Microbiological and chemical properties of kefir manufactured by entrapped microorganisms isolated from kefir grains

Abstract

In this study, various yeasts (Kluyveromyces marxianus, Saccharomyces turicensis, Pichia fermentans) and lactic acid bacteria (Lactobacillus kefiranofaciens, Lactobacillus kefiri, Leuconostoc mesenteroides) were entrapped in 2 different microspheres using an entrapment ratio for the strains that was based on the distribution ratio of these organisms in kefir grains. The purpose of this study was to develop a new technique to produce kefir using immobilized starter cultures isolated from kefir grains. An increase in cell counts with fermentation cycles was observed for both the lactic acid bacteria (LAB) and yeasts, whereas the cell counts of kefir grains were very stable during cultivation. Scanning electron microscopy showed that the short-chain lactobacilli and lactococci occupied the surface of the LAB microspheres, whereas the long-chain lactobacilli were inside the microspheres. When the yeasts were analyzed, cells at a high density were entrapped in cracks on the surface and within the microspheres, where they were surrounded by the short-chain lactobacilli. The distribution of the LAB and yeast species in kefir produced from grains and microspheres showed that there was no significant difference between the kefirs produced by the 2 methods; moreover, Leu. mesenteroides and K. marxianus were the predominating microflora in both types of kefir. There was no significant difference in the ethanol and exopolysaccharide contents between the 2 kefirs, although the acidity was different.

Kualitas Kimia, Fisik Dan Sensori Kefir Susu Kambing Yang Disimpan Pada Suhu Dan Lama Penyimpanan Berbeda

“…Kwak et al (1996) menjelaskan terjadinya penurunan kadar lemak selama penyimpanan dikarenakan terjadinya pelepasan lipase dari mikroorganisme dalam biji kefir. Selama penyimpanan kadar lemak mengalami perubahan kecil sehingga menghasilkan kadar lemak kefir yang relatif sama, hasil ini sejalan dengan peneliti sebelumnya oleh Irigoyen et al (2005), tetapi lebih tinggi dibandingkan penelitian oleh (Chen et al, 2009;Magalhães et al, 2011b) (Kwak et al, 1996). Kadar etanol kefir sangat bervariasi yaitu 0,01 sampai 1,00% tergantung pada kultur yang digunakan, lama fermentasi, suhu dan suhu penyimpanan jenis penyimpan.…”

Probiotic Food Products Classes, Types, and Processing

“…Kefir contains vitamins, minerals and essential amino acids that help the body with healing and maintenance functions and also contains easily digestible complete proteins. Kefir is rich in vitamins B1, B12, folic acid, vitamin K, and biotin, as well as calcium, magnesium, and phosphorus, beside essential amino acids such as tryptophan [83,84]. The benefits of consuming kefir in the diet are numerous.…”

“…Several substrates are produced in kefir aerobic fermentation includes lactic acid, acetic acid, CO2 alcohol (ethanol) and aromatic compounds. These substrates provide kefir with its unique sensorial characteristics: fizzy, acid taste, tart and refreshing flavors [83]. There are several methods of kefir production.…”

“…Grains can be dried at room temperature and kept at cold temperature to be used in the next inoculation. Kefir milk is cooled before consumption [81,83]. In the industrial process of kefir, different methods with the same principle are usually applied to produce kefir.…”

“…The coagulum is pumped and distributed in bottles. After maturing either at 12-14 • C or 3-10•C for 24h, kefir is stored at 4 • C [81,83].…”