Team D – Low Fat Saffron Ice Cream with Rose Water
Executive summary
In the previous unit, the texture of our ice cream was unsatisfactory when compared with commercial products. Therefore, the plan in this unit was to focus on improving and optimizing the texture of the ice cream. The Challenge encountered with the texture of our product was due to low fat content, as fat plays an important role in the structure of ice cream providing smooth texture and consistency. Specific kind of emulsifiers and stabilizers suitable for low fat ice cream were replaced to fulfill the desirable textural properties for our ice cream.
The equipment that are to be used, were chosen based on the production process, and ability to achieve the production target. Stainless steel equipment of various sizes with different compartments is used for receiving the raw materials and for transporting the raw materials while in process. The tanks can be supplied with cooling systems and measurement systems. For mixing and refrigeration one of the most important factor is the capacity of the equipment this is important to achieve the required capacity. Finally, for the packaging the total amount should ensure the maximum precision and at the same time should accelerate packaging as much as possible.
To determine the acceptability of each sample, the samples were presented to a panel of 56 untrained assessors. The factors that were assessed were Carageenan, Guar gum and Panodan at two levels to determine the influence of these factors on the responses (Iciness, Softness, Creaminess and overall preference). On conducting the analysis the result indicated that there was no significant difference between the samples produced with varied quantity of the factors.
Eight ice cream samples were prepared and presented to the assessors in one session and they were instructed to rate their preference for each sample using a 9-point hedonic scale. To analyze the data collected, Tukey's test for additivity was first conducted, if there was a significant interaction, a Friedman two-way analysis of variance (ANOVA) was conducted, if there was no significant interaction, one factor within subject ANOVA was conducted. The results showed that there was no significant difference in the preference of any sample based on their creaminess, iciness, softness and overall preference.
Ice cream undergoes a number of processing steps during manufacturing. Legislation requires that any potential hazards or risks to food safety be identified and also to put in place control measures in respect of these risks, in order to ensure that the final product is delivered to the consumer with the highest possible quality and stability.
To obtain the final product specifications and estimate the total nutritional contents of the final product, the nutritional contents and quantities of raw materials used were considered. Packaging requirements were determined and type of packaging was considered, as well as attracting the consumer attention towards the product.
1. Process and equipment flowcharts with description of the whole production process
Figure 1: Laboratory process flowchart
1) Dry Ingredient Mixing:
All the dry the ingredients are first mixed together as it becomes easy to mix them in the liquid later.
2) Wet/Liquid Ingredient Mixing:
The liquid ingredients of the ice cream are semi-skimmed milk; fresh cream and water are mixed together with constant stirring.
3) Mixing/Blending:
In this step the ingredients (dry and wet) are blended together. This is performed at room temperature. The dry ingredients are added into liquid ingredients.
4) Homogenization:
In this process, the fat droplets in the mix are reduced to a uniform size, so that the final product is also uniform. The average size of the fat droplets would be around 1μm or less. Homogenization is also done at room temperature. The homogenizer has the capacity from 1ml up to 12 liters and is ability to mix in-line with flow rates up to 20 liters/min. Its nominal maximum speed is 8000rpm (6000rpm under full load).
5) Aging:
The homogenized mix then is aged in the fridge for minimum of 4 hours at 0 to 4 0c. The purpose of ageing is to provide time for the fat, protein, and formation of ice crystals that improve the body and the texture of the ice cream. (Ice cream manufacture)
6) Freezing and mixing together:
It is very important to prevent the formation of large ice crystal from water during freezing and mixing. This process was done with the equipment in the laboratory GELATIERA Self-Refrigerating Ice Cream Maker
7) Packaging:
The finished product is immediately packed in plastic containers and stored in freezer.
8) Storage:
Ice cream has to be stored at low temperature; the optimum temperature for storing the ice cream is between -18oC to -23oC. (Ramesh C. Chandan, 2008). The product should be stored immediately packed & stored because if it melts and is then frozen there will be formation of large ice crystals.
Figure 2: Process Equipment Flow chart
Figure 3: Production Process Flow chart
1) Formulation:
All the ingredients are measured according to the recipe formulation.
2) Mixing:
In this step all the ingredients are mixed together at room temperature.
3) Pasteurization:
This process is done in order to reduce the microbial content of the mix as it is compulsory according to the legislation for the safety of consumer. The temperature for pasteurizing the mix is 175 o C for 25 seconds.
4) Homogenization:
Homogenization process is done to reduce the size of the fat globules and also to get a uniform mix. Homogenization is done at 180 bar working pressure.
5) Aging:
Aging is followed after homogenization. It is a process of quiescent storage of the mix with intermittent agitation for a period of 4 hours. During this process, the fat crystals that melted during pasteurization recrystallize, the gums and the stabilizers also complete the hydration process and the proteins complete their absorption at the fat/water interface.
6) Freezing:
Freezing is facilitated by the removal of heat from a substance. Also, the aim of freezing ice cream is to convert approximately 50% of the water in the mix to ice because the volume is being doubled.
7) Hardening:
In order to harden the ice cream, it is placed in a cold environment where large volumes of cold air sweep the surfaces of the packages for a period of time. The hardened ice cream is stored at -28oC and the time depends on the size of packages, the geometry, the air temperature, the air velocity and turbulence.
8) Cold storage:
Frozen and hardened ice cream is to be stored below -25oC temperature. The factors that affect the shelf life of the ice cream are the procedures, the transportation and the storage. (Ramesh C. Chandan, 2008)
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Team D – Low Fat Saffron Ice Cream with Rose Water
2. Factory layout
Unit III ReportPage18
Team D – Low Fat Saffron Ice Cream with Rose Water
1 – Receiving
2 – Tank truck manhole
3 – Cream storage
4 – Melting room
5 – Storage
6 – Non-fat dry milk storage
7 – Stabilizer hopper
8 – Mix tanks
9 – Raw products tanks
10 – Mix cooler, homogenizer
11 – Auto control panel
12 – Drivers’ room
13 – Air condition unit
14 – Tanks
15 – Mix storage tanks
16 – Freezers
17 – Fillers
18 – Pint fillers
19 – Freezers
20 – Palletizing area
21 – Palletizing room
22 – Receiving, shipping
23 – Coffee lounge
24 – Men’s locker room
25 – Women’s locker room
26 – Conference room
3 Process and ancillary equipment required to meet production of 10,000 units for every 8 hour shift
Transport
Completely stainless steel tanks of various sizes with different compartments are to be mounted on trucks for the transport of milk. The milk loading/unloading system can be based on the use of self-priming motor pumps or vacuum systems. On request, the tanks can be supplied with cooling systems and measurement systems.
Receiving
5,000l capacity semi skimmed milk receiving, cooling, and storage line. Built in stainless steel and composed of:
• Storage tank with level control system to receive milk either manually from drums or directly from tanker truck or other tank;
• Single-stage, sanitary centrifugal motor pump with two speeds for liquid transfer;
• Removable cartridge line filter equipped with manual by-pass and micrometric flow adjustment valve;
• plate-type cooler capable of cooling 5,000 liters of milk/h to 4° using water chilled to 1°C;
• 5,000 l capacity thermostatic cooler tank with 2 cooling cycles, manhole, agitator and autonomous CIP washing system;
• Electric command and control panel equipped with multi-purpose programmable.
Instrument that can also be managed by remote-control.Available in 15,000 l capacity, with 2 and 4 cooling cycles, automation and digital control systems.
Storage
10,000l capacity isothermal milk storage tank. Equipped with chilled water circulation cooling band complete with slow mixer, hatchway, level indicator and accessories. Constructed in stainless steel with particular attention dedicated to finish.
Mix preparation
For the preparation and blending of ice-cream mixtures, tanks with rapid blenders with or without heating or pump-type mixers (triblenders) with funnels for the addition of powders and ice-cream mixture circulation systems are used.
Preheating, Homogenizing, Sterilizing and CIP
The equipment combines ice cream mix, preheating, homogenizing, sterilizing and CIP as a continuous working unit special for ice cream processing functions. (Capacity: 500L~10000L/h)
Refrigeration
75 kg/h continuous freezer designed for the chilling of ice-cream mix to the freezing point. Capable of operation up to 100% overrun with incorporation of filtered air.
Constructed in stainless steel and equipped with:
•volumetric motor pump for ice-cream mix;
•suction motor pump for air filtered to 1 micron
•completely dismountable and sanitizable freezer cylinder with scraper paddles;
•refrigeration system with water condenser complete with compressor and safety pressure-switches;
•counter-pressure adjustment valve for product consistency adjustment;
•electric control panel for all machine functions
Capacity 150kg/h
Packaging
Automatic linear packaging machine with 8,000 containers/h capacity for ice-cream. Designed for packaging with pint, cups. Volumetric dosing that ensures the maximum precision and heat-sealing are performed automatically at the same time to accelerate packaging as much as possible, and the operator is required only to load the stacks of containers and caps in the respective magazines. The machine, which operates on more than one track depending on capacity which is up to 8,000 pieces/h for the 4-track version, is designed for the dosing of one or more flavors. Range of interchangeable formats up to 600g available. (Plants and Equipment for the Food Industry)
4 Conducting product and process optimization with design of experiments
In unit II a screening experiment was conducted using the 2k factorial design and varied the factors (milk and water ratio, and the quantity of xanthan) at high and low levels. A sensory analysis was conducted for melting property and creaminess, and all the products had low ratings and the texture was unacceptable, as the product was hard, had many large ice crystals, giving a very icy product.
For this unit, it was decided that factors that improve the textural qualities of our product should be found. The stabilizer (xanthan) was replaced with guar gum and carageenan and also an emulsifier (panodan) was introduced.
After searching on information on how to improve the texture, from website (Ice Cream: Regulations and Standards, Manufacturing Methods), it was found that panodan, carageenan and guar gum are best suited for low fat ice creams and the quantity used should not exceed 1g each (Jukes, 1997). Also from experiments conducted in unit II it was observed that using high levels of stabilizers and lecithin does not result in a satisfactory texture when compared to commercial products, thus levels higher than 1g were not considered.
To determine the optimal surface, 8 samples were produced based on 32 factorial designs. The purpose of this was to determine the effect these factors have on the textural (creaminess, softness and iciness) attributes and to also determine which of these samples will result in an optimized product. The three factors were carageenan, guar gum and panodan and these were varied at low and high levels. Table 1 shows how the factors were varied based on two level designs.
Table 1: product formulation
Factors / Product A / Product B / Product C / Product D / Product E / Product F / Product G / Product HCarageenan (g) / 0.1 / 0.1 / 0.25 / 0.25 / 0.1 / 0.1 / 0.25 / 0.25
Guar gum (g) / 1 / 1 / 1 / 1 / 0.5 / 0.5 / 0.5 / 0.5
Panodan (g) / 1 / 0.5 / 1 / 0.5 / 1 / 0.5 / 1 / 0.5
It was expected that an optimized formulation would be achieved after conducting the above experiments. Since there was no significant difference in all the formulations (see figures 4 to 7), and an overall preference test was also conducted, this also indicated that there was no significant difference in the preference of the sample. It was then decided that in the next unit further work will be done on the sample that had the highest means and another WHAT (flavor) which is mostly dependent on the quantity of saffron would be considered to optimize our product.
Figure 4: graph for response (Creaminess) Figure 5: graph for response (Softness)