Ketchup

Terminology

The term used for the sauce varies. Ketchup is the dominant term in North America and the UK, though catsup is commonly used in some southern US states and Mexico.^[10]

The term tomato sauce is also used in the UK.^[11]

Etymology

Look up ketchup in Wiktionary, the free dictionary.

The etymology of the word ketchup is unclear; there are multiple competing theories:^[12]

Mushroom ketchup

In the United Kingdom, from the 1600s ketchup was prepared with mushrooms as a primary ingredient, rather than tomatoes.^[20][21][22] In the United States, mushroom ketchup dates back to at least 1770, and was prepared by British colonists in the Thirteen Colonies.^[23]

Tomato ketchup

James Mease published the first known tomato ketchup recipe in 1812. An early recipe for "tomato catsup" from 1817 includes anchovies and insects.^[24]

In 1824, a ketchup recipe using tomatoes appeared in The Virginia Housewife (an influential 19th-century cookbook written by Mary Randolph, Thomas Jefferson's cousin). Tomato ketchup was sold locally by farmers. Jonas Yerkes is credited as the first American to sell it in a bottle.^[25] By 1837, he had produced and distributed the condiment nationally.^[26] By the mid-1850s, anchovies no longer featured as an ingredient.^[24]

Shortly thereafter, other companies followed suit. By 1897, the Sears catalog reported "there are hundreds of brands of Catsup on the market, a few of them good."^[27]

American cooks also began to sweeten ketchup in the 19th century.^[28] The Webster's Dictionary of 1913 defined "catsup" as: "table sauce made from mushrooms, tomatoes, walnuts, etc. [Also written as ketchup]." As the century progressed, tomato ketchup began to gain popularity in the United States. Tomato ketchup was popular long before fresh tomatoes were. People were less hesitant to eat tomatoes as part of a highly processed product that had been cooked and infused with vinegar and spices.^[29]

With industrial ketchup production and a need for better preservation, there was a great increase of sugar in ketchup, leading to the typically sweet and sour formula of today.^[24] In Australia, it was not until the late 19th century that sugar was added to tomato sauce, initially in small quantities, but today it contains just as much as American ketchup and only differed in the proportions of tomatoes, salt and vinegar in early recipes.^[30] While ketchup and tomato sauce are both sold in Australia, American ketchup is sweeter and thicker, whereas Australian tomato sauce is more sour and runny.^[31]

Modern ketchup emerged in the early years of the 20th century, out of a debate over the use of sodium benzoate as a preservative in condiments. Harvey W. Wiley, the "father" of the US Food and Drug Administration, challenged the safety of benzoate which was banned in the 1906 Pure Food and Drug Act. In response, entrepreneurs including Henry J. Heinz, pursued an alternative recipe that eliminated the need for that preservative.^{[citation needed]} Katherine Bitting, a bacteriologist working for the U.S. Department of Agriculture, carried out research in 1909 that proved increasing the sugar and vinegar content of the product would prevent spoilage without use of artificial preservatives. She was assisted by Arvil Bitting, her husband and an official at that agency.^[32]

Prior to Heinz, commercial tomato ketchups of that time were watery and thin, in part because they used unripe tomatoes, which were low in pectin.^[33] They had less vinegar than modern ketchups; by pickling ripe tomatoes, the need for benzoate was eliminated without spoilage or degradation in flavor. The changes driven by the desire to eliminate benzoate also produced changes^{[clarification needed]} that some experts (such as Andrew F. Smith^[34]) believe were key to the establishment of tomato ketchup as the dominant American condiment.^{[citation needed]}

Later innovations

In fast food outlets, ketchup is often dispensed in small sachets or tubs. Diners tear the side or top of ketchup packets and squeeze ketchup out of them or peel the foil lid off tubs for dipping.^{[citation needed]}

Some fast food outlets previously dispensed ketchup from hand-operated pumps into paper cups. This method has made a comeback in the first decades of the 21st century, as cost and environmental concerns over the increasing use of individual plastic ketchup tubs were taken into account.^{[citation needed]}

Composition

Some ketchup in the U.S. is labeled "Fancy", a USDA grade related to relative density (also known as specific gravity). Fancy ketchup has a higher tomato solid concentration than other USDA grades.^[35]

Nutrition

The following table compares the nutritional value of ketchup with raw ripe tomatoes and salsa, based on information from the USDA Food Nutrient Database.^[36]

Viscosity

Ketchup is a non-Newtonian fluid, meaning that its viscosity changes under stress and is not constant. It is a shear thinning fluid, which means its viscosity decreases with increased shear stress.^[37] The equation used to designate a non-Newtonian fluid is as follows: ${\displaystyle \eta =\tau /{\dot {y}}}$. This equation represents apparent viscosity where apparent viscosity is the shear stress divided by shear rate. Viscosity is dependent on stress. This is apparent when one shakes a bottle of ketchup so it becomes liquid enough to squirt out. Its viscosity decreases with stress.^[38]

The molecular composition of ketchup is what creates its pseudoplastic characteristics. Small polysaccharides, sugars, acids, and water make up the majority of the metastable ketchup product, and these small structures are able to move more easily throughout a matrix because of their low mass. While exposed to shear stress, the molecules within the suspension are able to respond quickly and create an alignment within the product. The bonds between the molecules are mostly hydrogen bonds, ionic interactions, and electrostatic interactions, all of which can be broken when subject to stress. Hydrogen bonds are constantly rearranging within a product due to their need to be in the lowest energy state, which further confirms that the bonds between the molecules will be easily disrupted. This alignment only lasts for as long as shear stress is applied. The molecules return to their original disorganized state once the shear stress dissipates.^[39]

In 2017, researchers at the Massachusetts Institute of Technology reported the development of a bottle coating that allowed all the product to slip out without leaving a residue.^[40]

In 2022, researchers at the University of Oxford found that splatter from a near-empty bottle can be prevented by squeezing more slowly and doubling the diameter of the nozzle.^[41]

Separation

Ketchup is one of the many products that are leachable, meaning that the water within the product migrates together as the larger molecules within the product sediment, ultimately causing water to separate out. This forms a layer of water on top of the ketchup due to the molecular instability within the product.^[42] This instability is caused by interactions between hydrophobic molecules and charged molecules within the ketchup suspension.^{[citation needed]}

Pectin is a polysaccharide within tomatoes that has the ability to bind to itself and to other molecules, especially water, around it. This enables it to create a gel-like matrix, dependent on the amount within the solution. Water is a large part of ketchup, due to it being 80% of the composition of distilled vinegar. In order for the water within the ketchup to be at the lowest possible energy state, all of the hydrogen bonds that are able to be made within the matrix must be made.^[43] The water bound to the polysaccharide moves more slowly within the matrix, which is unfavorable with respect to entropy.^[42] The increased order within the polysaccharide-water complex gives rise to a high-energy state, in which the water will want to be relieved. This concept implies that water will more favorably bind with itself because of the increased disorder between water molecules. This is partially the cause for water leaching out of solution when left undisturbed for a short period of time.^{[citation needed]}