Chestnut flour and chestnut pellets in pet food

Chestnuts are not a standard ingredient in pet food. Nevertheless, they appear repeatedly in specialty recipes. The reason lies in their clearly defined nutritional profile and technological properties. Based on the analyses and specifications of the

animalPro nutrition GmbH can clearly assess where this raw material can be used effectively and where its limitations lie.

Raw material base and legal classification

The sweet chestnut (Castanea sativa) is used. It is clearly different from the horse chestnut. To distinguish between what is toxic to dogs and cats and what plays no role in the animal feed sector.

Chestnut flour and chestnut pellets are single feedstuffs and are listed in the single feedstuffs catalogue under 5.12.1 "Chestnuts, whole or crushed". The description includes products made from the endosperm of the chestnut with some fine shell fragments.

Crude protein and crude fiber, in particular, must be declared.

Nutritional profile. Focus on carbohydrates

Chestnuts primarily provide carbohydrates. Protein and fat play a minor role.

Typical analysis data based on the original substance show:

• Crude protein approximately 7 percent

• Crude fat approximately 3 percent

• Crude fiber approximately 4 percent

• Crude ash maximum 3 percent

The dominant component is carbohydrates:

• Nitrogen-free extract (NFE, calculated carbohydrates) approximately 70 percent

• Strength approximately 50 percent

• Total sugar, predominantly as sucrose, approximately 13 percent

This is what makes chestnuts so different from classic starch sources. Besides starch, they contain a significant amount of sugar. This directly affects their energy content, taste, and processing.

In addition to starch content, a more detailed look at the carbohydrate fraction is worthwhile. Food analyses further show that some carbohydrates are present as sugars, while another portion consists of structural carbohydrates.

These include cellulose and other polysaccharide fractions such as pentosans and hexosans. These components contribute to the fiber fraction and influence digestion, water retention, and texture in the final product.

The fiber fraction consists predominantly of water-insoluble components, while soluble fiber is present only in small amounts. This results in a raw material that contributes not only energy but also structure-forming properties to the formulation.

The water content is below 12 percent, and the shelf life is up to 12 months if stored properly.

Technological behavior in processing

Chestnuts behave differently than classic starch sources like rice or corn. The significant sugar content considerably alters their behavior during the process.

Sugar has a different effect compared to pure starch: it is water-soluble, reduces the viscosity in the dough and influences the thermal processes during processing.

In practice, this manifests itself in several ways:

• Lower water binding compared to starch-dominated raw materials, as some of the carbohydrates are present as soluble sugars

• Reduced expansion during extrusion, as sugar inhibits starch gelatinization and swelling

• denser, sometimes more compact product structure in the final product

• stronger browning during thermal treatment through Maillard reactions and caramelization

• Influence on drying and residual moisture, as sugar is hygroscopic and water

binds differently

For the conduct of the proceedings, this means specifically:

• Water addition and dough moisture must be adjusted.

• Extrusion parameters such as temperature and pressure need to be readjusted.

• Drying times and conditions may change

• The desired texture (e.g., crispy vs. compact) must be actively controlled via the recipe.

be controlled

This is not a disadvantage, but rather a characteristic of the raw material. Chestnut can be used specifically to influence structure and browning. The prerequisite is that the recipe and process are tailored accordingly.

Chestnut flour and chestnut pellets in direct comparison

Both variants are based on the same raw material. The difference lies in the physical form and therefore in the practical application.

Chestnut flour is a coarse, light brown to grey powder. The particle size is

Defined, approximately 90 percent are below 2 mm. It can be used flexibly, but exhibits the fluctuations typical of plant-based raw materials.

Chestnut pellets are made from the same material, but are pelletized after grinding. This results in a more uniform structure with advantages in processing:

1. Improved dosing capability

2. Reduced dust generation

3. More stable behavior in the process

In practice, pellets exhibit higher batch consistency than flour. This can be particularly relevant for larger production volumes.

Natural variations and quality

Chestnuts are a natural raw material with corresponding natural variations.

Typical variations include:

• Residual moisture approximately ± 6 percent

• Crude protein approximately ± 0.5 percent

• Crude fat approximately ± 0.6 percent

• Crude fiber approximately ± 1.0 percent

• Crude ash approximately ± 0.5 percent

These differences affect, among other things, energy content and water retention. In practice, this means that the formula must be robust against such fluctuations.

Mycotoxins are also a relevant issue when considering plant-based raw materials. Analyses show that typical representatives such as deoxynivalenol, zearalenone, and fumonisins should be monitored and taken into account in raw material assessment.

Another practical point is availability. Chestnuts are available seasonally,

typically between January and April.

Classification for practical application

Chestnuts do not replace classic carbohydrate sources, but rather complement them in a targeted manner.

They deliver:

• readily available carbohydrates

• a moderate fiber content

• low in protein and fat

The comparatively high sugar content makes them technologically interesting, but at the same time requires a conscious integration into the recipe.

Chestnut flour is suitable for flexible applications where the raw material form can be freely chosen. Chestnut pellets offer advantages in process stability and dosing.

The application always takes place within the context of the overall formulation. The crucial factor is not the raw material itself, but how it is integrated into the recipe.

Brief overview of chestnut flour vs. chestnut pellets

feature	Chestnut flour	Chestnut pellets
Raw material form	coarse flour	pelleted form
Strength	approximately 50%	approximately 50%
Sugar	approximately 12.8%	approximately 12.8%
Protein/Fat	low	niexdrig
Processing, batch consistency	more flexible, more variable	more stable, higher
Dosage capability	restricted	good