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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Healthy Processed Foods Research » Research » Research Project #439532
Research Project: New Sustainable Processes, Preservation Technologies, and Product Concepts for Specialty Crops and Their Co-Products

Location: Healthy Processed Foods Research

2024 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 report documents progress for project 2030-41000-069-000D, titled, “New Sustainable Processes, Preservation Technologies, and Product Concepts for Specialty Crops and Their Co-Products”, which started in December 2020. In support of Sub-objective 1C, researchers in Albany, California, in collaboration with researchers from U.C. Berkeley investigated isochoric or constant volume freezing as one-step process to preserve and pasteurize orange juice and raw bovine milk at subfreezing temperatures. For raw bovine milk, the physicochemical and microbiological changes resulting from isochoric freezing at two different conditions of temperature and pressure were compared with those of refrigerated milk and pasteurized milk. For orange juice, the microbiological and physicochemical quality of isochoric frozen juice at three different conditions of temperature and pressure were compared with those of conventionally frozen juice and pasteurized juice. Overall, the study demonstrated that isochoric freezing can significantly increase the shelf-life of raw bovine milk and orange juice by reducing microbiological activity, whilst maintaining its nutritional content and physicochemical properties. Also, in collaboration with researchers from the produce safety and microbiology unit, in Albany, California, the effect of isochoric freezing at different conditions on pathogens (E. coli and Listeria monocytogenes) inoculated in raw milk and carrot juice was evaluated. Moreover, researchers in Albany, California, partnered with BioChoric LLC to study the impact of isochoric impregnation with CaCl2 on the microbiological, nutritional, and physicochemical properties of blueberries. They also investigated using isochoric freezing to enhance the quality and prolong the shelf-life of blueberries during refrigerated storage. The results showed a positive effect of the synergistic effect of calcium impregnation and isochoric freezing on the quality of blueberries. In support of Objective 3, ARS researchers in Albany, California, have collaborated with the researchers at North Dakota State University to investigate Maillard reaction between high-intensity ultrasound pre-treated pea protein isolate (PPI) and glucose. The impact of reaction time and pH on the conjugation process and the properties of conjugates were determined by browning index and glucose depletion. Secondary and tertiary structures of PPI were measured by Fourier-transform infrared spectroscopy analysis and intrinsic/extrinsic fluorescence spectroscopy. Furthermore, solubility and PPI and PPI-glucose conjugates solutions were evaluated. Moreover, significant progress was also made by developing snack extruded food products from by-products of wine making, evaluating their expansion and crunchiness characteristics, bioactive compounds, and sensory evaluation for product acceptability. Significant progress was achieved in Sub-objective 3A by researchers in Albany, California, in collaboration with researchers from the Technological Institute of Tepic, Nayarit, Mexico. This progress involved creating new formulations containing up to 20% jackfruit by-product. Subsequently, value-added expanded extruded snacks were manufactured and evaluated by 48 individuals of different ages and ethnic backgrounds, leading to positive feedback and high acceptability of the final products. Important progress was also made under Sub-objective 3B by optimizing the rheological behavior of high protein beverages made from various plant-based protein sources. The rheological profiles of nine selected commercial beverages and ten different formulations containing four to 20% of pea protein concentrate and 2two to 10% rice protein concentrate were evaluated under controlled temperatures of four degrees C (refrigeration temperature) and 22 degrees C (room temperature). After analyzing viscosity profiles at shear rates of up to 1000 reciprocal second (s-1), the viscosity value measured at 4 degrees C and a shear rate of 51.8 (s-1) was chosen. This selected value was closely related to previous studies suggesting that the approximate shear rate in the mouth is close to 50 (s-1). The chosen temperature was based on general acceptance that high-protein beverages are typically consumed at cool temperatures. All beverages evaluated, under the indicated temperatures, presented a non-Newtonian (linear) behavior, with a pseudoplastic characteristic. In support of Sub-objective 3C, ARS researchers in Albany, California, in collaboration with researchers at U.C. Berkeley, developed a new co-axial temperature controlled cryoprinting (TCC) system to produce plant-based printed food designed for dysphagia food. The system allows the food to self-crosslink and generate a gradient structure with complex textures. The technology was applied to print pea protein. ARS researchers are also working on modifying the system for flow production for the industry.


Accomplishments
1. Isochoric freezing provides safe raw bovine milk with extended shelf-life. Isochoric freezing can be used as a one-step process to pasteurize and preserve food products at subfreezing temperatures. However, there is a concern that despite potentially serious health risks, demand for raw milk is growing among consumers. ARS researchers in Albany, California, in collaboration with researchers from U.C. Berkeley have evaluated isochoric freezing as a one-step process to pasteurize and preserve raw milk. Isochoric freezing, when compared to refrigeration, and pasteurization resulted in superior milk quality with extended shelf-life. Isochoric freezing also inactivated pathogenic bacteria. This study indicates that isochoric freezing has the potential to pasteurize and significantly increase the shelf life of raw milk, while maintaining its nutritional and physiochemical content.

2. Isochoric freezing with calcium infusion results in high quality blueberries with extended shelf-life. Isochoric freezing allows food preservation at subfreezing temperatures without any ice formation inside the products. In addition, isochoric freezing can be used to infuse bioactive compounds into foods during preservation. Blueberries are a very popular fruit, but compared to other fruits, fresh blueberries are highly perishable. ARS researchers in Albany, California, have assessed isochoric freezing with calcium chloride infusion to preserve blueberries. Isochorically frozen blueberries showed similar appearance to fresh blueberries; the fruits did not lose weight during refrigeration and had higher nutrient content than refrigerated blueberries.

3. Glycation degree of PPI-conjugates prepared from the classic and ultrasound pretreated Maillard reaction. Pea protein isolate (PPI) has emerged as one of the most popular plant protein ingredients and greatly meets market expectations owing to its high nutritional value, competitive price, and sustainability. However, low water solubility has largely limited their broad applications in various food systems. Most studies performed glycation with the mixture of proteins and carbohydrates in the ultrasonic treatment process without subsequent heating. There is no study to assess the impact of high-intensity ultrasound as a pretreatment before the Maillard reaction on the functionalities of PPI. ARS researchers in Albany, California, have collaborated with researchers at North Dakota State University to compare the glycation degree of PPI-conjugates prepared from the classic and ultrasound pretreated Maillard reaction, respectively, and then evaluate the structural and solubility of the conjugates. This study could offer valuable insights into the study of soluble aggregates and the potential of high-intensity ultrasound for improving the solubility of pea protein isolate, thereby facilitating the utilization of pea protein as an alternative protein source in the food industry.

4. Isochoric freezing delivers high quality orange juice with extended shelf-life. The fruit and vegetable juice industries have been adversely affected by the decrease in demand for processed juices over the past few years. Commercial fruit and vegetable juices are traditionally heat-treated to destroy microorganisms. However, heat processing often induces undesirable changes leading to a decrease in consumer acceptance of processed juices. ARS researchers in Albany, California, in collaboration with researchers from U.C. Berkeley have evaluated isochoric freezing to preserve orange juice. Isochoric freezing retained the quality properties of orange juice and inhibited spoilage from microbial growth during refrigerated storage. Therefore, isochoric freezing can effectively be used to extend the shelf-life and improve the product quality in orange juice production with reduced pulp sedimentation, which has been a recognized technological issue in the juice industry.

5. New coaxial temperature controlled cryoprinting confers texture to 3D printed foods. 3D cryoprinting can provide texture to 3D printed foods. Food swallowing problems, a medical condition known as dysphagia, affects 1 of 6 adults in the United States. Studies have shown that dysphagia patients placed on texture modification diets based on pureed foods tend to have between 17-37% 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 U.C. 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.

6. Winemaking by-products fortification of formulations based on corn and lentil flour. The latest trends in food products focus on promoting consumer health by incorporating functional components, such as those found in winemaking by-products, into food formulations. This also helps to address the environmental issue of disposing of large amounts of grape by-products generated by the wine industry. ARS researchers in Albany, California, developed various formulations, including a mix of corn and lentil flour with natural flavoring agents, enriched with 5% and 20% of fermented Cabernet Sauvignon grape skin/seed and unfermented Chardonnay grape seed flours. The total phenol, total flavonoid, and anthocyanin content were higher in all formulations with 20% fermented Cabernet Sauvignon skin or unfermented Chardonnay seed flours, regardless of the content of corn and lentil flour in the formulations. This indicates that winemaking by-products have the potential to be used as functional and prebiotic ingredients, adding nutritional value to new functional food products while promoting diversified consumption of lentils and adding value to winemaking byproducts.


Review Publications
Su, X., Jin, Q., Xu, Y., Wang, H., Huang, H. 2024. Subcritical water treatment to modify insoluble dietary fibers from brewer’s spent grain for improved functionality and gut fermentability. Food Chemistry. 435. Article 137654. https://doi.org/10.1016/j.foodchem.2023.137654.
 Du, Z., Xu, Y., Liu, C., Li, Y. 2023. pLM4Alg: Protein language model-based predictors for allergenic proteins and peptides. Journal of Agricultural and Food Chemistry. 72(1):752-760. https://doi.org/10.1021/acs.jafc.3c07143.
 Gao, K., Chang, L., Xu, Y., Rao, J., Chen, B. 2023. Water-soluble fraction of pea protein isolate is critical for the functionality of protein-glucose conjugates obtained via wet-heating Maillard reaction. Food Research International. 174. Article 113503. https://doi.org/10.1016/j.foodres.2023.113503.
 Gao, K., Xu, Y., Rao, J., Chen, B. 2023. Maillard reaction between high-intensity ultrasound pre-treated pea protein isolate and glucose: Impact of reaction time and pH on the conjugation process and the properties of conjugates. Food Chemistry. 434. Article 137486. https://doi.org/10.1016/j.foodchem.2023.137486.
 Xu, Y., Sismour, E., Tucker, F., Rasberry, J., Zhao, W., Rao, Q., Zhao, Y., Haff, R.P., Yousuf, A., Gao, M., Chen, A. 2024. Structural and functional properties of Kabuli chickpea protein as affected by high hydrostatic pressures. ACS Food Science and Technology. 4(2):528-536. https://doi.org/10.1021/acsfoodscitech.3c00640.
 Du, Z., Ding, X., Hsu, W., Munir, A., Xu, Y., Li, Y. 2023. pLM4ACE: A protein language model based predictor for antihypertensive peptide screening. Food Chemistry. 431. Article 137162. https://doi.org/10.1016/j.foodchem.2023.137162.
 Zhao, W., Xu, Y., Dorado, C., Bai, J., Chau, H.K., Hotchkiss, A.T., Yadav, M.P., Cameron, R.G. 2023. Modification of pectin with high-pressure processing treatment of fresh orange peel before pectin extraction: Part II. The effects on gelling capacity and emulsifying properties of pectin. Food Hydrocolloids. 149. Article 109536. https://doi.org/10.1016/j.foodhyd.2023.109536.
 Zhao, W., Xu, Y., Dorado, C., Chau, H.K., Hotchkiss, A.T., Cameron, R.G. 2023. Modification of pectin with high-pressure processing treatment of fresh orange peel before pectin extraction: Part I. The effects on pectin extraction and structural properties. Food Hydrocolloids. 149. Article 109516. https://doi.org/10.1016/j.foodhyd.2023.109516.
 Bilbao-Sainz, C., Olsen, C.W., Chiou, B., Rubinsky, B., Wu, V.C., McHugh, T.H. 2024. Benefits of isochoric freezing for carrot juice preservation. Journal of Food Science. 89(3):1324-1336. https://doi.org/10.1111/1750-3841.16963.
 Chiou, B., Cao, T.K., McCaffrey, Z., Bilbao-Sainz, C., Wood, D.F., Glenn, G.M., Orts, W.J. 2024. Properties of gluten foam composites containing different fibers and particulates. Journal of Polymers and the Environment. https://doi.org/10.1007/s10924-024-03295-5.