Quadrocomil leading technology provider of security screening equipment, size reduction equipment for unparalleled results in particle size reduction. For more info, visit our website.

1. PARTICLE SIZE
REDUCTION AND ITS
IMPACT IN THE FOOD
INDUSTRY

2. BACKGROUND
Food particle size has become increasingly more important to the food
industry. Many food ingredients exist in some particulate form whether it
be powders, emulsions, suspensions, and/or pellets. Moreover, the
shape and size of these particles as well as their distribution affect flavor,
texture, and appearance of foods that we eat. Size and shape of
ingredients also affect the stability of a given product as well as
processability and functionality of the desired end product.
Advancements in research in terms of general food technologies,
biotechnologies, and nanotechnologies are bringing about an awareness
of the importance of food particle size/shape and its significance on
palatibility, digestion, bioavailability, and metabolism along with handling,
packaging, storage and transport of food stocks. The physical and
chemical properties of food ingredients such as particle size are of
increasing importance to insure consistent quality and safety of products.
These properties are also important to keep processing equipment
working properly and keep maintenance to a minimum.

3. For those of you who are chocolate lovers, chocolate particle size is critical
for sensory perception. The particle size will determine how the product
feels in your mouth, taste, and how it melts. Continued production and
development of new products is dependent on sensory and textural
properties for continued success to prevent product failures that have been
seen in the past. Proper texture and sensory experiences tends to ensure
repeat consumer purchases. As the public is demanding the production of
healthy foods that contain less fat and sugar, there is a need to find bioactive
or nutraceutical ingredients. These types of ingredients provide health and
medical benefits that have have been tested through research and clinical
trials and are known to prevent and treat diseases. As the food ingredients
are changing, this requires different forms of processing not only for taste
and texture but proper machine handling as well as new types of processing
equipment.
BACKGROUND
(CON’T)

4. The medical community has made it clear that diets that are low in fat
and cholesterol and high in fiber reduce the risk of cardiovascular
disease, diabetes, and certain cancers. If you recall, the first foods that
came out that were high in fiber tasted like the cardboard box they
came in. That certainly didn't settle well with the consumer so these
products did not sell well. However, we have come a long way since
then but this has taken millions of dollars of research to get here.
A fair amount of research has been done on particle size distribution
where pasting and rheological properties are concerned in terms of
starch and flour powders. This impacts how creamy a product is as
well as how crispy and crunchy it is. Pasting refers to foods that have
been pounded until they are reduced to a smooth creamy mass.
Whereas, rheology refers to the flow of liquids and/or soft solids.
Creamy texture and liquid flow are commonly found with substances
that have complicated micro-structures as is often found in foods and
food additives.
BACKGROUND
(CON’T)

5. BACKGROUND
(CON’T)
All in all, many industries depend on some form of particle
size reduction. This allows for separation of components to
create a desired product while controlling taste, texture,
quality, and safety. This is particularly important for the food
and pharmaceutical industry. Particle size determines
bioavailability for both nutrients in food as well as
medications.

6. PARTICLE SIZE
CONTRIBUTION
Particle size controls a number of chemical and physical
properties which include; reaction and dissolution rate,
packing density, sedimentation, appearance, and texture.
This list is by no means exhaustive but covers the major
contributions of particle size effects.

7. RATE OF
REACTION
Chemical reactions are dependent on the surface area of a
particle. Smaller particles are more likely to participate in the
making and breaking of bonds than larger ones. Biological
systems have developed enzymes to increase the rate at
which chemical reactions take place. Non-biologically,
particle size is another way to increase reaction rates.

8.
DISSOLUTION RATE
Particle size also effects how well it will go into solution.
This is particularly important for the food and pharmaceutical
industries. This is directly related to bioavailability. The
smaller the particle whether drug or food, the greater the
chance of it being absorbed by the gut. Whether the particle
of interest is water or fat soluble determines dissolution rate
as well. Molecules that are both water and lipid soluble often
have the best of both worlds.

9. PACKING DENSITY
Packing density refers to how well particles fit together. Usually, larger
particles don't pack as well in that they have more space between them
because they have a larger surface area. Smaller particles tend to pack more
densely because they have a smaller surface area. This is probably more
important when you are concerned about unoccupied volumes if you are
trying to maximize content and minimize cost of packaging and shipping.
Flour sacks often pack down during shipping and handling. Manufacturers
often suggest that you sift the flour before you use it. Food products such
as chewy health bars require larger particles to maintain their integrity.
Smaller food particles tend to be to hard to chew and crumble. Packing
density is particularly important to the metal industry where unoccupied
space creates a flawed product.

10. SEDIMENTATION
Sedimentation has to do with a particle's ability to precipitate
out of solution or soft solid. This is of particular interest to
the food and drug industries. Many products require that
they remain evenly distributed in solution (suspended). This
may be important to maintain drug dosages when the drugs
come in the form of a liquid. On the other hand, it could be
salad dressings (oil and vinegar suspension) which has
more to do with product perception.

11. PRODUCT
APPEARANCE
Particle size and distribution is an important characteristic
contributing to product appearance. Particle size affects the
overall bulk properties of the food item such as visual texture
and density as well as color. Larger particle size may
indicate a chewy food, whereas smaller particle size may
indicate crunchy and less moist.

12. PRODUCT
TEXTURE
Product texture can be easily affected by particle size.
Particle size also affects how you perceive a given product.
Large particle size and hence a more coarse texture alters
flavor. Large particle size tends to have less distinct flavor,
whereas fine particles have more flavor. One way to think of
this on a larger scale is with lunch meats. Consider the slice
thickness of prosciutto. A thick slice of this is difficult to
chew and has an unpleasant flavor. Thinly sliced, it melts in
your mouth and has a very delicate flavor.

13. RESEARCH ON
CHOCOLATE AND
GRAINS

14. CHOCOLATE
STUDY
Researchers at the University of Nottingham, School of Biosciences, in the UK
have demonstrated the impact on particle size on rheological and textural
properties of chocolate with reduced fat content. As the public is concerned with
consuming chocolate with a lower fat content due to health concerns, this group
of researchers were interested in how this would change the molten chocolate
viscosity. It was known that reducing fat content would increase viscosity. This
leads to a loss in mouth melting properties which makes the chocolate hard and
difficult to swallow. Current literature demonstrated that optimizing particle size
distribution (increased packing fraction) actually decreases the viscosity of
suspensions that are highly concentrated.

15. CHOCOLATE STUDY
(CON’T)
Their focus was on the impact of particle size distribution and fat content on flow
properties (rheology) and melting characteristics in this dispersion of sugar in
fat. They were able to demonstrate that optimizing the particle size distribution
while reducing the fat content to a critical amount (22 percent by weight) can
decrease the viscosity of the heated material and at the same time reduce the
hardness of crystallized chocolate. This decreases the inter-particle contact
which in turn reduces particle aggregate strength and structure buildup during
melting. In its crystallized state, the molecular network is less connected
providing for lower resistance to breakage and meltdown. This allows the
chocolate to have a lower fat content and still be creamy. In this case, particle
size and distribution allows for a healthier chocolate product (lower in fat) that
retains a positive sensory input important for palatability.

16. GRAIN STUDY
Researchers at the University Department of Medicine in Bristol UK looked at
the effects of plasma glucose and insulin responses to changes in particle
size of wheat, maize, and oat meal as well as the rate of starch digestion in
vitro. Data was collected from normal volunteers who ate isocaloric wheat-
based meals and their plasma glucose and insulin levels were monitored.
Isocaloric refers to a diet that has moderate carbohydrate and fat intake
where the dieter can take in the same amount of carbs, proteins, and fats
each day. This diet is often used by bodybuilders for quick weight loss with
minimal muscle (protein) loss.

17. GRAIN STUDY
(CON’T)
In this study, wheat-based plasma insulin levels increased in a step
wise fashion with whole grains less than cracked grains less than
coarse flour less than fine flour. They also found that insulin levels
were also greater with fine maize meal than with whole or cracked
maize grains but were similar with whole groats, rolled oats, and fine
oatmeal.
The high-to-low ratio of blood glucose was greater with wheat flour than
cracked or whole grains. They also demonstrated that in vitro starch
hydrolysis by the pancreatic enzyme amylase was faster with
decreasing particle size with all 3 cereals. They were able to determine
that particle size influences the digestion rate and changes in
metabolism of wheat and maize but not oats. They suggest that the
increased insulin response to finely ground flour may be relevant to the
cause of diseases linked to hyperinsulinemia (excess blood insulin
levels) and to the management of diabetes.

18. SUMMARY
Food technology has come a long way. Research is paving
the way to finding approaches that create a balance between
particle size reduction and improving the functional aspects
of foods. Particle size reduction increases sensory
perception such as taste and texture while increasing
bioavailability of bioactive molecules while improving on the
nutritional properties. This is great news for the consumer
as well as the medical community.

19. RESOURCE LIST:
General information on food processing and new equipment
http://www.chemicalprocessing.com/
http
://www.fda.gov/Food/GuidanceComplianceRegulatoryInformation/GuidanceDocuments/FoodIngredientsandPackaging/ucm300661.htm
Particle size of wheat, maize, and oat test meals: effects on plasma glucose and insulin responses and on the rate of
starch digestion in vitro.
http://ajcn.nutrition.org/content/47/4/675.short
http://www.leatherheadfood.com/droplet-and-particle-size
http://www.leatherheadfood.com/food-innovation-research
http://www.izon.com/applications/industrial-research-applications/
http://certifiedfoodscientist.org/Knowledge-Center/Read-IFT-Publications/Science-Reports/Scientific-Status-
Summaries/~/media/Knowledge%20Center/Science%20Reports/Scientific%20Status
%20Summaries/FuncationlMaterialsinFood_1106.pdf
Pasting Characteristics of Wheat and Sweet Potato Flour Blends
http://www.pjbs.org/pjnonline/fin1702.pdf
Impact of particle size distribution on rheological and textural properties of chocolate models with reduced fat content.
http://www.ncbi.nlm.nih.gov/pubmed/18034724
Fat reduced chocolate: can it ever taste good?
http://www.google.com/search?sourceid=navclient&ie=UTF-
8&rlz=1T4SKPT_enUS412US412&q=improving+chocolate+flavor+with+decreased+particle+size