A NEW CULTURE MEDIUM FOR THE MICROBIOLOGICAL ESTIMATION OF LYSINE IN FOODS
- VernacularTitle:微生物法测定食物中赖氨酸所用的一种新培养基
- Author:
Liangti HSIANG
;
Kwangchi YANG
;
Enfu YANG
- Publication Type:Journal Article
- From:
Acta Nutrimenta Sinica
1956;0(02):-
- CountryChina
- Language:Chinese
-
Abstract:
Owing to the deficiency of lysine in zein, the hydrolysate of this protein was used as the main source of amino acids in the preparation of the medium for microbiological estimation of lysine using Lcuconostoc mcsentcroides P-60. as the test ing microorganisms. Suitable quantities of tryptophane, arginine, cystine, glycine and serine were used to supplement the medium.The maximum rate of acid production by the microorganism in this medium is much higher than that in the medium used by Horn et al for the same purpose. The latter medium shows a rapid increase of acid production up to 80 ?g lysine per innoculated test, while our new medium gives a continuous increase of acid production up to 120?g. Thus, the range in which the amino acid can be estimated in much extended.Parallel analysis was made on 25 food samples with our new medium as well as those published in the literature. In 11 cases, the agreement was within 10%; in 13 cases, the results obtained with' our new medium were about 10% higher; and in only 1 case, the new medium gave a lower result. These differences are not due to routine analytical error as repeated estimation gave similar results.
