Functional Dehydrated Foods for Health Preservation
Table 4
Dehydrated plant products with probiotics.
Dehydrated food
Organisms
Impregnation procedure
Drying method
Evaluated parameters
Reference
Apple (cv. Granny Smith)
L. salivarius spp salivarius CECT 4063 L. acidophilus CECT 903 Two commercial fruit juices (mandarin Don Simon and pineapple/grape Don Simon) were selected as impregnation liquid Mandarin juice inoculated with L. salivarius spp. salivarius, pH 6 and 24 h → selected as impregnation liquid
Total soluble solids, pH, density of the juices, water activity, water content and microbial content An in vivo study was undertaken involving 5 children chronically infected with H. pylori
Pilot scale air dryer (40°C, 4 m s−1, 48 h) Rehydration using milk or apple juice (25°C, 24 h)
Volumetric impregnation parameter, volumetric deformation of the sample and effective porosity Microscopic observations Moisture content, water activity and pH of the dried products
Two methods: (i) Immersion (1 h, gentle agitation); (ii) Vacuum impregnation (50 mbar, 1.2 s)
Tray dryer: (i) At room temperature (ca. 20°C, 0.5 m s−1, one week); (ii) At 40°C, 1.5 m s−1, approx. 27 to 30 h + Storage (Vacuum conditions and in sterile Schott flasks under normal atmosphere conditions) at room temperature (ca. 20°C) and 4°C.
(i) Pilot scale air dryer at 40°C, air circulation of 1.8 m/min (28 h); (ii) Freeze drier (−86°C, 72 h); (iii) Cabinet air drier (40°C, 3 h) + radiant energy under vacuum (REV) dehydrator1 (9 min at 1200 W and 3 min at 600 W, absolute pressure at 98.4 kPa) Storage (in LDPE2) at room temperature (ca. 20°C) and 4°C
Enumeration of bacteria, cryoscanning electron microscopy, total titratable acidity, pH, moisture content, water activity, acid tolerance of free and incorporated bacteria Sensory evaluation
Cherry Tomatoes (Solanum lycopersicum var. cerasiforme)
L. acidophilus TISTR 1338 (added to a mixture of a formulated tomato extract (FTE) and sucrose syrup (20, 40 and 60°Brix))
Osmotic dehydration (OD) (soaking halved tomatoes in FTE) (atmospheric pressure, 6 and 12 h) Pulsed vacuum osmotic dehydration (PVOD) (soaking halved tomatoes in FTE) (50 mbar, 10 min); afterwards, the tomatoes were restored in atmospheric pressure for 6 and 12 h
Water loss, solid gain, lycopene, ascorbic acid, texture, color, enumeration of L. acidophilus
Vacuum impregnation natural fruit extract (4°Brix) and 15 and 30°Brix fruit juices (50 mbar, 5, 10 and 15 min) + atmospheric pressure (10 min)
Impregnated guavas and papayas (15°Brix extracted fruit juices) + cabinet dryer (40°C, 36 h) Storage in plastic bags (4°C, 4 weeks)
Structural and physicochemical analysis of raw materials (total soluble solids, pH, acidity, ripeness index, moisture content, apparent density, real density and fruit porosity) Scanning electron microscopy Bacteria counting Moisture content
Pilot-scale tray dryer (40°C, 1.5 m s−1, 24 h) Storage (sterile Schott flasks under normal atmosphere conditions) at room temperature (ca. 20°C) and 4°C