TasteLab Scientific Editorial Board

Lipid Oxidation in Insect Ingredients: The Hidden Shelf-Life Problem

Alternative Proteins · Shelf Life · Ingredient Stability
TasteLab Scientific Editorial Board

Abstract

Edible insects are often evaluated mainly for their protein content, but their lipid fraction can have a major impact on shelf life.

Cricket, mealworm and other insect powders may contain significant amounts of unsaturated fats. These lipids contribute nutritional value and flavour, but they are also vulnerable to oxidation.

Lipid oxidation can generate peroxide compounds, aldehydes and other degradation products responsible for rancid aroma, flavour deterioration and reduced product quality.

For food manufacturers, this creates an important distinction:

a microbiologically stable insect powder is not necessarily chemically stable.

Why Oxidation Matters

Unsaturated fatty acids react with oxygen through a chain of chemical reactions.

During the first stages, hydroperoxides are formed. These primary oxidation products can later break down into secondary compounds such as aldehydes and ketones.

Some of these compounds have very strong aromas and may create sensory defects described as:

• rancid;

• stale;

• grassy;

• cardboard-like;

• metallic.

Oxidation can therefore make an ingredient commercially unacceptable long before it becomes microbiologically unsafe.

Processing Can Increase Oxidation Risk

Oxidative stability is influenced by the entire processing history of the insect ingredient.

Important steps include:

• killing;

• blanching;

• drying;

• milling;

• defatting;

• packaging;

• storage.

Drying

Drying is necessary to improve microbial stability and enable milling, but temperature can accelerate oxidative reactions.

Different drying methods can also alter:

• lipid oxidation;

• aroma;

• colour;

• protein functionality.

Milling

Milling increases surface area and exposes internal lipids to oxygen.

A finely milled insect powder can therefore oxidise differently from the whole insect.

Defatting

Removing part of the lipid fraction can reduce oxidation risk, but it also changes:

• nutritional composition;

• flavour;

• protein extraction;

• functional properties.

Defatting should therefore be selected according to the target application.

Water Activity Does Not Tell the Whole Story

Water activity is one of the most important parameters for microbial shelf life.

Low a_w helps limit microbial growth.

However:

low water activity does not guarantee oxidative stability.

A dry insect powder may remain microbiologically stable while its lipid fraction continues to deteriorate.

Shelf-life design must therefore consider both:

microbial stability

and

chemical stability.

What Should Be Measured?

Peroxide value is commonly used to evaluate primary lipid oxidation, but it should not be used alone.

Hydroperoxides are unstable and can decrease after they decompose into secondary oxidation compounds.

A more complete evaluation may include:

Peroxide Value

Measures primary oxidation products.

p-Anisidine Value

Provides information on secondary oxidation products.

Hexanal

A volatile aldehyde often associated with oxidation of linoleic-acid-rich fats.

Totox Value

Combines primary and secondary oxidation indicators.

Free Fatty Acids

Useful for monitoring lipid hydrolysis, which is different from oxidation but can also affect product quality.

For professional insect ingredients, oxidation testing should become part of routine specification and quality control.

Packaging Is Part of the Shelf-Life System

Packaging does not simply contain the ingredient.

It controls its exposure to oxygen.

Oxidation can be influenced by:

• residual oxygen in the package;

• oxygen trapped between powder particles;

• package permeability;

• seal integrity;

• storage temperature;

• light exposure.

Possible strategies include:

• high oxygen-barrier films;

• nitrogen flushing;

• vacuum packaging;

• oxygen scavengers;

• light-protective packaging.

The correct solution depends on the lipid content, target shelf life and distribution conditions.

Storage Conditions Matter

Temperature strongly influences the rate of chemical reactions.

This is particularly important for insect ingredients distributed in:

• tropical climates;

• non-air-conditioned warehouses;

• e-commerce;

• international export.

A product validated at 20–25°C may behave differently after prolonged storage at higher temperatures.

Shelf-life studies should therefore reflect realistic commercial conditions.

What Should an Ingredient Supplier Provide?

For lipid-rich insect ingredients, a technical specification should ideally include more than protein percentage.

Useful information may include:

• total lipid content;

• fatty-acid profile;

• moisture;

• water activity;

• peroxide value;

• secondary oxidation markers;

• free fatty acids;

• drying method;

• milling process;

• defatting status;

• packaging structure;

• recommended storage conditions.

This allows food manufacturers to evaluate the ingredient as a complete system rather than only as a protein source.

Conclusion

Lipid oxidation is one of the most underestimated shelf-life challenges in edible-insect ingredients.

A cricket or mealworm powder may achieve good microbiological stability while gradually developing chemical and sensory deterioration.

For food manufacturers, shelf life should therefore not be defined only by safety.

It should also consider how long the ingredient maintains:

• flavour;

• aroma;

• nutritional quality;

• functionality;

• consumer acceptability.

The key principle is simple:

Shelf life is not only about microbes — it is also about chemistry.

As edible insects move toward more standardised industrial ingredients, oxidative stability should become part of both product development and supplier specifications.

Selected References

1. Bernardo Y.A.A., Conte-Junior C.A. Oxidative stability in edible insects: Where is the knowledge frontier? Trends in Food Science & Technology. 2024;148:104518.

2. Marzoli F. et al. Microbial and chemical stability of Acheta domesticus powder during one year storage period at room temperature. Frontiers in Sustainable Food Systems. 2023;7:1179088.

3. Domiszewski Z. et al. Comparative Study of Lipid Quality from Edible Insect Powders and Selected Cereal Flours Under Storage Conditions. Applied Sciences. 2026;16(1):13.

4. Balzan S. et al. Insect-based products commercialized online: a snapshot of lipid oxidation and mineral content. Italian Journal of Food Safety. 2024;13(4):11600.