Updated: Dec 25, 2020
Null Hypothesis 5 (Breakfast Cereals): Freeze-Dried Breakfast Cereals are Visually Indistinguishable from Their Former Selves
Conclusion: We were not able to reject this hypothesis.
Null Hypothesis 6 (Breakfast Cereals): Freeze-Dried Breakfast Cereals are Indistinguishable by Taste from Their Former Selves
Conclusion: We were not able to reject this hypothesis for all cereals.
Abstract: We bought Froot Loops, Corn Pops, Annie's Cocoa Bunnies, and Kashi Wheat Biscuits and freeze-dried them. Our testers visually inspected the freeze-dried cereals against their non-freeze dried counterparts. Our test subjects could not tell the cereals apart by appearance. Then our testers were blindfolded and tasted the cereals. They could tell some cereals apart but not others.
Kellogg's Froot Loops
Kellogg's Corn Pops
Annie's Cocoa Bunnies
Kashi Harvest Wheat Biscuits
Distributed cereal onto each tray. For Kashi, a single layer. For the thinner cereals, about 3/4 up the side of the trays.
Put all trays in the freezer overnight.
Started freeze drier to the non-liquid, pre-freeze setting (waited 30 mins.)
Once the pre-freeze cycle completed, placed the frozen trays in freeze dryer.
Started the freeze-drying cycle.
Removed trays from freeze-dryer.
Visually compared the freeze-dried cereals against the same cereal (not freeze-dried).
We taste tested the freeze-dried cereals against the same cereal (blind-folded).
Part 1 Results:
The temperature scanner showed an approximate average temperature of 95° F across the tray of cereals (we use an infrared food thermometer to scan finished trays of food to try and determine if there are ice crystals that measure as cold spots).
The photo below shows the freeze-dried Corn Pops:
The photo below shows the same Corn Pops before freeze-drying:
Each of our testers inspected a clear plastic bag full of freeze-dried Corn Pops against a normal Corn Pops, freezed-dried Froot Loops against normal Froot Loops, Annie's Cocoa Bunnies, and Kashi Wheat Biscuits, without being told which was which. All testers conceded that they could not tell the difference between any of the cereals before and after freeze-drying after visual inspection.
The next part was more interesting. Each of our subjects (my wife and two kids) was blindfolded. They were each given and asked to each each of the cereal samples, freeze-dried and normal. They tasted the food dry, without milk. They were each asked to identify which of the two samples of each cereal was freeze-dried. We were surprised to discover: (1) nearly all testers correctly identified which Froot Loops were freeze-dried; (2) most of our testers incorrectly identified the freeze-dried Corn Pops; (3) our testers could not identify which of the Cocoa Bunnies was freeze-dried; and (4) our testers correctly identified which Kashi Wheat Biscuits were freeze-dried.
Interestingly, but not relevant, Froot Loops seemed to have much less flavor after being freeze-dried while the other cereals seemed relatively unchanged. Also interesting, but not relevant, once the cereals were put in milk they all seemed impossible to distinguish either by taste or visual inspection.
The freeze-drier completed its ordinary cycle at 24 hours. We added no additional hours. By the end of the cycle everything appeared to be dried.
Our actual total starting weight of cereal on the four trays was .942 kg/2.08 lbs. (not including the trays themselves). Our total finished dried weight of the cereal was about .875 kg/ 1.93 lbs.
We measured .041 kg/.09 lb. of water removed from the cereal during freeze-drying.