Tapioca balls

Tapioca balls

Tapioca balls are a product that comes from tapioca, a starch which is in turn extracted from the cassava root.^[1] They are also known as boba (a transliteration of the word “bubble”) or “pearls” in bubble tea. Some boba are five-to-ten-millimeter starch balls, consisting of sweet potato powder, potato powder, or jelly. By adding different ingredients—water, sugar and seasoning—tapioca balls can be made to vary in color and in texture. Tapioca balls are typically neutral in flavor and gel easily, making it often used as a thickening agent in foods like pudding.^[2]

Name origin

In Taiwan, it is more common for people to refer to bubble tea as pearl milk tea (zhēn zhū nǎi chá, 珍珠奶茶) because originally small 1/12” tapioca pearls were used. It was only when one tea shop owner—in an attempt to make his tea stand out—decided to use larger tapioca balls and chose a more provocative name, “boba,” to represent the difference. In Chinese, the word boba, 波霸, is a combination of a word for bubble and a word for big, which, when found together, is slang for “big breasts” or “buxom lady.” When used to describe the drink, the characters 波霸奶茶 directly translate to boba milk tea, and loosely to bubble milk tea. This translation is commonly used by English speakers and refers to the variant with 1/4" tapioca pearls.^[3]

Popularity

Bubble tea has gained widespread popularity in recent years across Europe, and Germany in particular, after already converting young people across North America. McDonald's restaurants in Germany have begun selling the dessert beverage as part of its revamped McCafé menu.^[4]

Manufacturing

Tapioca pearls are derived as baked tapioca products, which are obtained from heat treatment of the moist cassava starch in shallow pans.

Preparation of wet flour

To create pearls, tapioca starch/flour is mixed with boiling water until a kneadable consistency is achieved. The dough is cut and rolled into a spherical shape. One method of achieving the correct shape is called the gangsor method. The starch is inserted into a long, cylindrical twill cloth bag and a jerking motion is used to toss the starch lumps back and forth. The lumps will become more firm and gain a more spherical shape. The process is repeated until the pearls have roughly become the desired size. Afterwards, the pearls will be sorted according to size.

Another method is to feed the moist flour into open cylindrical pans, which rotate for a certain amount of time and at a specific speed to form the pearls.^[5]

Gelatinization

Traditionally, during heat treatment, the temperature is kept moderate so that only the surface layer of the lumps of the moist starch begins to gelatinize, and this process is described as gelatinization. One process of gelatinization is performed by placing the pearls inside shallow pans, which are then placed inside a brick oven. The pans are covered with a towel soaked in oil or fat to prevent burning the starch. While the pearls are heated over a moderate fire, it is stirred continuously with large forks to prevent burning. When this hand-baking process is applied to manufacture pearls, irregularly shaped beads may be obtained, inferior in colour and in other qualities.

In order to produce first-rate products, the starch beads are poured onto plates in a thick layer, and the plates is slowly drawn through a tunnel charged with steam. In this way, uniform gelatinization is ensured.^[5]

Drying

During the gelatinization process, the moisture content does not change very much so another drying stage is required to achieve the desired moisture content of 12%. Drying is done in a chamber drier and when drying, it must have an initial temperature of below 40 °C to avoid further gelatinization.^[5]

Freezing

Other than drying, freezing could also be used to preserve pearls before consumption. After gelatinization, the pearls are soaked in ice water to decrease the viscosity and enhance its chewiness. Afterwards, it should be frozen using a quick freezing device, such as an air-blast freezer, or through an individual quick freezing process to avoid pearls from sticking together. ^[6] One important note is that retrogradation happens quickest at near 0 °C temperatures, which would lead to tougher pearls, so it is best to minimize the time that the pearls spend in that temperature range and freeze the pearls to lower temperatures quickly. ^[7]

Preparation for consumption

Consumers and food retail establishments can purchase raw tapioca starch and create their own pearls, or they can purchase partially cooked pearls, which have already gone through the gelatinization process. Raw tapioca pearls usually require 45 minutes of boiling whereas partially-cooked tapioca pearls require 30 minutes. To ensure chewy texture, the pearls are then cooled for approximately 20 minutes. One can verify whether the pearls are ready to serve is by taking a pearl and chew it, making sure it is well-cooked all the way to the center.

In addition to the shorter cooking time, another benefit of partially cooked tapioca is that it lasts longer, with a shelf life of 8 months compared with the shelf life of 6 months for raw tapioca. Cooked tapioca pearls should only be kept for around 4-6 hours. When serving tapioca pearls, please note that the pearls will harden once it is submerged in water and will eventually soften and lump together. Lumping of tapioca pearls can be avoided by stirring and adding sugar.^[8]

Additives

To support to the creation of tapioca pearls, some additives are used, especially during the tapioca flour making process.

• Sulfuric acid is added as a bleaching agent and helps to speed up the process of making flour.
• Aluminum sulfate is useful for increasing the viscosity of the flour.
• Sulfur dioxide is used to separate the starch from other unwanted substances as well as acting as a bleaching agent, and regulating microbial and enzymatic reactions.
• Chlorine helps to create a higher quality flour and also has disinfecting and bleaching properties.

The tables below list permitted additives in tapioca pearl products regulated under different regions.

Additives permitted as domestic food

Taiwan

Additives permitted as imported food

Philippine

Singapore

Controversy

German researchers from University Hospital Aachen tested the tapioca pearls from an unnamed Taiwanese chain. According to the Daily News, the report showed that carcinogenic chemicals were found in the samples. Chemicals found included styrene, acetophenone, and brominated substances, which were not permitted as food additives.^[11] Another German study found carcinogenic PCBs, or polychlorinated biphenyls, in the starchy balls as well.^[12]

But the German reports didn’t specify the amount of substances they found in the tapioca pearls, and were not published in peer-reviewed medical or scientific journals. That is saying the accuracy of the results are not ensured^[13].

Phthalates is a chemical added to plastics used for the purpose of strengthening plastic’s flexibility, durability, longevity and transparency. In 2011 there was a discovery of phthalates inside sold Canadian beverages. It was surprisingly found in processed food items such as concentrated juice beverages, tea drinks, and other food supplements. This low cost substance had replaced regular food additives, which would normally be an emulsifier for the contents inside the drinks to generate a more attractive and natural appearance. Over-consumption of these harmful compounds can lead to very serious negative health effects such as endocrine disruption, malformation of reproductive organs, infertility and abnormal neurodevelopment. It is important to know that the maximum daily intake for this chemical is 0.05 mg/kg/day for a 70 kg body weight individual. Fortunately, the study has shown that some beverages contain insufficient amount of phthalates levels that will not exceed the daily limit. In high concentrations, it could modify the product's appearance significantly as well. ^[14]

Jelly Tapioca Pearls (or Frog Egg Drink)

“Jelly tapioca pearls” are a kind of flavored tapioca ball. They get their Mandarin name, “frog eggs,” because they appear white in the center after cooking. Vendors who sell the drink usually add some syrup or creamer before serving, or serve it on top of shaved ice.^[15]

Heart Tapioca

Heart Tapioca is an authentic snack of Yilan.

The first Heart Tapioca Shop was opened in May, 1991. Wei Shu Feng and Xu Qiong Wen, a married couple who were running a restaurant, decided to invest in tapioca balls since they both liked douhua or tofu pudding, and tapioca balls. They thought that if traditional tangyuan (balls made from sticky rice) could be stuffed with different ingredients, then tapioca balls can be as well. Therefore, they started to come up with different ideas of stuffed tapioca balls, more popularly known as Heart Tapioca.

After a lot of research, testing and failures, the widely accepted “Red Bean Heart Tapioca”, which can endure continuous and repeated boiling, came into being. Heart Tapiocas look just like normal tapioca balls , but they contain red beans or other fillings, and more flavors are appearing on the market. Luodong, a town in Yilan, was where tapioca balls with fillings first came out in Taiwan.

References