[Intermediate moisture foods: polysaccharide and protein gels]

Area of Science:

• Food Science and Technology
• Food Chemistry
• Microbiology

Background:

• Developing shelf-stable, nutritionally complete food products is crucial for various applications, including emergency preparedness and convenience.
• Traditional food preservation methods often compromise nutritional value or sensory qualities.
• The need for convenient, long-lasting meal substitutes drives innovation in food formulation and processing.

Purpose of the Study:

• To formulate concentrated food gels (20-40% water) that are chemically and microbiologically stable.
• To create nutritionally balanced meal substitutes suitable for travel, camping, and snacks.
• To evaluate the impact of different gelling agents (pectin, starch, protein) and additives on food stability and quality.

Main Methods:

• Preparation of high and low methoxyl pectin gels with added sweeteners and humectants (glucose syrup, sorbitol).
• Formulation of starch-based gels incorporating proteins and lipids, with humectants for water activity reduction.
• Development of protein gels using processed cheese technology, adjusting texture and water activity with humectants.
• Microbiological and chemical stability testing, including mold growth assessment and sensory evaluation after storage.

Main Results:

• Pectin gels (20% protein) achieved water activity (Aw) of 0.75-0.78, showing no mold growth or significant changes after 4 months at 20-38°C.
• Low methoxyl pectin gels (35% water, 26% protein, 15% lipids) had reduced Aw (0.84) with humectants.
• Starch gels (30% water) achieved Aw of 0.84-0.88, with texture varying based on starch type.
• Protein gels exhibited reduced Aw (0.86) with humectants, mimicking processed cheese textures.

Conclusions:

• Concentrated pectin, starch, and protein gels can be formulated to be chemically, microbiologically, and sensorially stable for extended periods.
• The use of humectants is effective in lowering water activity (Aw) to inhibit microbial growth in these concentrated food systems.
• These developed gels demonstrate potential as versatile, stable, and nutritionally balanced meal substitutes for various applications.