'Nutritious and sustainable': Algae a promising alternative to soy protein for enhancing postprandial satiety and metabolism – latest study

Algae-based proteins had similar effects on metabolism and appetite as compared to soy protein, according to findings of a crossover study trial conducted by Singapore Institute of Food and Biotechnology Innovation (SIFBI).

This project was funded by the Singapore-New Zealand Bilateral Program on Future Food Research and SIFBI, a research arm of Singapore’s Agency for Science, Technology and Research (A*STAR).

“Our findings reveal that algal biomasses and protein concentrates are as comparable to soy protein concentrate in palatability, satiety, and metabolic outcomes, highlighting their potential as practical, sustainable, and nutritious ingredients,”​ wrote the researchers in Future Foods​.

The results indicated that algae-enriched meals were well-tolerated and comparable to soy in both visual appeal and smell – with algae-based proteins outperforming soy in aftertaste.

Notably, there were no significant differences between treatments in glucose, insulin, appetite/satiety, and GLP-1.

GLP-1 is a hormone that regulates insulin and promotes feelings of fullness after eating.

These indicate that algae-based proteins could be a viable alternative to soy proteins for patients with metabolic conditions.

However, little is known about their metabolic health impact and acceptability as meal ingredients.

To explore the effects of algae-based proteins on enhancing postprandial satiety and metabolism, a randomised, controlled five-way crossover trial was conducted.

The study​

The trial compared whole algal biomasses and their corresponding protein concentrates to soy protein concentrate in terms of palatability, appetite, satiety, and metabolic response.

Nineteen healthy Chinese males from 21–50 years old were recruited from the National University of Singapore.

They attended five study sessions at A*STAR, during which they consumed one of five investigational products.

Each session was separated by a minimum washout period of seven days. The order of the five study meals was randomised.

Prior to each study session, volunteers were instructed to consume a standardised evening meal of rice and chicken soup. This was to minimise any potential variations in blood results due to carryover effects from their previous meal before the measurement visit.

After their evening meal, participants will undergo an overnight fast of at least 10 hours before arriving at A*STAR.

Blood samples were drawn upon arrival to measure analytes at baseline – starting levels of blood markers.

Participants then rated their baseline appetite – hunger, fullness, and prospective intake – via visual analogue scales (VAS), with two ends describing each opposite extreme.

They were then served the study meal, which was noodles supplemented with 10 g of one of the following – nori biomass/protein concentrate (NB/NC), Chlorella vulgaris​ biomass/protein concentrate (CB/CC), or soy protein concentrate control (CON)

Upon finishing the meal, volunteers would immediately rate the meal via VAS in terms of visual appeal, smell, taste, aftertaste, and overall acceptability.

Throughout the 180 min postprandial (post meal) period, volunteers were provided with up to a maximum of 250 mL drinking water to ensure standardised assessment of satiety and fullness.

Subsequent postprandial blood samples were collected through the intravenous cannula at 15-, 30-, 45-, 60-, 90-, 120-, 150-, and 180-min time points following the start of meal intake.

Concurrently, participants also completed appetite ratings via VAS to indicate their postprandial satiety – hunger, fullness, and prospective intake – at each of these eight time points.

At the 15-, 60-, 120-, and 180-min time points, they also indicated their postprandial gastrointestinal symptoms, if any – such as bloating, gas, or abdominal pain.

The results​

The VAS scores indicated that the algae-enriched meals were generally well-received in terms of visual appeal and smell, showing comparable tolerance levels to those of the soy control.

In taste and aftertaste, the algae-enriched meals tended to have a better trend than the soy protein concentrate control. The aftertaste scoring demonstrated a significant difference, with both NB and CC scoring significantly higher ratings than CON.

For example, in terms of visual appeal, participants rated the soy protein concentrate and Chlorella vulgaris​ biomass around 60 points and 65 points respectively.

For the smell, the soy protein concentrate had a score of around 63 points, and the nori biomass had a score of around 70 points.

As for the taste and aftertaste, the soy protein concentrate scored around 65 points and 61 points respectively.

The other algae-based proteins had a score of 77 to 78 points for taste, and 77 to 79 points for aftertaste.

As for the blood markers for postprandial effects and satiety, there were no significant differences observed.

For example, glucose increased by 43.44 ± 5.05 points 180 minutes post-meal for the soy protein concentrate.

Within this same time frame, glucose increased by 44.32 ± 4.78 for nori biomass and by 39.97 ± 3.47 points for Chlorella vulgaris​ biomass.

Insulin increased by 126.67 ± 6.65 points for the soy protein concentrate and by 118.96 ± 7.24 points for nori biomass.

As for GLP-1, it increased by 1696 ± 365.8 points for the soy protein concentrate and by 1683 ± 344.6 points for the Chlorella vulgaris ​protein concentrate.​

In summary, the study found whole algae and protein-rich algal protein concentrates at dietary acceptable doses to have similar effects to soy protein concentrate on postprandial metabolic, satiety, and sensory outcomes in healthy Chinese males.

“With comparable acceptability and metabolic effects to soy, algae and algal proteins present a sustainable and nutritious food ingredient option, particularly for individuals who are unable to consume soy or have greater preference for or access to algae. These findings underscore the potential of algae as a viable food ingredient in future food applications, promoting its role as a source of sustainable and nutritious alternative protein,” concluded the researchers.

Source: ​Future Foods​

“Effects of the consumption of algal biomass versus protein concentrate on postprandial satiety and metabolism”​

https://doi.org/10.1016/j.fufo.2024.100436​  

Authors: Jia Yee Wu, Rachel Tso et al​.