Effect of impregnation solution ratio and periods on vacuum impregnated papaya

Papaya is a popular tropical fruit that is widely consumed in Thailand. In this study, fresh papaya fruit was subjected to vacuum impregnation to have a better understanding  about the process parameters, including impregnation solution ratio, impregnation time and relaxation time. The fresh fruit was cut into pieces, added to impregnation solutions at ratios of 1:5 or 1:10, vacuum impregnated at 50 mbar for 5 or 10 min and left for another 10 or 30 min in the impregnation solution. After separating the fruit from the solution, it was analyzed for the fruit physicochemical properties, including real porosity  (e r ), volume of fruit impregnated with an external solution (X value), fruit volume deformation (γ value), effective porosity (e e ), water loss and solid gain. Different factors investigated in this study significantly affected vacuum impregnated parameters of papaya pieces (p<0.05). The papaya treatment in the impregnation solution at 1:10 with 10 min vacuum time and 30 min relaxation time significantly produced the highest solid gain (3.36 ± 0.37%), X value (0.24 ± 0.01 m 3 liquid/m 3 sample), γ value (0.14 ± 0.03 m 3 /m 3 initial sample) and e e  value (0.11 ± 0.05%). At the same time, this particular papaya sample possessed the lowest water loss (–15.22 ± 3.65%) and e r value (0.16 ± 0.01%). Data in this  study strongly indicated higher impregnation solution ratio with longer impregnation and relaxation periods produced better infusion of impregnation solution in papaya pieces.