Figures (5)  Tables (4)

    • Figure 1. 

      Overview of the top lid of the device with the location of the openings for 12 glass jars containing produce.

    • Figure 2. 

      (a) Overview of the device. (b) Internal view of the gas expansion tubes immersed in the glycol solution.

    • Figure 3. 

      Cooling rate of the glycol solution and uniformity of temperature inside the container.

    • Figure 4. 

      Fluctuation of the temperature of the glycol solution around the set point of the refrigeration unit.

    • Figure 5. 

      Cooling rate of (a) apricot fruit, (b) white mushroom, (c) potato tuber, (d) pear fruit and (e) strawberry fruit according to their respective sample mass ranges.

    • Plant materialSample mass per range (g)Diameter (mm)
      (1)(2)(3)
      Apricot85.6222.4453.940–45
      White mushroom85.6203.5403.130–40
      Potato88.7206.6506.328–32
      Pear81.8249.7415.655–60
      Strawberry80.5190.9403.328–32

      Table 1. 

      Mass and size of product samples used in the experiments.

    • CommodityInitial
      temperature
      of samples (°C)      		Glycol
      temperature
      (°C)      		Time to 7/8 cooling (h)
      (1)*(2)(3)
      Apricot25.40.31.001.251.90
      White mushroom24.30.30.751.001.50
      Potato tuber24.40.31.001.002.25
      Pear23.70.32.002.002.00
      Strawberry24.70.30.751.001.75
      * Sample mass range (1) 80.5 to 88.7 g, (2) 190.9 to 249.7 g, and (3) 403.1 to 453.9 g.

      Table 2. 

      Initial temperature of samples, glycol, and time to 7/8 cooling.

    • CommodityC (h−1)R (°C·h−1)t1/2 (h)
      (1)*(2)(3)(1)(2)(3)(1)(2)(3)
      Apricot2.21.71.255.545.030.00.30.40.6
      White mushroom4.02.51.695.859.038.60.20.30.4
      Potato tuber2.42.41.557.657.236.60.30.30.5
      Pear1.10.81.123.817.724.40.70.90.6
      Strawberry3.22.01.279.450.028.80.20.30.6
      * Sample mass range (1) 80.5 to 88.7 g; (2) 190.9 to 249.7 g, and (3) 403.1 to 453.9 g.

      Table 3. 

      Cooling coefficient (C), instantaneous cooling rate (R) and half time cooling (t1/2) of samples.


    • Commodity      		Moisture
      (%)      		Specific heat
      (kJ·kg−1·°C−1)      		Respiration
      heat at 0 °C
      (kJ·kg−1·d−1)      		Density
      (kg·m−3)
      Apricot86.33.91.41,012−1,322I
      Mushroom91.84.09.4460−650II
      Potato tuber78.93.71.6*1,050−1,250III
      Pear83.83.81.3991−1,144III
      Strawberry91.64.03.91,043IV
      * Respiration heat at 5 °C. I[12], II[13,14], III[15], IV[16].

      Table 4. 

      Composition and specific heat[8], respiratory heat production[6] and density of fresh fruits and vegetables[12−16].