Food Chemistry about Philadelphia Cheese - Lab Report Example

Introduction The aim of this practical experiment was to discover how the food industry compiles nutrition labels, and to compare the results gained with those on an existing product – in this case, Philadelphia cheese. This product is a full-fat cream cheese made entirely from pasteurised milk (containing only two additives, E410 and E407), manufactured by Kraft and available on an international basis. All the results given below were found experimentally and then compared with those given by McCance and Widdowson. Methodology The experiments were carried out by reference to a given set of methods (see Appendix 1), although some changes had to be made, and some sections had to be omitted. For example, Philadelphia cheese does not contain any vitamin C or sugar, and as such those experiments were not undertaken. Between experiments, the cheese was kept refrigerated as instructed by the packaging. To prepare the Philadelphia for use, all that was required was to remove an appropriate sample of cheese and place this in the appropriate receptacle ready for use. Results Moisture Content of Food Mass of tin (g) Mass of tin + sample (before) (g) Mass of tin + sample (after) (g) Sample mass (g) % Moisture 24.56 27.29 25.37 2.74 29.70 24.20 27.61 25.33 3.42 33.20 25.10 27.46 25.87 2.36 67.10 Mean 24.62 27.45 25.53 2.84 43.33 Standard Deviation 0.45 0.16 0.30 0.53 20.66 Calculations used: (tin+sample)initial sample – (tin+sample)final mass x 100 = % Moisture mass of sample Ash Content of Food Mass of cruicable (g) Mass of cruicable + sample (before) (g) Mass of tin + sample (after) (g) Sample mass (g) % Ash 11.50 14.45 11.54 2.95 1.44 10.59 13.42 10.63 2.82 1.42 9.96 12.82 9.97 2.86 0.36 Mean 10.69 13.56 10.72 2.88 1.08 Standard Deviation 0.77 0.82 0.79 0.06 0.62 Calculations used: final mass-crucible mass x 100 = % ash mass of sample Determination of the protein content of food Mass of sample (g) Titre /ml Factor (from ‘Pearson’) %N % Protein in 0.32 1.96 6.38 0.86 5.47 0.34 0.99 6.38 0.41 2.60 0.33 2.11 6.38 0.90 5.71 Mean 0.33 1.69 6.38 0.72 4.59 Standard Deviation 0.01 0.61 0.00 0.27 1.73 Calculations used: Titre x 0.0014 x 100 = N% mass of sample Titre x 0.0014 x 100 x Factor = Protein % mass of sample Fat analysis by Buchi method   Sample weight (g) Empty cup weight Cup weight with fat Grams of fat per 100g sample   7.61 29.60 32.47 37.71   7.34 29.22 32.83 39.18 Mean 7.48 29.41 32.65 38.45 Standard Deviation 0.19 0.27 0.25 1.04 Calculations used: cup weight with fat – empty cup weight x 100 original sample weight Final results table: Experimental Values % McCance & Widdowson Values % Moisture Content 0.43 0.58 Ash Content 1.08 2.40 Protein 4.59 8.60 Fat 38.45 31.00 Carbohydrate 12.55 Trace Discussion The results gained experimentally were calculated in a similar way to those found in Atwater and Bryant’s tables that were published in 1904, all obtained by difference. The water, fat and protein content were all calculated and then subtracted from 100 to give a carbohydrate value. This is different to the McCance and Widdowson values, and this shows in some of the results. The experimental value for the ash content was 1.08%, which is only very slightly different from the given value of 2.40%. This suggests that the ash content measurement used (see Appendix 1) was fairly accurate. The standard deviation for this value was only 0.62, which is very small, again suggesting that this measurement is accurate and very consistent. The moisture content found, 0.43%, was also very similar to the given value of 0.58%. However, the standard deviation for this experiment was 20.66, suggesting an inconsistency in the method, which may account for the difference in carbohydrate values found, which is discussed later. The ash content found was also only 1.32% different to the given value, again suggesting an accurate method. The protein content found experimentally (4.59%) was also fairly similar to the given value (8.60%) although the standard deviation of 1.73 was slightly larger, suggesting that this method, whilst accurate, is slightly less consistent. The fat values were also slightly different but not so as to cause concern – 38.45% experimentally and 31% in McCance & Widdowson. These small differences could be accounted for by a change of recipe or production method since the original results were obtained in 1992. The main difference found was in the carbohydrate value. As previously mentioned, this was calculated by difference in this task, whereas McCance and Widdowson experimentally found a carbohydrate value. This shows in the difference in values – 12.55% of the Philadelphia was found to be carbohydrate, where the given value was only trace. This large difference suggests there may be other components not tested for and that calculation by difference is not particularly effective. Repeating this experiment could give more insight into why this difference was so different initially. As previously mentioned, Philadelphia cheese has no sugar or vitamin C content, and as such these experiments were not carried out and there are no results for these elements. However, it may have been worthwhile to conduct these experiments to prove this fact. Only two repetitions were carried out for the fat analysis as required by the Buchi method. An improvement to this task would be to repeat each stage more than 2-3 times to reduce the standard deviation and ensure that the mean is more accurate. This would have been difficult to do under the time constraints placed upon this particular set of experiments, but could help provide better results in the future. The purpose of this experiment, as outlined above, was to discover how a nutrition label is compiled and to compare the results with existing ones from McCance and Widdowson. The results above show that this has generally been achieved, although there are some anomalies which could be dealt with by repeating the experiment. An accurate nutrition label was produced from the results, which was the most important output, and thus the purpose of this particular exercise was fully achieved. References 1. McCance, Robert Alexander., and Widdowson, Elsie May., The Composition of Foods. Cambridge: Royal Society of Chemistry, 1992. Print. Read More