Abstract
The effects of various additives on fermented milk formation were examined by using a lactic acid bacterium, Lactobacillus helveticus B-1.
The stimulants of acid formation were nucleic acid derivatives such as adenine, hypoxanthine and their analogues as well as sodium formate. Yeast extract also had a stimulatory effect on acid formation by L. helveticus. It is highly probable by our present data that an active component in yeast extract is different from the above stimulants.
None of amino acids, vitamins and inorganic salts which had been tested were effective. Some amino acids such as glycine, threonine and methionine had a rather inhibitory effect. Guanine and its analogues were inhibitory to acid formation by L. helveticus. Among them GMP had the highest inhibitory effect.
There was a close relationship between the length of bacterium measured by microscopic observation and the acidity of fermented milk.
