Part IV General issues 21.1 Introduction Package design has great significance for the success of foodstuffs nowadays. Packages are clearly an integral part of the manufacturing and distribution processes. As clothes speak for their wearers, so too packages speak for the packed food product. Packages are developed not only to make weekdays easier for the consumer, but also to make times of celebration more festive. Many food products would not be in shops and on dining tables, if they had not been packed. Nowadays packages face difficult challenges and roles. They have to create the ambience that hitherto was forged by personal service. Packages replace the salesman. In addition, packaging has many other functions and requirements which it has to fulfil more and more effectively and economically. These functions and requirements are changing all the time and their importance in ensuring the success of the product is growing. The aim is to make the optimal package that satisfies all functional requirements in addition to meeting environmental and cost demands as well as possible. The answer to these complex demands is precision packaging. VTT Precision Packaging Concept has been developed in the Technical Research Centre of Finland and it is a new and unique tool to optimize packaging for foodstuff. Elsewhere optimization methods for transport packages have been developed, but not for primary packages, which are in direct contact with foodstuff. The VTT Precision Packaging Concept is based on the predetermined minimum shelf-life needed to allow the packed foodstuff to reach the consumer’s table from the factory. The shelf-life is naturally chosen to suit the market and the business strategy of the company. A longer shelf-life is 21 Optimizing packaging T. Lyijynen, E. Hurme and R. Ahvenainen, VTT Biotechnology, Finland needed for an export market than for a home market. Depending on the business strategy, the company can favour either short or long best-before times. It should be noted that the selling time of the product does not necessarily have any other connection to the real shelf-life but, naturally, the selling time is always shorter than the shelf-life. This chapter gives a description of the VTT Precision Packaging Concept for the optimization of food packages. At the end of the chapter, examples of optimization are given using different gas-packed foodstuffs. 21.2 Issues in optimizing packaging The basic aim in the optimization of food packages is to create a tool for decision-making policy for launching new products. The packaging optimization concept should not only advantageously help food manufacturers, but also packaging material and packaging manufacturers to evaluate and compare the feasibility of their new and present products. In today’s competitive market, packaging innovation can be a big advantage in efforts to persuade the consumer to buy a certain brand, and the packaging optimization concept may help to reduce the economic support and time needed for package development. Several factors should be considered in the optimization process for packages, covering the performance in logistics, marketing properties, consumer convenience, costs, and environmental stresses (see Fig. 21.1). The general goals in package optimization are the cost-effectiveness of the packaging process and environmental issues, e.g. source reduction of packaging materials. The importance of these factors is discussed below. 21.2.1 Performance in logistics One of the most important tasks of a food package is to afford protection from environmental conditions, like oxygen, light and moisture. This is crucial for maintaining the quality and safety of most packaged foods. Therefore, it is essential that a package has sufficient mechanical strength to protect the packaged product from environmental stresses during distribution and storage. Environmental issues, however, demand that packaging material consumption is kept to a minimum and that packaging materials be recoverable. This requires the food industry to use thinner materials that still have both sufficient mechanical strength and barrier properties. An optimized, downsized package may also reduce wholesaler and retailer costs. On the other hand, in some cases it may also be favourable to use relatively thick, recyclable monomaterial layers (e.g. polyethylene) suitable for energy recovery. In other words, an optimized food package minimizes the waste in the overall packaged product. New packaging solutions should also be technically feasible. That is, they may not set any limitations on either packaging speeds or the quality of seals. Package dimensions need to be logistically congruent with the secondary 442 Novel food packaging techniques package and pallet. The ratio of packaged product to package volume should be as high as possible. 21.2.2 Marketing properties The marketing properties of a package should be fulfilled as well as necessary, not as well as possible. This means that, optimally and cost-effectively, only adequate investment is needed to fulfil the need for, e.g., package design in terms of packaging material consumption, decoration and information. Keeping up the brand image of a product should be taken into account when making packaging decisions. It is important that package designers, manufacturers and users can co-operate closely to achieve an optimum package. 21.2.3 Costs From a food manufacturer’s point of view, especially, the costs of primary packaging materials as well as indirect packaging costs (storage, transportation, energy consumption, and labour costs) should certainly be as low as possible. A cost-competitive package is, of course, a benefit for both the packaging and the food manufacturers. A packaging innovation requiring a minimum of investment and giving consumers products they like, at affordable prices, can be seen to be a very attractive goal. Such innovations could be, e.g., easy-open seals or thinner materials which consumers find more environmentally friendly. 21.2.4 Consumer convenience Such properties of a package that make it convenient for the consumer include it being easy to handle, carry, store and dispose of/re-use, as well as its openability, resealability, and microwaveability. Fig. 21.1 The VTT Precision Packaging Concept is a customized tool for optimization of food packaging. Optimizing packaging 443 21.2.5 Environmental stresses Environmental aspects should be taken into account as far as possible in the optimized package. The relevant issues include the need for low environmental stresses from the packaging material and packaging, the necessity of a low ratio of package weight to product weight, the need for as little of the package volume to be waste as possible, and the incineration possibilities of different packaging materials. 21.3 The VTT Precision Packaging Concept The VTT Precision Packaging Concept includes several phases (see Fig. 21.2). The first task is to specify the required shelf-life for a foodstuff and determine the basic requirements for this food package, e.g. by using shelf-life prediction models. After that it is possible to choose different combinations of package types and to optimize the package. Optimization is performed in four steps: (i) scoring the tested package types, (ii) evaluating the importance of package characteristics, (iii) calculating the coefficients for each of the characteristics, and (iv) calculating the optimization result of each of the tested package types. 21.3.1 Determination of basic requirements for packaging Precision packaging is based on a pre-determined minimum shelf-life needed to allow the packed foodstuff to reach the consumer’s table from the factory. The shelf-life is naturally chosen to suit the market and the business strategy of the company. A longer shelf-life is needed for an export market than for a domestic market. Fig. 21.2 A scheme for determining the optimal package. 444 Novel food packaging techniques The VTT Concept uses mathematical modelling to determine the minimum package requirements for the foodstuff. The modelling of the shelf-life of foodstuffs is performed in the following steps: (i) selecting factors and responses, (ii) selecting the experimental design method (screening or more extensive method), (iii) carrying out tests, (iv) analysing results, (v) making shelf-life predictions and (vi) determining the minimum package requirements. The factors that might be relevant and might affect the quality deterioration of the foodstuff are chosen, for example, oxygen transmission rate of a packaging material, carbon dioxide concentration of a package, package volume and storage conditions (temperature, illumination, etc.). The quality parameters in shelf-life testing of food can include sensory and chemical analyses and microbiological determinations. The minimum package requirements can also be based both on the information of the shelf-life tests and on the literature data. 21.3.2 Determining different package and storage combinations After the required packaging parameters for a foodstuff at certain storage conditions have been determined, it is possible to select the different alternatives of packages and packaging materials, packaging methods and package conditions all of which give equally acceptable food quality at the end of the required shelf-life of the product (e.g. vacuum or gas-flushed package with specified packaging material and gas concentrations). 21.3.3 Scoring the selected alternative package types The selected, alternative package types giving the same minimum required shelf-life, are first scored by rating different characteristics of each package type. As an example, the following package attributes can be used in a Precision Packaging Concept: ? mechanical strength of a package ? suitability with respect to packaging standards ? ratio of package weight to product weight ? volume of package waste ? possibility of incineration ? life cycle assessment of packages ? marketing properties of a package ? consumer convenience ? consumer attitudes ? cost of packaging material ? indirect packaging costs. All these characteristics are scored on a scale from 1 to 5, with 1 corresponding to poor and 5 to excellent quality. Fractional numbers are also allowed. The scoring is performed in co-operation with experts representing wholesalers, food manufacturers, packaging material manufacturers and independent specialists of packaging technology and plastics industry. Optimizing packaging 445 Mechanical strength of a package This is determined using a simulated transportation test. For example in the VTT transportation test, a whole pallet positioned on a vibration table is subjected to a simulated road transportation of about 1000 km. As an example, during this 45- minute test run, the table is vibrated at a constant acceleration of 0.5 g, with the frequency of the table sweeping between 5 and 55 Hz. Since each package type resonates at its own specific frequency, every package tested is exposed to more or less high accelerations during the test procedure. In general, the packages in the top layer of a pallet are exposed to the highest accelerations, which can be even more than 6 g. After the test, all the possible flaws, such as flexes, fractures, open seals and product disorientation originating from the transportation tests are recorded, and the test packages are scored as follows: ? 1 point: if even one tested package in the pallet is leaking, the whole sample group is rejected. ? 3 points: there are some minor dents or flexes. ? 5 points: no package is affected by the vibration test. Suitability with respect to packaging standards This is evaluated by examining the volume occupied by the primary packages tested in a secondary package, which had the dimensions of the pallet area. Scores between 1 and 5 are given on the following basis: ? 1 point: relatively large empty space left in the secondary package. ? 5 points: primary packages tight together, no empty space in the secondary package. Ratio of package weight to product weight The score for this ratio ( Sm) is calculated using eqn 1 Sm 0:444 1 m p =m f 100 5 1 where m p weight of the empty package and m f weight of the packaged food. Equation 1 was formulated on the following basis: ? 1 point corresponds to an empty package weighing 10% of the weight of the packaged product, and ? 5 points correspond to an empty package weighing 1% of the weight of the packaged product. Volume of package waste This is scored from 1 to 5 on the following basis: ? 1 point: a rigid package, e.g. tray, which cannot be scrunched and which would require a large space in a household waste basket. ? 5 points: a package that is made of a thin flexible material, which can easily be put in a household waste basket without the need for stuffing or scrunching. 446 Novel food packaging techniques Suitability of the empty package for incineration This is evaluated as follows: ? 1 point: cannot be incinerated under any conditions, e.g., metal can. ? 2 points: can be incinerated in a plant specialized for problem waste. ? 3 points: can be incinerated in a plant for municipal waste. ? 4 points: can be incinerated in a power plant for fossil fuel resources. ? 5 points: can be incinerated in the home. Marketing properties of a package These are evaluated by awarding scores between 1 and 5 on the following basis: ? 1 point: package design or packaging material does not meet the requirements of brand/company image and logistics, it has poor printability, insufficient space for labels and poor visibility on the shelf. ? 5 points: excellent package design, proper packaging material, excellent printability, enough space for labels, excellent visibility of the packaged product on the shelf. Consumer convenience This is evaluated by awarding scores between 1 and 5 points as follows: ? 1 point: package dimensions and sharp corners make it difficult to handle, carry, store and dispose of, it is difficult to open without a tool and/or spillage of the product, it is not resealable, and is not suitable for microwave ovens. ? 5 points: package is easy to handle, carry, store and dispose of/re-use, as well as being easy to open, and reseal, and is suitable for microwave ovens, if necessary. Scored costs of packaging material These ( Sc) are calculated using eqn 2 based on the annual production reports given by the food manufacturers and the corresponding cost information for the necessary primary packaging materials given by the different packaging material manufacturers. The cost of the packaging material is first scored by the food manufacturers, as follows: ? 1 point represents a packaging material cost that is far too high compared to the total manufacturing cost of the product, whereas ? 5 points equals a very economical ratio of packaging material costs to the total manufacturing cost. Sc 4= c 1 c 5 1 c 5 c x 5 2 where c 1 and c 5 are the costs corresponding to 1 and 5 points, respectively, awarded by the food manufacturer, and c x is the cost of the packaging material of the sample. For example, if the food manufacturers rate packaging materials costs of 0.03 C= /package for a specified product as very economical whereas 0.13 Optimizing packaging 447 C= /package is far too expensive, 5 points would be awarded to 0.03 C= /package, 3 points to 0.08 C= /package and 1 point 0.13 C= /package. Indirect packaging costs These are estimated by including storage, transportation, energy consumption and labour costs. The estimations are made qualitatively. That is, different package types (flowpacks, form-fill-sealed-packs, preformed trays) are ranked against each other on a scale of 1 to 5. 21.3.4 Evaluating the importance of package characteristics After the characteristics of the selected, alternative packages have been scored, the importance of the characteristics is evaluated by the food and packaging material manufacturers, the wholesaler and independent packaging technology and plastics industry specialists. As an example, the importance of the characteristics evaluated by the food and packaging material manufacturers is presented in Fig. 21.3. 21.3.5 Calculating the coefficients The coefficients I for each of the characteristics are then calculated as follows (eqn 3): I 0:4 i f 0:25 i p 0:25 i w 0:1 i s 3 Fig. 21.3 The importance of the various characteristics of packages evaluated by Finnish food manufacturers and packaging material manufacturers. 448 Novel food packaging techniques where i f is the importance of a given package characteristic as evaluated by the food manufacturer of the product, i p is the mean rating for the importance of the package characteristic as evaluated by the packaging material manufacturers of the product, i w is the importance of the package characteristic as evaluated by the wholesaler, and i s is the mean importance of the package characteristic as evaluated by the independent specialist for the packaging technology and plastics industry. Since food manufacturers have a very significant role in the decision-making process in terms of package performance, applicability and functionality, the weighting of i f with a coefficient of 0.4 ensures that its influence on the coefficient I is the greatest. The significance of the influence of both the wholesaler and the packaging material manufacturers is rated as being quite important and so each of their importance scores is weighted with a coefficient value of 0.25. The influence of the independent specialists is rated the lowest and the corresponding importance score is, therefore, weighted with a coefficient value of 0.1. The coefficients used in eqn 3 were agreed between all the participants referred to above and VTT. 21.3.6 Calculating the optimization result The score, s, given to each of the characteristics of the tested packages is multiplied by the corresponding coefficient, I, given to these nine characteristics, where OR is the optimization result of a certain tested package type (eqn 4): OR s 1 I 1 s 2 I 2 s 3 I 3 . . . s 9 I 9 4 It is also possible to ignore some characteristics, and calculate the optimization result with, for example, only seven characters. In fact, this is the case in the examples in the section 21.4. That is, in an optimized package, the mechanical strength of a package and its suitability with respect to packaging standards are considered as the essential requirements that all packages should fulfil before being launched. Therefore, these requirements can be ignored when calculating the optimization result. 21.4 Examples of food packaging optimization The following examples illustrate the using of the VTT Precision Packaging Concept. The foodstuff examples are gas-packed cheese slices, raw chicken legs, roasted chicken balls and ham pizza. 21.4.1 Gas-packed cheese slices Storage and packaging are particularly important factors for the shelf-life of cheese. There are some basic packaging requirements that are the same for all types of cheese: firstly, oxygen must be excluded to prevent mould growth and Optimizing packaging 449 rancidity, and secondly moisture must be retained to preserve the texture and avoid weight loss. The effect of light must also be considered in the packaging of cheese. Modified atmosphere packaging can be used to package soft and crumbly textured cheeses without damaging them. Modified atmosphere packages are easier to open than vacuum packages and they also extend the shelf-life of cheeses. The example of packaging optimization was for sliced matured cream cheese. The amount of cheese slices in packages was 150 g. Modified atmosphere packaged cheese slices have a last day of use 13 weeks after packaging when the storage temperature is below +8oC. According to the results of the modelling test, an ideal gas-package for sliced matured cream cheese, considering a shelf-life of eight weeks (temperature 6oC) and keeping its quality to the maximum, may have following properties: ? protection from light during distribution ? oxygen transmission rate of packaging material: 5–95 cm 3 /m 2 24 h (at 23oC, 50% RH and latm) ? carbon dioxide concentration: 20% ? residual oxygen level: < 1% ? headspace volume: 55–275 ml/100 g cheese. The next step was to choose the different packaging alternatives for sliced cheese (see Table 21.1). Then the characteristics of selected, alternative packages scored and the importance of the characteristics evaluated by food and packaging material manufacturers, the wholesalers and independent packaging specialists (see Table 21.2). The most important factors affecting the optimization result were indirect packaging costs, marketing properties, and cost of packaging materials. The optimization results suggest that the selected, alternative packages differed most in the costs of their packaging materials. To compare the best (Package 4), see Table 21.2 and worst rated (Package 2), the following estimations can be made. If the annual production of the product is 10 million packages, Package 4 saves about 30 000 kg of packaging material annually compared to Package 2. Similarly, Package 4 saves about C= 109 000 annually in packaging material costs compared to Package 2. 21.4.2 Gas-packed raw chicken legs The shelf-life of cold stored fresh poultry is mainly restricted by microbial growth, especially by Pseudomonas and Acinetobacter. Psychrotrophs contaminate easily during slaughter, because psychrotrophs appear often in feathers and legs. Growth of these bacteria can effectively be slowed down using gas packaging. Spoilage can be noticed in sensory quality when the amount of bacteria is 10 6 –10 8 cfu/cm 2 , and slime formation exists when the amount of bacteria is 10 6 –10 8 cfu/cm 2 . The example of packaging optimization was for fresh industrially slaughtered chicken legs. The average weight of one chicken leg was 277 g and volume 262 ml 3 . The last date of use is seven days after packaging when the storage 450 Novel food packaging techniques Table 21.1 The sliced matured cream cheese packages used in the package optimization. Package information: 150 g cheese slices in the package and the package volume about 350 ml 3 . Secondary package was a cartonboard box Feature Package 1 Package 2 Package 3 Package 4 Package 5 Package 6 Package type tffs tffs tffs tffs tffs tffs Monomaterials used in package PA, PE, PA, PE, PA, PE, PA, PE PA, PE, PA, PE, EVOH EVOH, mPET PP, mPET PP, EVOH PP, EVOH EVOH Weight of an empty package (g) 7.6 7.7 4.9 4.8 5.4 5.0 Transparency clear lid and metallized lid, metallized lid, white lid, white lid, clear lid tray clear tray clear tray clear tray clear tray and tray Abbreviation: tffs = thermoformed tray/fill/seal Table 21.2 The scores of various characteristics of tested cheese slices packaging types, the calculated coefficients for each characteristic and the optimization results for tested packages Scores Characteristic I Package 1 Package 2 Package 3 Package 4 Package 5 Package 6 Mechanical strength 0.10 1 5 5 5 5 5 Suitability with standards 0.08 5 5 5 5 5 5 Package weight/product weight 0.05 3.2 3.2 4 4 3.8 4 Volume of package waste 0.06 5 4.5 4.5 5 5 5 Possibility of incineration 0.08 3 3 3 3 3 3 Marketing properties 0.17 3.09 3.67 3.25 3 2.92 3.59 Consumer convenience 0.11 3 3 3 3 3 3 Cost of packaging material 0.15 0.55 0.3 3.1 3.45 3 2 Indirect packaging costs 0.20 3 3 3 3 3 3 Optimization result 2.2 * 2.3 2.7 2.7 2.6 2.6 * Package 1 failed the simulated transportation test, and therefore, it was not acceptable. Note: The scores given for the mechanical strength of a package and its suitability for packaging standards have been ignored. temperature is below +6oC. According to the results of modelling shelf-life test, to achieve a maximum quality for raw chicken legs for seven days under the existing distribution conditions (temperature +6oC) the package parameters could be the following: ? oxygen transmission rate of package: 10–14 ml/package 24 h (at 23oC, 50% RH and latm ? carbon dioxide concentration: 50–80 % ? residual oxygen level: < 1 % ? protection from light: not necessary ? headspace volume: 50–110 ml/100 g product. The next step was to choose the different packaging alternatives for raw chicken legs. Five different packaging types were chosen as described in Table 21.3. The characteristics of selected, alternative packages were scored and the importance of the characteristics were evaluated by food and packaging material manufacturers, the wholesalers and independent packaging specialists (see Table 21.4). The most important factors affecting the optimization result were indirect packaging costs, marketing properties and cost of packaging materials. The optimization results suggest that the selected packages differed most in their marketing properties and consumer convenience: rigid preformed trays were evaluated significantly better than semi-rigid/flexible trays which were thermoformed just before packaging. In addition, the mechanical strength of the thermoformed trays was not satisfactory. To compare the best rated preformed tray (Package 2) and Package 5, the following estimations can be made. If the annual production of the product is 1 million packages, Package 2 saves about 35 000 kg packaging material annually compared to Package 5. In addition, Package 2 saves about C= 32 000 annually in packaging material costs compared to Package 5. Table 21.3 The raw chicken leg packages used in the package optimization. Package information: 1 kg raw chicken legs in the package and the package volume about 1800 ml 3 . Secondary package was an open plastic stackable and reusable box Feature Package 1 Package 2 Package 3 Package 4 Package 5 Package type preformed preformed tffs tffs preformed tray tray tray Monomaterials used in package PA, PE, PP PA, PE, PP PA, PE, PP PA, PE, PA, PE EVOH Weight of an empty package (g) 40 31 16 10 65 Transparency clear lid, clear lid, clear lid, clear lid, clear lid, white tray white tray and tray and tray black tray Abbreviation: tffs = thermoformed tray/fill/seal Optimizing packaging 453 21.4.3 Gas-packed roasted chicken balls Minced chicken balls belong to the group of ready-to-eat foods that are supposed to be heated before eating. The cooked prepared foods typically have low initial microflora levels and they are very sensitive to post-preparation contamination. Unpacked and air-packed cooked minced meat or poultry products usually spoil due to yeast and mould growth. The growth of these micro-organisms can be strongly retarded by using gas-packaging. The ingredients of the chicken balls were minced chicken meat, onion, breadcrumbs, potato, soy protein products, egg, potato flour, vegetable oil, salt, powdered chicken soup, seasonings, glucose and flavour intensifier. The last day for use is ten days after packaging when the storage temperature is kept below +6oC. Each package contained 400 g of chicken balls. The next step was to choose the different packaging alternatives for roasted chicken balls. Eight different alternatives were selected as described in Tables 21.5a and 21.5b. The characteristics of selected, alternative packages were scored and the importance of the characteristics were evaluated by food and packaging material manufacturers, the wholesalers and independent packaging specialists (see Tables 21.6a and 21.6b). The most important factors affecting the optimization result were indirect packaging costs, cost of packaging materials, and marketing properties. The optimization results indicate that flowpacks obtained the best scores, especially Table 21.4 The scores of various characteristics of tested raw chicken legs packaging types, the calculated coefficients for each characteristic and the optimization results for tested packages Scores Characteristic I Package Package Package Package Package 1 2 3 4 5 Mechanical strength 0.11 5 3 1 1 3 Suitability with standards 0.09 1 1 5 5 3 Package weight/product 0.07 3.7 4.1 4.7 5 2.6 weight Volume of package waste 0.05 1 1 5 5 3 Possibility of incineration 0.08 3 3 3 3 3 Marketing properties 0.13 4 3.5 1.5 1 4 Consumer convenience 0.10 4.5 4.5 2 1.5 4.5 Cost of packaging material 0.13 3.75 4.2 5 5 3.15 Indirect packaging costs 0.25 3 3 3 3 3 Optimization result 2.7 ** 2.8 ** 2.6 * 2.5 * 2.7 * Packages 3 and 4 failed the simulated transportation test, and therefore, they were not acceptable. ** The dimensions of Packages 1 and 2 were not suitable for the secondary package used for the product. Note: The scores given for the mechanical strength of a package and its suitability for packaging standards have been ignored. 454 Novel food packaging techniques in terms of packaging material costs and indirect packaging costs. The marketing properties of the flowpacks, however, were not evaluated as being as good as the properties of the other package types in general. Leaking seals were found in one type of flowpack, and from one type of preformed tray. Therefore, a modification in package/packaging material structure should be made before the mechanical strength of these package types will be at an acceptable level. To compare the best rated flowpack (Package 1), thermoformed tray (e.g. Package 5) and preformed tray (Package 6), the following estimations can be made. If the annual production of the product is 1 million packages, the annual savings in package material consumption for Packages 1 and 5 are 20 000 kg and 8 000 kg, respectively, when compared to Package 6. Similarly, the annual savings in packaging material costs for Packages 1 and 5 are about C= 48 800 and C= 32 000, respectively, when compared to Package 6. Table 21.5a The roasted chicken balls packages used in the package optimization. Package information: 400 g roasted chicken balls in the package. Secondary package was an open plastic stackable and reusable box Feature Package 1 Package 2 Package 3 Package 4 Package type flowpack flowpack tffs tffs Monomaterials used in package PET, PE, PE, PET PA, PE PA, PET, EVOH PE Package volume (ml 3 ) 1000 1000 800 1000 Weight of an empty package (g) 6 7 10 22 Transparency clear clear clear lid clear lid and tray and tray Abbreviation: tffs = thermoformed tray/fill/seal Table 21.5b The roasted chicken balls packages used in the package optimization. Package information: 400 g roasted chicken balls in the package. Secondary package was an open plastic stackable and reusable box Feature Package 5 Package 6 Package 7 Package 8 Package type tffs preformed preformed preformed tray tray tray Monomaterials used in package PA, PET, PA, PE, PA, PE, PE, PS, PE, EVOH PP PP EVOH Package volume (ml 3 ) 1100 1300 1200 1500 Weigth of an empty package (g) 18 26 27 42 Transparency clear lid, clear lid, clear lid, clear lid, yellow tray opaque tray opaque tray and tray Abbreviation: tffs = thermoformed tray/fill/seal Optimizing packaging 455 Table 21.6a The scores of various characteristics of tested roasted chicken balls packaging types, the calculated coefficients for each characteristic and the optimization results for tested packages Scores Characteristic I Package Package Package Package 1 2 3 4 Mechanical strength 0.10 5 1 5 3 Suitability with standards 0.09 5 5 5 3 Package weight/product weight 0.07 4.7 4.6 4.3 3 Volume of package waste 0.07 5 5 4 3 Possibility of incineration 0.07 3 3 3 3 Marketing properties 0.14 2 2 1.5 3 Consumer convenience 0.10 3.5 3.5 2 2.5 Cost of packaging material 0.14 5.14 5.57 5.53 4.33 Indirect packaging costs 0.23 5 5 3 3 Optimization result 3.4 3.4 * 2.6 2.6 * Package 2 was not acceptable since it failed the simulated transportation test. Note: The scores given for the mechanical strength of a package and its suitability for packaging standards have been ignored. Table 21.6b The optimization results for four different roasted chicken balls package types Scores Characteristic I Package Package Package Package 5 6 7 8 Mechanical strength 0.10 5 3 5 1 Suitability with standards 0.09 3 3 1 3 Package weight/product weight 0.07 3.4 2.6 2.4 0.8 Volume of package waste 0.07 3 1 1 1 Possibility of incineration 0.07 3 3 3 3 Marketing properties 0.14 2.5 3 2.5 3 Consumer convenience 0.10 2.5 3.5 2.5 3 Cost of packaging material 0.14 4.5 3.7 3.15 0 Indirect packaging costs 0.23 3 2 2 2 Optimization result 2.6 2.2 1.9 ** 1.5 * * Package 8 was not acceptable since it failed the simulated transportation test. ** The dimensions of Package 7 were not suitable for the secondary package used for the product. Note: The scores given for the mechanical strength of a package and its suitability for packaging standards have been ignored. 456 Novel food packaging techniques 21.4.4 Gas-packed pizza Pizza is a typical ready-to-eat food that must be heated before eating. Pizza is a complex food with a variety of components (carbohydrates, proteins and fats), so there are many substrates for microbial and chemical attack during spoilage. Quality impairment of pizzas is mainly due to mould growth and staling of bottom (pizza crust). Furthermore, exposure to light causes fading of colours, cheese becoming yellowish, and rapid oxidation of fat. The example foodstuff for package optimization was ham pizza. The ingredients of the ham pizza were wheat flour, crushed tomato, tomato ketchup, cheeselike vegetable oil product, cooked ham, onion, vegetable oil, water, salt, thickening agent and seasonings. The last date of use is 16 days after packaging when storage temperature is below +6oC. According to the results of the shelf- life modelling test and the other literature data, an ideal package for ham pizza, considering the present shelf-life (16 days) and keeping its quality to the maximum level, may have the following properties: ? protection from light ? oxygen transmission rate of the packaging material: 5–95 cm 3 /m 2 24 h (at 23oC, 50% RH and latm ? carbon dioxide concentration: 10–40 % ? residual oxygen level: < 1 %. Next step was to choose the different packaging alternatives for ham pizza. Five different alternatives were selected as described in Table 21.7. The characteristics of selected, alternative packages were scored and the importance of the characteristics was evaluated by food and packaging material manufacturers, the wholesalers and independent packaging specialists (see Table 21.8). The most important factors affecting the optimization result were indirect packaging costs, marketing properties, and cost of packaging materials. The Table 21.7 The ham pizza packages used in the package optimization. Package information: package volume about 600 ml 3 . Secondary package was an open plastic stackable and reusable box Feature Package 1 Package 2 Package 3 Package 4 Package 5 Package type flowpack flowpack flowpack tffs tffs Monomaterials used in package PA, PE, mPET, PE, PET, PE, PA, PET, PA, PET, carton-PP- carton-PP- carton-PP- PE, EVOH PE, EVOH plate plate plate Weight of an empty package (and plate) (g) 18 18 17 16 20 Transparency white film, metallized clear film, clear lid clear lid, white plate film, white white plate and tray white tray plate Optimizing packaging 457 optimization results indicate that flowpacks were better than thermoformed trays, the only benefit of the trays being the lower cost of packaging material. To compare the best rated flowpack (Package 3) and thermoformed tray (Package 5), the following estimations can be made. If the annual production of the product is 10 million packages, Package 3 saves 20 000 kg of packaging material annually compared to Package 5. On the other hand, the packaging material costs for Package 5 are about C= 168 000 less than for Package 3. 21.5 Conclusion: improving decision-making The VTT Precision Packaging Concept can benefit the packaging industry for example by providing the means for comparing different package types (e.g. flowpacks, form-fill-sealed-packages and preformed trays). The concept can help the food industries in choosing plastic packaging materials and considering the demands of logistics, cost savings and shelf-life and improving competitiveness. In addition, it gives packaging material exporters a method of optimizing materials in the different conditions of exporting countries and helping in the after-treatment of plastic-based packaging materials. Table 21.8 The scores of various characteristics of tested ham pizza packaging types, the calculated coefficients for each characteristic and the optimization results for tested packages Scores Characteristic I Package Package Package Package Package 1 2 3 4 5 Mechanical strength 0.11 5 5 5 3 3 Suitability with standards 0.08 5 5 5 1 1 Package weight/product 0.07 1.4 1.4 1.7 1.8 1.1 weight Volume of package waste 0.07 3 3 3 1 1 Possibility of incineration 0.07 3.5 3.5 3.5 3 3 Marketing properties 0.15 3 3.5 4 1.5 1.5 Consumer convenience 0.11 3.5 3.5 4 2 2 Cost of packaging material 0.14 2 1.2 2.6 3 5 Indirect packaging costs 0.23 5 5 5 3 3 Optimization result 2.7 2.7 3.0 1.9 * 2.1 * * The dimensions of Packages 4 and 5 were not suitable for the secondary package used for the product. Note: The scores given for the mechanical strength of a package and its suitability for packaging standards have been ignored. 458 Novel food packaging techniques