EXPERIMENT 1: THE EFFECTS OF PACKAGING MATEIAL ON SHELF LIFE OF CRACKERS
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.
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 .
Two bags (duplicate) of crackers for each packaging materials was provided.
The bags were filled with crackers, and then was weighed and stored at 25ºC for 2 weeks.
Two packets of crackers from the commercial packaging materials was weighed and stored at 25ºC 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:
The means of ‘crispiness’ was decided in group.
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.
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:
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...
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.
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