Ultrasonic Processing of Fruit and Vegetable Purees

In the competitive world of food production, besides the flavor of a product the sensory attributes of plant-derived products — especially texture and viscosity — play a crucial role in determining consumer acceptance. This is particularly true for tomato-based products like pasta sauces, salsas, and ketchup. Viscosity not only influences the visual appeal of these items but also affects mouthfeel and flavor release, all of which are critical for consumer satisfaction.

Ultrasonic Flavor and Texture Enhancement of Fruit and Vegetable Purees

The integration of ultrasonic processing in the production of fruit and vegetable pastes and purees offers a promising avenue for manufacturers seeking to optimize texture, enhance flavor, and reduce production costs. By leveraging this innovative technology, the food industry can meet evolving consumer demands for high-quality, flavorful products while maintaining efficiency and sustainability. After research and development has laid the scientific fundament and the food industry has adopted sonication as efficient technique for homogenizationa nd pasteurization, ultrasonic processing is on its way become the gold standard for creating superior plant-derived food products.
 

Understanding Viscosity in Plant-Derived Products

The viscosity profile of fruit and vegetable pastes is shaped by a complex interplay of insoluble solids—comprising pectins, hemicelluloses, cellulose, proteins, and lignin—interacting with a continuous matrix of soluble pectins, organic acids, sugars, and salts. While these naturally occurring compounds contribute to the overall viscosity, they often fall short of meeting the desired texture and mouthfeel required for optimal consumer acceptance.
To bridge this gap, food manufacturers frequently rely on thickening agents such as starches and gums (e.g., waxy maize starch, carrageenan, guar). However, these additives come with drawbacks, including increased costs, specialized handling requirements, and potential negative impacts on flavor and customer acceptance.

The Quest for Cost-Effective Solutions

Increasing the vegetable matter content in products can improve rheology but often leads to prohibitive formulation costs, especially in large-scale production. Traditional high-shear processing techniques, such as pressure homogenization, have been explored as a means to modify viscosity. However, these methods primarily disrupt cellular structures without significantly enhancing viscosity, particularly in higher solid-content products.
 

Advantages of Sonication and Manothermosonication of Vegetable Pastes and Purees

Ultrasonic processing represents a groundbreaking alternative for modifying the rheology of fruit and vegetable pastes. Manothermosonication – the synergistic combination of ultrasound with pressure and mild heat – is a proven alternative for conventional pasteurization to improve the microbial stability of vegetable purees and fruit juices.

Enhanced Nutritional Value:

• Increases bioavailability of lycopene, a powerful antioxidant linked to various health benefits.
• Preserves pectin levels, contributing to better gel formation and health benefits.
• Retains and enhances essential vitamins during processing.
• By effectively increasing the viscosity of products, ultrasonic processing can elevate perceived quality and value among consumers.

Improved Flavor:

• Extracts intracellular sugars, leading to a naturally sweeter flavor profile.
• Enhances overall taste experience by making sugars more accessible to the palate.
• Reduced Need for Additives: Ultrasonic treatment can enhance viscosity while decreasing the concentration of vegetable solids, leading to cost-effective formulations without compromising texture.
• Improved Mouthfeel: The treatment results in a ‘pulpier’ and creamier texture, enhancing consumer preference by presenting a more appealing mouthfeel.

Optimized Texture:

• Produces a smoother, more consistent texture in tomato products.
• Reduces unwanted graininess, resulting in a more appealing mouthfeel.
• Increases viscosity as intracellular sugars, carbohydrates and fibres are released.

Mild Non-Thermal Processing:

• Minimizes heat exposure, preserving sensitive nutrients and flavors.
• Reduces the risk of thermal degradation, maintaining the quality of the final product.

Microbial Stabilization and Pasteurization:

• Effectively reduces microbial load, enhancing food safety without compromising quality.
• Allows for lower processing temperatures, minimizing nutrient loss while ensuring product stability.

Increased Extraction Efficiency:

• Enhances the extraction of beneficial compounds, maximizing yield.
• Allows for lower water usage and reduced processing time.

Environmentally Friendly:

• Reduces energy consumption compared to traditional thermal processing methods.
• Potentially decreases waste and improves sustainability in food production.

Versatile Application:

• Can be applied to a variety of vegetable- and fruit-based products, from sauces to purees, allowing for innovation in product development.
• Suitable for the production of baby food.

Effect of sonication amplitude on the particle size distribution of tomato juice at 60°C for 15 min.
(picture and study: © Wu et al., 2008)

High-Performance Sonicators for Food Processing

Hielscher sonicators offer significant advantages for industrial food processing of vegetable and fruit purees, including sauces, soups, smoothies, and ketchups. Their advanced ultrasonic technology enhances the extraction of flavors and nutrients by breaking down cellular structures, resulting in smoother textures and improved mouthfeel. The convenient inline processing using ultrasonic inline reactors allow the reliable and efficient processing of large quantities under safe food-grade conditions.

The table below gives you an indication of the approximate processing capacity of our ultrasonicators:

Design, Manufacturing and Consulting – Quality Made in Germany

Hielscher ultrasonicators are well-known for their highest quality and design standards. Robustness and easy operation allow the smooth integration of our ultrasonicators into industrial facilities. Rough conditions and demanding environments are easily handled by Hielscher ultrasonicators.

Hielscher Ultrasonics is an ISO certified company and put special emphasis on high-performance ultrasonicators featuring state-of-the-art technology and user-friendliness. Of course, Hielscher ultrasonicators are CE compliant and meet the requirements of UL, CSA and RoHs.