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Lab repport determination of different juice compositions
Lab repport determination of different juice compositions
Lab repport determination of different juice compositions
Lab repport determination of different juice compositions
Lab repport determination of different juice compositions
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Lab repport determination of different juice compositions

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  • 1. Laboratory report Determination of different juice composition 10/18/2013 Level IV Food Biotechnology Lecturer: Janvier NTWALI
  • 2. Determination of different juice composition 1. Abstract Experiments were carried out to determine different contamination area found in juices, we prepared different area to develop bacteria to see where contamination is high and where is low. Different fruit composition that we determined are pH, degree Brix, carbohydrates content and ascorbic acid content. The intension was to test every parameter and compare both fruit types. Tests showed that those parameters are almost the same for both fruits. 2. Introduction The purpose of these experiments was to see and to compare different area about how the bacteria are grown in contact with materials or to see when you use some hygiene paper what happen before and after using them,The experiments are done in an easy way requiring materials and equipments most found in the institution laboratory. Afterpreparing crushing and filtration of the juices, we determined pH by using a pH meter then record the range for both juices for later comparison. The determination of Ascorbic acid consists of titration and doing calculations. Method used for determination of total carbohydrate is phenol. The last is determination of degree brix is carried out by Refractometer. 3. Methods & equipments Equipments Balance Volumetric flask Toilet paper Magnify Microscope Dishes meyerCrusher machine Erlen
  • 3. Reagents For measuring of pH, Brix degree and ascorbic acid in passion& pineapple juice(1st experiment) NaOH 0.01 Phenolphthalein 1% Distilled water For measuring of carbohydrate content in passion& pineapple juice(2ndexperiment) Phenol crystals H2SO4 Distilled water 1st experiment To measure Brix level we used Refractometer, and for pH we used pH meter. Method used formeasuring of ascorbic acid in passion & pineapple juice is Titration method, We washed and crushed the fruits to get juice which we used to get the sample used in experiment. We took 5ml of sample of juice in Erlemeyer of 250ml. We diluted with distilled water up to 100ml, we added 5 drops of phenolphthalein of 1% (as indicator) in diluted sample of juice. We titrated with NaOH 0.01N to get pink color. We recorded the quantity of NaOH 0.01 used in titration to get the exact and correct responses. We also titrated the blank (distilled water mixed with phenolphthalein of 1% titrated with NaOH 0.01).
  • 4. 2nd Experiment Method used in measuring of carbohydrate content in passion & pineapple juice is phenolsulfuric acid method, We washed and crushed the fruits to get juice which we used to get the sample used in experiment. We took 5ml of juice diluted with distilled water up to 100ml of volumetric flask and we took a sample of 1ml of the solution, we put it in test tube and we mixed well, the test tube was covered by paraffin paper. We prepared phenol crystals at 80% of concentration in volumetric flask, at this time we removed 0.05ml of phenol to mix with 2ml of previous diluted juice. We added 5ml of H2SO4, in both samples; we put the solution at 25oC in water bath in a period of 10 minutes for the purpose of cooling them. After cooling we took the sample of the cooled products to analyze them in spectrophotometer after calibrating it. 4. Results& discussion 1st experiment results: Ascorbic acid level in pineapple juice sample was 0.00154% while in passion juice sample was 0.007%. To get those result we used this formula: [(T-bl)*N*100*176.13*10-3]/Volume of sample Where T is volume of NaOH used in titration, bl is NaOH used in titration of blank and N is the concentration of NaOH. The Brix level in pineapple juice sample was at 13 while in passion juice sample was 15. The pH of pineapple juice sample was at3.6 and passion juice sample was at 3.8. 1st experiment discussion The pineapple juice had a high content of vitamin C compared to passion juice. Both juices were almost the same acidic media which is not easily attacked by microorganisms. For sugar content,passion fruit had a high sugar level than pineapple fruit. 2nd experiment results
  • 5. The concentration of glucose in pineapple was 0.941 and 1.145 for passion fruit. 2nd experiment discussion The passion fruit had high carbohydrates content than pineapple fruit. 5. Conclusion and recommendation Conclusion Our work has been effective as we found the difference of both passion and pineapple fruit by comparing some parameters for both such as brix level, pH, Carbohydrate content and ascorbic acid, these parameters enabled us to make a clear comparison. Recommendation Lecturer must be monitoring the students during the experiment. Lecturer must inform the required material and chemicals needed to accomplish the goals of experiment. The institution must build an appropriate laboratory for food biotechnology. The department must increase the number of lab experiments The must be present and attentive in laboratory.

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