Starch Analysis in Food and Feed

Starch is one of the primary carbohydrates found in plant-based materials and serves as a major source of energy in both human food and animal feed. It is naturally present in grains, cereals, legumes, and many processed products.
In nutritional analysis, starch is an important parameter used to evaluate energy content, ingredient quality, and processing performance.

Starch plays a central role in determining the nutritional and functional properties of food and feed.
In animal nutrition, starch contributes to:
‣ Energy supply as a primary carbohydrate source
‣ Growth performance and production efficiency
‣ Feed efficiency and nutrient utilisation
‣ Rumen fermentation and microbial activity (in ruminants)
‣ Variation in digestion depending on starch source and processing
In human nutrition, starch contributes to:
‣ Primary dietary energy supply
‣ Glycaemic response
‣ Digestibility
‣ Texture and functionality of foods
Because of this, accurate starch measurement is essential for formulation, quality control, and nutritional labelling.

Amylose is a linear polymer of glucose linked primarily by α(1→4) glycosidic bonds. Due to its relatively straight structure, it tends to form tightly packed, helical arrangements, making it less accessible to digestive enzymes compared to more branched starch components.
As a result, amylose is more slowly digested and contributes to the formation of resistant starch, particularly after cooling of cooked starches (retrogradation).

Amylopectin is a highly branched polymer of glucose, containing both α(1→4) and α(1→6) glycosidic bonds. Its branched structure provides multiple sites for enzymatic attack, making it more readily digested than amylose and a primary contributor to rapid glucose release and energy availability.
Amylopectin is also largely responsible for starch gelatinisation during heating, which affects the viscosity, texture, and stability of food products.
The ratio of amylose to amylopectin significantly influences digestibility, glycaemic response, and functional properties. Starches with higher amylopectin content tend to be more rapidly digested and produce softer, more cohesive textures, while higher amylose content is associated with firmer structures, reduced digestibility, and increased formation of resistant starch, particularly after cooling.

Starch digestibility varies depending on its structure and processing.
In feed, starch is broken down into glucose and fermented by microorganisms, particularly in ruminant animals. The rate and extent of starch digestion directly influence energy availability and animal performance.
In food, starch affects product texture, viscosity, and stability. During processing, starch undergoes gelatinisation, which increases digestibility and alters functional properties.

Starch analysis is typically performed using enzymatic methods that break down starch into glucose, which is then quantified. These methods allow accurate measurement of total starch content and can, where required, differentiate between digestible and resistant fractions across a wide range of food and feed matrices.

Starch testing is a routine analysis in food and feed laboratories. It provides valuable information on energy content, digestibility, and product performance.
When used alongside other parameters such as fibre, protein, and fat, starch analysis contributes to a more complete nutritional profile and supports informed decision-making in both food and feed applications.