Laminates PDF

LAMINATES  Any combination of distinctly different web materials (e.g.: plastic, paper, aluminum foil) to form a multilayer webs, which generally thicker than 6µm regardless of the method of manufacture ROBERTSON, 2012 No maximum number of webs, but two is the...

LAMINATES  Any combination of distinctly different web materials (e.g.: plastic, paper, aluminum foil) to form a multilayer webs, which generally thicker than 6µm regardless of the method of manufacture ROBERTSON, 2012 No maximum number of webs, but two is the minimum and one of these web must be thermoplastic  Thermal lamination The webs are heated before pressing them together into two roller & force to establish contact for bonding (Brown, 1992) Adhesive (tie/binding layer): polyolefins (PE, EVA) Methods: a) Wet bonding b) Dry bonding c) Solventless lamination  Extrusion lamination Two or more polymers are extruded (molten polymer) and joined together to form a single multiple layer. Involve molecular bonding without the use of adhesive Combination of webs accomplished at high pressure and temperature in sealed environment. Commonly used for food packaging that require high moisture and gas barrier, and excellent print quality. Example food packages: retort pouches, snacks packages, meat and cheese packages. Coating lamination/ Metallisation Specialised type of coating lamination Conduct by applying thin metal layer (aluminium) to plastic substrate (PET, PP, nylon) in evaporated vapor under high vacuum condition. Coating thickness: 8 to 50 nm Metallised plastic advantages: 1. Have excellent barrier to moisture, gas, and light 2. Resistant to flexing stress 3. Have decorative opaque appearance 4. Microwavable Example of lamination defect Paperboard laminated carton  Laminated pouch https://www.youtube.com/watch?v=20ntrnheV_4 Other types of laminated packaging Q1 A food company is considering switching from traditional packaging to laminated packaging for their extruded snack products. a) List out five (5) benefits they can expect from this transition? b) Construct the most suitable packaging laminates capable of preserving the quality of the product? Q2 Lamination is a process of combining different packaging materials to become a single-laminated material. a) Illustrate the structure of 6-layers laminates for carton packaging for papaya juice product. b) Differentiate between Adhesive and Extrusion lamination process. Q3 A food manufacturer plans to produce a new line of energy bar fortified with vitamin C. As a packaging technologist in the company, you are assigned to develop a laminated packaging of the product. a) Describe the criteria that should be considered for in designing of packaging laminates? b) Revise the packaging laminate construction if you were to change if consumer demanded for the visibility of the products. Briefly justify your answer. FST648 FOOD PACKAGING TECHNOLOGY SRR Aseptic packaging 1 ASEPTIC PACKAGING Filling of sterile containers with a commercially sterile product under aseptic condition, and then sealing them in hermetically sealed containers to prevent recontamination *Hermetic = Strictly air tight 5  APPLICATIONS Packaging of pre-sterilized and sterile product 1 e.g.: milk and dairy products, puddings, desserts, fruit and vegetable juices, soups, sauces and product with particulates 2 Packaging of a nonsterile product to avoid infection by microorganisms e.g.: fermented dairy products (yogurt) 6  ASEPTIC PACKAGING SYSTEM An aseptic packaging system should be capable to meet following criteria: Able to connect to the processing system in a manner that enables 1 aseptic transfer of product to take place 2 Able to be effectively sterilized before use Able to carry out the filling, sealing, and critical transfer operations in a 3 sterile environment 4 Able to be cleaned properly after use 7 8  REQUIREMENT FOR AN ASEPTIC FILLING The container and method of closure must be suitable for aseptic filling- must not allow microorganism get into sealed container during storage and distribution. Container/ part in-contact with products must be sterilized after it is formed and before being filled. Container must be filled without contamination by microorganism either from equipment surface or from surrounding atmosphere. If any closure needed- must be sterilized immediately before it is applied. Closure must be applied and sealed in place, while the container is within a sterile zone to prevent the passage of contaminating microorganisms. 9  Dry heat Steam UV light Hydrogen peroxide Package sterilization (H2O2) techniques Pulse light Peracetic acid (PAA) Ionisation  THERMAL Types: 1) Steam (moist heat) 2) Hot air (dry heat) Steam (121°c for 20 min) = Hot air (170°c for 60 min) Methods of thermal sterilization: 1. Steam 2. Hot air 3. Extrusion 11  Steam Steam generated in pressure chamber is used to sterilize packaging 350°C Superheated steam material After sterilization, steam condensate/adhering moisture on the packaging surface - must be removed otherwise it will dilute the product in the package Saturated steam Saturated steam Sterilization of plastic containers: Steam at 165°C, 600 kPa - for moulded PS cups (1.4s), foil lids (1.8s) Water Superheated steam STEAM GENERATOR Sterilization of tinplate, Al cans and lids in aseptic canning Sterilized at 220-226°C for 36-45s 12  Hot air/Dry heat Accomplished by conduction The heat is absorbed by the outside surface of the item, then passes towards the center of the item, layer by layer. The entire item will eventually reach the temperature required for sterilization to take place. Sterilization condition: 170°C (340°F) for 30 minutes 160°C (320°F) for 60 minutes, and 150°C (300°F) for 150 minutes or longer depending on the volume. 13  Extrusion Use heat and mechanical forces to sterilize and form packaging materials, primarily plastic films. Continuous process which involve residual heat (180-230°C) from extrusion, co-extrusion, blow moulding and thermoforming able to sterilized plastic containers. Weakness: Temperature distribution is not uniform Product pH < 4.5 – extruded container able to achieved 3-4 decimal reduction in microbial spores Product > 4.5 – extruded container must be post-sterilised with chemicals (H2O2 or peracetic acid) 14  CHEMICAL Hydrogen peroxide Peracetic acid (H2O2) (PAA) Destruction of most resistant spores on Effective against resistant bacterial spores packaging material is achieved by exposing at 20oC package at 30 – 50% H2O2 at 70 - 100°C Use to sterilize machine surfaces and PET Concentration of H2O2 present in food package bottles prior to aseptic filling shall < 500 ppb at the time of filling and 1̃ ppb within 24h Sterilizing chemicals used to sterile equipment and packaging materials Citric acid, lactic acid, acetic acid, ethanol, ethylene oxide, ozone 15  ASEPTIC PACKAGE INTEGRITY TESTING Package and seal integrity must be maintained to ensure safety of product Destructive Non Destructive Method Biotesting Leak inspection systems based on Electrolytic testing stimulus-response technique Dye penetration or bubble testing Computer-aided video inspection / automatic profiling of packages Disadvantages laborious ineffective because package profile time-consuming does not change immediately when not possible to test and reject all defective package leaks and air enters. packages 23  Past Exam Questions [Jan 2024] a) Explain the used of UV-C radiation and peracetic acid in sterilizing food contact surface of packaging material (5 marks) b) Demonstrate the sterilizing process for performed plastic cups intended for used in aseptic packaging systems (5 marks) [July 2023] a) A combination of chemicals using hydrogen peroxide and hot air treatment is commonly used for package sterilization. However, the used of UV irradiation together with chemical and heat treatment is more effective and safer. Explain Why. (5 marks) b) Use a schematic diagram to illustrate an aseptic packaging system (5 marks) [July 2022] a) Explain the six (6) requirements for sterilisation of packaging used for food and beverage products. (6 marks) b) Debate the pros and cons of the use of radiations for in-package sterilisation of food products. (6 marks) [Feb 2022] A company would like to apply an aseptic packaging technique on their food products. However, they are not sure whether to use the thermal or nonthermal aseptic techniques. As a food technologist of the company, you must provide adequate information to help them decide on the suitable method to be applied. a) Elaborate the thermal and nonthermal aseptic techniques used for sterilisation of packaging material. (8 marks) b) Provide the pros and cons of each technique. (6 marks) [Aug 2021] ABC company wants to sterilise their aseptic packaging material and decided to use the irradiation method. As a food technologist, you are required to advise the company management team on the different types of sterilisation methods available. Describe three (3) irradiation methods that can be used to 24 sterilise their product and packaging material.  Topic 7 PACKAGING REQUIREMENTS FOR SELECTED FOOD PRODUCTS PACKAGING REQUIREMENTS Key functions of food packaging: Protection, preservation, convenience, and communication Requirement of a package for certain products based on the degree of protection needed in order to provide necessary barrier to prolong shelf life: i) Product Characteristics Nature of product, form (solid,liquid/semisolid etc.) ii) Package properties Materials has barrier towards, moisture, O2,package-product interaction, etc. iii) Distribution/storage Package form, etc. FOOD SPOILAGE Deterioration in food quality making it unfit for consumption Causes: Biological – microbial growth, enzymatic activity Chemical – Oxidation, Maillard reaction Physical – Environmental factor, moisture absorption, bruise FACTOR CONTRIBUTE TO FOOD SPOILAGE Food compositions – Carbohydrate, protein, fat pH/ acidity of food – optimum microbial growth is at 4.6 – 7.5 Temperature Time Oxygen Moisture – Presence & availability of water Light – UV radiation & visible light causes oxidative deterioration of lipids, vitamins, protein and colorant in food MEAT AND MEAT PRODUCTS Major Quality Attributes of Fresh meats: Colour associated to freshness (consumer acceptability) Microbiological spoilage of meat associate to bacterial growth (shelf-life) Bacterial discolouration attributed to: high O2 demand of aerobic bacteria which reduces O2 tension at meat surface causes formation of brown MetMb. some bacteria produce by-product – H2S and H2O2 react with unstable Mb to produce green pigments sulfmyoglobin and choleglobin (pH > 6). Colour of frozen meat depend on rate of freezing: Fast freezing – small ice crystal, scatter light and make meat surface pale and opaque. Slow freezing – large ice crystal, poor light scattering, give meat dark, translucent appearance.  Packaging of Fresh/Red Meat Vacuum Packaging Plastic materials used must have low moisture and gas permeability and strong enough to hold weight of meat. Vacuum Packaging system: - Flexible Vacuum pack: eg. PA/LDPE coextruded as 5-layer films - Rigid Vacuum pack: eg. PVC or PVC/LDPE or PET/PVdC/LDPE - Skin pack: eg. PVC/LDPE or PS/EVOH/LDPE Modified Atmosphere Packaging (MAP) Consist of high O2 (50 to 100%) with CO2 (15 to 50%) to preserve fresh meat colour and prevent anaerobic spoilage - Flexible MAP pack: eg. PA/LDPE/OrientedPA/LDPE or PA/EVOH/LDPE or PP/EVOH/LDPE or LDPE/EVOH/LDPE - Rigid MAP pack: PS/EVOH/LDPE or PVC/OrientedPA/LDPE SNACKS AND BREAKFAST CEREAL SNACKS Major mode of deterioration: - Development of fat rancidity - Loss of crispness Packaging must provide good barrier: O2 Light Moisture Packaging of Snacks (Fried/Extruded/Puffed) Typically packaged in multilayer structures: - paperboard cans lined with Al foil or barrier polymer and sealed under vacuum (or flushed with N2 gas) with an LDPE/foil end (top closure). Potato chips - packaged in plastic laminates - eg. OPP/LDPE/PVC or HDPE/EVA copolymer. BREAKFAST CEREALS Major mode of deterioration: - Development of fat rancidity - Loss of crispness - Loss of vitamin, aroma from flavored products Packaging must provide good barrier: O2 Light Moisture Packaging of Breakfast Cereals Conventional: fiberboard boxes with waxed, glassine paper liner to protect product from mechanical damage and provide barrier to moisture, loss of flavour and aroma. Recent, glassine liner replace with HDPE and EVA (copolymer) liner. To protect from lipid oxidation, good O2 barrier required such as PVdC/PP/LDPE laminates. BEVERAGES Major mode of deterioration: - Off odor/flavor - Discoloration - Sedimentation - Loss of carbonation Packaging must provide good barrier: Gases/ O2 Light Chemically resistant to acidic Resistant to pressure  Packaging of Beverages Carbonated Beverages Glass bottle Aluminum cans PET Vacuum bottles Packaging system: Fruit juice Glass bottle PET, HDPE bottles Multi-layer carton Laminated films (Stand-up Pouch) DAIRY PRODUCTS MILKS Major mode of deterioration: Microorganisms Temperature Light Oxygen/other gases Packaging must provide good barrier: O2 Light Moisture  Packaging of Milks Transparent bottle transmit 58-79% light. Pigmented HDPE milk bottles (opaque) – add Ultra High Temperature Milk Common packaging material used for UHT milk TiO2 (1 - 2%) to reduced