Are hazelnuts and acorns "relatives"? I only found out after eating them for so many years...

Hazelnuts are a nut that many people like to eat, and they are known as the "king of nuts". Not only can they be eaten directly, but they can also be used in foods such as biscuits, cakes, chocolates, and candies. In addition, hazelnuts have a high oil content and can also be used to process hazelnut oil.

Hazelnuts look so similar to acorns that many people can't tell them apart. Don't worry, in this article we'll talk about the differences between the two, focusing on the nutritional value of the commonly eaten hazelnuts.

What is the relationship between hazelnuts and acorns?

Hazelnuts and acorns look a bit similar, and even though some people know that they are different, they are always suspected of being "related".

Hazelnuts are commonly eaten nuts, but few people eat acorns nowadays. The nut that the cute saber-toothed squirrel Scott in the movie "Ice Age" protected despite the dangers was an acorn.

▲Picture: Screenshot of the plot of "Ice Age" (In fact, the "hat" is not that strong and will fall off if touched)

In fact, apart from being nuts, the two have nothing to do with each other and are not relatives. Acorns are the fruit of the oak tree of the genus Quercus in the Fagaceae family, while hazelnuts are the fruit of the genus Corylus in the genus Corylus in the Betulaceae family. Acorns are a little long and have a "hat", while hazelnuts are rounder and have no small hat. The fruit is wrapped in green leaves. Acorns are usually ripe in August and fall from the tree, while hazelnuts are usually ripe in September.

▲Picture: Acorn with a hat

▲Photo: Acorn (left) and hazelnut (right)

▲Picture: Acorn kernels (left) and hazelnut kernels (right)

What nutrients do hazelnuts have?

Hazelnuts not only have a unique flavor, but are also nutritious. Hazelnuts contain 20 grams of protein per 100 grams, which is higher than walnuts, cashews, and pine nuts. They are also rich in the minerals magnesium, potassium, and zinc. The most prominent mineral is potassium, which is as high as 1244 mg per 100 grams. This is nearly five times the potassium content of bananas, making it very good for people who need to control their blood pressure. [1]

In addition, hazelnuts are rich in fat and can be used to make hazelnut oil.

How about hazelnut oil?

Although both acorns and hazelnuts are nuts, not all of them are suitable for oil extraction. Compared with the two, acorns have a lower oil content, only 1.04% to 6.86%, which makes them less suitable for oil extraction. However, they have a higher starch content, accounting for 50% to 70%, making them more suitable for making vermicelli, acorn cakes, acorn rice wine, acorn tofu, and other foods. [2]

Hazelnuts have a relatively high oil content of about 60%, which is higher than that of soybeans, peanuts, and sunflower seeds, making them very suitable for oil extraction. 100 kg of hazelnuts can produce 50 to 60 kg of oil, and it does not contain any toxic or harmful ingredients, and its fatty acid composition is also relatively healthy. [3]

The fatty acids in hazelnut oil mainly include oleic acid, linoleic acid, palmitic acid, stearic acid and linolenic acid. The content of unsaturated fatty acids is as high as 86%~94.31%, among which the content of oleic acid is more prominent, at 65.9%~83.4%, which is similar to the oleic acid content of olive oil. According to the data in the national standard GB/T23347-2021, the oleic acid content of olive oil is between 55% and 83%.

Oleic acid is a monounsaturated fatty acid that can lower low-density lipoprotein cholesterol (LDL-C), commonly known as “bad cholesterol”, but does not lower high-density lipoprotein cholesterol (HDL-C), also known as “good cholesterol”. It helps reduce the risk of heart disease and stroke and is beneficial to cardiovascular health. [4]

In addition, animal experiments have shown that after 40 days of gavage of soybean oil and different doses of hazelnut oil on hyperlipidemic rats, the soybean oil test group, the low-dose hazelnut oil group (50 mg/(kg·d)), the medium-dose group (500 mg/(kg·d)), and the high-dose group (1000 mg/(kg·d)) can all reduce the blood lipid levels of the rats, with hazelnut oil reducing the levels more significantly, helping to reduce lipid deposition in the liver of hyperlipidemic rats and having a certain protective effect on rat liver cells. [5]

However, hazelnut oil is not very common in the public kitchen and is relatively expensive. According to an e-commerce platform, 500 ml of extra virgin hazelnut oil costs nearly 300 yuan.

▲Picture: E-commerce platform

How to store hazelnuts

Whether it is hazelnuts or hazelnut oil, you must pay attention to the storage conditions, otherwise it will easily become oxidized and rancid and deteriorate.

Because hazelnuts have a high content of unsaturated fatty acids, they easily react with oxygen in the air to produce short-chain aldehydes, ketones, and acids, which produce pungent odors and unpleasant tastes, which is often called "rancid taste", causing hazelnuts or hazelnut oil to lose their edible value.

Some people have conducted experiments on the storage conditions of hazelnut oil and found that the higher the storage temperature of hazelnut oil, the faster its peroxide value increases and its quality deteriorates, and the shorter its storage period. [3]

Therefore, it is best to seal and refrigerate the hazelnuts or hazelnut oil you buy. You should also buy less at a time. According to the "Dietary Guidelines for Chinese Residents", 10 grams of nuts a day is enough, which is about 12 hazelnut kernels if you eat hazelnuts.

▲Photo: Taken by myself

Hazelnuts are rich in nutrition and have a unique taste. If you like to eat them raw, you can eat them fresh. If you like to eat them roasted, you can shell them and roast them in an oven at 160℃ for 20 minutes or 170℃ for 15 minutes. They have a crispy and sweet taste. However, different ovens have different "tempers", so you need to adjust them flexibly!

References:

[1] Yang Yuexin. Chinese Food Composition Table 6th Edition Volume 1[M]. Peking University Medical Press, 2018

[2] Hao Chengyi, Yu Lei, Hu Yang. Current status and prospects of acorn development and utilization in my country[J]. Journal of Jilin Medical College, 2017, 38(05): 361-363. DOI: 10.13845/j.cnki.issn1673-2995.2017.05.018.

[3] Liu Yinzhi, Hu Shuzhen, Zeng Xiangju, Ren Jiajia, Guo Rui, Li Shaohua. Research progress of hazelnut oil[J]. China Oils and Fats, 2017, 42(10): 22-25.

[4]https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/monounsaturated-fats

[5] Lü Chunmao, Lu Changying, Meng Xianjun, Dong Wenxuan, Wei Yajing, Liu Chanchan. Lipid-lowering effect of hazelnut oil on hyperlipidemic rats[J]. Journal of Food Science and Biotechnology, 2014, 33(03): 330-335.

Planning and production

Author: Xue Qingxin, one of the first nutrition instructors of the National Health Commission, and a registered nutritionist in China

Review | Ruan Guangfeng, Deputy Director of Kexin Food and Health Information Exchange Center