Project Summary

This proposal addresses the aquaculture research priority of enhancing the economic value of fish by extending their shelf-life and enhancing quality and consumer acceptance. Specifically, by including antioxidants and flavonoids in the diets of fish prior to harvest, we will decrease off odor formation, improving fillet quality and consumer acceptance. This change in diet formulation of fish will result in enhanced deposition of vitamins E and C and flavonoids (phytochemicals) in fish muscle, creating a value-added food product. Functional foods are associated with increases in antiviral and antibacterial activity which slow down lipid degradation responsible for off odors, resulting in increased economic value. The hypothesis of the proposed study is that feeding fish essential antioxidants, such as vitamins C and E, in combination with flavonoids, known for activity against antibiotic-resistant bacteria, will promote antimicrobial and anti-oxidative properties in fish fillets. These properties will extend the shelf-life during ice storage of fish, maintaining a high quality product while minimizing off odors. These processes will be evaluated by analyzing the release kinetics of volatile organic compounds using Selected Ion Flow Tube Mass Spectrometry techniques in concert with conventional methods, allowing the correlation of the concentration of specific volatile substances with fish quality. Sensory evaluation will be carried out with conventional methods of acceptance of the raw filets obtained from each of the five dietary treatment groups and compared to fresh (1 day storage), allowing the correlation of the concentration of specific volatile substances with fish quality and liking.

Objectives

1. To formulate 5 experimental diets containing (A) enhanced levels of ascorbyl phosphate (1,200 mg AP/kg) and tocopherol acetate (800 mg TA/kg), (B) supplement of flavonoids (myricetin, kaempferol, quercetin, and rutin),(C) a combination of A and B, (D) ethanol/water extract from tropical fruit of aguaje (Mauritia flexuosa) or Peruvian maca (Lepidium meyeni), and (E) control diet supplemented with the recommended fish diet requirement level of AP and TA.
2. To perform growth experiments with rainbow trout Oncorhynchus mykiss (OSU) and yellow perch Perca flavescens (UWM) juveniles fed the diets above, but with 26 or 14% lipids, respectively, until there is a 10-fold body weight increase. Growth, diet utilization, and whole-body chemical composition will be examined. A second experiment will use fish of a size so that they will reach marketable size with 60 days of feeding and fillets will be harvested and stored refrigerated for 3, 6, and 12 days.
3. To analyze muscle lipid content, fatty acid profiles, thiobarbituric acid reactive substances (TBARS) and microbial counts on the fillets.
4. To use Selected Ion Flow Tube Mass Spectrometry (SIFT-MS) to measure the volatiles from fresh, stored, and cooked fillets obtained from 2 species of fish fed the 5 different diets. To measure the effect of ice storage, cooking of fillet from fish fed different diets on both the characteristic and “rancid” volatile compounds generated.
5. To measure the effect of refrigerated storage in association with perception, liking, and food choice using methods of human sensory testing.
6. To transfer knowledge of improved fish diets to aquafeed manufacturers as well as enhanced fish fillets quality through the NCRAC and other  outreach programs (Seafood Products Association and National Fisheries Institute).

Duration:  2 Years (January 1, 2024-December 31, 2025.

Participants

PI:  Konrad Dabrowski-The Ohio State University

Co-PI:  Dong-Fang Deng-University of Wisconsin-Milwaukee

Project Outline

Proposal

Award Amount

$209,144

Award Number

2022-38500-38103, Year 1, $97,326

2023-38500-40773, Year 2, $111,818