Benefits of walnut

Walnuts are considered one of the healthiest foods in the world. They are a rich source of energy and contain many beneficial nutrients, minerals, antioxidants, and vitamins that are essential for well-being. To extract the edible part (kernels), walnuts undergo several processing operations including harvesting, hulling, drying, and shelling. During these operations, large quantities of by-products (leaves, hulls, shells, broken kernels) are produced and often underutilized, resulting in their wasted potential value. Producing high value-added products from the walnut processing by-products can increase the profitability of walnut processers and lead to several environmental and socioeconomic benefits. Consequently, it is important to fully understand the value of the by-products produced from the walnut processing operations and determine the technical feasibility of processing technologies to utilize the walnut wastes. This chapter discusses the production, economic value, health benefits, processing operations of walnuts, and characterization of the walnut main products and by-products produced during the processing operations. Additionally, this chapter reviews the current state of feasible processing technologies to convert the walnut by-products to value-added products that have food and nonfood applications.

Walnuts are a rich source of essential fatty acid and tocopherols. Whole walnut tree contain various important phytoconstituents which are basically present in leaves and fruits. Leaves mainly contain phenolic acid, tannin, essential fatty acid, and flavonoid. Quercetin is an important flavonoid present in walnut leaves. In addition to this, phenolic compounds such as 3- and 5-caffeoylquinic acid, 3- and 5-p-coumaroylquinic acid, quercetin 3-galactoside, and quercetin 3-pantocid derivatives are also present in walnut. Various naphthalene derivatives such as 5-hydroxy-1-4-naphthoquinone are also present in walnut tree. Organic materials such as citric acid, malic acid, phosphate, calcium oxalate, and glucose are mainly present in fruits of walnut.30

Nutrition facts

Walnuts are made up of 65% fat and about 15% of protein. They’re low in carbs — most of which consist of fiber.

A 1-ounce (30-gram) serving of walnuts — about 14 halves — provides the following nutrients (2Trusted Source):

• Calories: 185

• Water: 4%

• Protein: 4.3 grams

• Carbs: 3.9 grams

• Sugar: 0.7 grams

• Fiber: 1.9 grams

• Fat: 18.5 grams

Walnuts contain about 65% fat by weight

Like other nuts, most of the calories in walnuts come from fat. This makes them an energy-dense, high-calorie food.

However, even though walnuts are rich in fat and calories, studies indicate that they don’t increase obesity risk when replacing other foods in your diet

Walnuts are also richer than most other nuts in polyunsaturated fats. The most abundant one is an omega-6 fatty acid called linoleic acid.

They also contain a relatively high percentage of the healthy omega-3 fat alpha-linolenic acid (ALA). This makes up around 8–14% of the total fat content 

In fact, walnuts are the only nuts that contain significant amounts of ALA (8Trusted Source).

**Vitamins and minerals…

Walnuts are an excellent source of several vitamins and minerals, including:

• Copper. 

This mineral promotes heart health. It also helps maintain bone, nerve, and immune system function 

• Folic acid

Also known as folate or vitamin B9, folic acid has many important biological functions. Folic acid deficiency during pregnancy may cause birth defects 

• Phosphorus

About 1% of your body is made up of phosphorus, a mineral that is mainly present in bones. It has numerous functions

• Vitamin B6.

This vitamin may strengthen your immune system and support nerve health. Vitamin B6 deficiency may cause anemia

• Manganese

This trace mineral is found in the highest amounts in nuts, whole grains, fruits, and vegetables.

• Vitamin E. 

Compared to other nuts, walnuts contain high levels of a special form of vitamin E called gamma-tocopherol

Walnuts contain a complex mixture of bioactive plant compounds.They’re exceptionally rich in antioxidants, which are concentrated in the brown skin In fact, walnuts ranked second in a study investigating the antioxidant content of 1,113 foods commonly eaten in the United States

***Some notable plant compounds in walnuts include:

• Ellagic acid. 

This antioxidant is found in high amounts in walnuts, along with other related compounds like ellagitannins. Ellagic acid may reduce your risk of heart disease and cancer

• Catechin. 

Catechin is a flavonoid antioxidant that may have various health benefits, including promoting heart health 

• Melatonin

This neurohormone helps regulate your body clock. It’s also a powerful antioxidant that may reduce your risk of heart disease

• Phytic acid

Phytic acid, or phytate, is a beneficial antioxidant, though it can reduce the absorption of iron and zinc from the same meal — an effect that’s only of concern for those following imbalanced diets

***Health benefits of walnuts…

Heart disease — or cardiovascular disease — is a broad term used for chronic conditions related to the heart and blood vessels.

• Heart health

• Cancer prevention

• Brain health

What’s more, regularly eating walnuts may improve brain health and reduce your risk of heart disease and cancer.

** Adverse effects and individual concerns

• Reduced mineral absorption

Phytic acid, or phytate, is a plant substance that impairs the absorption of minerals — such as iron and zinc — from your digestive tract. This only applies to meals that contain high-phytate foods.

Sciencedirect… Written by Atli Arnarson BSc, PhD — Updated” on March 26, 2019

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