Functional Dehydrated Foods for Health Preservation
Table 5
Fruit powders with probiotics.
Vegetable
Organisms
Drying conditions
Evaluated parameters
Reference
Cashew apple juice
L. casei NRRL B-442
Cashew apple juice Bacterial cells (30°C, ~15 h) + maltodextrin or mixture of maltodextrin plus gum Arabic Spray dryer: Feeding rate = 0.3 L h−1 Hot air flow = 3.0 m3 min−1 Pressurized air flow = 30 L min−1 Inlet air temperature = 120°C Outlet air temperature = 75°C The powders were sealed in polyethylene bags and stored in the dark at 25 and 4°C at 68% relative humidity
Viable cell counts
pH Color Powder rehydration time Powder yield Viable cell count determination
L. rhamnosus were resuspended in a chestnut extract Spray dryer: Inlet/outlet temperatures: 140/60°C, 140/65°C, 140/70°C, 130/65°C
Moisture content of dried samples Enumeration of lactobacilli after spray drying Sensitivity test Production of chestnut mousse (pilot-scale anhydrous formulation) and sensory analysis
Two different procedures were followed: (i) Immersion of the fresh fruit pieces in the probiotic culture (1 h), drying (pilot-scale tray dryer, at 40°C, air flow of 1.5 m s−1, 24–48 h) and grinding (ii) Drying the fresh fruits in a pilot-scale tray dryer at 40°C and air flow of 1.5 m s−1, followed by grinding. Simultaneously, drying of probiotic culture by spray drying in skim milk with outlet temperature = 75°C and inlet temperature = 200°C and atomizing air pressure 4 bar Addition of dried probiotic to fruit powders (15 and 30%, w w−1 of dry weight)
Water activity of the fruit powders Enumeration of viable cells Storage (at room temperature or at 4°C)
Lychee juice + bacterial cells + maltodextrin, mixtures of maltodextrin plus inulin, gum Arabic plus inulin, or gum Arabic Spray dryer: Feeding temperature = 25°C Feeding rate = 0.6–1 L h−1 Atomizing pressure = 15 psi Inlet air temperatures = 150–170°C Outlet air temperature = 60–90°C
Quantification of the encapsulated cells Microstructure-scanning electron microscopy Glass-transition temperature Bulk density Solubility Hygroscopicity Water activity Moisture content Total phenolic compounds Ascorbic acid Total anthocyanins Survival of encapsulated probiotic cells in gastric or bile fluids
Inoculated Maoluang juices + Maltodextrin + Tiliacora triandra gum and/or inulin Spray dryer: Feeding temperature = 25°C Inlet temperature = 160°C Outlet temperature = 80°C Feeding rate = 0.6–1 L h−1 Atomizing pressure = 15 psi The powders were vacuum sealed in laminated bags (polyethylene terephthalate/ polypropylene/aluminum) and kept in a refrigerator
Viable cells after spray drying Microstructure analysis of spray dried probiotic-maoluang juice powders (SEM) In vitro stomach and small intestine experiments In vitro colon experiment
L. plantarum 299v Pediococcus acidilactici HA-6111-2
Orange juice + 10 DE maltodextrin + lactic acid bacteria Spray dryer: Feed flow rate = 25 mL min−1 Inlet air temperature = 150°C Outlet air temperature = 70°C Orange juice + 10 DE maltodextrin (with and without) + lactic acid bacteria Freeze-dryer: vacuum (6.7 × 10−2 mbar), 7 days, condenser at −55°C Orange pieces + Lactic acid bacteria (1 h) Pilot-scale tray drier: 40°C, 48 h, 1.5 m s−1 Grinding
Drying yield for spray dried powders
Dissolution test Color Vitamin C Enumeration of LAB cultures Storage conditions (180 days, 4°C and room temperature, in the presence or absence of daylight, = 0.03–0.11)
Fermented orange juice + maltodextrin or gum Arabic (both at 15% (w w−1)), 25°C, 30 min Spray dryer: Inlet air temperature = 140°C Nozzle air flow rate = 30 L min−1 Hot drying air flow rate = 3.5 m3 min−1 Feed flow rates = 0.2, 0.5 and 0.7 L h−1 Spouted bed dryer: Inlet air temperature = 60°C Fluidizing air flow rate = 1.7 m3/min Nozzle air flow rate = 30 L min−1 Feed flow rates = 0.2, 0.3 and 0.4 L h−1
Microbial viability Moisture content Water activity Glass transition temperature (DSC) Particle size Scanning electron microscopy Rehydration time Rheological characterization Storage conditions (sample with the best viability, moisture and Tg results): 3 weeks in hermetically sealed polypropylene packages at 25°C
Orange juice + 10 DE maltodextrin or gum Arabic + lactic acid bacteria Spray dryer: Feed temperature = 40°C Feed flow rate = 5 mL min−1 86% of drying air flow rate Compressed air flow rate = 550 L/h Inlet air temperature = 120°C Outlet air temperature = 65°C
Drying yield of the dried products Data adjustment: Logistic model
Pomegranate juice + bacterial cells (37°C, 48 h) + gum Arabic and maltodextrin Spray dryer: Inlet air temperatures = 130, 140 and 150°C Feed flow rate = 3 mL min−1 Outlet air temperature = 70°C Freeze-dryer: −40°C, 48 h
Moisture content Bulk density Solubility Water activity Color pH Acidity Bacterial enumeration Total anthocyanin content Reconstitution of probiotic pomegranate juice powder Shelf-life studies (aluminum laminated foil, room temperature, 4 weeks)
Watermelon and carrot juices + Lactobacillus cell suspension (37 °C, over a period of 44 h) + maltodextrin Spray dryer: Inlet air temperature = 120–160°C Feed flow rate = 2.0–5.0 mL min−1 Atomization pressure = 1.0–3.0 kg cm−2
Determination of viability Determination of lycopene content β-carotene assay Vitamin C assay Measurement of moisture content Calculation of bulk and tap density Measurement of particle density, porosity, Carr index (flowability), Hausner ratio (cohesiveness) and water solubility index Colour Wettability time Sensory Evaluation Scanning Electron Micrographs Differential Scanning Calorimetry
