Abstract:

In order to reduce the salting time for pickled mushrooms, this work established a rapid impregnation technique
by which mushroom slices were immersed in a saline solution loop system and consequently subjected to Na+ and Cl-
ion current generated by electromotive force through the alternating magnetic flux. The results showed the samples with
a porosity of 41.4% could rapidly improve the infiltration of salt content after the ion current treatment than traditional
pickling. Salt content and firmness of the mushroom were monotonically increased with increasing impregnation time and
saline concentrations. Micrographs of the mushroom tissues subjected to ion current impregnation showed that mushroom
possessed porous structure and the amount of salt appeared in the interior of the sample tissue. Saline concentration and
processing time were identified to be main variables that influence pickling efficiency by the single-factor method. Based
on the principles of central-composite design, the two variables at four levels of response surface analysis were employed
to obtain a fitting model for salt content with correlation coefficient (R2) of 0.966 9. The fitting model developed for all
responses was applied to predict the salt content of samples after ion current impregnation, and obtained mushroom slices
with salt content of 3.8%. Verification results showed good fitting degree of the regression model. It is believed a rapid
impregnation technique based on induced ion current would be advantageous for pickling process depending on the porous
structure of agricultural products and food materials. This research provides references for the development of rapid
impregnation technique.

Key words: electromotive force, ion current, mushrooms, pickling, porous