A comparative study of High Pressure Processing (HPP), continuous flow microwave volumetric heating (MVH) and conventional heating (CH)

Transcription

1 A comparative study of High Pressure Processing (HPP), continuous flow microwave volumetric heating (MVH) and conventional heating (CH) Craig Leadley, Campden BRI, T: +44 (0) , E:

2 Contents Introduction to Campden BRI Background and project outline Brief intro into the techs of interest Comparative studies Overview of study methods & results Key conclusions Questions

3 Campden BRI - Practical science, technology and knowledge services for the food and drinks industry We ve been around for almost 100 years 400 staff across 5 sites

4 We work with industry worldwide 2,400 members 75 countries Top 10 UK retailers 15 top global manufacturers Many of the world s biggest brands

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6 Background/context 45% increased demand for energy 50% increased demand for food 30% increased demand for water By 2030 Prof. John Beddington s Perfect Storm

7 HPP in brief Now established process for non-thermal pasteurisation. Typical pressure MPa Can inactivate vegetative microorganisms (above 300 MPa) Sometimes used to bring about desirable changes to the food. Image courtesy of Holmach

8 Come up Stages of a HPP cycle Hold Come down Pressure fluid temp Image courtesy of Avure

9 MVH in brief Microwave Volumetric Heating Patented, world-leading technology, cross sectoral application Equipment is scalable from laboratory-scale to full industrial scale Customised applications are available for new applications Slide courtesy of AMT - unedited

10 Key features of MVH Microwave energy is focused on a microwave transparent pipe containing the liquid which remains at the same temperature as the liquid. No hot surfaces to damage product: much reduced fouling. Breakthrough is the delivery and focusing of the microwave energy allowing penetration in liquids of 42mm. A world first. In a 42 mm pipe, all the molecules in the entire volume of the liquid are heated evenly and instantly. This is - Microwave Volumetric Heating Slide courtesy of AMT - unedited

11 Vegetative cells E coli in PBS Listeria in PBS Slide courtesy of AMT - unedited

12 Campden BRI project Collaboration with centre for sustainable energy use in food chains. Involves universities of Brunel, Manchester and Birmingham Energy comparison work HPP MVH Conventional continuous flow heat process Product quality evaluation Working on orange juice Vitamin C retention Headspace volatiles

13 Juice production 300 Kg orange purchased from a single local supplier FMC pilot scale reamer used to express juice All OJ placed into buckets,chilled stored at 5 C and covered in black bags All juice processed within 2 hours of extraction

14 Test equipment overview - MVH 4 magnetron unit 116 L/hr flow rate Targeted process equivalent to 70 C for 2 minutes (z = 7.5 C ) Process was 75.6 for 26 seconds in holding tube Product cooled and clean filled into PET bottles.

15 Test equipment overview HPP juice production 135 litre NC Hiperbaric unit Bottled product chilled transported to contract processor (around 90 min transit time) Processed at 600 MPa for 4 min 20 sec. In line with typical commercial HPP treatments Image courtesy of NC Hiperbaric

16 Test equipment HPP energy work Lab-scale unit 800 ml capacity (EPSI) Processed at 600 MPa with 3 min hold Pressure fluid was mains water with 3% MKU (oil based corrosion inhibitor) Compressive heating rates previously established as close to water (approx 4.3 C per 100 MPa Image courtesy of NC Hiperbaric

17 Test equipment Conventional heating FT74XTS miniature-scale UHT/HTST processing system (Armfield, UK) Targeted process equivalent to 70 C for 2 minutes (z = 7.5 C ) set to be at 76.8 o C for 15 seconds at a flow rate of 20 L/h. Note unit was electrically heated

18 Quality evaluation Headspace volatiles using GC/MS Data analysed using Agilent 7890 GC Agilent 7200 accurate mass Q-TOF MS via a CTC combi-pal Autosampler Vitamin C analysis

19 Vitamin C retention Inherent variation within each process type was quite wide The variation between each process was, by comparison, small.

20 HPP vs conventional heat Strawberry purée Other studies have shown improved vitamin C retention using HPP See e.g. Patras et al (2009) No error bars Patras et al, 2009

21 Chromatogram Comparisons HPP Microwave UHT

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23 The orange juice that had been processed at 75⁰C was presented to a taste panel at approximately weekly intervals. The summary of the hedonistic scores for each attribute are presented in Appendix Figure 9 illustrates how there was no significant difference in the appearance, aroma, flavour, after HPP s MVH: Taste tests taste and overall acceptability of the raw (nb defrosted), HPP and MVH processed juice. Furthermore, the degree of heat recovery used did not impact on the organoleptic quality of the orange juice. Conclusions Advanced Microwave Technologies Ltd 2016 Page 11 of 36 HPP and AMT processed orange juice were indistinguishable to a test panel after 11 weeks Slight preference for AMT juice in first few weeks Advanced Microwave Technologies Ltd 2016 Page 11 of 36 Slide courtesy of AMT - unedited

24 Typical lab scale cycle - HPP

25 Lab versus industrial HPP cycle

26 Typical cycle - MVH

27 Typical cycle - Conventional

28 Assumptions/limitations for cost/l calculation Fluids are close to that of water. Steady state Includes the power to auxiliary functions (pumps, cabinet air conditioning) 0.1 p.kwhr is the flat rate energy cost. The HPP filling ratio has a significant impact on costs. Our trials had a fill ratio of only 36% Figures taken no account of the difference in processing scale of the 3 methods

29 Commercial implications Energy cost per litre ( /l) CH MVH HPP* *Based on 36% fill ratio not realistic

30 Commercial implications Energy cost per litre ( /l) CH MVH HPP* *Based on 60% fill ratio more realistic

31 Commercial implications Energy cost per litre ( /l) CH MVH HPP* *Based on 95% fill ratio reportedly achievable on Hiperbaric 1050 bulk

32 Summary Minimal differences in headspace volatiles and Vitamin C were noted across the 3 treatments MVH was competitive with conventional heating HPP offers significant energy saving potential but highly dependent on fill ratio All data should be treated as indicative, there are lots of assumptions and scaling limitations Real industrial data would add significant value and I d welcome the opportunity to talk

33 Acknowledgements This work was conducted in collaboration with Brunel University London and the EPSRC Centre for Sustainable Energy Use in Food Chains (CSEF) whose support is gratefully acknowledged.