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FST528 FOOD PROCESSING LABORATORYLAB REPORTNO. OF EXPERIMENT: 5TITLE OF EXPERIMENT: PRODUCTION OF ICE CREAM (DIFFERENTCRYSTALLISATION OF ICE)NAME: ORNELLA LYNN JOSEPHMATRIC NO: 2020983037GROUP: AS2465BDATE OF EXPERIMENT: 5TH MAY 2021DATE OF SUBMISSION: 19TH MAY 2021LECTURER NAME: TS DR SO’BAH AHMADI...

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FST528 FOOD PROCESSING LABORATORY LAB REPORT

NO. OF EXPERIMENT: 5

TITLE OF EXPERIMENT: PRODUCTION OF ICE CREAM (DIFFERENT CRYSTALLISATION OF ICE)

NAME: ORNELLA LYNN JOSEPH

MATRIC NO: 2020983037

GROUP: AS2465B

DATE OF EXPERIMENT: 5TH MAY 2021

DATE OF SUBMISSION: 19TH MAY 2021

LECTURER NAME: TS DR SO’BAH AHMAD

INTRODUCTION Ice cream is a frozen dairy product created by agitating an ice cream mix and freezing it. It is made up of a variety of food ingredients, including milk, sweeteners, stabilisers, colours, spices, and egg products. Before freezing, this ice cream mix is commonly pasteurised and homogenised. Freezing is the process of rapidly removing heat from a mixture while agitating it to incorporate air. 64% water, 18% sugars, 10% non-fat milk solids, and 8% milk solid fats are the standard parameters for a dairy base ice cream. All of these parameters are expected to have a stable structure maintaining its characteristics in negative temperature with smooth texture (without the appearance of ice crystals), spreadable (can work at their preservation temperature), and stable (maintain his characteristics at serving temperature) (Corvitto, 2011). Ice cream is an emulsion, a dispersion, and a foam all in one. A freeze-concentrated aqueous serum phase containing sugar and the dry matter contents surrounds dispersed ice crystals and fat globules in the dispersion and emulsion (Marshall et al., 2003). Air pockets (about 20 to 50 μm diameter) scattered in the emulsion form the foam, which is supported by partiallycoalesced fat globules (Goff, 2002; Marshall et al., 2003). Overrun refers to the volume of air in an ice cream (Clarke, 2012). Air in ice cream gives it a light texture and affects its melt down and hardness properties. However, these parameters are influenced not only by the volume of air introduced or overrun, but also by the distribution of air cell sizes. According to Marshall and Arbuckle (1996), many factors affect the development of air cells in ice cream. The size of ice crystals is affected by the amount of air added during freezing, with larger ice crystals found at lower overrun (Arbuckle, 1977). OBJECTIVE 1. To investigate the effect of crystallisation of ice on overrun and melting point of ice cream. INGREDIENTS Formulation of ice cream Ingredients (hard)

Amount (g)

Ingredients (soft)

Amount (g)

Full cream evaporated milk

600

Milk powder

1 kg

Butter

100

Butter

150

Sugar

240

Sugar

500

Flavour

0.90

Flavour

3.0

Stabiliser and emulsifier

9.0

Stabiliser and emulsifier

35.0

Water

1000 mL

Water

3500 mL

EQUIPMENT Homogeniser, ice-cream machine, freezer PROCEDURE 1. Water is slowly added into the vessel containing evaporated milk/milk powder. It is mixed thoroughly to dissolve the milk powder. The mixture is heated to about 50°C. 2. All the dry ingredients are mixed in another vessel and the dry ingredients mixture is added into milk and is stirred until dissolved. 3. The mixture is heated to 85°-90°C for about 20 minutes and the mixture is thoroughly stirred. 4. The mixture is cooled to room temperature. Then, it is poured into the ice cream making machine. The ice cream is stored for 24 hours in a freezer. 5. The melting characteristic is determined. The ice-cream is removed from the freezer and is left at room temperature. The time taken for the first drip to occur is recorded. DATA RESULT Data obtained from Journal (Ice Cream Structural Elements that Affect Melting Rate and Hardness)

DISCUSSION Based on Table 4 of the data obtained from the journal, it can be seen that high level of PS80 and low (second) level of draw temperature, the overrun tends to increase. Increased levels of destabilised fat, which provides air cell stability, were encouraged by higher PS80 levels and longer whipping times (lower freezing temperature). The range of overruns created in this analysis, however, was relatively narrow, ranging from about 40% to 70% as stated on the journal. Ice creams with lower overruns (80 percent) were tougher but melted faster than those with a 120 percent overrun (Sofjan & Hartel, 2004). Increased overrun caused larger air cells to break up into smaller ones during freezing, resulting in a higher percentage of smaller air cells in 120 percent overrun ice cream than in 80 percent overrun ice cream. This effect may be linked to the ice cream slurry's apparent viscosity rising as more air was added during freezing. The overrun level is thought to have a secondary impact on ice crystal formation (Arbuckle, 1977). In comparison to HFCS, which had the lowest levels of destabilised fat, ice creams made with 20 DE CS had the highest levels of destabilised fat. The higher degree of destabilised fat in 20 DE CS ice creams can be due to the high percentage of ice during freezing, which resulted in high shear forces and fat destabilisation, lowering the melting rate. Higher concentrations of air in the sample resulted in a thinner unfrozen phase distributed across the air bubbles. The foam structure could act as a physical barrier during the freezing process, minimising the chance of ice crystal collisions and confining the crystals to the thinner unfrozen phase. This structural change could eventually affect the recrystallization process in ice cream storage. In Table 6, the ice creams made with 20 DE CS melted the slowest, while the ice creams made with HFCS melted the quickest. With higher PS80 levels and lower (second)

draw temperatures, the melting rates slowed. Differences in fat destabilisation or air cell and ice crystal sizes may explain these results. The most significant factors (largest explanatory variables) were fat destabilisation and ice crystal size. Changing the types and amounts of emulsifiers causes varying levels of fat destabilisation, which affects the rate at which ice cream melts. Increasing the amount of polysorbate 80 (PS80) greatly reduced melt rate, while increasing the amount of mono- and diglycerides reduced melt rate to a lesser degree (Cropper et al., 2013). The addition of more emulsifiers to ice cream resulted in increased fat destabilisation (Bolliger et al., 2000). A higher degree of fat destabilisation in the ice cream increased melting resistance and resulted in a lower melt rate during the meltdown process (Warren, 2015). Another reason for the slower melt down with higher overrun may be the difference in heat transfer rate caused by the presence of more air. Since air is a strong insulator, higher overrun slowed the rate of heat transfer into the ice cream. CONCLUSION In conclusion, the effect of crystallisation of ice on overrun and melting point of ice cream is investigated. Overrun was not found to be a determinant factor in the melting rate due to the limited range of overruns in the ice cream produced based on the result obtained from the journal. The extent of fat destabilisation and the size of the ice crystals had the greatest impact on melting time. REFERENCES 1. ADAPA, S., SCHMIDT, K. A., JEON, I. J., HERALD, T. J., & FLORES, R. A. (2000). MECHANISMS OF ICE CRYSTALLIZATION AND RECRYSTALLIZATION IN ICE CREAM: A REVIEW. Food Reviews International, 16(3), 259–271. doi:10.1081/fri100100289

2. Cook, K. L. K., & Hartel, R. W. (2010). Mechanisms of Ice Crystallization in Ice Cream Production. Comprehensive Reviews in Food Science and Food Safety, 9(2), 213– 222. https://doi.org/10.1111/j.1541-4337.2009.00101.x

3. Deosarkar, S. S., Khedkar, C. D., Kalyankar, S. D., & Sarode, A. R. (2016). Ice Cream: Uses and Method of Manufacture. Encyclopedia of Food and Health, 391–397. doi:10.1016/b978-0-12-384947-2.00384-6

4. Fiol, C., Prado, D., Romero, C., Laburu, N., Mora, M., & Iñaki Alava, J. (2017). Introduction of a new family of ice creams. International Journal of Gastronomy and Food Science, 7, 5–10. doi:10.1016/j.ijgfs.2016.12.001

5. Sofjan, R. P., & Hartel, R. W. (2004). Effects of overrun on structural and physical characteristics

of

ice

cream.

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Dairy

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262. doi:10.1016/j.idairyj.2003.08.005

6. Wu, B., Freire, D. O., & Hartel, R. W. (2019). The Effect of Overrun, Fat Destabilization, and Ice Cream Mix Viscosity on Entire Meltdown Behavior. Journal of Food Science, 84(9), 2562–2571. https://doi.org/10.1111/1750-3841.14743...