EXPERIMENT 1: THE EFFECTS OF PACKAGING MATEIAL ON SHELF LIFE OF CRACKERS Introduction The type of food, chemical composition, size, storage conditions, expected shelf life, moisture content, aroma and appearance are just a few of the characteristics that must be taken into consideration when selecting the right material for a food product. A continuing trend in food packaging is the design of packages to extend the shelf life of foods while maintaining fresh-like quality.
This places a high demand on selecting materials that not only provide the needed properties to maintain the quality of the food but it must be done at a cost effective price. The permeability of the packaging material is one of the most critical features of the package for affecting the quality of the food product. Objectives: I) To calculate the moisture uptake of different packaging materials II) To assess the texture hardness of the products by sensory analysis and texture analyzer III) To determine the estimated shelf-life of the products Materials:
Crackers, packaging materials- HDPE, PP, Paper bag, aluminium foil, etc: plastic sealer: weighing balance, texture analyzer . Procedure: Two bags (duplicate) of crackers for each packaging materials was provided. The bags were filled with crackers, and then was weighed and stored at 25? C for 2 weeks. Two packets of crackers from the commercial packaging materials was weighed and stored at 25? C for 2 weeks as control. Each of the packets was reweighed after a week and the mean moisture uptake was determined after a week.
After 1 week, for the commercial products, the packet was kept empty by removing all traces of the contents and the weight of the empty packages was weighed. The original mass of the contents was calculated according to the calculation given. From the results, the time (in weeks) before packages allow to uptake of 1% moisture (based on the mass of the content) was calculated. At this point (1% moisture uptake) was assumed, the product had reached the end of its shelf life, and the result of the estimated shelf life was reported. Assessment of Crispiness: A) The means of ‘crispiness’ was decided in group. Sensory Analysis
The commercial crackers as ‘standard’ was taken and each one of the crackers was bite down by using the incisor teeth only. The degree of crispiness was noted and this crispiness of the rating was given of 100. The crispiness of crackers was rated from different types of packet in the same manner by comparing each to the ‘standard’. As example, if you feel a biscuit is half as crispy as the standard, give it a rating of 50: if it twice as crispy gives it a rating of 200. A mean rating and SD of crackers of each type of packaging was calculated. B) Texture Analysis This method is using texture analyser TA-XT2 with the 3 point bending rig
The operating parameters of the analyzer was set and followed as below: TA setting Force in compression Return to start Approach speed : 1. 0 mm/s Test speed : 0. 1 mm/s Post test speed : 2mm / s Distance : 10 mm (this may be made smaller if the crackers easily break Units : Newtons and millimeters Rig distance 40. 0 mm apart At least two crackers were prepared. the width and thickness of the crackers was measured, in the plane of the probe by vernier caliper. The crackers were placed on the right side up on the rig supports. The test was run.
The Young’s Modulus was calculated from point 1. The breaking force from point 2 was recorded. With the cursor, from the graph that had been illustrated after the test run, the point 1 at d = 0. 1 mm was identified. The force and distance was recorded (chown on top left of screen). The force was converted from grams to Newtons and distances to metres. With the cursor, the point 2, the breaking point was identified. The force and distance was recorded. The force was converted from grams to Newtons and distance to metres. Identified whether Young’s modulus or breaking force are more reproducible parameter on the biscuits.
Discussion: Moisture sensitive foods are susceptible to change in their environment and if it left opened will first become stale. Water migration and diffusion is considered to be one of the most important factors for the moisture sensitive foods. Moisture content analysis allows for a quantitative measure of the total amount of water present in a food item which can influence the texture, taste, and appearance of food products. According to military specification PCR-C-037, “Crackers, Fortified, Packaged in a Flexible Pouch, Shelf Stable”, moisture content shall be not less than 1. 5 percent and not greater than 4. percent. From the result obtained in this experiment, we discovered that the percentage of moisture content after 1 week for crackers in commercial packaging for mean for both sample was 0. 48% and 0. 48% after 2 week. Next for the HDPE packaging the moisture content for week 1 for sample 1 and 2 was 0. 95% and increased to 2. 14 % at week 2. The same situation happened for the PP packaging, the mean moisture content of crackers for week 1 for sample 1 and 2 1. 19 % then decreased to 0. 95 % at week 2. For the paper bag, the mean moisture content of the crackers for sample 1 and 2 at week 1 was 3. 2 % but increased to 4. 54% after 2 week. From the result, we observed that the commercial packaging material had lowest moisture loss followed with PP, HDPE and paper bag had the highest lost of moisture content of the crackers. It is because the paper bag had a high porosity to allow the moisture absorb on the paper. Sensory analysis allows for evaluation of food items with respect to appearance and palatability. Acceptability of the crackers was determined by a trained sensory evaluation panel, which assessed and rated the cracker for flavor, taste, odor, and texture.
Ratings were based on a 9-point qualitative scale for each cracker attribute, along with an overall quality score for the cracker. According to military specification PCR-C-0372, “Crackers, Fortified, Packaged in a Flexible Pouch, Shelf Stable”, the cracker must receive an overall score of 5. 0 or higher based on the 9-point scale to be considered acceptable. From the evaluation of the crackers in different types of packaging materials, we observed the texture for both sample was ranked as 8 means it have a very good texture and do not stale, the color of the commercial packaging was very bright gold and ranked as 8.
For the odor and taste, the commercial packaging was ranked as 7 which mean the aroma of the crackers was retained and retain the freshness of the taste of the crackers. The appearance of the crackers was ranked as 8 because the condition and shape of the crackers was still retained in original shape. The overall acceptability of the commercial packaging crackers was ranked as 7 and the crackers with commercial packaging have the highest ranked among the other packaging materials.
In short, we can concluded from the sensory evaluation the texture of the crackers was well preserved by using commercial packaging followed by PP, HDPE and lastly paper bag. For the color of the crackers, the commercial packaging obtained the highest ranked followed by PP, HDPE and lastly paper bag. The color of the crackers in the paper bag packaging was very light yellow indicates the staling of the crackers. For the odor evaluation, as the same expected, the commercial packaging had the better odor, followed with HDPE, PP and lastly paper bag.
Nest the evaluation of appearance, the commercial crackers packaging had better appearance followed with PP, HDPE and lastly crackers in paper bag packaging had poor appearance because the crackers had not retain the original crackers shape. The taste of the crackers was difficult to evaluate but the crackers from commercial packaging had the better taste and the freshness of crackers was retained, while the crackers from HDPE and PP packaging had the same crackers taste but the crackers from paper bag packaging had a very poor taste, the taste of the crackers was lost because of the moisture uptake of the crackers.
The overall acceptability of the crackers from commercial packaging was 7 which means acceptable followed by PP and HDPE packaging but the crackers from paper bag packaging was assumed had a very poor acceptability due to the moisture uptake. The texture analysis was conducted because the presence of moisture is known to affect the hardness of food items like the crackers, as they absorb moisture from the environment around them. The crispiness means the force at which is the significant break in curve (not always present) or force at which material fracture.
From the texture analysis, the result had showed that the crispiness of the crackers from the commercial packaging for sample 1 was 923. 45 and 773. 2 for sample 2, with overall mean for these two samples was 848. 32. Nest for the HDPE packaging the crispiness of the texture were lowest compared to commercial packaging which result 632. 7 for sample 1 and 990. 2 for sample 2 with overall mean for two samples was 811. 45. The PP packaging showed for the sample the crispiness of the crackers was 858. 85 for sample 1 and 993. 45 for sample 2. Lastly for the paper bag packaging, the sample 1 had 1093. 25 and 793. forsample 2 and the mean for crispiness for both sample was 943. 53. For the determination of crispiness of the crackers in different type of packaging, we observed that crackers from commercial packaging had the highest crispiness rating which was 100 0 followed with PP packaging with reading obtained 75 0, HDPE 50 0 and lastly the crackers from the paper bag packaging with rating 25 0. Food packages made with plastic are permeable at different degrees to small molecules as example gases, water vapour, and organic vapour and to other low molecular weight compounds like aromas, flavour, and additives present into food.
As a consequence of the barrier properties of the material, the transfer of this molecules ranges from high to low. The information of the solution/diffusion/permeation behaviors of these molecules through the polymer film has become important for polymers used in the food packaging. Many factors that can influence the polymer packages performance must be taken into consideration to design the correct package market solution.
The use of different polymers in food packaging industry depends on the properties of the food product and also in manufacturing, handling, and packaging engineering procedures can influence the final properties of packaging material, especially in terms of barrier properties which are related to the intrinsic structure of the polymer such as degree of crystallinity, crystalline, nature of polymer, thermal and mechanical treatment before and after food contact, chemical groups present into the polymer, degree of cross-linking, and glass transition temperature.
High density polyethylene (HDPE) was first developed for packaging as a film before being introduced as a bottle for milk in 1964. Its use for packaging has increased because of its low cost, flexibility, durability, ability to withstand the sterilizing process, and resistance to many chemicals. Polyethylene plastics have the generally advantageous properties of toughness, high tensile strength, and good barrier properties to moisture.
A particularly important property of polyethylene plastics, which is due to their relatively low melting point ranges, is the ease with which packaging can be heat-sealed. The barrier properties of polyethylene plastics to oxygen andorganic substances are only moderate. These characteristics, along with properties such as clarity and stiffness, vary with the basic polyethylene parameters of density/crystallinity, molecular weight, and molecular weight distribution As food packaging, HDPE is most commonly associated with milk, oil, and juice bottles.
Non-food packaging uses include supermarket bags, cleaning product containers, motor oil containers, agricultural films and chemical containers, paper bag liners, bags, crates, drums, and pails. Different grades of HDPE are used for different purposes. For example, there is a blow mould grade (used for milk bottles, and detergent bottles) and an injection grade material (ice cream containers). Disadvantages of HDPE as a packaging material include its low resistance to UV light and gas permeability.
New technologies, such as barrier coatings and multi-layer materials, are being introduced to improve these characteristics. Conclusion: From the result from moisture content, sensory evaluation and texture analysis we can conclude that the packaging that had the highest moisture uptake which was 3. 82% for week 1 and 4. 54% for week 2 while the lowest moisture uptake was crackers with commercial packaging which was 0. 48% for first and second week. This is also supported by the texture analysis which obtained that crackers for commercial packaging had 0. 48 kg, for PP packaging was 0. 811 kg followed with 0. 926 for HDPE packaging and 0. 943 kg for paper bag. The crispiness ratings obtained described that crackers from commercial packaging had the highest crispiness rating which was 1000, PP 750, PP 500 and paper bag was 250. From this evaluation, we conclude that the commercial packaging was the most preferred way in preserving the crackers quality, followed with HDPE packaging, PP packaging and the paper bag was the less preferred packaging for crackers due to highest moisture ptake. References: Philip T. , (2003). Packaging Materials Polyethylene for Food, Packaging Applications, 1-68 Nagi. H. P. S. , Kaur. J. , Dar. B. N. and S. Sharma (2012). Effect of Storage Period and Packaging on the Shelf Life of Cereal Bran Incorporated Biscuits. American Journal of Food Technology, 7: 301-310. Valentina. S. (2012). Food Packaging Permeability Behaviour: A Report, International Journal of Polymer Science, Volume 2012, 1- 11.