high pressure treatment in food preservation
TRANSCRIPT
High pressure Treatment in Food Preservation
Speaker
Mahmoud Said Mohamed
Content Introduction Pressuring Systems Mode of Action Some Advantages of HHP Technique High Pressure Treatment Applications in Food Preservation Microbiological Quality Attributes Sensory Quality Attributes Chemical Quality Attributes Some Limitations of High Pressure Treatment. Financial Evaluation of High Pressure Treatment Recommendations
Introduction Consumers demand for high quality, natural and fresh tasting food, free from preservatives and additives, with a clean label and an extended shelf life has increased.
High pressure processing inactivates microorganisms, denatures proteins and extends the shelf life of food products. But in the meantime, unlike heat treatments, high pressure treatment can also maintain the quality of fresh foods, with little effects on flavor and nutritional value.
It is an opportunity to preserve food, by applying intensive pressure in the range of 300-900 MPa, without adversely affecting organoleptic, textural and nutritional qualities as thermal processing like pasteurization and sterilization may do.
Pressurizing Systems
Indirect Pressurization System
Direct Pressurization System
Mode of Action on Factors Affecting Food Deterioration
Food spoilage & Pathogenic Microorganisms -A
-Effects on Cell Membrane:-1
Cell membrane is considered to be the major target for the pressure-induced inactivation of microorganism.
the leakage of intracellular constituents through the permeabilized cell membrane is the most direct reason of cell death by high pressure treatment.
However, if applied pressure was not severe enough to induce a total permeabilization of cell, the permeabilization took place only in the outer membrane, in the case of gram negative bacteria the permeabilized membrane was rapidly restored after pressure release.
Lethality of microorganisms after high-pressure processing at 300 MPa
-Effects on Bacterial Spores:-2
Bacterial spores are known to be pressure resistant, and the inactivation mechanism is
different from that of other vegetative microorganisms. It was assumed that pressure caused inactivation of spores by first initiating germination and then inactivating germinated
forms.
-Enzymes Causing Deterioration: –B Typical phase transition curve of proteins in the PT diagram. The relation between heat, cold and pressure-denaturation of proteins is presented by the sign of enthalpy changes and volume changes.
Structural and functional changes in microorganisms at different pressures
Some Advantages of HHP Technique
1. It enables food processing and causes microbial death whilst virtually eliminating heat damage thus reducing the amount of thermal energy needed for food products during conventional
processing.
2. It does not break covalent bonds; therefore, the development of flavors alien to the products is prevented, maintaining the natural flavor of the products.
3. It can be used to create ingredients with novel functional properties.
High Pressure Treatment Applications in Food Preservation
Quality Attributes
Microbiological Quality
High Pressure Efficiency
Total Plate Count variation of cloudy pomegranate juice during storage
Y&M variation of cloudy pomegranate juice during storage
Effects of HPP VS TP on Microbial Quality of grapefruit juice.
Effects of HPP VS TP on Microbial Quality during storage of Orange juice
Effects on Strawberry Juice During High Pressure Storage(Alternative Storage Method)
Effects of HPP in smoked dolphin fish (Complementary Preservation Technique)
Aerobic plate counts for pressurized (300 MPa) and unpressurized
smoked dolphin fish during chilled storage.
Microbial evolution in sliced vacuum-packed dry cured ham during storage at 4 °C
From Previous Results
The sensitivity in juices maybe explained by the exposure of cell structures to lower pH, which had a synergistic effect with HP treatment.
Sensory Quality Attributes
Color Measurements variation of cloudy pomegranate juice during storage
Anthocyanins Content variation of cloudy pomegranate juice during storage
Color density due to tannins (CDT) values of pomegranate juice samples
as a function of the processing pressure at different temperature levels and
treatment times.
Total anthocyanins (AC) values of pomegranate juice samples as a
function of the processing pressure at different temperature levels and
treatment times.
Browning Index (BI) values of pomegranate juice samples as a function
of the processing pressure at different temperature levels and treatment
times.
Maintaining pH During Storage in
Grapefruit Juice.
Maintaining pH is an important criterion for both quality and
stability of health beneficial compounds such as ascorbic acid.
Maintaining Limonin During Storage in
Grapefruit Juice.
Softening Changes in Olives During Storage.
Sensory Quality of Olives During Storage.
Overall sensory quality:
7–5: perfect, optimal to typical with slight deviations,
4.9–3: noticeable deviations to noticeable detractions and slight defects,
2.9–0: distinct to strong defects.
Odors scale: From 0 (very disagreeable or unacceptable) to 5(agreeable).
Off-flavors descriptors: rancid (r), cheese (ch), pit (p), mould (m), soapy (s),
putrefaction (pu), spicy (y), alpechin (a), zapateria (z) and fermentation (f).
Enhancing Sensory Quality of smoked dolphin fish
Water holding capacity (WHC) of smoked dolphin fish processed at
different conditions.
Water holding capacity (WHC) during storage of pressurized smoked dolphin fish at 300 Mpa.
Shear strength during storage of smoked dolphin fish pressurized at 300 Mpa.
Chemical Quality Attributes
Thiobarbituric Acid
Thiobarbituric acid of smoked dolphin fish processed at
different conditions.
Thiobarbituric acid During Storage
Thiobarbituric acid reactive substances in pressurized (300
MPa) and unpressurized smoked dolphin fish during chilled
storage.
Total Volatile Basic Nitrogen
Total volatile basic nitrogen in pressurized (300 MPa) and unpressurized
smoked dolphin fish during chilled storage.
Some limitation of HPT 1. Food enzymes and bacterial spores are very
resistant to pressure and require very high pressure for their inactivation.
2. The residual enzyme activity and dissolved oxygen results in enzymatic and oxidative degradation of certain food components.
3. Most of the pressure-processed foods need low temperature storage and distribution to retain their sensory and nutritional qualities.
A Financial Recommendation of High Pressure Processing
Thank you
Evolution of pH During Storage Time.
HPT Effects on Orange Juice Microbial Quality
Browning Index
Summary of some food quality characteristics after HPP
Log reductions of Lactobacillus plantarum
Log reductions of S. cerevisiae
Log reductions of Penicillium ssp
Total Polyphenol content (g/L of gallic acid) values of pomegranate
juice samples as a function of the processing pressure at different
temperature levels and treatment times.
The denaturation of key enzymes in microorganism by pressure has been regarded by another important reason of cell death. Membrane bounded ATPase Enzyme was considered to such a key enzyme.
Effects of HPT on Deterioration Factors
HPT does not break down the covalent hydrogen, ionic or hydrophobic bonds. Covalent bonds are resistant to pressure, which means that low molecular weight food components responsible for nutritional and sensory characteristics remain intact during pressure treatment, whereas high molecular weight components whose tertiary structure is important for functionality determination are sensitive to pressure.
Techniques & Equipments
Once the desired pressure can be maintained without further need for energy input. The process is isostatic, so pressure is transmitted rapidly and uniformly throughout both the pressure medium. It is equal from all sides so there is no ‘squashing’ effect and product is not affected.
lab-scale high hydrostatic pressure system
Log reductions of E. coliO157:H7
Total color density (TCD) values of pomegranate juice samples as a
function of the processing pressure at different temperature levels and
treatment times.
Turbidity values of pomegranate juice samples as a function of the
processing pressure at different temperature levels and treatment times.
Changes observed in free acidity data during storage time.
Instrumental Color Parameters
High Pressure Storage as An Alternative Food Storage
Technique
High pressure Treatment and its Role in Maintaining Quality
During Storage
Adding Functional Properties
In many cases High Pressure Treatment used as a complimentary preservation
method in order to adding specific characteristics.
Parameters measured on sliced skin vacuum packed dry-cured ham that showed interaction between light storage time and treatment at 600 MPa or between
light conditions after 50 days of refrigerated storage and treatment at 600 MPa.
Effect of storage time after 50 days of refrigerated storage and HPP at 600 MPa on sensory attributes of sliced skin vacuum packed dry-cured ham
PRESERVATION OF NUTRITIVE PROPERTIES OF TOMATO SAUCE BY HIGH PRESSURE CO2 PASTEURIZATION
Inactivation of Bacillus subtilis in tomato sauce at 35 °C and 90 bar.
Batch inactivation of Bacillus subtilis in tomato
sauce at 90 bar, 45 min and different temperature.
