Conidia of black aspergilli as new biological adsorbents for ochratoxin A in grape juices and musts.
Biological removal of ochratoxin A (OTA) by living and heat-treated dead conidia of black Aspergillus isolates representing the species Aspergillus niger, Aspergillus carbonarius, and Aspergillus japonicus in synthetic and natural grape juices was found to be a two-stage phenomenon. Several lines of evidence suggest that the first observed stage was passive, metabolism was not required, and OTA adsorption on conidia of black aspergilli could be involved. This removal was fast, without delay just after conidial inoculation both in synthetic and natural grape juices. Moreover, even nonviable, heat-treated conidia were capable of removing OTA. Finally, no OTA degradation products were detected. In the second observed stage, removal of OTA was linked to degradation by live conidia only. Ochratoxin alpha, a degradation product of OTA, was detected in the medium after incubation for 30 and 14 h for biseriate (A. niger and A. carbonarius) and uniseriate (A. japonicus) black aspergilli, respectively, when well-developed mycelium appeared. Comparisons between the three black Aspergillus isolates tested showed that A. carbonarius detoxified grape juice most effectively. However, this species often produces OTA. A. niger and A. japonicus isolates were also effective and because those species are not systematically OTA producers, they could be interesting for further OTA detoxification processes in grape juices and musts.
Bejaoui
H
H
ENSAT/INPT: 1, Av. de l'Agrobiopôle BP32607, Auzeville-Tolosane, Castanet-Tolosan, 31326, France.
Mathieu
F
F
Taillandier
P
P
Lebrihi
A
A
D000327:Adsorption; D001230:Aspergillus; D001234:Aspergillus niger; D001628:Beverages / Q000032:analysis*; D005511:Food Handling / Q000379:methods; D005638:Fruit / Q000737:chemistry / Q000382:microbiology*; D009793:Ochratoxins / Q000737:chemistry*; D013172:Spores, Fungal / Q000737:chemistry*; D027843:Vitis / Q000737:chemistry / Q000382:microbiology*
D009793:Ochratoxins; C025589:ochratoxin A