This document discusses shelf life and factors that influence it. Shelf life is defined as the time a food product remains safe, retains desired characteristics, and complies with label declarations when stored under recommended conditions. Factors like raw materials, processing, packaging, storage and consumer handling impact shelf life. Internal changes from moisture, oxygen, light, chemical reactions and microbes also influence shelf life. Packaging acts as a barrier to moisture, gases and light. Microbial growth depends on water activity and relative humidity. Lipid oxidation is a chemical change leading to off flavors and packaging helps prevent photo-oxidation and auto-oxidation through use of antioxidants.
In this ppt Modified atmosphere packaging (MAP) is expalin in details, Gases, Method for creating Modified atmosphere packaging, Passive And Active Packaging, Advantage and disadvantage of MAP.
you will learn about the purpose,history their advantage and disadvantage of modified atmosphere packaging used in meat technology.you will also know about the gases used in modified atmosphere packaging.
The main objective is to extend the shelf life or to improve the quality and saftey of the packed food.
It involves uses of Antioxidants , Antimicrobials, and other naturally/synthetic molecules to achieve this goal.
When anti-microbial systems such as silver based or Triclosan incorporated into conventional polymers such as PE,PP,PVC is called ACTIVE PACKAGING
When substance such as oils, chitosan,bio flavonoids etc. Known for their microbial, antithrombotic,antioxidant, antiinflamatory,cholestrol lowering and anti cancer properties when incorporated into packaging material constitute BIOACTIVE PACKAGING.
Suitable bioactive substances for incorporation into package wall include, phenolic compounds, phytoestrogens, cartenoids, organosulphur compounds, plant sterols, sutable dietary fiber, prebiotics, enzymes etc
In this ppt Modified atmosphere packaging (MAP) is expalin in details, Gases, Method for creating Modified atmosphere packaging, Passive And Active Packaging, Advantage and disadvantage of MAP.
you will learn about the purpose,history their advantage and disadvantage of modified atmosphere packaging used in meat technology.you will also know about the gases used in modified atmosphere packaging.
The main objective is to extend the shelf life or to improve the quality and saftey of the packed food.
It involves uses of Antioxidants , Antimicrobials, and other naturally/synthetic molecules to achieve this goal.
When anti-microbial systems such as silver based or Triclosan incorporated into conventional polymers such as PE,PP,PVC is called ACTIVE PACKAGING
When substance such as oils, chitosan,bio flavonoids etc. Known for their microbial, antithrombotic,antioxidant, antiinflamatory,cholestrol lowering and anti cancer properties when incorporated into packaging material constitute BIOACTIVE PACKAGING.
Suitable bioactive substances for incorporation into package wall include, phenolic compounds, phytoestrogens, cartenoids, organosulphur compounds, plant sterols, sutable dietary fiber, prebiotics, enzymes etc
Rancidity is a common problem in rendered animal products. It can have detrimental effects on both the quality and safety of the product.
It is caused by the oxidation of fats and oils, leading to the formation of harmful compounds such as free radicals and hydroperoxides.
The best way to prevent rancidity is through proper storage, packaging, and handling techniques, as well as the use of antioxidants to slow down the oxidation process. It is important for manufacturers and consumers to be aware of the potential for rancidity in rendered animal products and take the necessary precautions to ensure the safety and quality of the product.
Rancidity testing is essential in the feed industry, as a key indicator of product quality and shelf life.
It is conducted to determine the level of oxidation in samples of feed or feed ingredients
Rancidity is a chemical change that results in an unpleasant odour and taste in a fat or oil.
Types of Rancidity
Hydrolytic rancidity
Oxidative rancidityOil becomes rancid due to the decomposition of fats it contains
Milk turns rancid due to not heating it in the humid atmosphere.
Butter changes its smell and taste when it is kept in an open atmosphere for a longer duration.
Hydrolytic rancidity develops due to the presence of moisture and by growth of microorganisms in the fat.
The microorganisms secrete lipases which split the triglycerides into glycerol and fatty acids.
Hydrolytic rancidity of butter releases volatile butyric acid which gives the bad odour and taste.
Oxidative rancidity occurs in oils and fats containing unsaturated fatty acids due to exposure to air.
Unsaturated fatty acids are converted into hydroperoxides, which break down into volatile aldehydes, esters, alcohols, ketones, and hydrocarbons, some of which have disagreeable odours.
Fats contaminated with enzymes like lipase undergo partial hydrolysis and oxidation of unsaturated fatty acids at the double bonds.
This is even brought about by the atmospheric moisture and temperature. Due to this, there is release of hydrogen peroxide giving a bad odour and taste to the fat.
Rancidity can be prevented by antioxidants like vitamin E, vitamin C, phenols, hydroquinone’s, etc.
Rancidity Process: Rancidity happens in food products that have oil and fatty acids in them. Any substance turns rancid in basically three steps:
I. Initiation Reaction: Initiation reaction leads to the formation of radicals on the food substances because of external factors like heat and air that stimulates this reaction. A radical is an atom molecule or ion that has an unpaired electron. These unpaired electrons make radicals very reactive chemical substances.
RH ⇒ R- + H+
Propagation Reaction: In this step, oxygen present in the atmosphere gives rise to peroxides. These peroxides react further with unsaturated fatty acids and then produce new radicals.
Termination Reaction: In the third stage, two radicals combine together to form a new single bond.
2. Shelf Life
Analysis Type Shelf Life Length Date Coding
Microbiological changes Short-life (up to 1 wk) “Use by”
Chemical changes Medium to Long (3 wks – 1 yr) “Best Before”
Sensory changes Medium to Long (3 wks – 1 yr) “Best Before”
Shelf-Life is defined as the time during which the food product will:
a) Remain safe;
b) Be certain to retain desired sensory, chemical, physical and
microbiological characteristics;
c) Comply with any label declaration of nutritional data, when
stored under recommended conditions
3. Factors Affecting Shelf Life
External Conditions influencing shelf-life:
• Raw material selection and quality
• Product formulation and assembly
• Processing environment
• Processing and preservation techniques
• Packaging
• Storage and distribution
• Consumer handling
Internal Changes influencing Shelf-Life:
• Moisture loss and gain
• Physical transfer of oxygen, water vapor, odors and flavors
• Light induced changes
• Chemical changes
• Microbiological changes
4. Packaging
• Barriers prevent moisture, gases, and light
• Total barrier such as glass above 17 μm (total barrier to
moisture and all gasses)
• Amber glass 2mm thick provides almost complete barrier up
to 450 nm
•When a product contains fat an oxygen barrier is required for
packaging
• Use odor barrier to keep desirable odors and flavors
5. Microbial and Mold Growth
• Water Activity – ability of moisture to migrate in food products.
Major parameter for inhibiting microbial growth and molds
• Equilibrium relative humidity (ERH) – ERH of the environment is
key to surface-growing organisms
6. Water Activity
AW < 0.86
(Pathogenic
bacteria
can’t grow)
AW = 0.60
(Osmophillic
yeasts can
grow)
9. Photo-Oxidation
• Photo-oxidation uses light as a sensitizer with little or no
induction period
• Type I – excitation of lipids
• Type II – excitation of oxygen
10. Auto-Oxidation
•Autoxidation – spontaneous reaction of atmospheric
oxygen with lipids
•Aldehydes commonly contribute to the off-flavors that
develop during lipid oxidation
Decomposition Auto-oxidation Off-Flavors
Soybean Oil Beany
Fish Oil Fishy flavor
Milk Fat Creamy or Metallic Flavor
12. Measure of Oxidation
•Visual
• Oxidative deterioration may cause bleaching of foods due to
the reaction of pigments, especially caratenoids
• Sensory Panel
• Hexanal detection with age
•Qualitative
• Monitor weight
•Quantitative
• Headspace Analysis (Dynamic/Static)
• Solid Phase Microextraction (SPME)
• Peroxide Value (PV)
• Para-anisidine value (absorbs at 350 nm)
• Thiobarbituric acid value (absorbs at 532 – 535 nm)
• Induction Period Tests
13. Types of Antioxidants
• Primary antioxidants – scavenges free radicals and are consumed
during induction period, vitamin E (phenolic compounds)
• Secondary antioxidants – bind metal ions, scavenge oxygen, convert
hydroperoxides to non-radical species, absorb UV radiation, or
deactivate singlet oxygen, Citric Acid (sequestering agents) and ascorbic
acid (reducing agents)
“Antioxidants are effective when added to fresh oils of good quality
and are less effective in delaying oxidative rancidity development
when oxidation has already started”
14. US Regulations on Antioxidants
“Antioxidants should satisfy several requirements before being
accepted for incorporation into food products/ The antioxidant
should be soluble in fats; it should not impart a foreign color,
odor or flavor to the fat even on on long storage; it should be
effective for at least one year at a temperature between 25 and
30C; it should be stable to heat processing and protect the finished
product, ; it should be easy to incorporate and it should be
effective at low concentrations. “
15. Plan
•Cleaning
• Use of metal chelating agents can be used to prevent
oxidation
• Water activity – measuring and controlling provides a
means of monitoring and controlling pathogenic and
spoilage bacteria
• Mixing
• Check bulk flavorings with GC-MS for quality control
• pH of all e-liquid should be at 6. Maximum degradation
of peroxides occurs in the pH region of 5.0 - 5.5
• Yeasts thrive between a pH of 4.5 – 5.5
• Addition of antioxidants (antioxidants must not exceed
0.02% by weight based on fat content of food)
• Bottling
• Pumping introduces more oxygen
• Opening and closing 5 gallon batches to bottle introduces
more oxygen in lipids and in headspace
• Storage
• Light and Temperature Control
Editor's Notes
Oxidative deterioration can be initiated by light or metals or the enzyme lipoxygenase
Metal ions are the most important pro-oxidant in foods (even in ppm level or less)
Sensitizer molecules = pigments such as chlorophyll and riboflavin, and heavy metals which are all naturally occurring in animal and vegetable fats and oils.
Lag period or induction period is the lifespan of anti-oxidants until until about 90% has been destroyed where the timespan/length of the lag period is due to anti-oxidant concentration.