LABORATORY FOR CHEMISTRY AND TECHNOLOGY OF PLANT AND ANIMAL PRODUCTS Group : | 8 | Title : | Processing of yoghurt | Date of experiment : | 30 September 2009 |
Lecturers : | Profesor Madya Dr. Azis Ariffin and Dr. Anis Shobirin Meor Hussin | Group members: | Matric Number |
Nor Haafiz Bin Idris | 140532 |
Wan Nur Mazurawan Mansor | 141377 |
Nur Ain Salmi Abdul Hamid | 141597 |
Nurhana Bt Mohamad Tamyiz | 141794 |
Mozhiarhasi A/P Sandra Sagrin | 142925 |
Dea Yik Hwa | 143003 |
Liew Joo Tat | 143096 |
Tai Yunn Fang | 143439 |
Lee Leng Chea | 143523 |
Li Siau Leng | 143635 |
Noraziemah Mohamad Noor | 145012 |
Tittle : Processing of Yoghurt
This experiment was carried out to:
1. Observe the significant difference between two different yoghurt processing techniques (namely acid and enzyme methods) by determining the physical property and sensory attributes of prepared yoghurt. 2. Provide the practical experience/overview of yoghurt production. 3. Collect, analyse and evaluate the experimental data.
4. Collaborate with companion students both in experiments as well as in documentation of the experiments. Abstract :
Yogurt is a dairy product produced by bacterial fermentation of milk. This experiment was carried out to compare the effect of two different yoghurt processing techniques on the physical property and sensory attributes of yoghurt. In this experiment, dadih was prepared by acid method and enzymatic method. Eight formulations were used. The first 4 formulations by using acid method while the other four formulations by adding different thickening agent. The pH of dadih produced using the eighth formulation is 6.05 while the o Brix obtained is 17.0. On the other hand, the viscosity is 0.6594. For sensory evaluation, the scores obtained for texture, flavour, taste and overall acceptability for the eighth formulation are 5, 4, 3, 4 where 1 is very dislike and 5 is very like.
‘Dadih’ is a traditional food normally consumed as a dessert in the northern region of Peninsular Malaysia. Physically, it is a sweet soft solid with a fine texture resembling custard and does not break easily when scooped. It is produced by adding acid or enzyme, which causes the curding effect to the milk itself. This process gives dadih its refreshingly milk flavor with unique pudding-like texture. Chemical analysis of ‘dadih’ reveals that it contains fat, protein and total sugars (7.05, 4.79 and 17.2%, respectively), if it is made from buffalo’s milk, as traditionally prepared in the early days where buffalo was easily available. Although milk of various animals has been used for yogurt production in various parts of the world, most of the industrialized dadih production uses cow's milk giving a lower fat content of around 2.8%. Whole milk, partially skimmed milk, skim milk or cream may be used. The processing of dadih by using enzyme method is quite different compared to acid and inoculum method. In this method, curding process is due to the action of protease enzyme which is known as Rennilase (R) 46L that can be found from A/S Novo Industry, Copenhagen, Denmark. Milk curding process is done at ambient temperature without any specification method. However, 5 % of non-fat milk solid over the weight of milk used should be added into the production of dadih to get a good texture, as well as to firm the texture of the dadih. In this experiment, acid method was used. This method is quiet similar to inoculum method. But, 10% of citric acid is used to replace inoculum. Dadih is preserved by its acidity which inhibits the growth of putrefactive or pathogenic bacteria. With lids intact, this dadih can be kept for at least a month or two in the refrigerator. Traditional way of preparing ‘dadih’ is as an inoculum method. Inoculum is prepared...