Starter cultures for milk fermentation and their characteristics

Abstract

This paper reviews the different types of fermented milks and their microflora and includes recent work on yogurt, soft cheese and buttermilks, kefir and koumiss. There is considerable interest in the ‘new’ health promoting products which are now available. These are also discussed in the light of some recent findings on the ability to lower the blood cholesterol concentration and stimulate the immune response. Biotechnology techniques are being developed for many of the lactic acid bacteria involved in dairy fermentations, and in the final section some potential improvements are briefly reviewed.

Determination of Organic Acids and Volatile Flavor Substances in Kefir during Fermentation

“…Many researchers have studied the composition of the micro#ora present in ke"r grains. They have isolated Streptococcus lactis (Kandler and Kunath, 1983), actobacillus brevis (Marshall et al, 1984;Angulo et al, 1993),¸actobacillus viridescens,¸actobacillus gasseri,¸actobacillus fermentum and¸actobacillus casei (Angulo et al, 1993),¸actobacillus ke,r (Kandler and Kunath, 1983;Marshall et al, 1984;Angulo et al, 1993),¸actobacillus acidophilus (Angulo et al, 1993;Marshall, 1993),¸euconos-toc (Rosi and Rossi, 1978),¸actobacillus ke,ranofaciens (Toba et al, 1987;Mukai al., 1992),¸actobacillus ke,rgranum and¸actobacillus parake,r (Takizawa et al, 1994) from ke"r grains. Both the homofermentative or heterofermentative pathways are employed by these bacteria, leading to an acidi"ed product.…”

“…Yeasts are primarily responsible for the alcohol production in ke"r. The yeasts commonly isolated from ke"r grains are Saccharomyces cerevisiae (Rohm et al, 1992;Angulo et al, 1993), Candida ke,r (Angulo et al, 1993), the imperfect form of Kluyveromyces lactis (Engel et al, 1986;Angulo et al, 1993;Marshall, 1993), Saccharomyces delbruecki (Engel et al, 1986), ¹orulopsis holmii (Iwasawa et al, 1982), Candida holmii and Saccharomyces unisporus (Engel et al, 1986;Angulo et al, 1993), Kluyveromyces marxianus (Rohm et al, 1992), ¹orulospora delbrueckii and Candida friedricchi (Angulo et al, 1993). Although yeasts are commonly recognized for ethanol-producing ability, the bacterium,¸.…”

Preservation of Kefir Grains, a Comparative Study

“…The microflora of kefir grains is variable, depending on the source of the grain. Among the yeasts isolated include: Candida kefir, the imperfect form of Kluyveromyces lactis (2,3,17,18); Kluyveromyces lactis (3,18); Saccharomyces cerevisiae (3,17,19,20); Saccharomyces delbrueckii (18,19); Torulopsis holmii (21), Candida holmii and Saccharomyces unisporus (3, 18); Torulaspora delbrueckii and Candida friedricchii (3); Pichia lwt/vol. 30 (1997) fermentum and Kluyveromyces marxianus (20).…”

“…It is important to note that although differences exist between morphological features of the colonies, these are difficult to detect. The following are among the lactic acid bacteria described in kefir grains of different sources: Lactobacillus brevis (3,(22)(23)(24), Lactobacillus viridescens, Lactobacillus gasseri, Lactobacillus fermentum and Lactobacillus casei (3), Lactobacillus kefir (3,6), Lactobacillus acidophilus (3,17,23), Lactococcus lactis subsp. lactis (3,17,23), Leuconostoc (3,17,24), Lactobacillus kefiranofaciens (25,26).…”

Isolation and Characterization of Lactic Acid Bacteria Involved In the Fermentation of Millet and Sorgum Sold In Nkwo-Achara Market, Abia State

“…Unwanted products could be achieved at the end of the fermentation (Nout, 1992). To achieve a good fermentation products, the most predominant microorganisms found in an acceptable product are isolated and purified according to Marshall, (1993). The medium used for such process will then be pasteurized to exclude most unwanted microorganisms and the purified microorganism is introduced to initiate the fermentation process.…”