Fermentation process for production of apple-based kefir vinegar: microbiological, chemical and sensory analysis

Abstract

The aim of this study was to develop a kefir apple-based vinegar and evaluate this fermentation process using new methodology with Biospeckle Laser. Brazilian kefir grains were inoculated in apple must for vinegar production. In this study, the microbial community present in kefir, and correspondent vinegar, was investigated using Matrix Assisted Laser Desorption/Ionization – Time of Flight Mass Spectrometry (MALDI-TOF MS) technique. Saccharomyces cerevisiae, Lactobacillus paracasei, Lactobacillus plantarum, Acetobacter pasteurianus and Acetobacter syzygii were the microbial species identified. S. cerevisiae, L. plantarum, A. pasteurianus and A. syzygii were found in smaller quantities at the beginning of the alcoholic fermentation, but were found throughout the alcoholic and acetic fermentation. Kefir grains were able to utilize apple must as substrate to produce ethanol, and acetic acid. Acetate, volatile alcohols and aldehydes in the vinegar-based kefir were also produced. The yield of acetic acid in the kefir vinegars was ∼79%. The acetic acid concentration was ∼41 g L−1, reaching the required standard for the Brazilian legislation accepts it as vinegar (4.0% acetic acid). Kefir vinegar showed good acceptance in the sensory analysis. The technology proposed here is novel by the application of immobilized-cell biomass (kefir grains) providing a mixed inocula and eliminating the use of centrifuge at the end of the fermentative process. This step will save energy demand and investment. This is the first study to produce apple vinegar using kefir grains.

The Buffer Capacity and Calcium Concentration of Water Influence the Microbial Species Diversity, Grain Growth, and Metabolite Production During Water Kefir Fermentation

“…The identification of the microorganisms of the present study was performed with MALDI-TOF MS, a culture-dependent dereplication and identification technique for microbial isolates. That is of increasing importance in food microbiology studies, including water kefir (Viana et al, 2017;De Roos and De Vuyst, 2018;Laureys et al, 2018). Lactobacillus hilgardii, Lb.…”

“…Water kefir grain growth during fermentation is mainly influenced by the water kefir grain inoculum, besides environmental factors such as available nutrients, and can change gradually over the course of multiple backsloppings (Waldherr et al, 2010;Laureys et al, 2018). Nutrient availability and hence the capacity to use different fruits and other matrices, such as various vegetable and fruit juices, have been investigated for water kefir production (Zanirati et al, 2015;Corona et al, 2016;Fiorda et al, 2016a,b;Randazzo et al, 2016;Viana et al, 2017;Laureys et al, 2018).…”

Kefir fermentation as a bioprocess to improve lentils antioxidant properties: is it worthwhile?

“…For the fermented products, the results are in agreement with previous studies already conducted with kefir grains. Viana et al (2017) used 28 °C as incubation temperature in a fermentative process using kefir in order to produce an apple-based kefir vinegar and obtained a yield of 79% acetic acid. Fiorda et al (2016a) showed that an incubation temperature of 30 °C was the most adequate for high growth of kefir grains.…”

Microorganisms in functional food supplementation: A review

“…The kefir grains can easily adapt to different substrates and lead to production of new probiotic products (Magalhães et al, 2010;Nalbantoglu et al, 2014). Recent studies show new functional kefir beverages such as whey-based beverages (Magalhães et al, 2010), cocoa pulp-based beverages (Puerari et al, 2012), walnut milk beverage (Cui et al, 2013) and vinegar kefir (Viana et al, 2017).…”