The Effects of Quinoa milk Fermented with Lactic Acid Bacteria on Gut Microbiota

Abstract

The request for alternatives to dairy products have increased for some years now. This has led to an increase of different kinds of vegetable milks and yoghurts on the market. Quinoa is a herb from South America and due to the versatility of this herb and its exceptional nutritional value it is an excellent example on functional food with health effects that is induced from all the active compounds it consists of. If the quinoa is mixed into an aqueous vegetable drink and then fermented with probiotic lactic acid bacteria there is potential to develop a product that is for everybody. The fermented quinoa milk will be free from lactose, gluten and cholesterol.

Strains of lactic acid bacteria, Lactobacillus pentosus, Pediococcus pentosaceus and Lactobacillus plantarum, that has known probiotic capabilities had been isolated from Bolivian quinoa in previous projects. These bacterial strains were used in the trials in the making of a fermented quinoa milk. To classify a product as probiotic it is required that it contains enough health beneficial bacteria, where a large amount will survive through the gastrointestinal tract. Therefore, it was of great importance for the project to investigate if the lactic acid bacteria, in the fermented quinoa milk, survive until they reach the large intestines.

The study consisted of two parts. The first part was the formulation of the fermented quinoa milk. The synergy of the bacteria strains was evaluated by culture dependent methods to find the best option with enough living bacteria, either as a combination of two strains or one strain individually. The acidity, pH, was evaluated to confirm the quality of the fermentation and the shelf-life was investigated by the means of viable bacteria.

The second part of the study consisted of a human study (a pilot study), where 8 healthy participants consumed fermented quinoa milk for 2 weeks. Saliva- and faecal samples were collected after a 2 week wash-out period, the day before the study started, and then again on the day after 2 weeks of consumption. The samples were then analysed by culturing on Rogosa agar to compare the lactobacilli concentration before and after the study. DNA was extracted from isolates (on the after-samples) and a Sanger sequencing was made in the hope of seeing the chosen bacteria as one of the viable ones. To gain a profile over the bacterial flora in the samples and to determine the diversity, Terminal Restriction Fragment Length Polymorphism (T-RFLP) was used.

A strain of L. pentosus was chosen for the study with a mean pH value of 4,06, and at least 1010 cfu/250 ml which was the daily dose for the human study. No significant difference could be seen between the concentration of lactobacilli in the human samples comparing the before and after samples. Neither a significant difference could be seen on the diversity (Shannon index) between the samples which is also good since it is not decreasing and stays stable. What was interesting though was that the L. pentosus strain was possibly reisolated from the faecal samples, which could confirm the survivability of the strain. Unfortunately, this strain is too closely related to L. plantarum and they cannot be distinguished by the 16 S rRNA gene sequence analysis and further analysis needs to be done to evaluate this.

Popular Abstract

The request for alternatives to dairy products have increased for some years now. This has led to an increase of different kinds of vegetable milks and yoghurts on the market. Quinoa is a herb from South America and due to the versatility of this herb and its exceptional nutritional value it is an excellent example on functional food with health effects that is induced from all the active compounds it consists of. If the quinoa is mixed into an aqueous vegetable drink and then fermented with probiotic lactic acid bacteria there is potential to develop a product that is for everybody. The fermented quinoa milk will be free from lactose, gluten, and cholesterol.

For this study strains of lactic acid bacteria, that has known probiotic capabilities, had been isolated in previous projects. These bacterial strains were used in trials making fermented plant-based beverages. To classify a product as probiotic it is required that it contains enough health beneficial bacteria, where a large amount will survive through the gastrointestinal tract. Therefore, it was of great importance for the project to investigate if the probiotic bacteria, in the fermented quinoa milk, survive until they reach the large intestines.

To investigate the survivability of the probiotic bacteria an in vivo pilot study was performed where 8 healthy participants consumed fermented quinoa milk. Saliva- and faecal samples were collected before and after two weeks of consumption. The participants also answered a symptoms questionnaire since it was of great importance to know their opinion about the product and experience in consuming this alternative natural product. Mostly positive comments were made except for the taste of the drink which it is expected to be improved in the future. Some participants were so excited about the results of their symptoms that they asked for more fermented quinoa milk to continue the consumption even though they did not like the taste.

No significant difference could be seen between the concentration of lactobacilli in the human samples comparing results before and after 2 weeks of consumption of fermented quinoa milk. However, what was interesting though was that the probiotic bacteria used for fermenting the quinoa milk, was re-isolated from the saliva and faecal samples, confirming the survivability of the applied Lactobacillus strain, meaning that the bacteria survive through the human gastrointestinal tract and the fermented quinoa milk could be considered as a probiotic drink.

• author: Olsson, Hanna
• supervisor: Pamela Rosario Canaviri Paz
• organization: Department of Food Technology, Engineering and Nutrition
• course: KLGM01 20191
• year: 2019
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Fermented quinoa milk, In vivo study, Plate count, Terminal Restriction Fragment Lenght Polymorphism, Food technology
• language: English
• id: 9065935
• date added to LUP: 2021-09-22 15:49:46
• date last changed: 2021-09-22 15:49:46