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Department of Employment, Economic Development and Innovation
Maximising revenue from your prawn harvest
Carl PauloInnovative Food Technologies
2© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Project No. 2010/707
Loss minimisation in farmed prawns through improvements in storage life and colour
3© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Project Overview
Project officially started as of September
1. Shelf life extension of cooked chilled prawns• Improve the keeping quality to 14 days• Achieved through natural antimicrobials and novel packaging
2. Colour retention during frozen storage of cooked prawns• Extend frozen storage quality up to 12 months???• Maintain colour grades above 8 on the APFA colour chart
4© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Shelf life extension of cooked chilled prawns
Isolate specific spoilage organisms
Screen natural antimicrobials onability to retard SSO growth
Trial plant extracts, commercial products and packaging treatments on efficacy
Identify suitable packagingthat promote shelf life
Our approach
5© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Identification of Specific Spoilage Organisms
Are SSO region specific?
• 2 farms from Far North Qld
• 2 farms from Mid Coast Qld
• 2 farms from SE Qld
• Crystal Bay
6© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Identification of Specific Spoilage Organisms
What we have done• Crystal Bays, Far North and SE Qld farms• Duplicates from each farm• Frozen prawns• SSO have been isolated• In the process of identification
What’s Next• Mid coast farms• Chilled prawns• Natural antimicrobial screening
7© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Colour retention during frozen storage
What we have done so far
• Colour and Astaxanthin method development• Glaze natural additives prelim trial• Glaze uptake trials
8© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Colour and Astaxanthin method development• Laboratory method developed. Currently optimising• Able to identify different forms of astaxanthin• Method has limiting factors. Exploring alternatives• General idea of the degradation rate of astaxanthin• Future analyse legs as opposed to body
Rate of astx degradation. Unglazed prawn body
Total astaxanthin
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
0 20 40 60 80 100 120 140
Storage time (days)
Ast
x. c
on
c. (
ug
/g)
-13°C
-20°C
9© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Glaze natural additives prelim trial
• Monodon and Crystal Bays• Trialled 5 different treatments
A. GlazEx Plus (Commercial product)
B. GlazEx (Commercial product)
C. Tea extract with bioactive honey
D. Kakadu plum powder with bioactive honey
E. Ascorbic acid with Sorbitol powder and Sucrose
F. Control (No Glaze)
10© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Glaze natural additives prelim trial - Methodology
Blast freeze prawns 20 min @ -20°C
Spray with glaze solution
Blast freeze 5 min
Repeat
Frozen storage -20°C
• ~10% glaze except Control with no glazing• Prawns sampled 2, 4, 6 and 8 months later
11© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Glaze natural additives prelim trial - 6 months
12© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Glaze natural additives prelim trial - 8 months
13© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Glaze natural additives prelim trial - 8 months
14© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Glaze natural additives prelim trial
Sample Total Astx (ug/g)
Control legs 6.4
Treat A legs n/a
Treat B legs 43.5
Treat C legs 34.6
Treat D legs 39.7
Treat E legs 34.9
Thai legs 39.0
Sample Total Astx (ug/g)
Control body 3.71
Treat A body 2.59
Treat B body 4.93
Treat C body 2.49
Treat D body 4.76
Treat E body 5.49
Thai body 8.53
~11 months oldThai prawn
• Astaxanthin concentrations after 6 months• Imported Thai prawns (11 months old) included as comparison
15© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Glaze natural additives prelim trial - what’s next
• Pick best treatments– Ascorbic acid & GlazEx Plus– Have since identified another commercial glazing product– What other commercial products are available?
• Include water glaze• Quantify astaxanthin over storage life
16© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Glaze uptake
• What variables impact glaze uptake?
Thaw prawns overnight @ 4°C
Weigh ~1kg into prawn baskets and IQF @ -20°C
Dip to glaze
Blast freeze @ -30°C then re-weigh
17© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Glaze uptake - Results
Prawn core temp -10°C. Ice slurry dip. Varying salinity
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
2 20
Dip time (sec)G
laze
(%
) 0ppk
25ppk
50ppk
Prawn core temp -10°C. Differing dip temp
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
2 20
Dip time (sec)
Gla
ze (
%)
Ambient dip
Chilled dip
18© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Glaze uptake - Results
Prawn core temp -10°C. Ice slurry dip. Varying size
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
2 20
Dip time (sec)G
laze
(%
) 16/20
10/15
U10
2sec pre-wash in 50ppk
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
2 20
Dip time (sec)
Gla
ze (
%)
No pre-wash
Pre-wash
19© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Glaze uptake - Results
Ambient dip. Differing core temp
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
2 20
Dip time (sec)
Gla
ze (
%)
-10°C core temp
-20°C core temp
Ice slurry dip. Differing core temp
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
2 20
Dip time (sec)G
laze
(%
)
-10°C core temp
-20°C core temp
20© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Glaze uptake
• Recommendation ONLY for optimising glazing conditions• Each processing practice is different
• Factors identified that heavily influence glaze uptake:– Dipping time– Dip solution temperature (chilled is much better)– Salinity (fresher is better)– Grading size
21© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
What next?• Milestone deadline 8 February 2011• Deliverables:
– Current production practices and issues– Colour and Astaxanthin method developed– Qld map of specific spoilage organisms– Begin frozen storage trials for current season– Packaging options reviewed
Questions ?
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