Undiscovered appeal? South African researchers find wild fruits’ potential to aid nutritional deficiencies

08 Jul 2021 --- South African researchers have found that wild African fruit can supplement low protein diets and aid in nutritional deficiencies.

A variety of essential amino acids within 14 species of fruit was discovered during the research by the University of Johannesburg.

“The research shows possibilities to develop new commercial crops and new products for niche markets. It shows governments and NGOs where support for research and development in this area is needed,” professor Ben-Erik van Wyk, national research chair in indigenous plant use at the University of Johannesburg, tells NutritionInsight.

“This study was the first exploration of many of the fruits. There are others that are much more studied and not commercialized yet,” adds professor Annah Moteetee, previous head of botany and plant biotechnology department at the University of Johannesburg.

Bursting with nutrition
The study examined the white olive, jacket plum, Lowveld milkberry, woodland waterberry, wild date palm, water berry, mobola plum, African mangosteen, transvaal milkplum, coastal kei-apple, sunbird tree, kei-apple, sour fig and a Carissa macrocarpa species called amathungulu.The Lowveld milkberry was found to have the highest concentration of carbohydrates (Credit: Ben-Erik van Wyk).

It revealed that the fruits contain nutrients that are essential for the development of children and the maintenance of health in adults.

For example, all of the fruits in the study contain lysine, an essential amino acid for healthy immune function.

Growing freely in the wild
The research on the wild African fruit inspired by Moteetee’s background where she “grew up in a very rural area, where almost every plant has some use for medicine, food, or something else.”

She began questioning what was in wild medicinal plants, fruits and vegetables in Southern Africa.

Regarding commercialization for the fruits in the study, Moteetee believes it’s too early to tell if they can be commercialized or not. “When you know that a fruit is marketable, people can harvest it in the wild and sell it. But harvesting from the wild is not sustainable in the long term for indigenous plants,” she outlines.

Additionally, the process of commercialization consists of several steps. “The first step is to select favorable variants from the wild. These are the variants with tasty and large enough fruits that people would like to buy,” van Wyk adds.

The white olive and amino acids
The white olive (Halleria lucida)’s fruit grows directly from the tree’s bark. This preliminary nutritional research suggests that the unique berries are high in essential amino acids).

The white olive has the highest concentration of histidine (1.56 mg per 100 g) of all the wild fruits studied in the research. Histidine is an essential amino acid for infants.Southern African fruit that is abundant in the wild has the potential to aid in nutritional deficiencies.

Additionally, the white olive contains a high concentration of isoleucine (0.30 g per 100 mg), leucine (0.47 g per 100 g), phenylalanine (0.31 g per 100 g) and valine (0.39 g per 100 g).

The white olive fruits were found to have a protein content of 6.98 mg per 100 g and carbohydrate content of 36.98 mg per 100 g.

The Lowveld milkberry and energy
Among the fruits studied, the Lowveld milkberry, or Manilkara mochisia, proved to be the best source of carbohydrates. The nutritional content of the fruit is also examined for the first time.

A 100 g portion of the fruit contains 169 kJ of energy. Carbohydrates have a comparable value of 36.98 g per 100 g.

The jacket plum and immune health
The researchers found that the fruit of the jacket plum (Pappea capensis) is dense in lysine leading to it exceeding the recommended daily requirement for humans.

“The tree is used by many cultures in Southern Africa for traditional medicine. The plant is related to the lychee in the family Sapindaceae. The edible part in both is not the fruit itself but a fleshy attachment to the seed, which is called an aril,” van Wyk adds.

In young children, lysine promotes healthy growth and development. It’s also necessary for maintaining a strong immune system, particularly against viruses.

Recently, lysine was used in Evonik’s omega 3 lysine complex, AvailOm, which delivers faster absorption and bioavailability than a traditional oil-based ethyl-ester omega 3 formulation.

Methionine (0.15 g per 100 mg) and threonine (0.31 g per mg) were particularly prevalent in jacket plums. Its methionine content is comparable to WHO’s recommended daily allowance but lower than the FDA’s recommendation.

By Nicole Kerr