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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

2022 Annual Report

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.

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
In support of Objective 1, ARS researchers in Albany, California, investigated the effects of isochoric freezing on the physicochemical, nutritional and microbiological qualities of sweet cherry and pomegranate and compared those with refrigeration and conventional freezing. Researchers also evaluated isochoric impregnation as a potential novel technology to infuse bioactive compounds into solid foods for the development of fortified functional food products during isochoric freezing preservation. Significant progress was made towards commercialization of the previously patented Pop Oats snack product, including processing equipment upgrades, the introduction of packaging equipment, shelf life evaluation, and sensory testing. In support of Objective 2, ARS researchers developed novel intermittent infrared drying (IRD) technology for brewery spent grain (BSG) that was shown to be as efficient as more costly hot air-drying technology. Dense nutrient concentration, low cost and large volume availability makes dried BSG a desirable potential value-added waste product. The novel intermittent infrared drying (IRD) with mixing requires less time and thermal energy than hot air drying (HAD), while achieving a safe water activity, crispy texture, and roasted aroma. BSG dried via IRD and HAD were compared by chemical and physical analysis. A mice-feeding study was conducted in which BSG dried by the two drying methods was incorporated into diet at three concentrations to determine potential health benefits. Also, dry fractionation by particle size was demonstrated as a practical technology to increase protein and dietary fiber in dried BSG fine fractions and was evaluated relevant to nutritional and health benefits of high protein and dietary fiber dry-fractioned BSG fines in comparison to regular dried BSG powder. In support of Objective 3, ARS researchers used novel ingredients from specialty crops and original extrusion cooking processing conditions to develop gluten-free snack products with added functional properties. The influence of the adding fiber-rich ingredients, such as soluble corn fiber and passion fruit, was also evaluated. The incorporation of these ingredients in gluten-free formulations based on chickpeas and rice could provide functional formulations for innovative, gluten-free, extruded snack products as an alternative for people with celiac disease.

1. Influence of drying methods on health indicators of brewers spent grain for potential upcycling into food products. Brewers spent grain (BSG), a by-product of beer brewing, is known to be high in nutritional content including protein and fiber. It can be dried and used as a nutritional supplement or food additive, but the cost of traditional hot air drying can be prohibitive. ARS researchers in Albany, California, applied a novel infrared drying technology to BSG and demonstrated that nutritional content of the dried product was not significantly different as compared to hot air drying. This research provides the means for more economical use of BSG to add value and nutrition to other food products.

2. The effect of isochoric freezing on fruit quality. Bacterial and fungal infection are among the leading causes of reduced quality in fruits. ARS researchers in Albany, California, have demonstrated the efficacy of isochoric freezing to prevent infection in cherries and pomegranates while maintaining quality typically affected by traditional freezing. Isochoric frozen fruits were successfully preserved for 30 days with similar properties to fresh fruits. This technology provides the means for higher quality fruit and reduced food waste.

Review Publications
Vega-Galvez, A., Uribe, E., Pasten, A., Vega, M., Poblete, J., Bilbao-Sainz, C., Chiou, B. 2022. Low-temperature vacuum drying as novel process to improve papaya (Vasconcellea pubescens) nutritional-functional properties. Future Foods. 5. Article 100117.
Inzunza-Soto, M., Thai, T.T., Sinrod, A., Olson, D.A., Avena Bustillos, R.D., Li, X., Rolston, M.R., Wang, S.C., Teran-Cabanillas, E., Yokoyama, W.H., McHugh, T.H. 2021. Health benefits of first and second extraction drum-dried pitted olive pomace. Journal of Food Science. 86(11):4865-4876.
Thai, T.T., Avena Bustillos, R.D., Alves, P., Pan, J., Osorio-Ruiz, A., Miller, J.D., Tam, C.C., Rolston, M.R., Teran-Cabanillas, E., Yokoyama, W.H., McHugh, T.H. 2022. Influence of drying methods on health indicators of brewers spent grain for potential upcycling into food products. Applied Food Research. 2(1). Article 100052.
Zhao, H., Avena Bustillos, R.D., Wang, S.C. 2022. Extraction, purification and In Vitro antioxidant activity evaluation of phenolic compounds in California olive pomace. Foods. 11(2). Article 174.