Problem 18.3 Avocado oil may be extracted from avocado paste using the following

steps: (1) dilute the paste with water, (2) adjust the pH of the paste, (3) heat

the paste at 98oC for 5 minutes, (4) let the paste settle, (5) centrifuge the

paste. We may vary the dilution rate (3:1 water or 5:1 water), pH (4.0 or

5.5), settling (9 days at 23oC or 4 days at 37oC), and centrifugation (6000g

or 12000g). Briefly describe experimental designs for each of the following

situations. You may assume that the paste (prior to any of the five steps

mentioned) may be used any time up to a week after its preparation. You

may also assume that the primary cost is the processing; the cost of the paste is trivial.

(a) We wish to study effects of the four factors mentioned on the extraction

efficiency. Avocado paste is rather uniform, and we have enough

money for 48 experimental units.

(b) We wish to study effects of the four factors mentioned on the extraction

efficiency. Avocado paste is not uniform but varies from individual

fruit to fruit. Each fruit produces enough paste for about 20 experimental

units, and we have enough money for 48 experimental units.

(c) We wish to study effects of the four factors mentioned on the extraction

efficiency. Avocado paste is not uniform but varies from individual

fruit to fruit. Each fruit produces enough paste for about 10 experimental

units, and we have enough money for 48 experimental units.

(d) We wish to determine the effects of the pH, settling, and centrifugation

treatments on the concentration of -tocopherol (vitamin E) in the oil.

Each fruit produces enough paste for about six experimental units, and

we have enough money for 32 experimental units. Furthermore, we

can only use four experimental units per day and the instruments need

to be recalibrated each day.