Location: Food Processing and Sensory Quality Research
2023 Annual Report
Objectives
The objective of this research project is to stimulate consumer demand for U.S. farm raised catfish products and increase the profitability of the Catfish Industry through improved product quality.
Approach
By improving methodology for detecting the presence of off-flavor compounds in farm raised catfish, fewer off-flavor fish should reach the consumer, resulting in an increased demand and market share for U.S. farm raised catfish. To improve quality, this project will assess and provide feedback to individual catfish processing plants on the proportion of fish with off-flavors, passing through their plant and will work directly with these plants to control off-flavor issues at the plant. Additionally, current methods for mitigating off-flavors are primarily pre-harvest approaches, and can be costly, time consuming and increase fish stress. Post-harvest research is proposed to treat mildly off-flavored fillets with weak acids and marinades to mitigate the off-flavor compounds and expand the catfish line of products. Furthermore, methods for improving shelf life of fresh and frozen fillets will be examined using UV-C light, and vacuum packaging. Research proposed here will enable the existing U.S. Catfish Industry to better control quality, provide new co-products and improve shelf life.
Progress Report
In support of Objective 1, ARS researchers at New Orleans, Louisiana in collaboration with Riverence Holdings LLC, conducted a sensory evaluation study of trout fillets with 132 consumers to identify a rejection threshold for geosmin-induced off-flavor in fillets. The studies were conducted with two types of geosmin. One denoted with a minus sign and one denoted with a plus sign. Previous results indicated that levels of geosmin up to 600 parts per trillion (ppt; half minus, half minus, geosmin) were not sufficient to cause rejection. Therefore, researchers used a pure minus geosmin, to which people are more sensitive. The method achieved levels up to 2,000 ppt geosmin in fillets. ARS scientist have planned a second sensory evaluation study to determine practical limits in fish, where tasters reject the product. Trout fillets will be used as a model system for this research.
Also in support of Objective 1, research on consumer lexicons (postponed 12-month milestone) and sensitivity to geosmin off-flavor in water is currently being conducted. This is a multiregional study in the U.S. Where, ARA scientists have collected data from 188 consumers in the Southern region (at Louisiana State University), 115 consumers in the Northeastern region (at Rutgers University), and have expanded the research to include consumers in the Midwestern region (Bowling Green State University). Data from the first two regions have shown differences in the words consumers use to describe the aroma and flavor of geosmin in water between regions, and differential sensitivity to the compound between individuals.
Also in support of Objective 2, ARS scientists in New Orleans, Louisiana developed a method that uses stable isotope dilution to increase accuracy and precision when detecting geosmin and other off-flavor compounds in fish flesh. This method corrects for variability in traditional methods, which previously varied from 20-85%. This new method will let scientists conduct more accurate quantification of off flavors in fish flesh. In comparison to the traditional microwave distillation approach, which only processes single samples, this new method is able to analyze up to 20 samples at once, resulting in an approximately 160-fold increase in sample throughput. Additionally, it reduces the need for glassware as well as time spent on preparation and cleanup. These improved techniques can help identify strategies for prevention and mitigation treatments for off flavors in fish flesh moving forward.
In support of Objective 2, ARS researchers collaborated with Kodiak Island WildSource, a Sun’aq Tribe owned seafood business, to produce smoked catfish bellies as a value-added product. ARS scientists shipped catfish fillets and bellies, that were wet- or dry-brined, from a catfish processor to collaborators for smoking. FPSQ scientists conducted preliminary sensory testing on these prototypes with 70 consumers that commonly consume smoked meat. Seventy-five percent of these consumers reported positive purchase intent for wet-brined catfish bellies. These preliminary data also indicated that smoky flavor was considered “just about right.” The research has potential to add value to undervalued catfish nugget portions and oversized fish.
In support of Objective 2, ARS researchers at New Orleans, Louisiana have conducted a study to evaluate the capability of low doses of germicidal UV-C light for reducing the number of surface bacteria on fresh catfish fillets. This technique was found to reduce bacteria found on treated fillets five times, compared to untreated fillets. This reduction in bacteria was maintained over six days of refrigerated storage. Furthermore, no negative changes in quality, such as color or rancidity were observed following the treatment with UV-C light. These findings suggest that UV-C light can be effectively used, and used alongside other shelf-life extending techniques such as modified atmosphere packaging to improve the shelf life of fresh catfish fillets. In order to further explore this application, ARS scientist have started collaborations with Louisiana State University to investigate various packaging technologies and their effects on fish fillet shelf-life when combined with UV-C treatments.
Accomplishments
1. Sixty-eight percent of consumers are willing to try novel foods made from seafood byproducts. The demand for seafood is increasing, and greater production is resulting in more waste. Edible seafood byproducts such as bones and skin often go to waste or to non-food production streams. However, these byproducts can be safe to eat and provide valuable nutrients and health-promoting compounds. This research, led by Louisiana State University, in collaboration with ARS scientists at New Orleans, Louisiana, surveyed 904 consumers to explore perceptions of seafood byproducts. After learning of the safety and health benefits, 68% of consumers said they would try a food containing seafood byproduct. Providing appropriate product concepts can encourage trial of novel food sources like seafood byproducts. These data suggest that product development should begin with fish and seafood as a vehicle for seafood byproduct usage.
2. Air-fried catfish skin chips are well-received by consumers. Increasing the value of fish byproducts such as catfish skin can reduce waste and help support sustainable food systems. In research led by Louisiana State university, in collaboration with ARS scientists at New Orleans, Louisiana, evaluated sensory perceptions of air-fried catfish skin chips. Plain, lemon & pepper, paprika, and barbecue flavored chips were tested in two studies with 115 consumers each. Consumers liked barbecue flavored chips the most. Repeated exposure to the product increased acceptance and purchase intent. Information about protein content and sustainable byproduct usage also had a positive effect. Keeping catfish processing byproducts such as skins in the food supply can support food sustainability and increase profitability for the catfish industry. Air-fried catfish skin chips offer an acceptable food use of this byproduct.
Review Publications
Dupre, R. A., Ardoin, R., Trushenski, J., Jackson, C., Grimm, C., Smith, B. 2023. Dietary uptake of geosmin in Rainbow Trout (Oncorhynchus mykiss). Aquaculture. 571, 739458. https://doi.org/10.1016/j.aquaculture.2023.739458
Murillo, S., Ardoin, R., Prinyawiwatkul, W. 2023. Factors influencing consumers’ willingness-to-try seafood byproducts. Foods. 12(6), 1313. https://doi.org/10.3390/foods12061313.
Murillo, S. Ardoin, R., & Prinyawiwatkul, W. 2023. Consumers’ acceptance, emotions, and responsiveness to informational cues for air-fried catfish (Ictalurus punctatus) skin chips. Foods. 12(7), 1536. https://doi.org/10.3390/foods12071536
