Maintaining a soft, chewy texture in high-protein snack bars over their shelf life can be challenging due to various factors that contribute to hardening. Understanding these causes and implementing strategic formulation adjustments are crucial for maintaining the desired softness over time.
Causes of Hardening in High-Protein Snack Bars
There are several mechanisms leading to bar hardening including protein-protein interactions, Maillard reactions, water activity and migration, and sugar crystallization. Milk proteins and plant based protein powders absorb water at variable rates and form networks that increase rigidity of the bar matrix, becoming too firm in texture over time. The Maillard reaction between reducing sugars and amino groups in proteins leads to the formation of cross-links, contributing to increased hardness. This reaction is more pronounced during storage, especially at higher temperatures. Imbalances in water activity between the different components of the bar can cause moisture migration. This migration can lead to localized drying and hardening of certain regions within the bar. Sugars and polyols used as sweeteners can crystallize over time, contributing to a harder texture. The extent of crystallization depends on the types of sugars used and storage conditions.
Strategies to Maintain Softness in Formulations
There are many ingredient and formulation strategies that can be employed to mitigate bar hardening if they are properly implemented. Examples include use of protein blends, modified proteins, non-crystallizing sweeteners such as glycerin, soluble fiber syrups and softening agents such as vegetable oils and nut butters. Enrobing bars in chocolate and adding high protein crisps can be beneficial in improving texture. High moisture barrier packaging such as metalized films delays hardening effects.
Merlin has helped bar manufacturers reformulate high protein snack bars with these strategies that resulted in increased shelf life, eliminated sugar crystallization, and maintained bar softness.
By carefully selecting and modifying ingredients, optimizing the formulation, and controlling processing and storage conditions, manufacturers can develop high-protein snack bars with milk proteins that maintain their softness and consumer appeal throughout their shelf life. Contact Merlin if you’d like to discuss how we may be able to help.