Comparison of bifidobacterial growth-promoting activity of ultrafiltered casein hydrolyzate fractions

Wan

et al. 2014

Int J of Food Sci Tech

Soy protein isolate was hydrolysed with Alcalase, Papain, Flavorzyme and Protemax, respectively, and further fractioned by ultrafiltration. The resulting soy protein hydrolysates (SPH) and their ultrafiltration fractions were used to examine their effects on the growth and fermentation performances of brewer's yeast. Results showed that degree of hydrolysis, molecular weight distribution and amino acid composition of SPH significantly affected the growth, viability and fermentation performance of brewer's yeast. The SPH prepared from different proteolytic enzymes exhibited distinct growth-and fermentation-promoting activity for brewer's yeast. The SPH treated with Protemax for 9 h and with the molecular weight below 3 kDa showed the highest growth-promoting activity and induced more rapidly reducing sugar consumption and higher ethanol production. The relatively lower molecular weight and the hydrophilic and electropositive amino acid residues (Lys, His, Arg and Ile) in SPH might be responsible for its functionality, promoting the growth and fermentation of brewer's yeast.

Section: Resultsmentioning

confidence: 97%

Effects of soy protein hydrolysates on the growth and fermentation performances of brewer's yeast

Wan

et al. 2014

Int J of Food Sci Tech

Journal of Applied Microbiology

“…An inoculum size of 50 ml l −1 was chosen for further experiments as it gave the most reliable set of results. Similar inoculum levels have been applied (Ventling & Mistry 1993; Proulx et al . 1994) and are also recommended as a selection criterion for starters in fermented milk products (Kurmann 1988).…”

Section: Methodsmentioning

confidence: 99%

Use of small ruminants’ milk supplemented with available nitrogen as growth media forBifidobacterium lactisandLactobacillus acidophilus

Gomes

Malcata

1998

A .M .P . GO ME S AN D F . X. MA L CA TA . 1998. Growth of, and acid production by Bifidobacterium lactis and Lactobacillus acidophilus using ovine and caprine milk as media were evaluated for their potential use in cheese-making. A protein hydrolysate (MHP, obtained from incubation of bovine milk with protease) or a mixture of free amino acids (FAA, similar to the amino acid fraction of MHP) was added as a nitrogen enrichment source. Bifidobacterium lactis and Lact. acidophilus were inoculated at 50 ml l −1 and incubated at 37°C with growth supplements added at ratios in the range 25-50 ml l −1. The maximum viable counts of Bif. lactis were lower in plain ovine and caprine milk than in nitrogen-enriched milk, and MHP was a better growth promoter than FAA. A similar trend was observed with the acidity values developed, and attempts to correlate growth with acidity were successfully performed. The highest uptake rates of amino acids in ovine milk were observed for lysine, isoleucine, leucine and proline, but only isoleucine was taken up at a similar rate in caprine milk. Final bacterial viable counts of Lact. acidophilus in the plain and enriched forms of ovine milk did not differ greatly from each other, although FAA was statistically a better growth promoter than MHP. Unlike results in ovine milk, cultures of Lact. acidophilus in caprine milk exhibited drops of 1-1·5 log cycles in viable cell counts by 24 h of fermentation, irrespective of the nature of the nitrogen source. Parallel studies indicated that the excess of fatty acid residues in caprine milk could be responsible for the poor growth of Lact. acidophilus.

“…(1993) also found that the length of peptides is an important factor for the growth and acid production of lactic acid bacteria. In addition, Proulx et al. (1994) reported that small peptides (<2000 Da) were the best for stimulating growth of bifidobacteria .…”

Section: Resultsmentioning

confidence: 99%

Influence of casein hydrolysates on the growth and lactic acid production of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus

Zhang

Ren

et al. 2011

Int J of Food Sci Tech

The growth performance of Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) and Streptococcus thermophilus (S. thermophilus) was determined in the presence of casein hydrolysates produced by the action of five proteolytic enzymes (Alcalase, Flavorzyme, Neutrase, Papain and Trypsin) with various degrees of hydrolysis (DH). In addition, these five kinds of casein hydrolysates were fractionated by ultrafiltration and the influence of the amino acid composition of the peptides on the growth and lactic acid yield of yoghurt lactic acid bacteria (LAB) was studied. The results showed that the ultrafiltered fraction (<3000 Da) was the determinant stimulator in crude hydrolysates. Furthermore, the hydrophilic amino acid residua including His, Lys, Glu and Ser were beneficial for bacterial growth. Compared with control, the cell growth and lactic acid yield of yoghurt LAB were increased with the supplementation of the peptides fraction (<3000 Da) produced with papain by 65.1% and 49.6%, respectively.