Nutritional Composition Differences of Alaska Pollock (Gadus Chalcogrammus) During and Between Bering Sea a and B Seasons Clara A
NUTRITIONAL COMPOSITION DIFFERENCES OF ALASKA POLLOCK (GADUS CHALCOGRAMMUS) DURING AND BETWEEN BERING SEA A AND B SEASONS CLARA A. HINTERMEISTER, CHRISTINA A. MIRELES DEWITT, QUENTIN FONG COASTAL OREGON MARINE EXPERIMENT STATION OSU SEAFOOD LAB ASTORIA, OR BACKGROUND
• Schooling whitefish native to North Pacific • One of the largest single- species fisheries in the world • Majority caught in the Bering Sea • Season A: winter-spring • Season B: summer-fall BACKGROUND • Economically valuable: • 45% of production volume and 33% of total value of Alaska fisheries in 2014 • 67% of total Alaska groundfish catch in 2015 • Many products produced from Alaska Pollock: • Surimi and surimi seafood • Fillets • Fish Sticks • Mentaiko and Tarako • Shirako • Fish meal OBJECTIVES AND IMPORTANCE • To determine if seasonality and catch date affect nutritional composition • To develop nutrition profile(s) for Alaska Pollock fillets, milt and roe • To provide valuable information to processors about possible composition changes • To aid in the development of value-added Alaska Pollock products SAMPLE COLLECTION AMERICAN SEAFOODS, 2015 A Season B Season
Fillet, Roe, Milt – Fillet, Roe* – n=10/date/type n=10/date/type • February 3 • July 15 • February 17 • August 15 • March 3 • March 16 *Roe only on 7/15 • March 31
Ntotal = 150 Ntotal = 30 ANALYSES
PROXIMATE: • FAT • PROTEIN • MOISTURE • ASH FAT-SOLUBLE VITAMINS (A, D, E) FATTY ACIDS AMINO ACIDS MINERALS PROXIMATE ANALYSIS
Fat Protein
Acid hydrolysis Kjeldahl nitrogen Mojonnier determination
Moisture Ash
Drying oven Muffle furnace 16 h at 103°C 12- 48 h at 525°C VITAMIN METHOD DEVELOPMENT • Based off Zonta (1982) • Two 25 cm C18 columns • 44°C • Mobile phase: • A - 80% Acetonitrile / 20% Methanol • B - Water • Flow rate:1.5 ml/min • 40 minute gradient program VITAMIN METHOD DEVELOPMENT Vitamin E Standard Curve Vitamin D2 Standard Curve 400000 100000 y = 281250x - 1317.5 y = 1E+06x - 1019.8 300000 80000 R² = 0.9961 R² = 0.9998 60000 200000
Area 40000 Axis Title 100000 20000 0 0 0 0.5 1 1.5 0 0.02 0.04 0.06 0.08 ug Alpha-Tocopherol ug Ergocalciferol
E A D2 D3
Vitamin A Standard Curve Vitamin D3 Standard Curve 800000 120000 y = 6E+06x - 898.66 100000 y = 2E+06x - 187.13 600000 R² = 0.9989 80000 R² = 0.9998 400000 60000 Area Area 40000 200000 20000 0 0 0 0.02 0.04 0.06 0.08 0.1 0.12 0 0.02 0.04 0.06 0.08 ug Retinol ug Cholecalciferol VITAMIN METHOD DEVELOPMENT • Saponification • 50% KOH • 30 minutes at 70°C • Extraction • Hexane • Evaporation • Under nitrogen • Sample resuspended in 50% ethanol/50% methanol VITAMIN METHOD DEVELOPMENT
Fillet
A D2 D3 E
Milt E A D2 D3
Roe E A D2 D3 RESULTS – FILLET PROXIMATE ANALYSIS
Sample Date % Fat % Protein % Moisture % Ash 2/3/15 0.44 ± 0.20 14.51 ± 0.83 83.07 ± 0.37 1.31 ± 0.02a 2/17/15 0.40 ± 0.09 14.87 ± 0.86 83.12 ± 0.59 1.30 ± 0.08ab 3/3/15 0.46 ± 0.08 15.13 ± 0.57 83.07 ± 0.78 1.35 ± 0.04ab 3/16/15 0.37 ± 0.14 15.14 ± 0.88 83.31 ± 0.53 1.36 ± 0.05b 3/31/15 0.39 ± 0.08 15.23 ± 0.89 83.77 ± 1.10 1.29 ± 0.06ab Season A Average 0.41 ± 0.13 14.98 ± 0.82 83.27 ± 0.37 1.32 ± 0.02 7/15/15 0.57 ± 0.10x 16.18 ± 0.71x 82.61 ± 0.68 1.45 ± 0.07x 8/15/15 0.44 ± 0.08y 15.35 ± 0.68y 83.02 ± 0.53 1.36 ± 0.08y Season B Average 0.50 ± 0.10* 15.77 ± 0.80* 83.02 ± 0.53* 1.40 ± 0.07* * Denotes Season B averages significantly different from Season A averages (p<0.05) ab Denotes significant differences within Season A (p<0.05) xy Denotes significant differences within Season B (p<0.05) RESULTS – ROE PROXIMATE ANALYSIS
Sample Date % Fat % Protein % Moisture % Ash 2/3/15 1.72 ± 0.16 23.99 ± 3.00 71.45 ± 2.74 1.61 ± 0.16 2/17/15 1.78 ± 0.28 23.66 ± 2.36 71.13 ± 2.51 1.49 ± 0.11 3/3/15 1.64 ± 0.34 22.92 ± 2.14 71.56 ± 2.42 1.63 ± 0.30 3/16/15 1.62 ± 0.23 23.36 ± 1.16 71.70 ± 1.54 1.64 ± 0.18 3/31/15 1.64 ± 0.17 22.53 ± 2.01 72.41 ± 5.83 1.63 ± 0.21 Season A Average 1.68 ± 0.24 23.17 ± 1.87 71.65 ± 2.28 1.60 ± 0.20 Season B Average 2.87 ± 0.20* 23.60 ± 2.11 70.22 ± 5.80* 1.63 ± 0.14
* Denotes Season B averages significantly different from Season A averages (p<0.05) RESULTS – MILT PROXIMATE ANALYSIS
Sample Date % Fat % Protein % Moisture % Ash
2/3/15 1.93 ± 0.17ab 12.77 ± 0.17 84.60 ± 0.07ab 1.71 ± 0.08bcd
2/17/15 2.13 ± 0.53b 12.22 ± 0.53 85.30 ± 0.07a 1.61 ± 0.07ad
3/3/15 1.99 ± 0.20a 12.44 ± 0.20 84.92 ± 0.04ab 1.56 ± 0.07a
3/16/15 1.72 ± 0.18a 12.37 ± 0.18 84.91 ± 0.14ab 1.64 ± 0.08abcd
3/31/15 1.75 ± 0.17ab 13.02 ± 0.17 84.10 ± 0.11b 1.75 ± 0.06bc
Season A Average 1.91 ± 0.32 12.57 ± 0.77 84.76 ± 0.85 1.65 ± 0.11
abcd Denotes significant differences within Season A (p<0.05) RESULTS - FAT Changes in Fat Content During and Between Catch Seasons for Fillets, Milt and Roe 3
2.5
2 Fillets
1.5 Roe % Fat Milt 1 Season A Season B
0.5
0 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug Catch Date RESULTS – FILLET VITAMINS Sample Date A (µg/85 g) D3 (µg/85 g) E (mg/85 g) 2/3/15 2.78 ± 0.68a 0.76 ± 0.36 0.25 ± 0.21 2/17/15 3.80 ± 0.85b 0.74 ± 0.31 0.23 ± 0.17 3/3/15 2.29 ± 0.64b 0.57 ± 0.28 0.35 ± 0.19 3/16/15 2.89 ± 0.32ab 0.77 ± 0.25 0.25 ± 0.21 3/31/15 3.63 ± 0.97ab 1.25 ± 0.88 0.47 ± 0.17 Season A Average 3.38 ± 0.83 0.87 ± 0.50 0.31 ± 0.20 7/15/15 3.79 ± 0.67 1.32 ± 0.41 0.20 ± 0.11x 8/15/15 4.52 ± 1.20 1.33 ± 0.59 0.42 ± 0.22y Season B Average 4.14 ± 1.00* 1.33 ± 0.49* 0.31 ± 0.20 * Denotes Season B averages significantly different from Season A averages (p<0.05) ab Denotes within Season A xy Denotes changes within Season B RESULTS – ROE VITAMINS
Sample Date A (µg/15 g) D3 (µg/15 g) E (mg/15 g) 2/3/15 7.61 ± 4.61ab 1.10 ± 0.45ac 0.76 ± 0.37 2/17/15 6.45 ± 3.19ab 1.38 ± 0.82c 0.78 ± 0.28 3/3/15 15.16 ± 9.74a 0.74 ± 0.69a 1.03 ± 0.45 3/16/15 6.28 ± 3.45b 0.72 ± 0.27ac 1.01 ± 0.44 3/31/15 11.99 ± 7.93ab 0.57 ± 0.27b 0.93 ± 0.55 Season A Average 9.38 ± 6.92 0.90 ± 0.60 0.91 ± 0.43 Season B Average 10.87 ± 4.70 0.32 ± 0.15* 0.90 ± 0.35 * Denotes Season B averages significantly different from Season A averages (p<0.05) abc Denotes significant differences within Season A (p<0.05) xy Denotes significant differences within Season B (p<0.05) RESULTS – MILT VITAMINS
Sample Date A (µg/15 g) D3 (µg/15 g) E (mg/15 g)
2/3/15 2.94 ± 1.64 0.13 ± 0.06 0.25 ± 0.12
2/17/15 3.70 ± 1.41 0.19 ± 0.19 0.25 ± 0.12
3/3/15 4.86 ± 1.99 0.15 ± 0.19 0.29 ± 0.21
3/16/15 3.48 ± 1.13 0.12 ± 0.15 0.19 ± 0.13
3/31/15 3.51 ± 1.80 0.21 ± 0.18 0.28 ± 0.16
Season A Average 3.70 ± 1.70 0.16 ± 0.16 0.25 ± 0.15 NUTRITION LABELING- THINGS TO KNOW • Protein % daily values not accurate without amino acid profile • Amounts of saturated and trans fats will be determined with fatty acid profile • Vitamin daily values based on recommended daily intake amounts • Vitamin A – 900 µg • Vitamin D – 20 µg • Vitamin E – 15 mg Season A Season B
NUTRITION LABELS- FILLETS • Differences: • Calories • Vitamin D • Things to note: • Fat is 0 g • Vitamin A is 0% DV • Protein %DV may not be accurate since amino acid profile not completed NUTRITION LABELS- ROE • Differences: • Calories • Vitamin D • Vitamin A • Things to note: • Fat is 0 g • Protein %DV may not be accurate since amino acid profile not completed Season A Season B NUTRITION LABEL - MILT
• Things to note: • Fat is 0 g • Vitamin D is 0% DV • Vitamin A is 0% DV • Protein %DV may not be accurate since amino acid profile not completed COMPARING FILLETS, MILT AND ROE- VITAMINS PER 100 g
Type Season Vitamin A (µg/100g) Vitamin D (µg/100g) Vitamin E (mg/100g) Fillet A 3.97 5.77 5.09 B 4.87 8.84 7.80 Roe A 62.54 5.97 6.04 B 72.46 2.14 5.99 Milt A 24.68 1.07 1.68 % DV OF VITAMINS PER 100 g SAMPLE ON A WET AND DRY BASIS Type Season Vitamin A (% DV) Vitamin D (% DV) Vitamin E (% DV) Wet Dry Wet Dry Wet Dry Fillet A 0.44 2.64 5.09 30.45 2.41 14.39 B 0.54 3.15 7.80 45.40 2.43 14.14 Roe A 6.95 24.51 29.84 105.26 40.30 142.14 B 8.05 27.04 10.72 36.00 39.92 134.04 Milt A 2.74 18.00 5.36 35.18 11.22 73.59
Reference Daily Intake (RDI) values for adults and children ≥ 4 years: Vitamin A – 900 µg Vitamin D – 20 µg Vitamin E – 15 mg PROXIMATE ANALYSIS – DRY BASIS
Type Season % Fat % Protein % Ash
Fillet A 2.42 ± 0.79 88.06 ± 11.53 7.91 ± 0.39
B 2.930 ± 0.62 91.78 ± 4.10 8.15 ± 0.37
Roe A 5.94 ± 0.85 81.98 ± 6.77 5.70 ± 1.00
B 9.69 ± 0.90 79.34 ± 4.62 5.52 ± 0.81
Milt A 12.54 ± 2.17 82.52 ± 3.71 10.84 ± 0.47 THOUGHTS AND CONCLUSIONS
• Roe and milt had higher fat content than fillets (2% compared to <0.5%) • Roe was highest in protein (23%) and all vitamins and lowest in moisture (71%). However, on a dry basis, fillets were highest in protein. • Fillets generally had the lowest vitamin content • Milt was lowest in protein (12%) and highest in moisture (85%) • Milt was higher in vitamins A and E than fillets, and roughly tied with fillets for vitamin D content THOUGHTS AND CONCLUSIONS • Season and catch date DO affect nutritional content, especially total fat and vitamin D. Increases in fat content correlate to a decrease in moisture. • However, the changes may not always be large enough to affect nutrition labeling • Increase in fat content in B season fillets and roe likely due to the tendency to heavily feed in summer • Consistency of vitamin E content likely due to its role as an antioxidant in cell membranes, whereas vitamins A and D are more heavily concentrated in the liver Still several more analyses to go! ACKNOWLEDGEMENTS
MANY THANKS TO: PCCRC COASTAL OREGON MARINE EXPERIMENT STATION OREGON STATE UNIVERSITY COLLEGE OF AGRICULTURE QUESTIONS?