Appearance of white powder on cheese is really irritating and takes away the pleasure of having cheese, this also reflect poorly on the manufacturer of the cheese.
With a mind to develop a solution, we spend couple of evenings trying to develop a model that could simulate the development of the white powder on cheese and have solutions for the same.
Just so its useful to any cheese manufacturer, Here is what we developed:
Objective: Understanding the reasons and conditions that lead to the development of efflorescence in cheese and ways to prevent it.
Development of the model:
Crystallisation and appearance of fine solid particulates on the surface called Efflorescence, during storage and transportation and at the hand of consumers is a known phenomenon in many solid/ soft solids like brick, cheese, soaps where there are free electrolytes. This happens since these products loose moisture from the surface and the electrolytes dissolved in that moisture crystallizes out. Overtime, there will be a diffusion of moisture and the dissolved electrolyte in it from the bulk to the surface of the product and later this moisture that traveled to the surface would also volatilize away leaving more fine particulates on the surface of the product. This is the basis for a product to exhibit efflorescence.
Efflorescence is always to be prevented/controlled by close manipulation of level of electrolytes, processing, storing conditions and in incorporation of additives that provide humactancy or create a gel network and retain moisture or a coating that prevents moisture loss from the surface.
Why does efflorescence occur in cheese?
PKa of monosodium, disodium and trisodoum phosphates are 2.15, 7.2 and 12.4 respectively. Hence, at the given pH for manufacturing of cheese, the dominant species is DSOP.
The source of DSOP that appear as efflorescence is the residual DSOP that was added but didn’t get utilized and didn’t get precipitated as CaPO4.
The solubility of DSOP in water is limited. Since cheese matrix is porous and contain large amount of free moisture, there are slow evaporation of moisture from the surface and as such the moisture from the inner matrix flows to the surface by capillary action/ diffusion. Along with this water, the dissolved salt as well travel to the surface and as the moisture from the surface evaporates, the DSOP salt precipitate out on the surface and overtime gets accumulated and can be felt by hand (since white fine powder, maynt be visible to naked eyes unless one really looks for it).
Effect of various factors on generation of efflorescence:
1. pH
PKa of monosodium, disodium and trisodoum phosphates are 2.15, 7.2 and 12.4 respectively. Hence, at the given pH for manufacturing of cheese, the dominant species is DSOP and as the PH is raised towards, 7.2, more and more DSOP would be present. Given the relatively low solubility of DSOP, the efflorescence is due to precipitation of DSOP.
However, no manipulation of pH is being recommended since it would adversely affect the organoleptic profile of the finished cheese.
2. Amount of sod phosphates added: This is having profound effect on the level of efflorescence. More sod phosphate added, more will be the extent of phosphate and its level should be rigorously optimized and controlled. The appearance of efflorescence is a clear indication that the amount of sod phosphate added can be lowered. Enhanced mixing, as suggested later, can help facilitate it.
3. Amount of moisture in the cheese matrix: More the free moisture in the cheese matrix, more will be the evaporation from the surface overtime and this will lead to more efflorescence.
Hence, the level of the final moisture should be fixed and controlled at an optimized level without compromising the organoleptic profile of the product.
4. Time held at the final moisture (Desiccation): Longer the residence time, higher will be loss of moisture from surface and hence higher would be extent of efflorescence. Hence, the time for desiccation should be optimized so as to have the desired organoleptic profile of the cheese.
4. Cheese matrix/environmental temperature and relative humidity: Higher the cheese matrix/environmental temperature, higher will be the saturation pressure of the surface moisture and hence higher will be loss of moisture from the surface which would lead to higher level of efflorescence.
5. Temperature cycling: Temperature cycling is like to lead to efflorescence since repeated temperature cycling will lead to creation for softening of the structure leading to creation of more channels for movement of water. However, for a product like cheese, don’t think this can be avoided. However, this wouldn’t matter is the proposed solutions as explained later are implemented.
6. Extent of mixing and homogenization:
This is a critical parameter and can play a critical role in prevention of the efflorescence. Firstly, sufficient time should be given to mixing and dissolution/ hydration of the ingredients added. If small particulates of the ingredients added remain undisssolved/unhydrated then these will act as seeds for the DSOP crystals to form and grow at a faster rate. Insufficient mixing resulting in incomplete hydration is the reason that can possibly explain the seeker’s observation that ‘cheese formulations utilizing large quantities of milk protein concentrate (MPC) as a source of casein are more susceptible to sodium phosphate crystallization than are formulations more heavily relying on natural cheese’. Secondly, the time and extent of the homogenization must be optimized since this will ensure that the emulsification proceeds to completion and residual DSOP level is minimized and thus prevent efflorescence.
Thirdly, this will help in ensuring that unutilized DSOP doesn’t get retained in cheese matrix and so efflorescence gets eliminated.
7. Compaction level: The extent to which compaction is done is to be optimized to the extent that it doesn’t compromise the taste of the product. Higher level of compaction will lead to minimization of the porosity which will result in reduction/elimination of the efflorescence. However, there may be a limitation to the extent of compaction possible since this is likely to have an impact on the size impression of the product and also on mouth feel.
8. Water activity: Lower the water activity of the cheese produced, lower would be the possibility/extent of generation of efflorescence. The water activity of the cheese could be lowered by various ways- addition of salts having high water of crystallisation, gellants like bentonite clay or humectants like Glycerin (IP grade). Since, the additive mustn’t change the organoleptic profile of the product, the additive being recommended to be added is glycerin at 1% level. It is being expected that the cheese would retain around 0.1-0.25 glycerin which would be sufficient to lower the water activity of the product to the extent that help retain the moisture and thus eliminate efflorescence.
Test to study efflorescence:
Store the product at 1. Room temperature 2. At 20oC & 40 % relative humidity 3. At 20oC and 90% relative humidity. Observe it every week for 6 week. It is being recommended, the timing for evaluation and during of the storage study is optimized based on data that is generated over a period of say six month.
The rating of efflorescence should be given in a scale of 0 to 5.
Proposed solutions to prevent efflorescence:
1. The product should be (if possible) sold in completely shrink sealed packs which will ensure that there would be no efflorescence till the product reaches the hand of consumers.
2. Ensure sufficient mixing after addition of each of the solids so as to ensure complete dissolution/hydration. Increase the homogenization time by 10minutes at the end to ensure maximum emulsification.
3. Optimize the level of phosphates added with the enhanced mixing so as to ensure that there is minimal unused sodium phosphate left.
4. Add 0.5-1% glycerin at the end of the emulsification to lower the water activity of the product.
The last three suggestions together would ensure that even in the hands of consumers, there would be no efflorescence in the cheese.
Note: The solutions suggested above wouldn’t require any change in the normal cheese processing and especially to pasturisation process.
Anyone if free to use the solutions proposed above. We will just request that you just in line to acknowledge the use of the solutions articulated here and if you derive commercial benefit from the above ideas, assign a value to it and share a reasonable part of it with us.
With a mind to develop a solution, we spend couple of evenings trying to develop a model that could simulate the development of the white powder on cheese and have solutions for the same.
Just so its useful to any cheese manufacturer, Here is what we developed:
Objective: Understanding the reasons and conditions that lead to the development of efflorescence in cheese and ways to prevent it.
Development of the model:
Crystallisation and appearance of fine solid particulates on the surface called Efflorescence, during storage and transportation and at the hand of consumers is a known phenomenon in many solid/ soft solids like brick, cheese, soaps where there are free electrolytes. This happens since these products loose moisture from the surface and the electrolytes dissolved in that moisture crystallizes out. Overtime, there will be a diffusion of moisture and the dissolved electrolyte in it from the bulk to the surface of the product and later this moisture that traveled to the surface would also volatilize away leaving more fine particulates on the surface of the product. This is the basis for a product to exhibit efflorescence.
Efflorescence is always to be prevented/controlled by close manipulation of level of electrolytes, processing, storing conditions and in incorporation of additives that provide humactancy or create a gel network and retain moisture or a coating that prevents moisture loss from the surface.
Why does efflorescence occur in cheese?
PKa of monosodium, disodium and trisodoum phosphates are 2.15, 7.2 and 12.4 respectively. Hence, at the given pH for manufacturing of cheese, the dominant species is DSOP.
The source of DSOP that appear as efflorescence is the residual DSOP that was added but didn’t get utilized and didn’t get precipitated as CaPO4.
The solubility of DSOP in water is limited. Since cheese matrix is porous and contain large amount of free moisture, there are slow evaporation of moisture from the surface and as such the moisture from the inner matrix flows to the surface by capillary action/ diffusion. Along with this water, the dissolved salt as well travel to the surface and as the moisture from the surface evaporates, the DSOP salt precipitate out on the surface and overtime gets accumulated and can be felt by hand (since white fine powder, maynt be visible to naked eyes unless one really looks for it).
Effect of various factors on generation of efflorescence:
1. pH
PKa of monosodium, disodium and trisodoum phosphates are 2.15, 7.2 and 12.4 respectively. Hence, at the given pH for manufacturing of cheese, the dominant species is DSOP and as the PH is raised towards, 7.2, more and more DSOP would be present. Given the relatively low solubility of DSOP, the efflorescence is due to precipitation of DSOP.
However, no manipulation of pH is being recommended since it would adversely affect the organoleptic profile of the finished cheese.
2. Amount of sod phosphates added: This is having profound effect on the level of efflorescence. More sod phosphate added, more will be the extent of phosphate and its level should be rigorously optimized and controlled. The appearance of efflorescence is a clear indication that the amount of sod phosphate added can be lowered. Enhanced mixing, as suggested later, can help facilitate it.
3. Amount of moisture in the cheese matrix: More the free moisture in the cheese matrix, more will be the evaporation from the surface overtime and this will lead to more efflorescence.
Hence, the level of the final moisture should be fixed and controlled at an optimized level without compromising the organoleptic profile of the product.
4. Time held at the final moisture (Desiccation): Longer the residence time, higher will be loss of moisture from surface and hence higher would be extent of efflorescence. Hence, the time for desiccation should be optimized so as to have the desired organoleptic profile of the cheese.
4. Cheese matrix/environmental temperature and relative humidity: Higher the cheese matrix/environmental temperature, higher will be the saturation pressure of the surface moisture and hence higher will be loss of moisture from the surface which would lead to higher level of efflorescence.
5. Temperature cycling: Temperature cycling is like to lead to efflorescence since repeated temperature cycling will lead to creation for softening of the structure leading to creation of more channels for movement of water. However, for a product like cheese, don’t think this can be avoided. However, this wouldn’t matter is the proposed solutions as explained later are implemented.
6. Extent of mixing and homogenization:
This is a critical parameter and can play a critical role in prevention of the efflorescence. Firstly, sufficient time should be given to mixing and dissolution/ hydration of the ingredients added. If small particulates of the ingredients added remain undisssolved/unhydrated then these will act as seeds for the DSOP crystals to form and grow at a faster rate. Insufficient mixing resulting in incomplete hydration is the reason that can possibly explain the seeker’s observation that ‘cheese formulations utilizing large quantities of milk protein concentrate (MPC) as a source of casein are more susceptible to sodium phosphate crystallization than are formulations more heavily relying on natural cheese’. Secondly, the time and extent of the homogenization must be optimized since this will ensure that the emulsification proceeds to completion and residual DSOP level is minimized and thus prevent efflorescence.
Thirdly, this will help in ensuring that unutilized DSOP doesn’t get retained in cheese matrix and so efflorescence gets eliminated.
7. Compaction level: The extent to which compaction is done is to be optimized to the extent that it doesn’t compromise the taste of the product. Higher level of compaction will lead to minimization of the porosity which will result in reduction/elimination of the efflorescence. However, there may be a limitation to the extent of compaction possible since this is likely to have an impact on the size impression of the product and also on mouth feel.
8. Water activity: Lower the water activity of the cheese produced, lower would be the possibility/extent of generation of efflorescence. The water activity of the cheese could be lowered by various ways- addition of salts having high water of crystallisation, gellants like bentonite clay or humectants like Glycerin (IP grade). Since, the additive mustn’t change the organoleptic profile of the product, the additive being recommended to be added is glycerin at 1% level. It is being expected that the cheese would retain around 0.1-0.25 glycerin which would be sufficient to lower the water activity of the product to the extent that help retain the moisture and thus eliminate efflorescence.
Test to study efflorescence:
Store the product at 1. Room temperature 2. At 20oC & 40 % relative humidity 3. At 20oC and 90% relative humidity. Observe it every week for 6 week. It is being recommended, the timing for evaluation and during of the storage study is optimized based on data that is generated over a period of say six month.
The rating of efflorescence should be given in a scale of 0 to 5.
Proposed solutions to prevent efflorescence:
1. The product should be (if possible) sold in completely shrink sealed packs which will ensure that there would be no efflorescence till the product reaches the hand of consumers.
2. Ensure sufficient mixing after addition of each of the solids so as to ensure complete dissolution/hydration. Increase the homogenization time by 10minutes at the end to ensure maximum emulsification.
3. Optimize the level of phosphates added with the enhanced mixing so as to ensure that there is minimal unused sodium phosphate left.
4. Add 0.5-1% glycerin at the end of the emulsification to lower the water activity of the product.
The last three suggestions together would ensure that even in the hands of consumers, there would be no efflorescence in the cheese.
Note: The solutions suggested above wouldn’t require any change in the normal cheese processing and especially to pasturisation process.
Anyone if free to use the solutions proposed above. We will just request that you just in line to acknowledge the use of the solutions articulated here and if you derive commercial benefit from the above ideas, assign a value to it and share a reasonable part of it with us.
