (Less)
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author
Göransson, Madeleine LU
supervisor
organization
course
KLG820 20162
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Microbiology, Product development, Lactic acid, Lactobacillus plantarum 299v, ProViva Apple drink, Preservative, food technology, livsmedelsteknologi
language
English
id
8896063
date added to LUP
2016-12-22 09:38:27
date last changed
2016-12-22 09:38:27
@misc{8896063,
  abstract     = {This master thesis aimed to evaluate the possibilities of inhibition of Lactobacillus plantarum 299v metabolism of malate by introduction of lactic acid in ProViva apple drinks. The malate metabolism of L. plantarum have been found to promote an overproduction of carbon dioxide in ProViva apple drinks and thereby the metabolism was tried to be inhibited. The experiment included three different concentration of apple juice in combination with three different concentrations of lactic acid. This lead to a total of nine different apple drinks to examine and the drinks were evaluated with respect to carbon dioxide production, pH changes and organic acids alternations. Besides this, the amount of live probiotics and the absence/presence of molds and yeast were documented. The analyses were performed specific days from the drinks had been produced until the drinks had been stored in 8oC for 36 days. Sensorial analysis were performed to highlight possible flavor differences during storage and also to grade the different drinks with respect to how tasty they were.
 
It was found that the concentration of lactic acid does affect the L. plantarum and its metabolism. The bacterium was inhibited in growth due to the addition of lactic acid and the gas formation was decreased. It was also found that with a lactic acid concentration equal to or above 7g/l the L. plantarum started to die. At the same time a lactic acid concentration of 4g/l seemed to be a promising concentration for a future ProViva apple drink. The sensory analysis showed that no significant difference in organoleptic properties could be found during the storage of the drinks. The amount of added lactic acid to the apple juices did not significantly matter for the shelf life of the drinks since the yeast and mold present in the analysis appeared to occur randomly.},
  author       = {Göransson, Madeleine},
  keyword      = {Microbiology,Product development,Lactic acid,Lactobacillus plantarum 299v,ProViva Apple drink,Preservative,food technology,livsmedelsteknologi},
  language     = {eng},
  note         = {Student Paper},
  title        = {Inhibiting malate metabolism in L. plantarum 299v by introducing lactic acid in ProViva apple drinks},
  year         = {2016},
}