Course:FNH200/2014w Team17 FrozenDinners

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Introduction

mac and cheese[1]

Macaroni and cheese has been considered a comfort and staple food in North America for decades. In today’s market, a variety of ‘mac and cheese’ products are available as frozen entrees, canned products and boxed with cheese powder. Since Kraft introduced the boxed macaroni and cheese in 1937 which sold 9 million boxes in its first year, its sales continue to rise and presently, over 1 million boxes are sold every day! [2] Because of mac and cheese’s continual popularity and the fact that it is a quick, easy and inexpensive meal (especially for students!) we have chosen to explore more on this topic.

With this project, we aim to learn how different versions of macaroni and cheese are processed, specifically frozen and boxed products and whether their production process varies significantly.

  • How is the macaroni/pasta made?
  • How do the different products differ in terms of their production process?
  • How does the manufacturing process affect the quality of the product and how can the quality of the final product be preserved and improved?

History

Mac and Cheese was thought to be first made in southern Italy between the mid 13th century and the early 14th century. The first recipe was not actually made with macaroni pasta. In fact, it was made with cut up lasagna sheets then tossed with cheese. This was recorded in a Latin cook book called the Liber de Coquina which was written by an anonymous person who was under Charles II of Anjou. [3] The recipe was thought be first brought back to America by Thomas Jefferson from his travels in Italy. He brought back a pasta machine along with many recipes and ideas from his travels. Most importantly, he brought back the recipe for the pasta itself. In fact, to impress his peers, he even served mac and cheese at the 1802 state dinner. [4]

Manufacturing Process

Mixing

The manufacturing process of every macaroni and cheese product begins with the production of pasta. Pasta is made from water and some type of flour. Typically, semolina flour obtained from high-protein durum wheat is used to produce the highest quality pasta.[5] Other types of flour including durum wheat flour, common wheat flour and potato flour can be used to manufacture pasta but the final product will have a lower appearance, colour and cooking quality. [6] Water in the amount of 18-25% of the weight of dry materials is added to the flour and is mixed at a temperature of 40°C until it forms a batter with a moisture content of 30% and a lumpy consistency.[7] During the mixing process, the first initial stage is completed at high speed at lasts for 2 minutes to ensure that every semolina particle is hydrated to prevent formation of white specks or streaks in the final dried product.[6] The 2nd stage is less rapid and lasts for 20 minutes to ensure complete hydration. [6] Additional ingredients to enhance nutrition, flavouring and colouring of the product may also be added during this step.

A set-up of the common machinery used for the manufacturing of pasta. Semolina and water are first mixed and then transported into an extrusion chamber where the dough is formed and then extruded through the die to form the desired shape.

Extrusion

Immediately after the mixing stage, the mixture is moved into the extrusion chamber where it is kneaded at a pressure of 80-120 kg/cm2 to develop into a dough.[6] Kneading the dough also helps to produce a springy, elastic texture of the final cooked product which is the preferred eating quality.[8] During this kneading process, the temperature must be kept below 50°C to minimize destruction to the gluten matrix and the failure to create protein links in the product that would result in reduced firmness and quality of the cooked product. [7] Both the mixing and kneading process is performed in the presence of a vacuum which removes the presence of small air bubbles from the dough which improves the appearance of the product and prevents any defects in the final product.[6] The vacuum also decreases oxidation of pigments (specifically carotenoid and xanthhophyll) to minimize the colour lost of the pasta. [6] Oxidation of these pigments decreases the yellow colour typical of pastas.

Shape of the macaroni is created by feeding the dough into an extruder which pushes it out through circular metal dies where rotary cutters cut it into the preferred size. [6] The curved shape of elbow macaroni is formed as opposite sides of the dough passes through the extruder at different speeds. Pieces of the cut pasta are then moved onto a conveyor belt that is exposed to circulating hot air which prevents the pieces from sticking together and shapes the product by partially drying and reducing the moisture content by 5%. [6]

Drying

There are a variety of drying processes for pasta but all have the same outcome of reducing the moisture content to 12.5%. [9] Careful control of the temperature, moisture and duration of drying is required to produce an acceptable product. A uniform rate of water removal has to be achieved to prevent the outer surface from drying too quickly that ultimately results in the formation of fractures in the product. [6] The product must also not be dried at low rate as that promotes the development of moulds, discolouration and souring. [8]

Diagram of drying process of pasta. The drying stage is carefully controlled at different temperatures to produce an acceptable product in terms of colour, cooking texture and moisture content.
  • In Italy, pasta may be sun dried outdoors.[8]
  • Low temperature drying at a maximum of 60°C for 18 hours is considered the traditional method of drying pastas. [6] This method requires a lot of space and time, resulting in a higher cost of the final product. [9]
  • 3-stage high temperature drying process[8]
1. Pre-drying period: Heated air at 55-90°C circulates around the product and dries it until it contains a moisture content of 17-18%. This takes approximately 1 hour.
2. Sweating period: Pasta is rested to allow the moisture to equilibrate between the inner core and outer surface.
3. Drying period: Alternate between heated air circulation (45-70°C) and sweating period for 6 hours.
  • Rapid drying process using microwave energy[8]
1. Pre-drying: Circulating hot air at 71-82°C for 30 minutes to reduce moisture content to 17.5%
2. Microwave stage: Pasta is dried to desired moisture content of 12.5% at 30kW and air temperature of 82°C for 10-20 minutes
3.Cooling/equalization stage for 40-60 minutes

Frozen Mac and Cheese

blue menu mac and cheese

In the production of frozen macaroni and cheese products, a pre-made dry macaroni product (produced same way as detailed above) is first pre-cooked then placed in a tray where it undergoes rapid freezing. This process is divided into 3 main stages[10]:

  1. Preparation and processing of food
  2. Loading into packaging
  3. Freezing

During preparation, the dehydrated macaroni is heated in water to a temperature of at least 97°C and a moisture content of 60-70% to retain the desirable texture and firmness for the consumer after reheating. [11] If the macaroni is cooked at lower temperatures, starch can leach out of the pasta which deteriorates the texture into a soft and sticky product [11] The macaroni can then be further dried at a temperature of 135-175°C for 2-10 minutes to reach a moisture content of 40-60%.[11] This extra step is implemented to decrease the rate of moisture absorption during the freezing and reheating stages to help retain the texture of the product.[11] After cooking, the macaroni is rinsed with water to remove any soluble carbohydrates remaining of the surface and can additionally be coated with a thin layer of vegetable oil to prevent water from entering after the freezing stage. [12] Dehydrated macaroni is generally used because cooking dehydrated pastas and then subsequently freezing it will retain better firmness than simply freezing fresh raw pasta since fresh pasta can absorb more moisture from the packaged sauce. [11]

Michelina's mac and cheese

The cooked macaroni and cheese sauce is then packaged into a paper or plastic carton containing pre-printed labels and directions. An automated conveyor system moves the cartons to filling machines which place equal amounts of food into each carton.[10] After being filled, the conveyor moves cartons to a packaging station where they are covered with paper or plastic and are then sealed to create a partial vacuum to prevent evaporation. [10]

During freezing, cartons are rapidly frozen using the cold air blast method. [10] These cartons pass through a freezing tunnel that contains a series of refrigerated coils that generate the cold air. Fans inside the tunnel blows cold air as low as -59°C towards the product and freezes it. [10] The packaged product is then stored in cardboard cases in a refrigerated storage facility and are transported in refrigerated trucks at a temperature of -18°C.

Boxed Mac and Cheese

Boxed macaroni and cheese products are packaged with dried macaroni and a packet of dried powdered cheese sauce. The dried macaroni is processed the same way as other pastas that are sold individually (as detailed above: mixing, extrusion, drying). Powdered cheese is processed through spray drying.[13] Before drying, the cheese is first melted into a liquid form where the cheese rind is removed, the cheese is disintegrated and salts are added with water to the cheese. [13] Some ingredients that can also be added during this step are dairy ingredients (whey, skim milk solids), starch, maltodextrins, flavour enhancers and colouring agents. .[14] The cheese is melted until it contains approximately 35% solid contents and is heated to a temperature of 75-85°C to form a slurry.[13] The liquid is then dried in a spray dryer with a stream of air at a temperature of 180-190°C into a powder form. [13]

Quality Preservation during Manufacturing

Although ways to improve the quality of the final product have been briefly touched upon in the Manufacturing Process section, other ways to preserve quality are explained in more detail here.

Pre-Mixing

Although the high temperature drying of pasta will likely inactive or kill microorganisms, a sample of the semolina used is checked for yeast and mould levels, pathogens that may be of concern including Salmonella and Staphylococcus aureus and contaminants including pesticides, mycotoxins and heavy metals.[7] Semolina should also be checked for any pathogens or contaminants before the mixing stage as the high temperature and moisture level during this stage are suitable for microbial growth.[7]

Mixing

During the mixing process, the initial high speed mixing helps to separate all the semolina particles to make sure each particle is hydrated. The next stage of mixing is less vigorous and lasts for 20 minutes to make sure there is complete hydration of semolina which allows for the free movement of gluten and starch to form a proper gluten matrix during extrusion that ultimately contributes to the firmness and texture of the final product after rehydration. [7]

Extrusion

Extrusion of pasta has to be maintained below 60ºC to prevent denaturation of gluten and gelatinization of starch. [7] Presence of a vacuum is needed during transport of pasta dough from mixer to extruder to reduce the number of air pockets in the dough that may result in white specks and decreased strength in the final product.[7]

Drying

The target moisture content for the dried pasta product is below 12.5% because a water activity level of 12.6% in pasta can support survival of some hydrophytic mould.[7]

High temperature drying improves the colour appearance of pasta compared to low temperature drying due to the inactivation of lipoxygenase at temperatures approaching 70°C. [7] Lipoxygenase is a bleaching enzyme that causes a loss of yellow pigments and its inactivation will preserve the colour typical of pastas. [6] High temperature also helps set up a permanent protein network that entraps starch granules which prevents these granules from leaching out during cooking and therefore improves the desired integrity and firmness of the cooked product.[7]

While high temperature drying creates a safer product that better retains its texture and sensory qualities upon cooking, increased exposure to high heat may cause fractures and non-enzymatic reactions. [9]High temperature drying of pasta for a long duration can result in the Maillard reaction which causes brown discolouration. [6] The Maillard reaction cause also cause a loss of nutritional quality, including the loss of lysine and vitamins. [6] Furthermore, drying the product too rapidly with a high temperature removes water from the surface of the product which creates a high moisture content gradient between the surface and inner core of the pasta that eventually results in fracturing and cracking of the pasta. [7]

Ingredients

Since the manufacturing process (particularly high temperature processes) of pasta and cheese powder can degrade some sensory qualities and nutrients of the product, some ingredients are added to enhance and recover these characteristics. Other ingredients/food additives are also used as a necessity to manufacture the product or as a preservative.

Additives in Frozen Mac and Cheese

Below is a list of additives and their general function used in the production of Michelina's Frozen Mac and Cheese.

  • Lipase: Food additive used as a food enzyme[15]
  • Sodium Phosphate: An emulsifying, gelling, stabilizing and thickening agent[15]
  • Sodium Alginate: An emulsifying, gelling, stabilizing agent [15]
  • Annatto: Used as a colouring agent.[15] Annatto is the seed or extract from the achiote tree, and is used heavily in central and South America as a food dye. Its colors can range in color from bright yellow to deep orange. This is used to form the bright orange colour of cheese.
  • Maltodextrin: A carbohydrate based fat substitute that is commonly used as a food additive which produces a smooth mouthfeel of the product.

Additives in Boxed Mac and Cheese

Below is a list of additives and their general function used in the production of No Name Brand Mac and Cheese.

  • Thiamine, niacin, riboflavin, folic acid: Are not considered 'food additives' but are added to enrich the product with B vitamins that are needed to help the body use energy from food and to make red blood cells in the body to prevent anemia. [16]
  • Tartrazine: Used as a colouring agent.[15] This is used to create a bright yellow-orange colour of the cheese powder as spray drying may degrade some of the colour.
  • Disodium phosphate: Used as an emulsifier or as a texture-modifying agent [17]
  • Disodium guanylate and Disodium Inosinate: Used in combination as flavour enhancers. [18] These are used to increase the flavouring as thermal processes can degrade some flavour.

Conclusion

mac and cheese burger

What most people think is a simple dish of macaroni and cheese actually is the result of a long expedition across the Atlantic ocean and copious amounts of research. The fact that mac and cheese is available so readily whether it be fresh, frozen, or dried is nothing short of years of hard work from hundreds of people. As mac and cheese is known as such a comfort food for so many people it has also fueled a food revolution of sorts to bring comfort home food to high class restaurants. In addition to the amazing variations created by restaurants, many different types appear in our groceries in all three forms. Macaroni and cheese is not only a piece of history but also a versatile and delicious dish enjoyed around the world.

Reflection

After extensive research and completion of this project, we were able to gain some insight on the manufacturing process of macaroni and cheese. Although macaroni and cheese has been popular for several decades and the production of pasta has existed even before that, we focused solely on recent and modern methods of this process. Even though we didn’t look into the traditional methods of pasta processing, we have a general understanding on how specific and elaborate the process was given the specific requirements needed for modern processing. We now understand and were surprised that manufacturing of macaroni and cheese requires extensive control over temperature, moisture content, duration and speed of each different process to ensure maximum quality of the final product. This was something we did not expect from a product that is so affordable and simple to cook.

From this project, we also learned what additional ingredients are added to macaroni and cheese during manufacturing to enhance its qualities. Additives such as tartrazine (colouring) and disodium guanylate and disodium inosinate (flavor enhancers) were added to one of the boxed macaroni and cheese products. Although we only looked into a few products, not all brands contained these ingredients. We hope to inquire about this discrepancy in the future and whether such ingredients are necessary or can alterations to the manufacturing process diminish the need for such additives.

Video

https://www.youtube.com/watch?v=PbKt5JIZdX4&feature=youtu.be

Final Exam Question

Question:
For Kraft Dinner (packaged as dried macaroni and cheese powder), what manufacturing and preservation processes are required to make this product?
A) Spray Drying
B) Extrusion (cooking) Drying
C) Microwave Drying
D) Two of the above
E) All of the above

Answer:
All of the above. The packaged cheese powder is produced by dehydrating melted cheese through a spray dryer to form a powder. One method of drying the macaroni pasta product rapidly is through microwave drying (using microwave energy) to lower its moisture content to prevent microbial growth. And although extrusion drying is not the principal method of drying for the pasta product, the pasta dough is still required to go through a die under pressure to form the characteristic elbow-shape of macaroni. Extrusion drying also results in some dehydration of the product by lowering its moisture content by 5%.

References

  1. ↑ PhamFatale.com
  2. ↑ Myers, D. (2014, December 17). Things you didn't know about Kraft Macaroni & Cheese. Retrieved April 15, 2015, from http://www.foxnews.com/leisure/2014/12/17/things-didnt-to-know-about-kraft-macaroni-cheese/
  3. ↑ Did You Know: Food History - Origin of "Macaroni and Cheese" (n.d.). Retrieved April 15, 2015, from http://www.cliffordawright.com/caw/food/entries/display.php/topic_id/16/id/105/
  4. ↑ Rhodes, J. (2011, March 22). Marvelous Macaroni and Cheese. Retrieved April 15, 2015, from http://www.smithsonianmag.com/arts-culture/marvelous-macaroni-and-cheese-30954740/?no-ist
  5. ↑ How Pasta is Made. (n.d.). Retrieved April 15, 2015, from http://www.madehow.com/Volume-2/Pasta.html
  6. ↑ 6.00 6.01 6.02 6.03 6.04 6.05 6.06 6.07 6.08 6.09 6.10 6.11 6.12 Marchylo, B. A., & Dexter, J. E. (2010). Pasta production. (pp. 109-130)
  7. ↑ 7.00 7.01 7.02 7.03 7.04 7.05 7.06 7.07 7.08 7.09 7.10 Kill, R. C., & Turnbull, K. (2001). Pasta and semolina technology. GB: Wiley-Blackwell.
  8. ↑ 8.0 8.1 8.2 8.3 8.4 Kent, N. L. (1983). Technology of cereals: An introduction for students of food science and agriculture. New York; Oxford [Oxfordshire]: Pergamon.
  9. ↑ 9.0 9.1 9.2 Pasta production, drying and packaging. (2013, February 1). Retrieved April 15, 2015, from http://italianfoodmaterialsandmachinery.com/pasta-production-drying-and-packaging/
  10. ↑ 10.0 10.1 10.2 10.3 10.4 How TV Dinner is Made. (n.d.). Retrieved April 15, 2015, from http://www.madehow.com/Volume-5/TV-Dinner.html
  11. ↑ 11.0 11.1 11.2 11.3 11.4 Barne, G., Hsu, J., & Wyant, L. (1993, May 17). Patent EP0531743A1 - Frozen pasta. Retrieved April 15, 2015, from http://www.google.com/patents/EP0531743A1?cl=en
  12. ↑ Sun, D. (2006). Handbook of frozen food processing and packaging. Boca Raton, FL: Taylor & Francis.
  13. ↑ 13.0 13.1 13.2 13.3 Písecký, J. (2005). Spray drying in the cheese industry. International Dairy Journal, 15(6), 531-536.
  14. ↑ Koca, N., Erbay, Z., & Kaymak-Ertekin, F. (2015). Effects of spray-drying conditions on the chemical, physical, and sensory properties of cheese powder. Journal of Dairy Science.
  15. ↑ 15.0 15.1 15.2 15.3 15.4 Food and Drug Regulations (C.R.C., c. 870). (n.d.). Retrieved April 15, 2015, from http://laws-lois.justice.gc.ca/eng/regulations/C.R.C.,_c._870/page-160.html#docCont
  16. ↑ B Vitamins. (n.d.). Retrieved April 15, 2015, from http://www.dietitians.ca/Your-Health/Nutrition-A-Z/B-Vitamins.aspx
  17. ↑ Robinson, A. (n.d.). Food Additives: What is Sodium Phosphate? Retrieved April 15, 2015, from http://www.livestrong.com/article/40858-sodium-phosphate-label/
  18. ↑ Cooper, K. (2011, November 10). Disodium Guanylate vs. Monosodium Glutamate. Retrieved April 15, 2015, from http://www.livestrong.com/article/551058-disodium-guanylate-vs-monosodium-glutamate/
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