FST528- ICE Cream - lab report PDF

Preview

Summary

FST528: FOOD PROCESSING LABORATORYEXPERIMENT 5: PRODUCTION OF ICE CREAM (DIFFERENTCRYSTALLISATION OF ICE)INTRODUCTIONIce cream is a frozen dairy product. It is sold in soft and hard status. The market success of the product depend on the textural attributes of ice. It is a microcrystalline network o...

Description

FST528: FOOD PROCESSING LABORATORY EXPERIMENT 5: PRODUCTION OF ICE CREAM (DIFFERENT CRYSTALLISATION OF ICE)

INTRODUCTION Ice cream is a frozen dairy product. It is sold in soft and hard status. The market success of the product depend on the textural attributes of ice. It is a microcrystalline network of liquid and solid phases. Liquid phase contains air cells that are in trapped and many other components like proteins, fat globules, stabilizer, sugar, soluble and insoluble salts which are also present in this phase (Syed Q.A et al., 2018). The mains steps in making ice cream is to eliminate the microlobiological hazards are by pasturization, freezing and hardening. The main ingredients of ice cream is the products of dairy origin. These include fat, sugar, milk solids and emulsifying agent, flavoring and sometimes coloring. The fat can be from milk, cream or butter or from a non-dairy source. For a frozen dessert to be termed as ice cream, it should contain at least 10% of milk fats, 20% of total milk solid by weight. In ice cream, the cream percentage is typically higher than milk (Syed Q.A et al., 2018). For flavor enrichment, fruits, nuts, candies and syrup are optionally added into ice cream. Ice cream are unique frozen food because they are consumed in the frozen state, usually as a scooped product or as a single-serving item, sometimes on a stick and often with other confectionary items. In order to establish the desired structure and texture, these products rely on a concomitant freezing and wiping process. The manufacturing process for most of these products are similiar (Deosarkar S. et al., 2016). Ice cream should contain at most 50% of air. Premium ice cream have higher fat content and lesser air content. The air is in corporated into the ice cream by churning the mixture before freezing. It is because of the aeration process that ice cream are often soft and fluffy. The amount of air added in an ice cream is called overrun (Clarke C., 2012). In commercially produced ice creams this varies from 60-100% or more. In some countries there is a legal maximum of 120% overrun (Fellows P., 2008). In this experiment, there are two types of ice cream will be produced and evaluate which are soft icre cream and hard ice cream.

OBJECTIVE 1) To prepared soft ice cream and hard ice cream. 2) To differentiate the different characteristics between soft ice cream and hard ice cream.

MATERIALS a) Ingredients for formulation of hard ice cream 1. 600 g full cream evaporated milk 2. 100 g butter 3. 240 g sugar 4. 0.90 g flavour 5. 9.0 g stabiliser and emulsifier 6. 1000ml water

b) Ingredients for formulation of soft ice cream 1. 1 kg milk powder 2. 150 g butter 3. 500 g sugar 4. 3.0 g flavour 5. 35.0 g stabiliser and emulsifier 6. 3500ml water

EQUIPMENT 1. Homogeniser 2. Ice-cream machine 3. Freezer

METHODS

1. Water was slowly added into the vessel containing evaporated milk/milk powder. It was mixed thoroughly to dissolve the milk powder. The mixture was heated to about 50°C.

2. All the dry ingredients was mixed in another vessel and the dry ingredients mixture was added into milk and was stired until dissolved.

3. The mixture was heated to 85°C - 90°C for about 20 minutes and was stired thoroughly the mixture.

4. Then, the mixture was cooled to room temperature. The mixture was poured into the ice cream making machine. The ice cream was stored for 24 hours in a freezer.

5. The melting characteristic was determined. The ice-cream was removed from the freezer and was leaved at room temperature. The time taken for the first drip to occur was recorded.

6. The overrun for the hard ice-cream was calculated with the following formula: % overrun = �100

RESULT Table 1: Scale Sweetness

1 Very slightly

2 slightly

3 moderately

Creaminess

Very slightly

slightly

moderately

Iciness

Very slightly contain ice Very slightly hard

Slightly contain ice Slightly hard

Moderately contain ice Moderately hard

Hardness

Table 2: Sensory analysis of ice cream Sweetness Creaminess Iciness Hardness

Hard ice cream 4 3 2 3

Soft ice cream 4 4 1 1

Table 3 Hard ice cream Soft ice cream Initial Volume 1949.9 ml 5188 ml Final Volume 3300 ml 10276 ml Assume 1g of mixture = 1 ml of ice cream volume

4 Extremely sweet Extremely creamy Extremely icy Extremely hard

CALCULATION % Overrun =

(Volume of ice cream produced−Volume of mix used ) Volume of mix used

% Overrun in hard ice cream =

� 100

(3300 ml−1949.9 ml) × 100 1949.9 ml

= 69.24% % Overrun in soft ice cream =

(10276 ml−5188 ml) × 100 5188 ml

= 98.07%

DISCUSSION In this experiment, the two type of ice cream which are soft ice cream and hard ice cream has been produced and the sensory analysis of the ice cream was evaluated in the terms of sweetness, creaminess, iciness and hardness. Both ice cream used a different ingredients in order to produce the desired texture of the ice cream. Ingredients A was used to produced hard ice cream and ingredients B was used to produce soft ice cream. These two types of ice cream have some major differences in the way they are made. According to the Jessie Oleson Moore (2017), soft ice cream also called "soft serve” has less milk fat and more air than harder ice cream. It also produced at a lower temperature about -4 oC and churned more constantly yielding a smoother, lighter texture which is relatively higher than the temperature used in ice cream production at freezer temperature which is -18oC. In this experiment, after mix all the ingredient, the ice cream was being heated to 90 oC for pasturised. Pasteurization is necessary for all ice cream mixtures for the destruction of pathogenic bacteria and allows the ingredients to bind like sugar dissolves, protein hydrate, stabilizers swell, fats bind and the emulsifier allows all the ingredients to form smooth texture created perfect ice cream base (Deosarkar S. et al, 2016). After that, the mix is also homogenized and take place at the pasturizing temperature. The high temperature produces more efficient breaking up of the fat globules to form a better emulsion and contribute to a smoother, creamier ice cream. It also

reduces fat clamping and ensures that the emulsifiers and stabilizers are well blended and evenly distributed in the ice cream mix before it is frozen (Deosarkar S. et al, 2016). The different between hard and soft ice cream during mixing process was the soft ice cream was introduced into homogeniser for a longer time than hard ice cream because to create more smoother and soft texture. Then, after mixing process, soft and hard ice cream were poured in ice cream machine and after 20 minutes only hard ice cream was taken out from the machine to store at freezer temperature in order to have the hard texture (Deosarkar S. et al, 2016). There is a wide range of ingredients that be used in ice cream making. The main constituent of ice cream is fat which comes from the milk and butter. A variety of milk product can be used such as cream, whole milk, or instant milk powder. In this experiment, hard ice cream used full cream evaporated milk while soft ice cream used milk powder. According to Shital Deosarkar et al (2016), fat is important: 

to increase the richness of the ice cream flavor



produce a smooth texture and give ‘body’ to the ice cream



produce good melting properties when the ice cream is eaten.

The milk solid-not-fat (MSNF) it comparises lactose, casein, whey proteins, minerals, vitamins and other minor components of the milk or milk products from which they were derived such as skim milk powder and condensed milk. According to Shital Deosarkar et al (2016) 

milk solid-not-fat play an important role in the body and texture of ice cream by stabilizing the air that is incorporated during the freezing process



allow a higher overrun, produce a thicker, less icy product.

According to Qamar Abbas Syed et al. (2018), Sugars was used to: 

Sweeteners improve the flavour, texture and palatability of ice cream



Sweetners also lower the freezing point of the mix to allow water to remain unfrozen at serving temperatures. A lower freezing point makes ice cream easier to scoop and eat.



Increase the viscosity and enhance solid contents. Viscosity of mix is enhance due to water-holding capacity of proteins which imparts a desired body in the ice cream, increase the meltdown time of ice cream and contributes to reduced iciness.

Next, according to Qamar Abbas Syed et al. (2018) basic types of stabilizers added in ice cream are of two sources which is aminal source and plant or vegetable source. Stabilizer importnat in smoothens the ice cream texture and functions to: 

Add viscosity and control ice crystallization. Over time during frozen storage small ice crystals naturally migrate together and form larger ice crystal.



Help keep the small crystal isolated.



Prevent the growth of large crystals, which causes ice cream to be coarse, icy and unpleasent to eat.

Emulsifier also used in the making of ice cream to : 

Help keep the milk fat evenly dispersed in the ice cream during freezing and storage. A good distribution of fat helps stabilize the air in corporated into the ice cream and provide a smooth product (Syed Q.A et al., 2018). Based on the the result sensory analysis in Table 2, the different characteristics between

soft ice cream and hard ice cream were able to determined. The sensory analysis was evaluated in terms of sweetness, creaminess, iciness and hardness. In terms of sweetness, both of soft ice cream and hard ice cream have extremely sweet taste due to presence of sugars used as a sweeteners that help in improving the flavour, texture and palatability of ice cream and increase pleasing sweet flavor (Syed Q.A et al., 2018). Beside that, in terms of creaminess, soft ice cream has more creamy appearent which is extremely creamy compared to the hard ice cream which is moderately creamy due to the softness of final product. Soft ice cream also more creamy due to have more milky-smell of an ice cream since it use 1 kg of milk powder meanwhile hard ice cream only used 600 g of full cream evaporated milk.Creaminess as well as melting resistance is related to the distribution of air cells in the product. A more uniform air cell distribution in the ice cream results in a creamier and slower melting ice cream (Deosarkar S. et al, 2016). Furthermore, in terms of iciness, soft ice cream has very slightly contain ice with a very small size of ice crystal while hard ice cream has slightly contain ice means there are larger size of ice crystal than soft ice cream. The crystal development in soft ice cream is more small due to the stabilizer and emulsifier. In hard ice cream making only 9.0 g of stabilizer and emulsifier used compared to soft ice cream that used 35.0 g of stabilizer and emulsifier. Stabilizers are used to

help bind together the complex mixture of fats, sugars, air and tiny ice crystals that are present in ice cream thus give a smooth texture. The stabilizers are hydrated and dispersed in water reducing the amount of free water in the ice cream mix, resulting in an increased viscosity of the ice cream and produce smoothness in body and texture ice cream thus reduce ice crystal growth during storage (Deosarkar S. et al, 2016). Then, in terms of hardness, the major difference between both types of ice cream can be seen wheres soft ice cream is very slightly hard means it have finer and smoother texture compred to hard ice cream that has moderately hard texture. This is due to more emulsifier added in soft ice cream which is 35.0 g to smoothen the texture and thorough distribution of air cells (Syed Q.A et al., 2018). Emulsifiers are sometimes integrated with the stabilizers in proprietary blends, but their function and action are very different from the stabilizers. Emulsifiers facilitate the mixing of fat and water because these molecules have two domains, one that likes water (hydrophilic) and another that likes fat (hydrophobic). When the hydrophobic part of a surfactant interacts with the fat, the water-loving part of the molecule can interact with water, thus facilitating the suspension of fat in water. Soft ice cream making used more water than hard ice cream. Therefore, the presence of emulsifiers in ice cream leads to smoother texture and better shape retention while improving the ability of the mix to incorporate air (Deosarkar S. et al, 2016). The percent overrun for both soft ice cream and hard ice cream was calculated. Table 3 shows the final volume (volume of ice cream produced) and initial volume (volume of mix used). Overrun is the percentage of ice cream that is air incorporated in the product during the freezing process to expand and make more product with less materials (Deosarkar S. et al, 2016). In the calculation, hard ice cream has 69.24% of overrun while soft ice cream has 98.07% overrun. This means that hard ice cream with an overrun of 69.24% it have expanded the product by 69.24%. Meanwhile soft ice cream with an overrun of 98.07% it have expanded the product by 98.07%. Ice cream overrun affects smoothness, consistency & taste of the product, therefore affecting the profitability because it is the amount of servings that can produce with the given materials. Since ice cream is sold by volume, the amount of air in the finished product has an important effect on profitability. Small batch freezers can only beat small amounts of air into the mixture as it freezes, to give an overrun of 50% or less. Commercial freezers are more efficient at incorporating air and overruns can be 100% or more (Fellows P., 2008).

CONLUSION As a conclusion, soft ice cream and hard ice cream were able to produce and the different characteristic between soft ice cream and hard ice cream was also able to analysed by sensory analysis. Soft ice cream has a small ice crystal compared to hard ice cream. The addition of emulsifier and stabiliser reduced the melting of the ice cream as well as limit the growth of large ice crystals.

REFERENCES Chris Clarke, (2012). The Science of Ice Cream: Edition 2. RSC Publishing. United Kingdom. Pp 1-4. Retrieved from https://pubs.rsc.org/en/content/ebook/978-1-84973-127-0 Jessie Oleson Moore, (2017). A Guide to the Different Types of Ice Cream. Blueprint Article. Retrieved from https://www.mybluprint.com/article/types-ice-cream Peter

Fellows,

(2008).

Ice

Cream

Production.

Practical

Action.

Retrieved

from

http://cdn.dairyasia.org/dairyasia/file/Information/Manuals_dairy_extension_materials/Dairy_Fa ct_Sheet_Ice_Cream_Production.pdf Qamar Abbas Syed, Saba Anwar, Rizwan Shukat, Tahir Zahoor, (2018). Effects of Different Ingredients on Texture of Ice Cream. Journal Nutritional Health Food Engineering. Vol 8(6). Pp 422-435. Retrieved from 10.15406/jnhfe.2018.08.00305 Shital Deosarkar, Chandraprakash D. Khedkar, Shrikant D Kalyankar, and Anand Rangrao

Sarode, (2016). Ice Cream: Uses and Method of Manufacture. The Encyclopedia of Food and Health. Vol. 3. Pp 391-397. Retrieved from 10.1016/B978-0-12-384947-2.00384-6...