Why does eating nuts make your saliva taste like water?

Nuts are nutritious and delicious. The reason for not eating nuts is not only that they are expensive, but also that they have a bad taste.

Just as unappetizing as eating a bitter melon seed is the strong rancid smell you get when you put a handful of nuts into your mouth.

Have you eaten all the nuts you bought during the Spring Festival? Are they well preserved? Do they have a rancid smell?

If there is a rancid smell, how does your family deal with it? Is your mother willing to throw it away?

If you are reluctant to throw it away, Tadpole will teach you how to quickly and accurately convince your mother to throw it away.

Image source: hippopx

01

Where does the rancid smell of nuts come from?

We all know that nuts are generally high in fat.

Many people may be discouraged when they hear the word "fat". People who are afraid of getting fat can actually eat fat in moderation, because fat is a good energy storage substance for the body. It can also protect internal organs, maintain body temperature, and help absorb fat-soluble vitamins.

Fat is a triglyceride composed of glycerol and fatty acids. The glycerol molecule is relatively simple, while the types and lengths of fatty acids are different.

Fatty acids can be divided into three categories according to their saturation: saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. Nuts mainly contain unsaturated fatty acids, which are subdivided into monounsaturated fatty acids - oleic acid and polyunsaturated fatty acids - linoleic acid and α-linolenic acid.

The unsaturated fatty acids mentioned above are very beneficial to the body. Monounsaturated fatty acids can help patients with three highs lower their cholesterol levels. Alpha-linolenic acid can be converted into DHA in the human body (those with babies at home must be familiar with this term). DHA is the main element for the growth and maintenance of nerve cells and plays an important role in the formation of the brain and retina. Therefore, the role of DHA is particularly important during the critical period of infant growth.

DHA helps babies develop their brains. Image source: pxhere

Although the fat in nuts has many benefits for the human body, they are unsaturated fatty acids. From a chemical structure point of view, unsaturated fatty acids have unstable double bonds compared to saturated fatty acids, resulting in poor stability. This chemical bond is easily affected by external environmental factors. If it reacts with oxygen during processing and storage, it will produce what we call "rancid smell".

Difference Between Unsaturated Fatty Acids and Saturated Fatty Acids

Unsaturated double bond diagram source from: Wikipedia

In addition to the "restless" structure mentioned above, there are many other factors that lead to fat oxidation in nuts.

During the processing of nuts, they may be fried, coated with batter, and other operations. Flour also contains unsaturated fatty acids, active enzymes and other substances, which can also trigger oxidation reactions and produce rancid smells. The high temperature during the frying process and subsequent storage can also cause oxidation of fats, microorganisms and food residues, leading to the production of odors. In addition, if the nut packaging materials are unqualified, air leaks will cause outside air to penetrate into the packaging bag, and the nuts will react when they come into contact with oxygen.

All of the above may cause nuts to have a rancid taste that is unpalatable.

Bags of nuts, image source: hippopx

02

How to keep nuts fresh?

Although nuts are delicious, they can easily go bad due to various reasons. Nut lovers must be troubled. Is there any way to always eat fresh and delicious nuts?

1. Buy fresh nuts and don’t buy too much at one time. Buy more after you finish eating them.

2. The purchase of nuts increases significantly during festivals. In this case, you can divide them into multiple portions after buying them while they are still dry, and store them in a sealed, low-temperature, and light-proof environment.

3. There are also some opinions on the containers for storing nuts. Glass bottles are the first choice. After the glass bottles are cleaned, they should be exposed to the sun to dry. This can prevent the nuts from getting damp after being placed in them and prevent the reproduction of microorganisms.

4. If conditions permit, you can also put bagged desiccant, deoxidizer, etc. in the sub-packaging bottle. Desiccant can prevent nuts from getting damp, and deoxidizer, as the name suggests, can reduce the oxygen content in the bottle.

Desiccant Image Source: Author

Deoxidizer Image source: Author

03

How to convince your mom to throw away the spoiled nuts

Whenever I’m ready to throw away nuts that have gone bad, I’ll hear the elders say something like, “They’re not bad, why can’t we eat them? They’re quite expensive.”

So can we eat spoiled nuts? The answer is: No!

Rancid nuts produce a large number of oxidative free radicals. Once these substances enter the human body, they can cause great harm to the human body, ranging from nausea, vomiting, abdominal pain, to digestive system diseases. Excessive intake can also lead to problems such as peptic ulcers. More importantly, these substances can destroy beneficial enzymes in the human body, causing abnormalities in the body's normal metabolism, and causing symptoms such as loss of appetite, insomnia, and forgetfulness.

Image source: hippopx

Long-term and large-scale consumption of rancid nuts may also cause cancer. These nuts produce a carcinogen, malondialdehyde, which can damage normal human cells and induce cell cancer.

Many people would say, "Well, it's OK if I cook or roast it before eating it, right?" This is not advisable either. No matter how it is processed, the production of these substances is irreversible, so don't turn a blind eye and end up hurting your body. (You must remember these reasons and explain them clearly to your mother)

Of course, changing taste and spoilage are not the characteristics of nuts. Many foods rich in fat, such as pickled foods and fried foods, may produce a rancid smell.

We must pay attention to the preservation of these foods in our daily lives. At the same time, don’t feel sorry if you encounter food that has a rancid smell; you should throw it away.

If your mother still can't bear to throw it away, then throw it away secretly behind her back. (What expired food have you thrown away secretly behind your mother's back?)

END

Reviewer: Wang Guoyi, Postdoctoral Fellow in Food Safety.

Tadpole Musical Notation original article, please indicate the source when reprinting

Editor/Heart and Paper