PRACTICAL 1 TITLE :EFFECT OF BENZOIC ACID ON THE SHELF-LIFE OF CHILLI SLURRY. INTRODUCTION : Preservatives are important in order to extend the life of processed food. The absence of preservatives accelerates the growth of mould, yeast andbacteria. This problem creates challenges to food manufacturingindustry. The choice of food preservatives depend on the pH, moisture,processing conditions, packaging conditions, and storage temperatureand distribution requirements. There are a lot of preservatives availablein food industry. Benzoic acid and its salts are used as food preservatives. Benzoic acid inhibits the growth of mould, yeast and some bacteria. It is either added directly or created from reactions with its sodium, potassium, or calcium salt. The mechanism starts with the absorption of benzoic acid in to the cell. If the concentration of the benzoic acid is higher, the shelf-life of the food will be increase. The efficacy of benzoic acid is thus dependent on the concentration of the benzoic acid. Typical levels of use for benzoic acid as a preservative in food are between 0.05–0.1%. Foods in which benzoic acid may be used and maximum levels for its application are laid down in international food law.
HYPOTHESIS : Different concentration of benzoic acid will give different effect the shelf-life of chilli slurry. The higher the concentrationof benzoic acid, the longer the shelf-life of chilli slurry.
OBJECTIVES : To study the shelf-life of chilli slurry preserve at a different concentration of benzoic acid.
METHODS : 1. Dried chilli was cleaned by rinsing it under running tap water. 2. The chilli was boiled to soften it. It was drained and cooled it to room temperature. 3. The chilli was blended with water at a ratio of 2 : 1. 4. The pH of the chilli slurry was measured and recorded in the Data Sheet. 5. Four bottles was labelled with 0 (control), 500, 1000, 2000ppm respectively of the preservatives used. 6. The same amount of chilli slurry was weight out into each of the labelled bottle. 7. Then, the preservatives wereweighed out as accurately as possible according to the labelled bottle.
8. The content was stirred thoroughly (at least five minutes of continues stirring) and it was covered with aluminium foil or Para film. 9. The bottle was arranged and stored at room temperature. 10. The sample was observed daily to see signs of spoilage for two weeks.
RESULT:
DISCUSSION :
In this practical, we gained the knowledge how to study the shelf-life of chilli slurry preserve at a different concentration of benzoic acid. In this experiment, we use four bottles that labelled with 0 (control), 500, 1000, and 2000ppm respectively of the preservatives used. The bottle was arranged and stored at room temperature. The sample was observed daily to see signs of spoilage for two weeks. All the result was recorded in the Table 1.2 for 0 ppm, Table 1.3 for 500 ppm, Table 1.4 for 1000 ppm and Table 1.5 for 2000 ppm on Results Data Sheet by refer to Table 1.1. The graph for each spoilage types with different concentration of benzoic acid was plotted by refers the entire table. Graph 1 is about level of mould growth over days, Graph 2 is about level of slime formation over days, Graph 3 is about level of bubbles formation over days, Graph 4 is about level of off-odour over days and Graph 5 is about level of colour changes over days. In Graph 1,Graph 2, Graph 3and Graph 5shows,if we compare all the concentration, both concentration of 2000 and 1000 ppm have a lower amount of mould, lower amount of slime formation, lower amount of bubble formation and it has slightly orange in colour than others. While in Graph 4, concentration 2000 ppm shows it still has slightly off-odour if compared with other which extremely off-odour . After we compared four of the different concentration of benzoic acid, the concentration of 2000 ppm is has a long shelf-life than other. This is because, the concentration of benzoic acid is higher. As we know, benzoic acid inhibits the growth of mold, yeast and some bacteria. It is either added directly or created from reactions with its sodium, potassium, or calcium salt. The mechanism starts with the absorption of benzoic acid in to the cell. If the concentration of the benzoic acid is higher, the shelf-life of the food will be increase. The efficacy of benzoic acid is thus dependent on the concentration of the benzoic acid.
CONCLUSION: In this practical, we are able to know, the different concentration of benzoic acid will give different effect the shelf-life of chilli slurry. The results is, the concentration of 2000 ppm is has a long shelf-life than other. This is because, the concentration of benzoic acid is higher. If the concentration of the benzoic acid is higher, the shelf-life of the food will be increase. The efficacy of benzoic acid is thus dependent on the concentration of the benzoic acid. The higher the concentration of benzoic acid, the longer the shelf-life of chilli slurry. The hypothesis is accepted.
REFFERENCES: 1. http://eprints.ptar.uitm.edu.my/825/1/HAIRUNNISA_MOHD_ANAS_KHAN_08_24.pdf 2. Sodium Benzoate & Benzoic Acid I.P. Retrieved from http://www.shreeadditives.com/htmlsite/5f.htm 3. http://www.scribd.com/doc/29688215/Print-Thesis 4. http://onlinelibrary.wiley.com/doi/10.1002/yea.320080703/abstract 5. http://en.wikipedia.org/wiki/Benzoic_acid 6. Encyclopedia Britannica: Benzoic Acid retrieved from http://www.livestrong.com/article/293450benzoic-acid-used-as-preservatives-in-foods/
