Nutritional Composition Changes in Alaska Pollock (Gadus chalcogrammus) During and Between Bering Sea A and B Seasons

• Main Author: Hintermeister, Clara A.
• Other Authors: DeWitt, Christina A., Häse, Claudia C., Kwon, Jung Y., Park, Jae W., Food Science and Technology, Oregon State University. Graduate School
• Format: Master Thesis
• Language: English; unknown
• Published: Oregon State University
• Subjects: alaska pollock; Bering Sea; Alaska
• Online Access: https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/6t053n239

Alaska pollock (Gadus chalcogrammus) is a schooling whitefish native to the Bering Sea that is prized for its fillets, surimi, roe, and milt. Fillets are frequently used for popular products such as fish and chips. If collected, roe and milt are commonly exported to South Korea and Japan. However, no markets currently exist for roe and milt in the United States. The Alaska pollock fishery is one of the largest and most sustainably managed in the world. The fish are caught during two seasons in the year, season A and season B, which correspond to pre- and post-spawning periods in the fish reproductive cycle. To date, there has been no in-depth published data on seasonal changes in the composition of Alaska pollock fillets, roe and milt. In fact, there has been little data published on milt composition at all.This study found that the nutritional composition of Alaska pollock changes significantly from season A to season B, with only small changes within seasons. Fillets were higher quality in season B, with significantly higher protein, fat, vitamin D, omega-3 fatty acids, and essential amino acid index (EAAI) scores than in season A (p<0.05). Remarkably, the 1% increase in fat in season B correlated to a 20% increase in vitamin A, 99% increase in vitamin D and a 34 % increase in omega-3 fatty acids. The fat content in roe increased 71% from season A to season B, which correlated to significant increase in omega-3 and omega-6 fatty acids (p<0.05). However, vitamin D in roe decreased from the start to end of season A, with significant differences between Feb 3 and Mar 31 catch dates (p<0.05). Vitamin D content was significantly lower (64%) in season B than in season A (p<0.05). Milt composition remained remarkably consistent throughout season A, with only sporadic changes in fat, moisture and ash content (p<0.05). No other compositional changes were observed. Mineral content in fillets, roe and milt did not change significantly by catch date or season. On a dry basis, roe and milt have high protein, ...