Course:FNH200/Projects/2021/Frozen Pizza

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Introduction/History

Flat bread from Herculaneum (Ancient Period)
Totino's Party Pizza

Pizza can be simply defined as baked flat dough bread with toppings on top. However, with this definition, it is difficult to discover pizza's origin. In 2200 B.C, Egyptians consumed flat bread with a spread called "dukka[1]." Later, some evidence also suggest that flat bread consumed in Italy in 2000 B.C was not a derivative form of pizza from Egypt. Then from 930-730 B.C, the Persians, Etruscans and Greeks started making something we can identify more clearly as pizza[1]. Therefore, it is difficult to state where pizza was first really consumed because of the various ancient cultures that made it differently.

It is unknown exactly when or who first created frozen pizza which is a worldwide famous frozen food. However, some evidence suggest that it might have been created around in the 1950s. Frozen pizza was purchasable in the 1950s in Northern America at grocery stores when pizza had only recently become popular in America in the early 1950s[2]. Then later in the early 1950s, pizza restaurants started to offer refrigerated pizza for customers to easily cook in their homes. Around that same time, some restaurants also started selling frozen versions of pizza[2]. In fact, in 1950, a man named Joseph Bucci in Philadelphia filed the first official patent for frozen pizza, titled “Method for Making Frozen Pizza.[2]”

Not long after, frozen pizza businesses entered the economic market in America. Jim Totino began mass production of frozen pizza in Minnesota in 1962, which is now famously known as Totino's Pizza[2]. By the 1970s, Totino's frozen pizza became the top-selling frozen pizza in America[2]. This start had led to the launch of other brands by other people.

How It is Made (Manufacturing Process)

The frozen pizza industry has a complete and mature production line. The process of frozen pizza production starts with the preparation of pizza doughs. The materials used to produce pizza doughs include commercial wheat flour, water, salt, oil and yeast. All of the ingredients are mixed into a develop that allows for the dough to ferment. During the fermentation, the dough is punched several times to knock out the gas inside. After fermentation, it is divided into loaf-sized pieces and rolled into sheets. [3]The pizza manufacturing machine is dedicated for various types of frozen pizza with capacities that depend on different flavours and thickness of the crusts. Then specific pizza sauce toppings and cheese are added through different pizza topping systems. The waterfall pizza topping system is equipped with a recirculation system that distributes large amounts of individual quick freezing (IQF) materials including vegetables, ham and grated cheese onto the applicator. The target pizza topping system has accurate target applicators for strewing various ingredients using fixed shaped travelling hoppers which allow the rim of the pizza to be free of toppings (also called border-free topping system). [4]After adding toppings, the pizza is cooked through multi-stage baking and sliced. Then it is placed into the spiral freezer to freeze. After being frozen in the spiral freezer, the crusts have to be packed as quickly as possible and immediately stored in the warehouse freezer to prevent the interruption of the cold chain. [5]

Manufacturing Process of Frozen Pizza

Preservation Method (Freezing)

Freezing during production

As its name implies, the primary method of preservation for frozen pizza is freezing. One popular method of freezing for frozen pizzas is through the usage of a spiral freezer where pizzas are frozen for around 20 minutes at -25 degrees Fahrenheit[6]. From lesson 7.3, this method is also known as "Air Blast Freezing" where freezing takes place relatively quickly due to strong circulation of cold air. Specifically, after the pizzas are processed (as described above), they are transported to a spiral freezer[6] which is essentially a freezer that has self-stacking, multi-tiered belts organized in a spiral shape[7]. Spiral freezers usually use mechanical or cryogenic refrigeration methods[7] along with the usage of high-velocity air[7] moving over the pizzas in either a horizontal (crossflow) or vertical (downflow) arrangement[7]. The rapid movement of cold air over the pizzas allows for heat to be removed relatively quickly and thus for the freezing process to be completed in an efficient manner.

Freezing from the consumer side

As for the consumer, however, considerations concerning freezing for frozen pizza are related to the maintenance of the frozen state of the pizza until consumption. One concern in regards to this is the duration for which frozen pizza can be frozen for. According to a study done in 1998 on frozen pizzas topped with pork sausage and pepperoni, TBA (thiobarbituric acid) values for pork sausages, which were used to estimate the amount of lipid oxidation in the pork sausage, increased as storage time increased[8]. However, for the pepperonis, although TBA values did increase as storage times increased, the change in oxidation was much less compared to that of the pork sausages[9]. This phenomenon was likely attributed to the presence of nitrites and antioxidants in the pepperonis, inhibiting the process of rancidity[9], which is a process that was also discussed thoroughly throughout this course. Using lipid oxidation as a proxy for pizza quality[10], these results indicate that longer storage times tend to decrease the quality of frozen pizzas as lipid oxidation of meat toppings tends to increase over time even under frozen conditions[8]. Lastly, through the usage of sensory evaluation using "flavour scores", the study also found that the flavour scores of pizzas generally decreased as storage times increased[8] which was expected given the higher lipid oxidation levels. Overall, these results are not surprising as we know that perfect freezing methods do not exist as chemical and microbiological processes can still occur in foods under frozen states. As time passes, foods deteriorate and begin to lose their initial freshness and quality.

Spiral Freezer

The other major consideration that consumers need to consider when freezing frozen pizza is temperature. According to the study, the results showed much lower flavour scores for frozen pizzas stored at -7°C than for frozen pizzas stored at -18°C[8]. These results tend to indicate that lower storage temperatures are better for preserving frozen pizza quality. Given that the Canadian government's recommendation for freezer temperatures is below -18°C[11], this is in line with proper food safety measures. Surprisingly, however, according to the study, exposure to freeze-thaw cycling did not affect mean flavour scores[8]; in the study, boxes of pizza were moved from -18°C storage to 5°C storage to sit for seven hours in order to simulate temperature fluctuations that frozen pizzas usually experience during transit[12]. In the course, we labelled this treatment of frozen foods as "temperature abuse." However, the fact that such treatment of the frozen pizzas did not result in a significant decrease in its sensory qualities is surprising[8]. Perhaps this result is due to the fact that one long period of temperature change was used[12] instead of the usual multiple short cycles of temperature fluctuations that usually happen in transit, leading to better retention of pizza quality. On the other hand, it could simply be the fact that temperature abuse does not have an as pronounced effect on the quality of frozen pizza in particular. A further detailed analysis would need to be conducted in order to arrive at either of those conclusions.

Packaging

Frozen Pizza Packaged in Paper Board

The packaging for frozen foods is unique because of the different conditions that frozen foods need to go through. Reaction rates are lower when the food is in freezing temperatures vs when the food is in refrigerated conditions. Microbial growth is slower at freezing temperatures. Because of this, lesser packaging and fewer additives are needed at these temperatures compared to when refrigerated. The pizzas also have a longer shelf life when frozen. Vacuum packaging is not sufficient for frozen pizza because when kept in vacuum, the texture of the bread is negatively affected.[13] The packaging for frozen pizzas also needs to be compatible with low temperature environments (-18 degrees celsius). The most commonly used packaging is paper-board based folding cartons which are coated with moisture barriers.[14] The packaging also needs to be microwaveable, so that the consumer does not have to keep the pizza in a separate container in order to heat it. The packaging material must therefore also be resistant to high temperatures without melting into the food itself. Crystallized polyethylene terephthalate is used as a tray to heat the pizza in a microwave because of its heat resistant properties.[15] Micro-perforated holes in the pizza box enable proper steaming of the pizza by providing ventilation. These holes are invisible to consumers. In addition to these requirements, it is also necessary that the packaging is resistant to oil, made of food grade materials, and durable and leakproof. Other types of packaging for frozen pizza include polyolefin shrink film, which is FDA approved and it helps prevent freezer burns and prevents the formation of vapour and moisture. Another option is Chipboard boxes, which are sturdy and easy to shrink wrap.[16]


Health Concerns

Totino's Pepperoni Pizza Nutrition Facts

Frozen pizzas contain high amounts of sodium in comparison to their size and to freshly made pizzas sold at restaurants. Therefore, many manufacturers have reduced their frozen pizzas' sodium level to better fit the daily recommended sodium intake and to better fit the criteria suggested by the Food and Drug Administration without significantly interfering with the flavor[17]. However, sodium is an essential and effective ingredient in enriching the flavor of frozen pizzas and it also acts as a preservative agent[18]. Therefore, many manufacturers could not reduce their products' sodium level by an extreme amount to make the product healthier, because in doing so, it will affect the flavor.

Excessive intake of sodium could result in severe health consequences[18]. Major health risks associated with excessive sodium intake are heart diseases and stroke. High sodium intake leads to increases in blood volume which could stiffen blood vessels, leading to high blood pressure, heart attack, and stroke[18]. Therefore, many parts of the world recommend a daily intake of sodium in the range of 1500 to 2300 milligrams per day to best reduce the risks of these consequences. Health Canada also recommends people to consume sodium within that range[19].

Exam Question (1)

Frozen pizzas with meat toppings held in frozen storage undergo:

A) Restoration

B) Fortification

C) Lipid oxidation

D) Gelatinization

E) Fermentation

Answer: C, Lipid oxidation

Our question should be included on the final exam because it is relatively straightforward but at the same time a little bit tricky since perhaps people would not expect frozen foods to be able to undergo lipid oxidation. However, since the other choices are fairly obviously wrong, those who have studied the course material will be able to eliminate the wrong answer choices and hopefully recall that freezing foods doesn't 100% preserve those foods and that chemical and microbiological processes can still occur even when foods are frozen.


References

  1. ↑ 1.0 1.1 Ovadia, David (8 March 2017). "Bubbles in Food 2 (Chapter 39 - A History of Pizza)". Science Direct.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Huddleston Jr., Tom (2 May 2020). "The history of frozen pizza—how a frozen food staple became a multibillion-dollar business". CNBC.
  3. ↑ Pacheco de Delahaye, Emperatriz (May, 2005). "Effect of enrichment with high content dietary fiber stabilized rice bran flour on chemical and functional properties of storage frozen pizzas". Journal of Food Engineering. 68: 1–7 – via Science Direct. Check date values in: |date= (help)
  4. ↑ Alimec (2006). "Pizza Automatic Production".
  5. ↑ Mihu, Catalina (July 5, 2018). "Exclusive: Manufacturing Frozen Pizza And Pastries – Special Focus". Worldbakers.
  6. ↑ 6.0 6.1 Allard, Martin (Nov 14, 2011). "How It's Made Frozen, Pizzas". Produced with the financial participation of the Canadian and Quebec government.
  7. ↑ 7.0 7.1 7.2 7.3 Subramanya, Shiva (Feb 1, 2020). "Maximizing Spiral Freezer System Efficiency in Frozen Foods Production".
  8. ↑ 8.0 8.1 8.2 8.3 8.4 8.5 V., Komolprasert (July 1, 1988). "The Effect of Temperature, Light, Freeze—Thaw Cycling, and Package Material On the Flavor Stability of Frozen Pizza". Journal of Plastic Film & Sheeting: 232.
  9. ↑ 9.0 9.1 V., Komolprasert (July 1, 1988). "The Effect of Temperature, Light, Freeze—Thaw Cycling, and Package Material On the Flavor Stability of Frozen Pizza". Journal of Plastic Film & Sheeting: 237.
  10. ↑ V., Komolprasert (July 1, 1988). "The Effect of Temperature, Light, Freeze—Thaw Cycling, and Package Material On the Flavor Stability of Frozen Pizza". Journal of Plastic Film & Sheeting: 227–228.
  11. ↑ Health Canada (2021-07-05). "Safe food storage".
  12. ↑ 12.0 12.1 V., Komolprasert (July 1, 1988). "The Effect of Temperature, Light, Freeze—Thaw Cycling, and Package Material On the Flavor Stability of Frozen Pizza". Journal of Plastic Film & Sheeting: 231.
  13. ↑ Sand, Claire Koelsch. "Frozen Food Packaging Heats Up". IFT.
  14. ↑ (2) barrier film ensures: Fresh frozen pizza. (frozen food products: A product source guide for frozen food packaging). (2002). Food & Drug Packaging (1995), 66(2), 26.
  15. ↑ Nisticò, R. (2020). Polyethylene terephthalate (PET) in the packaging industry. Polymer Testing, 90, 106707. https://doi.org/10.1016/j.polymertesting.2020.106707
  16. ↑ Barbosa, A. A. L., de Moura, J. A., & de Medeiros, D. D. (2021). Positioning of design elements on the packaging of frozen convenience food and consumers’ levels of attention: An experiment using pizza boxes. Food Quality and Preference, 87, 104044. https://doi.org/10.1016/j.foodqual.2020.104044
  17. ↑ Kummer, Corby (5, Oct, 2016). "Is It Possible to Make a More Healthful Frozen Pizza?". NY Times Megazine. Check date values in: |date= (help)
  18. ↑ 18.0 18.1 18.2 "Salt and Sodium". Harvard - School of Public Health.
  19. ↑ "Sodium Intake of Canadians in 2017". Health Canada (Government of Canada). 23, Jul, 2018. Check date values in: |date= (help)
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