Transcript
VACUUM FRYING TECHNOLOGY
Ranasalva N
May 2, 2023 2
• Originated - Frying foods - Middle East - two millennia before
the birth of Jesus Christ
Introduction
Sautéing Shallow frying Deep frying
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• High pressure
• Atmospheric pressure
• Low pressure/Vacuum
Deep fat frying – carried out under
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Conv
Water
Cond
Penetrated oil
Surface oilCRUST
CORE
Mode of heat and mass transfer during deep fat frying (DFF)
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CRUST
CORE
Starch degradation
Non enzymatic browning
High temperaturesFrying oil thermal degradation
Beneficial compounds degradation
Water vaporization
Atmospheric conditionsFrying oil oxidation
Frying oil hydrolysis
Moisture loss
Oil uptake
Key structural components changes
Changes in product during DFF
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FOOD
OIL
UPT
AKE
DEHY
DRAT
ION
WATER
HYDROLYSIS
OXYGEN
OXIDATION
Cyclisation
Polymerization
HIGH TEMPERATURES (140 -200°C)
Isomerization
HEAT
Mono glyceridesDi glyceridesGlycerolFree fatty acids
AldehydesKetonesAcidsEpoxidesDimers - trimers
Hydro peroxides
Polar CompoundsFRYING OIL
Trans fatty acids
Cyclic Compounds
Dimers – trimersPolymers
Changes in oil during DFF
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?VACUUM FRYING
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Torricelli’s vacuum experiment in 1644. The level AB of mercury in both tubes C and D was equal, independent of the size of the additional volume E in tube D.
Democritus - 460 to 375 B.C. Bronze statue around 250 B.C., National Museum in Naples
History of vacuum science
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Otto von Guericke in 1672
Inventor of vacuum pump principle
Plenists Vs vacuists
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Non condensable gasNon condensable gas
VACUUM PUMP
Liquid condensate
Steam & Non condensable gas
SPINNER MOTOR
VACUUM FRYING CHAMBER
OIL HEATER
FRYING BASKET
CHILLER
LIFT ROD
Vacuum frying system
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1. Depressurization - 1.33 - 10 kPa
2. Frying and De-oiling – Heat and mass transfer occurs and
surface oil is removed
3. Pressurization – To atmospheric condition
4. Cooling – Product is cooled to room temperature and
stored
Stages of vacuum frying
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• Process Factor
– Pre frying
– Frying
– Post frying
• Product factor
• Oil factor
Factors affecting vacuum frying
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•Maltodextrin
•Drying
•NaCl2 soaking
•Citric acid
•Gelatinization
•Freezing
•Hydrocolloids
Pre frying (pretreatments)
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Paulo et al ,2008
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Properties influences Properties influenced by
•Moisture content •Weight and moisture loss
•Pore structure •Oil absorption
•Pressure •Diameter shrinkage•Thickness - expansion•Penetration pressure
Process temperature
May 2, 2023 15Temperature at different locations within the product during frying process (T =185°C, T=20°C)
Aman-Mohammad, 2009
Whole process (frying and cooling)
Cooling period
Process temperature
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• Oil absorption
• Browning Index
• Color
• Shrinkage
• Moisture content
Paulo et al ,2008
Process time
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• The frying is carried out from 1.33 kPa to 90 kPa
• Surface of food• Centre of the food• Head space of the chamber
Paulo et al ,2008
Process pressure
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DP – Depressurization; FR – Frying; PR – Pressurization; CL – Cooling; temperature of 120°C
Carla, 2010
CentreSurface
Head space
Pressure
Effects of process parameters
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Temperature of 130°C Temperature of 140°C
Carla, 2010
Effects of process parameters
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• Oil absorption - 80% absorbed during cooling
• Potato chips – 14% in core and 86% on the surface
• Pressure gradient between the product and atmosphere
cause intensive absorption of oil
• De-oiling – under vacuum - centrifuging speed 350 – 1200
rpm for 30 s to 30 min
(Garayo & Moreira, 2002, Moreira et al.,2009)
Post frying process
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• Size and shape - oil absorption increases thickness is reduced & product surface is increased
• Ripeness of fruits – suitable for high sugar products• Taste – Stronger taste of high concentration of taste
components• Surface roughness - Cells broken during cutting are a
privileged location for oil absorption• Solid content – high density product shows reduced oil
absorption• Moisture content
Product factors
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• Moisture content
• Oil content
• Microstructure
• Diameter - shrinkage
• Thickness - expansion
• Bulk density
• True density and
• Porosity
Changes in product
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Stages of Moisture loss
• Initial warm up period• Constant rate period• Falling rate period Moisture diffusion coefficient,
De,
(Broker et al., 1992)
Mdb - moisture content in (g/g solid), Mo - initial moisture content (g/gsolid) Me- equilibrium moisture content (g/g solid), t - frying time (s) a - half thickness of the product slice (m)
Moisture content
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Effect of oil temperature and vacuum pressure
(Garayo and Moreira, 2002)
Shrinkage
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Oil distribution pattern in vacuum fried potato slices at 130°C
(Carla, 2010)
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Vacuum frying Vs Traditional Frying
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Oil content within product
S.No Frying temperature
(°C) & method
Internal oil content
(g/g solid )
Surface oil Content
(g/g solid )
Total oil content
(g/g solid )
1. Vacuum frying at 120 0.072 0.339 0.410
2. Vacuum frying at 130 0.062 0.413 0.475
3. Vacuum frying at 140 0.059 0.398 0.457
4. Atmospheric frying at 185 0.50 - -
(Carla, 2010)
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Oil content various products
Comparison between oil content of product fried in vacuum and traditionalfryers (white-bar: traditional fryer; and black-bar: vacuum fryer)
(Paulo et al., 2008)
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Blue potato fried - vacuum fryer Blue potato fried - traditional fryer
Green bean fried - vacuum fryer Green bean fried - traditional fryer
(Dueik et al., 2010)
Color of product
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Sweet potato fried - vacuum fryer Sweet potato fried - traditional fryer
Mango fried - traditional fryerMango fried - vacuum fryer
(Dueik et al., 2010)
Color of product
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Oil properties affects Frying
Oil properties get affected during Frying
•Viscosity •Oxidation
•Oil aging •Hydrolysis
•Stability
•Free fatty acids
Oil property
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Oil quality
• TBHQ- SO - sunflower oil with synthetic antioxidant (tertiary- butylhydroquinone) • HOSO - sunflower oil with high oleic acid
Quality Factors• Oil degradation • Fatty acid composition - PUFA and MUFA• ᾳ - Tocopherol
Peroxide Value in TBHQ-SOv treatment, are higher than TBHQ-SOt at least 2.32 times in period 2 and 1.86 times in the period 3
(Crosa et al., 2014)
PUFA - Poly unsaturated fatty acid; MUFA - mono unsaturated fatty acid
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S.No Quality parameters Traditional frying
Vacuum frying
TBHQ –SO
HOSO TBHQ –SO
HOSO
1. Free fatty acid (g oleic acid/100 g) 0.201 0.327 0.073 0.099
2. p- Anisidine (AnV) 207.0 82.0 25.8 33.3
3. Total polar compounds (%) 25.0 21.9 11.2 6.44. Reduction in ᾳ - Tocopherol (%) 53.62 99.76 4.90 96.87
*TBHQ- SO - sunflower oil with synthetic antioxidant (tertiary- butylhydroquinone)*HOSO - sunflower oil with high oleic acid content
(Crosa et al., 2014)
Comparison of quality parameters
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• Preserves natural Color
• Low moisture content - < 6%
• Reduced Shrinkage
• Low water activity - < 0.3
• Heat sensitive nutrients – preserves 90% of trans –carotene
• Prevention of carcinogenic compounds formation – 97% less acrylamide in potato chips
• Reduce the fat content – 80 – 85% less oil in potato chips
• Suitable for high sugar content products
• Less adverts effects on oil quality
Granada et al, (2004), Clara. 2010.,
Merits of Vacuum frying
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• Skilled person
• Requires special packaging
• Pre – frying steps – Battering, instant extrusion
• Cost
• Time
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Limitations
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• The vacuum frying conditions (temperature and time) for various food products varied considerably and there was also a wide variation in the vacuum pressures used
• The choice of the vacuum frying conditions for the food samples was dictated by a range of physical parameters, as well as pre-treatment conditions
• There was no other way to design a vacuum frying process for a specific product except to carry out experiments to obtain an optimized process
Summary
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• Crosa, M. J, Verónica, S., Mónica, C., Laura, O., Roberto, S., Gabriela, S., and Marina, T. 2014. Changes produced in oils during vacuum and traditional frying of potato Chips. Food Chem. 146 (4) 603–607
• Dueik, V., Robert, P and Bouchon, P. 2010. Vacuum frying reduces oil uptake and improves the quality parameters of carrot crisps. Food Chem. 119 : 1143–1149
• Garayo, J., and Moreira, R. G. 2002. Vacuum frying of potato chips. J. Food Proc. Engng. 55(2): 181-191
• Granda, C., Moreira, R. G., and Tichy, S. E. 2004. Reduction of acrylamide formation in potato chips by low-temperature vacuum frying. J. of Food Sci. 69(8): 405- 411
References
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• Mariscal, M. and Bouchon, P. 2008. Comparison between atmospheric and vacuum frying of apple slices. Food Chem. 107: 1561–1569
• Moreira, R.G., Da Silva, P.F., and Gomes, C. 2009. The effect of a de-iling mechanism on the production of high quality vacuum fried potato chips. J. of Food Engng. 92: 297-304
• Muanmai, A., Kuluma, C., Punnarai, S., and Noppawan, T. 2007. Effect of antibrowning agents on banana slices and vacuum-fried slices. J. of Food Agri.and Envi. Vol.5:151 -157
• Ophithakorn, T., & Yamsaengsung, R. 2003. Oil absorption during vacuum frying of tofu. In PSU-UNS international conference. Energy and the environment, December 2003, Hat Yai, Songkhla, Thailand
• Paulo F. Da Silva and Rosana G. Moreira. 2008. Vacuum frying of high-quality fruit and vegetable-based snacks. Food Sci. and Technol.41 (8):1758 – 1767
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• Perez-Tinoco, M.R., Perez, A., Salgado-Cervantes, M., Reynes, M. and Vaillant, F. 2008. Effect of vacuum frying on main physicochemical and nutritional quality parameters of pineapple chips. J. of Sci. Food and Agri. 88: 945–953
• Rafael.H. V. V., Quiceno G. C. M., and Giraldo G. G. A. 2012. Effect of vacuum frying process on the quality of a snack of mango (Manguifera indica L.). ACTA AGRONÓMICA. 61 (1): 40-49
• Shyu, S.L Lung-Bin, H., and Hwang, L. S. 1998. effect of vacuum frying on the oxidative stability of oils .J. American Oil Cor. Soc. 75 (10): 132 – 138
• Song X, Zhang M, Mujumdar A. S. 2007. Optimization of vacuum microwave pre-drying and vacuum frying conditions to produce fried potato chips. Drying Technol, 25: 2027-2034
• Sonntag, R.E., Claus, B., and Gordon, J. V.W., 2003. Fundamentals of Thermodynamics. John Wiley & Sons, Inc. USA. 1894- 1921
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INNOVATIONS CONTINUES UNTIL THE THRUST FOR KNOWLEDGE
CONTINUES!!!!!!
NEED - ENDLESS
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