I am afraid of avocados turning into brown mush. I love guacamole but don’t dare to make it for everyday use because, unless you eat it all, it soon turns into bad, unappetizing brownish chunks.
Avocadoes rapidly brown after they are cut open because their cells become exposed to air. The oxygen in air reacts with the enzyme polyphenol oxidase (PPO) and forms brown pigmentation called melanoidin. The avocado animation shows browning of an avocado from right after it is cut open to 300 minutes (5 hours) later.
This polyphenol oxidase reaction often causes other produce, such as apples and potatoes, to brown. Often, polyphenol oxidase browning is desirable. Who doesn’t love the deep brown color of raisins, tea or coffee – all due to polyphenol oxidase browning.
But, we do hate unappetizing brownish-green guacamole. People suggest many ways to prevent or slow down guacamole browning. One of my friend’s family members advocates putting avocado pits into the guacamole, while others suggest adding lime or lemon juice. Some folks swear by adding oils to prevent browning while others swear by wrapping it tightly (preventing oxygen). One of the most straight forward ways of reducing enzymatic browning is to apply heat (aka cooking) to denature polyphenol oxidase. However, cooking may lead to unfavorable texture and taste changes.
Being curious, I decided to perform a mini experiment on avocado/guacamole browning.
Pit Inside the Guacamole
According to my many Mexican American friends, putting the avocado pit inside guacamole is an age old tradition that is believed to reduce the browning of avocados. In our experiments, putting the pit in mashed avocados didn’t have any effect on its browning. On a side note, those small slippery avocado pits are big choking hazards.
Adding Lemon or Lime Juice
Covering Avocados with Plastic Wrap
During my first experiment, I forgot to put the guacamole designated for the refrigerator inside of it. I conducted the experiment again with a different batch of avocados. This resulted in a different time scale for browning of the avocado, but the ultimate before and after result remains the same.
Each Avocado is Unique
Fresh Homemade Guacamole
The store bought guacamole is preserved by high pressure vacuum packaging, and by adding a lot of preservatives to add to shelf life. Many filler ingredients, such as oils and starch are added to reduce cost. In 2006, a Californian sued Kraft food because their guacamole had less than 2 percent avocados and instead was filled with food starch, oils, and food coloring. An example of a refrigerated guacamole on sale in a grocery store shows that this commercial guacamole has no less than 36 ingredients, avocado being the 18th item on the list.
How to reduce browning of guacamole?
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