Power Ultrasound-Assisted Impregnation of Apple Cubes with Vitamin B12

Abstract

This work explores the use of ultrasound (US) as a means of intensifying the impregnation of apple cubes with vitamin B12 (cyanocobalamin). The effect of different US power densities (90 and 200 WL−1) and treatment times (5, 10, and 15 min) was evaluated, on vitamin load, vitamin stability, and physicochemical and microstructural properties of the fruit matrix. The US enhanced the impregnation producing high cyanocobalamin content products (0.12–0.19 mg vitamin/g db.). Vitamin losses in the sonication medium due to US application were not significant. Impregnated samples exhibited higher moisture and lower soluble solids with respect to the untreated fruit. Changes in chromatic coordinates were well correlated to vitamin uptake. Only at the highest treatment intensities (200 WL−1, 10, and 15 min) was a marked softening observed, which agreed with the microstructural changes observed in fruit tissues. Results permit US-assisted impregnation to be considered a promising technology in the preparation of vitamin B12 fortified apple cubes.

Measurement of microstructural changes promoted by ultrasound application on plant materials with different porosity

“…The intensification of water transfer from a hypotonic solvent into vegetable cells because of US application has already been reported by other authors. For instance, Vasile et al [8] , who subjected apple samples to an immersion treatment in water enriched with cyanocobalamin, observed a water gain with US application (200 W/L for 15 min) larger than that observed without US. Among the three investigated materials, apple was the most affected when using water as an immersion medium.…”

“…This type of ultrasound has high intensity (10–1000 W/cm 2 ) and low frequency (20–100 kHz) [4] and has been applied to numerous unit operations in the food industry. These operations include extraction [5] , [6] , osmotic dehydration [7] , impregnation [8] , drying [9] , emulsification [10] , defoaming [11] and so forth. US has also been applied as an immersion pre-treatment for further processes such as drying [12] , hydro distillation of essential oil [13] , physicochemical modification of starches [14] and others.…”

Assessment of ultrasound-assisted vacuum impregnation as a method for modifying cranberries’ quality

“…Irazoqui et al [33] observed such an effect on lettuce surfaces. On the other hand, Vasile et al [34] noted that a significant increase in water content was lacking (mass of samples) in apple tissue during ultrasound-assisted impregnation using a hypotonic solution containing vitamin B12. Substantial simultaneous impregnation of the tissue with vitamin B12 was found.…”