Project : USDA ARS

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Research Project: New Sustainable Processes, Preservation Technologies, and Product Concepts for Specialty Crops and Their Co-Products

Location: Healthy Processed Foods Research

2025 Annual Report

Objectives
The overall long-term objective of this project is to develop commercially-viable new sustainable processes, preservation technologies, and product concepts for specialty crops (fruits, vegetables, nuts, and legumes) and co-products of these crops. Specifically, during the next five years we will focus on the following objectives: Objective 1: Enable economical, input-efficient, and sustainable methods for processing and preservation of specialty crops while improving product quality and value. Subobjective 1A: Develop solar thermal alternatives for heat-intensive specialty crop processing unit operations. Subobjective 1B: Develop preservation strategies for reducing or eliminating the use of sulfites in dried fruit crops. Subobjective 1C: Develop more energy-efficient alternatives to conventional drying and freezing unit operations. Objective 2: Increase the commercial value of specialty crop co-products and difficult-to-market (No. 2 grade, for example) fruits/vegetables by processing into functional food ingredients. Objective 3: Enable value-added processing strategies for novel/emerging specialty crops, including protein sources from plants. Subobjective 3A: Develop new, protein-balanced ready-to-eat (RTE) pasta and snack foods with relevant functional attributes and acceptability made from legumes and specialty crops, through environmentally-friendly processing technologies. Subobjective 3B: Design innovative, delicious functional beverages and high-moisture foods from sustainable plant-based protein ingredients, using state-of-the art, minimally-thermal processing technologies to render products that have unique nutritional attributes and health benefits. Subobjective 3C: Leverage the unique advantages of 3D multilayer lithography and 3D cryo-lithography technology to form optimally-textured meat analogs from plant-based protein ingredients.

Approach
1A: Utilize solar thermal energy in evaporative concentration, blanching, and bin drying, with the goal of deriving up to 100% of the required heat from sunlight. For each system, the processing conditions will be established, an exergetic analysis performed, and the process designed and tested at pilot scale. Product quality will be measured and optimized alongside processing conditions. 1B: Reduce the sulfite content of dried fruits by 50% to 100% while maintaining organoleptic quality and nutrition equivalent to sulfited controls. For each fruit, various preservative ingredients and blanching pretreatments will be screened for individual and synergistic benefits on product quality metrics. Synergistic combinations will be applied to fruits that will be dried using various protocols. Optimal combinations of preservatives, blanching treatments, and drying protocols will be determined. 1C: Utilize infrared drying, isochoric freezing, and other promising technologies to obtain high-quality fruit and vegetable products and assess the energy efficiency of these technologies, with the rationale that these technologies will shorten processing time and operate at milder temperatures than conventional controls. 2A: Determine optimal operating conditions for processing raw co-products and low-grade products into shelf-stable ingredients, balancing throughput and product quality. Raw materials will be processed with pilot-scale unit operations such as drying, blanching, pasteurization, vacuum forming, casting, and freezing. 2B: Incorporate powdered specialty crop co-products with known antioxidant and antimicrobial activities into edible films and coatings applied to perishable foods via casting, dipping, and electrostatic spraying. Cast films will be characterized by scanning electronic microscopy, water vapor and oxygen permeability, mechanical properties, and various other quality metrics. 3A: Process legume pulses’ and specialty crops’ fractions (peels and hulls) into ready-to-eat, protein-balanced expanded extruded snacks and functional pasta. A co-rotating twin-screw extruder system will be used to process novel-formulated mixed flours into the new products. Processing variables will be studied to optimize product quality and mechanical/thermal energy input. 3B: Transform legume pulse protein concentrates, isolates, and specialty crops into novel healthy beverages and meat analogs. For beverages, legume pulse proteins and other fiber- and phytonutrient-rich specialty crop ingredients will be blended into nutritionally-balanced mixtures, solubilized, and processed by a high-pressure homogenizer. Meat analogs will be developed using high moisture protein fibration extrusion. 3C: Transform plant proteins into meat analogs with desirable functional and sensory properties using 3D multilayer lithography and 3D cryo-lithography. Various formulations of pulse- and legume-based proteins and other specialty crop-based additives will be tested. Processing parameters will include syringe temperature, extrusion speed, and nozzle temperature/diameter. Chemical, physical, rheological, and sensory properties of the 3D-printed products will be optimized.

Progress Report
This is the final report for project 2030-41000-069-000D, "New Sustainable Processes, Preservation Technologies, and Product Concepts for Specialty Crops and Their Co-Products", which has been replaced by new project 2030-30600-005-000D, "Novel and Sustainable Processing Technologies and Healthy Food Ingredients". For additional information, see the new project report. In support of Sub-objective 1, significant progress was made by ARS researchers in Albany, California, in collaboration with researchers from the University of California, Berkeley, by developing a new freezing technology that is more energy-efficient than conventional freezing. This technology, named isochoric freezing, is a pressure freezing technique that allows preservation of food materials at subfreezing temperature without formation of ice, eliminating ice damage and generating a pressure as high as 210 MPa at minus 22 degrees C. Therefore, isochoric freezing can be used to extend the shelf-life of food products by reducing deleterious chemical reactions through storage at subfreezing temperatures as well as hinder microbial growth at high pressures. During the life of the project, researchers have shown the potential of isochoric freezing to preserve quality and nutritional properties of solid and liquid foods such as tomatoes, cut potatoes, cherries, tilapia fish, pomegranate arils, strawberries, blueberries, carrot juice, pomegranate juice, orange juice, and raw milk. Researchers also demonstrated that isochoric freezing could be a beneficial alternative to conventional heat treatment for pasteurization of juices and raw milk since the applied pressures resulted in pathogenic bacteria inactivation. Also, this technology was used to infuse bioactive compounds into solid foods for the development of fortified functional food products. Researchers increased the vitamin C content in cut apples, cut potatoes, pomegranate arils, cherries, and strawberries as well as the calcium content in blueberries and strawberries. Furthermore, emulsion-based foods such as milk, cream, and sauces are highly susceptible to physical instability during conventional freezing and thawing processes. The thawed product can destabilize into an oily and water phase. The absence of ice crystal formation during isochoric freezing enabled the preservation of emulsion-based food products such as dairy cream with freeze-thaw stability. In addition, scientists demonstrated that isochoric freezing could reduce energy expenditure on an industrial level as no ice formation takes place inside the food. At a global scale, if the total frozen food capacity (estimated at about 31.3 billion kg) were processed under isochoric conditions at minus 5 degrees C rather than isobaric conditions at the industry-standard of minus 18 degrees C, energy use could be reduced by as much as 6.49 billion kWh each year (equivalent to 843.33 million U.S. dollars in annual savings). For Objective 3, ARS researchers in Albany, California, collaborated with researchers at ARS in Fort Pierce, Florida, Florida State University, North Dakota State University, and Kansas State University to utilize different non-thermal processing technologies (high pressure processing, ultrasound, and enzymatic hydrolysis) to improve the functionality of plant-based proteins, including chickpea, pea, and sorghum. Researchers demonstrated that high-pressure processing (HPP) modified chickpea protein’s secondary and tertiary structures, therefore enhancing their functional properties, including water/oil absorption capacities, emulsification, and foaming capacities. The results demonstrate that HPP treatment may be beneficial for potential functional food ingredient applications. In addition, high-intensity ultrasound pretreatment was also found to alter secondary and tertiary structures of pea protein isolates and is an effective method to improve their solubility. Researchers also used a novel enzymatic approach to address the current challenge in the extraction of sorghum protein. The results demonstrated that the enzymatic processing using a-amylase and cellulase on sorghum materials is feasible in producing sorghum proteins and provides insights into their basic properties and functionality. Important progress has also been made under Objective 3. ARS researchers in Albany, California, in collaboration with researchers at Virginia Tech and Kansas State University, have conducted a techno-economic analysis of producing antioxidant peptides from whole sorghum stillage, a by-product of bioethanol production and rich in protein content. Whole sorghum stillage holds promise as a source for producing antioxidant peptides, and evaluation of the economic feasibility of converting it into antioxidant peptides through enzymatic hydrolysis is essential. The process design entails enzymatic hydrolysis, followed by separation and drying processes to yield both an antioxidant peptide product and a high-fiber co-product. Three distinct scenarios were examined, and each considered different protease sources and enzymatic hydrolysis conditions. The processing facility is assumed to be adjacent to a sorghum bioethanol plant, and total capital investments (TCI) were estimated. The minimum selling price of antioxidant peptides (MSPP) was determined for the economic viability of processing compared to the market prices of protein and artificial antioxidant products. Furthermore, an economic sensitivity analysis was conducted to identify critical parameters influencing the economic performance of the process. It was found that implementing advancements in processing parameters and reductions in economic variables could significantly decrease the minimum selling price. This study furnishes essential economic metrics for antioxidant peptide production from whole sorghum stillage, offering valuable insights applicable to the treatment of other grain stillage or protein-rich agricultural waste. Significant progress has been achieved in support of Sub-objective 3A. ARS researchers in Albany, California, in collaboration with researchers from Universidad Complutense de Madrid in Spain, Universidad Nacional de Moquegua in Peru, and the Technological Institute of Tepic in Mexico, have developed several new, protein-balanced ready-to-eat (RTE) pasta and snack foods with relevant functional attributes and acceptability made from legumes and specialty crops through extrusion process. In detail, new functional extruded products have been developed based on combinations of corn and lentil flour with added salt, sugar, and resistant starch V, and fortified winemaking by-products (fermented and unfermented pomace/pomace seeds). The developed extrudates were analyzed for bioactive content. The findings show that among the experimental formulations, those with the highest concentration (20 percent) presented the greatest amounts of total dietary fiber, arabinoxylans, resistant starch, phenols, flavanols, and anthocyanins, and the lowest content of raffinose and stachyose. Moreover, new gluten-free extruded snack-type products based on rice and chickpea and fortified with passion fruit skin have also been developed, and the functional properties of extruded snack-type products. The results demonstrated that the extruded formulations preserved the amounts of the phenolic compounds but caused a decrease in the antioxidant activity of 50 percent of the analyzed samples. The results of the effects of the ingredients used for fortifying the formulations highlighted the complexity of the analyzed formulations, revealing that their composition is influenced not only by the presence of Fibersol® and passion fruit but also by the interaction between these two ingredients. These study results clearly demonstrate that extrusion is an effective method for developing new healthy food products and adding value to underutilized commodities. Relevant progress was made under Sub-objective 3C, by developing a Temperature Controlled Cryoprinting (TCC) with coaxial nozzle printing technique to print food suitable for dysphagia patients. Dysphagia, a medical condition of difficulty swallowing, affects one of six adults in the United States. Studies have shown that dysphagia patients placed on texture modification diets based on puree foods tend to have between 17 to 37 percent lower energy intake than those on regular diets because of the loss of food appeal. ARS researchers in Albany, California, in collaboration with researchers from the University of California, Berkeley, have developed a new co-axial temperature controlled cryoprinting system to manufacture printed foods designed for dysphagia food. The new system allows the generation of structures that confer texture to 3D printed food, providing dysphagia patients with visually and texturally appealing nutritious foods. Scientists also demonstrated that TCC enables printing of super low-viscosity materials while maintaining high printing accuracy, which is an advantage over conventional 3D printing. TCC can also modify the texture of printed foods without the need to change the food formulation. Furthermore, a novel printing strategy based on TCC was introduced to replicate a more natural marbling structure to enhance the visual appeal of dysphagia-friendly foods.

Accomplishments
1. Techno-economic analysis of antioxidant peptides production from whole sorghum stillage. Over 30% of sorghum grown in the United States is used for bioethanol production, resulting in large quantities of the by-product whole sorghum stillage (WSS). While WSS is rich in protein and shows promise as a source for producing antioxidant peptides for value-added utilization, the economic viability of the production process remains uncertain. To address this, ARS researchers in Albany, California, in collaboration with researchers at Virginia Tech and Kansas State University, have conducted a techno-economic analysis to assess the economic feasibility of enzymatic hydrolysis of sorghum for antioxidant peptide production and to identify potential strategies for cost reduction. The results suggested that optimizing processing parameters while combining with reductions in economic variables can substantially decrease the minimum selling price. This study provides critical economic benchmarks for antioxidant peptide production from WSS and offers valuable insights that may apply to other grain stillage or protein-rich agricultural by-products.

2. A new approach for better preserving emulsion-based food products at subfreezing temperatures. Many types of foods contain oil-in-water emulsions, including milk, creams, fruit beverages, desserts, dressings and sauces. Some of these foods could benefit from storage at subfreezing temperatures to increase their shelf-life. However, ice formation during freezing causes food destabilization, such as oil separation, ruling out their preservation at subfreezing temperatures. ARS researchers at Albany, California, in collaboration with researchers from U.C. Berkeley, have developed a method for maintaining freeze-thaw stability of emulsion-based products. The method is based on isochoric freezing, a technology involving storage under pressure that allows preservation at subfreezing temperatures without ice formation within the food, eliminating the cause of food destabilization. This method provides a valuable tool to the food industry to develop emulsion-based frozen food products in the market.

3. A novel approach for improving postharvest preservation of fresh strawberries. Strawberries are highly perishable, with rapid microbial spoilage, weight loss and softening during storage. Traditional refrigeration slows decay but does not fully preserve freshness, limiting shelf life and contributing to postharvest losses. ARS researchers at Albany, California, in collaboration with researchers from U.C. Berkeley, developed and applied an isochoric impregnation technique where strawberries were immersed in sucrose-based solutions containing calcium chloride and vitamin C, and stored under pressure at sub-zero temperatures. The strawberries were then transferred to standard refrigeration. Compared to control refrigerated strawberries, the treated strawberries showed reduced weight loss and microbial load, and better firmness and color. The application of isochoric freezing and impregnation could transform postharvest handling of soft fruits. This technology may help farmers, distributors and retailers reduce spoilage, extend market reach and minimize food waste, especially for export-oriented supply chains and high-value produce.

4. A novel approach for preventing discoloration in ground beef. The cattle industry is a vital part of the U.S. economy, and global consumption of beef is predicted to increase by 10% between 2023 and 2032. However, in the United States, an estimated 194.7 million kg of nutritious beef is discarded each year due to discoloration, causing economic losses of $3.73 billion. The industry has used modified atmosphere packaging for fresh meat products to increase shelf-life and reduce oxidative deterioration. However, as soon as the meat is exposed to air, it will oxidize and turn brown. ARS researchers in Albany, California, in collaboration with researchers from U.C. Berkeley, developed a method to preserve color and reduce microbial load during refrigeration storage. When compared with control refrigerated samples, ground beef processed under very cold and pressurized conditions maintained its red color much longer and had a greatly extended shelf-life. The meat industry could readily adapt their package methods to incorporate this approach, thereby increasing food availability and revenue.

U.S. DEPARTMENT OF AGRICULTURE

Healthy Processed Foods Research: Albany, CA