ESTIMATION OF FUNGAL INFECTION OF PEANUT KERNELS BY DETERMINATION OF FREE GLUTAMIC-ACID CONTENT

Peanut kernels (Tainan 9, a Spanish cultivar) inoculated with Aspergil lus parasiticus, A. flavus, A. niger, or A, ochraceus as well as nonin oculated kernels were incubated in a humidified environment (relative humidity, 100%) at 25 degrees C for 7 weeks, Internal fungal populatio ns and changes in moisture and sucrose content and free amino acid com position of the kernels were determined periodically, Fungal populatio ns determined by using A. flavus and A. parasiticus agar and rose beng al chlortetracycline agar as enumerating media were closely correlated , Moisture content in the kernels increased from 5.8 to 20.4% (dry bas is), and changes in individual free amino acid contents varied, depend ing upon the incubation time and type of fungus used as an inoculum, I n the early infection period (up to 5 weeks), sucrose contents and log arithms of threonine and tyrosine contents increased while logarithms of free glutamic acid content decreased linearly,vith incubation time. A negative linear relationship was further obtained between logarithm s of fungal populations and the logarithm of free glutamic acid conten t (R(2) > 0.80) of the infected peanut kernels.