Technology Transfer: University Research to Industry Ohmic Cooking for Accurate Evaluation of Surimi Gels

Transcription

1 Technology Transfer: University Research to Industry Ohmic Cooking for Accurate Evaluation of Surimi Gels Jae W. Park, Professor Oregon State University Seafood Research and Education Center Astoria, OR, USA

2 Background Surimi Processing (water washing) does not remove all proteolytic enzymes: Before washing Activity Cathepsin B Cathepsin L Cathepsin H Temperature (C) 125 After washing Activity Cathepsin B Cathepsin L Cathepsin H An et al. (1994) J Food Sci Temperature (C) P239, Surimi and Surimi Seafood (Park, 25)

3 Background Proteolytic enzymes degrade myofibrillar proteins at 4-75C depending on species: An et al. (1996) Trends Food Sci and Tech P232, Surimi and Surimi Seafood (Park, 25)

4 Cold/Temperate Water Species Pacific Whiting Tropical/Warm Water Species Lizard Fish 45-75ºC 4-65ºC Dr. Yongsawatdigul s Lab An et al. (1994) J Food Sci

5 Background A) Gelation properties of surimi is evaluated using gels cooked in water bath (Slow heating) B) Surimi seafood (Crabstick) is processed in a continuous thin sheet (Fast heating) mm Slow heating 3. mm Fast heating

6 FAST HEATING SLOW HEATING A) One sausage (15 g) cooking in 14.5 L water (9C) B) Ohmic: 25 Volt to 93C 3 cm dia tube

7 Heating of a surimi test gel cross-section with 3 cm (ID) requires >35 min to reach 9 C in the center 9 C External Temperature (Water Bath) 4-6C The center, where gel punch is made, is exposed to enzyme active temperatures for > 4 min, resulting in poor gel value (inaccurate analysis)

8 Gel-strength Activity Makinodan et al. (1985) J Food Sci Temperature (C) P246, Surimi and Surimi Seafood (Park, 25)

9 Discrepancy Slow cooking for Test Gels Fast cooking for Finished Products (Crabstick)

10 Test Gel Cooking Device that mimics Fast Cooking (Crabstick Line) is Greatly Needed!

11 Heat is generated by Electrical Resistance between two electrodes. OSU: 26-3 cm sausage tube

12 Objectives To measure the feasibility of ohmic heating that mimics crabstick production for accurate gel quality assessment. To determine gel softening phenomena according to their grade and/or species.

13 Materials Pacific whiting surimi Alaska pollock surimi (AA, KA, RA) Catfish surimi Arrowtooth Flounder surimi Giant squid surimi Surimi added with dried egg white Surimi added with whey protein concentrate 15

14 Cooking Methods Water Bath Sausage casing (3. cm Dia) at 9C for 3 min Ohmic Cooking 2 V or 25 V heating (5-35 sec cooking) with or without holding at 9C for, 45, 9 sec

15 Ohmic Gels Water Bath Gels

16 Texture Analysis All Gels were subjected to penetration using spherical probe (5 mm dia) after being equilibrated to room temp. Crosshead speed: 1mm/sec Measured breaking force (g) and deformation (mm) at rupture

17 Shear Stress (kpa) No Gel Pollock No Gel Whiting Shear Strain No Gel No Gel Heating Rate ( C/min)

18 Pacific Whiting Force (g) % salt, 78% moisture 2 V (g) 25 V (g) 2 V (mm) 25 V (mm) WB s 45 s 9 s Ohmic Cooking Deformation (mm)

19 KA Alaska pollock 2% salt, 78% moisture Force (g) V (g) 25 V (g) 2 V (mm) 25 V (mm) WB s 45 s 9 s Ohmic Cooking Deformation (mm)

20 RA Alaska pollock 35 2% salt, 78% moisture 2 Force (g) V (g) 25 V (g) 2 V (mm) 25 V (mm) Deformation WB s 45 s 9 s Ohmic Cooking

21 AA Alaska pollock 2% salt, 78% moisture V (g) 25 V (g) 2 V (mm) 25 V (mm) Force (g) WB s 45 s 9 s Ohmic Cooking Deformation

22 Catfish Surimi (2 V 9 s) 3% salt addition and no moisture adjustment Force (g) Force Deformation Deformation (mm) WB OH

23 Arrowtooth Flounder Surimi 3% salt, no moisture adjustment Water Bath/cooked in 3 cm (dia) casing

24 Force (g) Giant Squid Surimi WB (g) OH (g) WB (mm) OH (mm) Deformation (mm)

25 2% salt, 78% moisture

26 3 2% salt, 78% moisture

27 2% salt, 78% moisture

28 2% salt, 78% moisture

29 Force (g) Pacific Whiting Surimi Texture as Affected by Cooking Method and Protein Additives Force Role of Ohmic - controlling proteolytic enzyme Deform. 2% salt, 78% moisture Role of DEW inhibition & gelling ability WB OH WB OH WB OH CON CON DEW DEW WPC WPC Cooking Method Deformation (mm)

30 Force (g) Alaska Pollock (RA) Surimi Texture as Affected by Cooking Method and Protein Additives 2% salt, 78% moisture 25 V Force WB OH WB OH WB OH CON CON DEW DEW WPC WPC Cooking Method Deformation (mm)

31 75 Whiteness of Surimi Gels as affected by cooking methods and additives Whitness, L*-3b* Water Bath Cooked PW WB AP(RA) WB AP(RA) WB Ohmic Cooked PW/2v AP(RA)/2v AP(RA)/25v 55 5 % additives 2% DEW 2% WPC 35

32 Current Efforts Microwave Cooker Great results Too large to be portable >US$ 6,? Failed to penetrate Ohmic Cooker Great results Small enough to be portable About US$15,? Just introduced by Kami Steel (Seattle, WA, USA)

33 CONCLUSIONS Ohmic heating enabled to cook 3 cm diameter sausage properly and rapidly. Pacific whiting surimi, catfish surimi, arrowtooth, RA grade pollock surimi and all tropical surimi significantly improved their gel values by ohmic cooking: Accurate Quality Assessment (Not Cheating) More Values Ohmic gels were relatively whiter than waterbath gels.

34 FAST Cooking Ohmic (Joule) Heating: Better Utilization, More Value, and Accurate Analysis of Surimi More Profit and Better QC