Production of zinc-enriched yeast extracts

Gaudreau, H Conway, J Champagne, CP

H. Gaudreau et al., Production of zinc-enriched yeast extracts, J FD SCI M, 38(4), 2001, pp. 348-351

26

INGLESE

Article

Food Science/Nutrition

JOURNAL OF FOOD SCIENCE AND TECHNOLOGY-MYSORE

0022-1155 → ACNP

38

4

2001

348 - 351

ISI

0022-1155(200107/08)38:4<348:POZYE>2.0.ZU;2-A

Dried zinc-containing yeasts (5 g zinc / 100 g yeast) were rehydrated at 20 % solids and subjected to autolysis at 50 degreesC for 24 h. Either of the following enzymes, glucoamylase, mannanase, beta -1, 3 glucanase, fungal a cid protease, validase FP or papain was added to promote lysis. Autolysis y ields, recovery of zinc in the yeast extract (YE) as well as composition of the YE (nitrogen, sugars) were determined. In the absence of added enzymes , autolysis yield with fresh Bakers' yeast was 46 %, while that with the re hydrated zinc-enriched yeasts was 21 %. All adjunct enzymes increased autol ysis yields (up to 41 %) from the rehydrated zinc-enriched yeast. The fract ion of the zinc that was recovered in the YE ranged from 64 to 81 % of the total amount originally present in the yeast, depending on the enzymes used (beta -1, 3 glucanase and validase FP gave best results). Yeast extracts o btained from glucanase had higher contents of glucose, but lower contents o f a-amino nitrogen than those produced with the proteases. The use of enzym es to obtain YE from rehydrated zinc-containing yeasts generated YE having 15 g of zinc/100 g of yeast extract.