Maraschino Cherry: A Laboratory-Lecture Unit

Authors


Abstract

ABSTRACT:  Oregon State Univ. has offered FST 102 “Maraschino Cherry” as a 1-credit orientation course since 1994. The maraschino cherry serves as a vehicle from which faculty give their disciplinary perspective, for example, the chemistry of the maraschino cherry, processing unit operations, microbiology and food safety, food law, sensory analysis, product development, and so on. This laboratory-lecture unit was developed to provide reference background information, including instructions for making maraschino cherries. The unit explains the functions of SO2, CaCl2, acidulants (citric or HCl), and sodium chlorite in cherry brine formulations, as well as the critical role of pH in cherry brine formulation and processing of maraschino cherries. How to estimate °Brix of sugar syrups by the Pearson square method is described. The unit gives students an understanding of the regulatory distinctions between certified colorants and colorants exempt from certification; artificial, natural, and with other natural flavors (WONF) flavorings; and additives and ingredients. A brief historical perspective of maraschino cherries is given. Study questions and suggested student projects are included.

Introduction

Dr. E. H. Wiegand, who founded Oregon State Univ.'s Food Science and Technology Dept. in 1919, is frequently given credit for inventing the maraschino cherry. More accurately, he developed the brining process for preserving cherries, which made production of high quality maraschino cherries possible. Actually, it was entrepreneurs in the Eastern United States who developed the formulations using artificial colorants and natural and artificial flavors to give the maraschino cherry its characteristic color and flavor. Their inspiration was brandied cherries from the Mediterranean region (France and Italy) that had been colored and flavored with a liqueur made from the Black Marasca cherries grown in Bosnia; this delicacy is often eaten with ice cream. The maraschino cherry, which we associate with ice-cream sundaes and the Manhattan and Old Fashioned cocktails, is quite different in color, flavor, and texture from the European original.

Materials and Methods

Preparation of sulfite primary bleaching brine

Ingredients (use food grade): Sodium metabisulfite (2.1%), Citric acid (0.2%), Calcium chloride (1%)

Procedure:

  • 1Dissolve 21 g sodium metabisulfite and 2 g citric acid in 1 L of water. After sodium metabisulfite and citric acid are in solution, add calcium chloride (10 g; Bullis and Wiegand 1931; Payne and others 1969). (Dissolving 2 level tablespoons of sodium metabisulfite and 1 level teaspoon to 0.5 gallon of water can make a brine solution with this same approximate composition; subsequently 2 level tablespoons of calcium chloride is added; Filz and Henney 1951.) Use plastic, glass, or stoneware containers.
  • 2Place fresh sweet cherries in brine solution and keep submerged for at least 3 wk. Cover containers with lids or plastic film.

Note: Brine should be prepared in a well-ventilated room. Asthmatics sensitive to SO2 should not consider making this brine solution.

Preparation of chlorite secondary bleaching brine

Ingredients: Sodium chlorite (food grade) and glacial acetic acid.

Procedure:

  • 1Prepare 0.75% solution (w/v) of sodium chlorite. Adjust pH to 5 using glacial acetic acid (approximately 0.22 mL/L; Beavers and others 1970a; Waters and Woodroof 1986). Caution: Prepare solution in hood or well-ventilated space. Wear eye protection and neoprene gloves.
  • 2Leach pitted, primary bleached cherries with running water until SO2 content of cherries is less than 200 ppm. The leaching process takes 1 to 2 d. Boiling for 10 min, draining, and repeating the process 2 subsequent times will accelerate the process.
  • 3Drain water from leached cherries and add 2 volumes of sodium chlorite brine solution. Use plastic containers and cover container with plastic film. Bleaching of brown discolorations will take from 5 to 10 d.
  • 4Leach secondary bleached cherries in running water for 1 to 2 d to remove residual sodium chlorite. Return cherries to primary bleach solution where they can remain until processing is convenient.

Maraschino cherry processing

Maraschino cherries can be produced by following either the hot or cold process outlined in Figure 1. Fresh sweet cherries must be used for brining; hence, this project is limited by the availability of fresh fruit. Alternatively, you may be able to purchase brined cherries from commercial companies. Two potential sources are: Oregon Cherry Growers Inc., Salem, Oreg., U.S.A. and Gray & Co., Forest Grove, Oreg., U.S.A.

Figure 1—.

Flow diagram of unit operations for processing maraschino cherries.

Discussion

Brine formulation

Solutions of sulfur dioxide (SO2) at levels of 0.5% or higher are effective inhibitors of most yeasts, molds, and bacteria. On a commercial scale, a brine can be prepared (Waters and Woodroof 1986) by adding 14 lb of sodium bisulfite (NaHSO3) to 100 gal of water with stirring, followed by 5 fl oz of hydrochloric acid and 7 lb of anhydrous calcium chloride (CaCl2). The pH is adjusted to 3.2 to 3.4 with additional HCl. This brine will contain about 1% SO2 and 0.85% CaCl2. A home recipe for brine preparation (Filz and Henney 1951) directs that 2 level tablespoons of sodium metabisulfite and 1 level teaspoon of citric acid be dissolved in 0.5 gal of water; subsequently, 2 level tablespoons of calcium chloride is added. The bleaching solution should have approximately the following composition by weight: NaHSO3 (2.1%), citric acid (0.2%), and CaCl2 (1%). The transformations between free SO2, sulfurous acid (H2SO3), bisulfite (HSO3), and sulfite (SO−23) are pH-dependent, the relative proportions being shown in Figure 2 (Payne and others 1969).

image
Figure 2—.

Effect of pH on the proportions of H2SO3, HSO−13, and SO−23 in aqueous solution.

The pH of the brine solution is very critical. The preservative action against bacteria, yeasts, and molds is attributed to sulfurous acid; un-ionized SO2 is believed to penetrate microbial cell walls and inactivate essential cellular enzymes (Payne and others 1969; Davidson and Juneja 1990). At a low pH, for example, 1, SO2 would be the major species present, and a much lower concentration of metabisulfite could be used in the brine formulation. This is not practical, however, since the free SO2 would be lost to the atmosphere. At the recommended pH of 3.5, cherries can be preserved in the brine for months since HSO3 provides sufficient free SO2 through chemical equilibria to prevent microbial growth and HSO3 will not be depleted to any significant extent for a long time. Calcium plays a very important role in the brine formulation by giving the cherry a firmer texture. If the pH is greater than 4, calcium will precipitate from solution as CaSO3 and not be available (refer to above reaction). The divalent cation forms salt linkages between the galacturonic units of 2 adjacent pectin molecules (Figure 3). The pKA for the galacturonic acid to galacturonate transformation is 3.6; the brine solution needs to be of this approximate pH since the galacturonate form is necessary for the salt-bridging reaction. This cross-linking of cell-wall polysaccharides results in a firmer fruit texture that is not only more acceptable from a sensory standpoint but also facilitates mechanical pitting. This feature of Wiegand's original brine formulation (Bullis and Wiegand 1931) was a major quality improvement over cherries that had been preserved by exposure to sulfurous acid solutions without inclusion of a firming agent.

Figure 3—.

Schematic for cross-linking of pectin molecules with Ca++.

Both dark- and light-colored sweet cherry cultivars are used for brining. Anthocyanin pigments are responsible for the red blush on the surface of the Royal Anne variety of sweet cherries while the same pigments, but in much higher concentrations, impart the deep burgundy color of the flesh and skin of the Bing variety. Both cultivars will be bleached through the reaction of bisulfite with anthocyanins (Figure 4). The brined cherries are yellow in color since the yellow carotenoids are not affected by bisulfite. It should be emphasized that the primary function of bisulfite is to prevent microbial growth, and that bleaching of the cherry is a secondary role. SO2 also inhibits unwanted enzyme reactions such as polyphenoloxidase-catalyzed oxidation of phenolics. Because of this, colorants need to be added during processing to restore color. With the advent of mechanical harvesting of cherries in the 1960s, the number of cherries with defects from bruising increased substantially. Cellular damage permits the enzyme polyphenoloxidase to come in contact with fruit phenolics-forming quinones, which subsequently polymerize to form brown pigments (Figure 5). This pigmentation is not bleached by bisulfite. A secondary bleaching process utilizing sodium chlorite was developed by Oregon State Univ. researchers that bleaches the brown discoloration along with the carotenoids to produce a snowy white cherry (Beavers and others 1970a; Waters and Woodroof 1986). Today both primary and secondary bleached cherries are available for maraschino cherry processing.

Figure 4—.

Reaction of anthocyanin pigments with HSO3 to form a colorless sulfonic acid addition product.

Figure 5—.

Polyphenoloxidase catalyzed reaction of phenolics to form quinones and melanoidin pigments.

Unit operations for processing maraschino cherries

Removal of brine, pitting, sorting, leaching The cherries are drained to separate the fruit from the brine solution. This is also an appropriate stage for sorting cherries of different sizes, blemishes, and those with stems from those without. The pits are removed mechanically. William H. Decker invented the mechanical cherry pitter in 1902 when he was working for the Dunkley company in Kalamazoo, Mich., U.S.A. Dunkley Intl. Inc. is still a leading producer of cherry pitters, their equipment having a capacity in the order of 1 ton of cherries per hour.

Efforts are made to reuse as much of the brine as possible to minimize the amount sent to the sewage treatment plant (Beavers and others 1970b). Disposal of spent cherry brine is a major environmental and economic issue facing today's brined cherry industry. The cherries are subsequently washed with cold water to further remove residual brine. SO2 levels need to be reduced from levels in the order of 2000 to < 200 ppm since high levels will impart an objectionable flavor. This process will also leach sugars, organic acids, bleached anthocyanin pigments, and other water-soluble compounds from the fruit. This contributes to the biological oxygen demand (BOD) of the brine and the problems of waste disposal. High temperature (boiling) will accelerate SO2 diffusion and removal. Accurate measurement of SO2 in brine, cherries, and syrups is necessary for quality control. Iodine titration is an effective method for measuring SO2 (Payne and others 1969; AOAC 1995). In this procedure, the solution to be measured is acidified to shift equilibria to H2SO3 (refer to previously mentioned reaction). Sulfurous acid is subsequently oxidized with standard iodine solution to SO−24 (refer to reaction mentioned subsequently showing oxidation of HSO−13 by I2; the stoichiometric reaction permits measurement of the amount of SO2). Starch is included in the standard iodine solution since amylose and free iodine form a blue-colored complex. When the excess free iodine is reduced to HI, there will be no free iodine to complex with starch and the solution will be colorless. This is the titration endpoint.

image

Syrup formulation and sugar equilibration Sugar concentration of cherry juice, brines, and syrups are conveniently measured by refractometry since the refractive index of aqueous sugar solutions varies linearly. Portable hand-held refractometers calibrated in percent soluble solids or °Brix (these are interchangeable terms) are used in the orchard as well as the processing plant for measuring sugar content. A few drops of juice squeezed from the cherry are placed on the refractometer, and the °Brix read directly. °Brix is defined as the percent sugar by weight; for example, 10 g of sugar dissolved in 90 g of water will give a 10 °Brix solution. The natural fruit sugars are located in the vacuole. Sweet cherries have relatively high sugar content, the FDA standard for single strength sweet cherry juice being 20 °Brix (Anon 1993). The range that naturally occurs is considerable, and even higher values will occur in the field. When harvesting fruit for brining, full-sized but slightly under ripe cherries are preferred since they will have a firmer texture than fully ripe to overripe fruit. The optimum °Brix of cherries for brining is from 12 to 15° compared to 18 to 22° for fresh market or canning. If a heavy rainstorm occurs when cherries are fully ripe, water will diffuse into the cells and rupture will occur from high turgor pressure. This causes splitting of the cherries, which can be a severe economic loss to the farmer.

Maraschino cherries commonly have a °Brix of 40°. The drained, brined cherries cannot be immediately introduced to 40 °Brix syrup or shriveling will occur as water rapidly diffuses from the fruit to the syrup. Therefore, the drained cherries are introduced to dilute sugar syrup, for example, 15 °Brix and sufficient time, for example, 12 h, is allowed for equilibration. The sugar concentration is increased in 3 to 4 °Brix increments to gradually introduce sugar without tissue damage. Since the SO2 levels have been markedly reduced, preservatives such as potassium sorbate and sodium benzoate are included in the syrup to prevent microbial growth (Davidson and Juneja 1990). An initial syrup formulation will typically contain corn syrup diluted to 15 °Brix, 0.1% potassium sorbate, 0.1% sodium benzoate, and 0.25% citric acid. The pH during processing and final bottling is targeted for approximately 3.6 to 3.8. Citric acid has several functions

  • • It provides flavor, the °Brix: acid ratio giving a good numerical index for the sweetness to sourness taste quality. This index is calculated by dividing the °Brix by the titratable acidity.
  • • The effectiveness of sodium benzoate and potassium sorbate as antimicrobial agents is dependent on pH (Payne and others 1969; Davidson and Juneja 1990). Un-dissociated benzoic acid is the form with antimicrobial activity, optimum activity occurring in the pH range of 2.5 to 4. Sodium benzoate is most active against yeast and bacteria and least effective against molds. Sorbic acid and its sodium and potassium salts are particularly effective in preventing mold growth, the activity increasing with decreasing pH.
  • • It is critical that the pH of the final product is 4.5 or less so that pasteurization can be used to ensure microbial safety. Low-acid foods (having a pH above 4.5) must be thermal processed in retorts to destroy Clostridium botulinum spores. If these spores are not inactivated, the organism will form a deadly toxin. The more severe heat treatment from retorting would have a negative impact on the texture of the fruit.

Syrup equilibration can be accelerated by using elevated temperatures, for example, 50 °C. Diffusion occurs at a faster rate at the higher temperature, shortening processing time; the higher temperature also helps to prevent microbial growth. Dilution of sugar syrups to give the desired °Brix must be done accurately. The Pearson square method is very useful for determining what proportion of ingredients to use to obtain the desired °Brix.

Example (Figure 6) A 75 °Brix corn syrup solution is to be diluted with water to 15 °Brix. To solve this problem by the Pearson square method, place the desired °Brix (15°) in the center of the square and the °Brix of the most concentrated sample (75°) in the upper left hand corner. The °Brix of the lower sugar content solution (water = 0°) is placed in the lower left hand corner. Subtract these figures from the center figure, placing the result in the diagonal position.

Figure 6—.

Diagram illustrating Pearson square method for determining proportions of ingredients to obtain desired °Brix syrup.

Answer Fifteen parts (by weight) of 75 °Brix corn syrup diluted with 60 parts water (by weight) will give a 15 °Brix corn-syrup solution.

Coloring and flavoring There is no standard of identity for maraschino cherries. Therefore the processor has flexibility in selecting what sweeteners, acidulants, colorants, and flavoring agents are used. The ingredients must be on the generally recognized as safe (GRAS) list and approved by FDA for food use. It will take 5 to 7 d for the sugar concentration to reaches 40 °Brix with the hot process and approximately 4 wk with cold. The cherries are dyed during the latter stages of the infusion process. Approximately 4 d are required for the colorant to diffuse from the syrup to the cherry and uniformly color the cherries. A typical maraschino cherry formulation will have a concentration of FD & C Red nr 40 in the order of 100 to 150 ppm. Artificial colorants and their regulatory status are an interesting case study in both food law and the evolution of the scientific discipline of food toxicology (Newsome 1990; Jones 1992). Their use in maraschino cherries has particularly been fraught with controversy. FD & C Red nr 4 (Ponceau SX) was first approved for use in 1929 and it became the most popular colorant for maraschino cherries because of its brilliant hue and stability. In 1965, FDA withdrew permission for its general use because of evidence that dogs fed on high levels of FD & C Red nr 4 had adrenal gland and urinary bladder damage. While FD & C Red nr 2 (Amaranth) had been on the FDA approved list of colorants since passage of the Food and Drug Act of 1906; maraschino cherry manufacturers found it unacceptable for their application because of its purplish hue and lesser stability to SO2 and light. Maraschino cherry manufacturers need a colorant that is resistant to bleaching by SO2 and stable to light since their customers want a product packed in glass that will have a long shelf life at ambient temperatures. Processors felt they had no acceptable alternative to FD & C Red nr 4 and FDA approved their petition for restricted use of Red nr 4 in maraschino cherries, which was not to exceed a concentration of 150 ppm. The logic was that consumers would receive very little exposure with this limited usage. When FD & C Red nr 40 (Allura Red) became available in 1971, it was found to be an effective colorant for maraschino cherries, and permission for use of FD & C Red nr 4 was subsequently withdrawn. Perhaps because of that special dispensation in regards to use of FD & C Red nr 4 for 7 y, the maraschino cherry is sometimes indicted for being a purveyor of harmful additives.

The structure of FD & C Red nr 40 is shown in Figure 7. A key structural feature is the presence of 2 sulfonic acid substituents in the sodium salt form. The sodium salt imparts water solubility to the molecule. This is necessary from the standpoint of functionality, since water solubility is necessary to give an aqueous solution with high clarity. This property is also important from a toxicological standpoint since its metabolic breakdown products are water soluble and readily excreted in the urine, minimizing risk of exposure. While the European Union did not permit use of FD & C Red nr 40 until January 1995, FD & C Red nr 2 (Amaranth), which has 3 sulfonic acid substituents (Figure 7), was permitted. FDA banned the use of FD & C Red nr 2 in 1976. Russian studies in 1970 reported Amaranth to be carcinogenic and embryo toxic to rodents (Andrianove 1970); FDA withdrew permission for use of FD & C Red nr 2 in 1976 stating that their studies failed to clearly demonstrate safety. FDA's action remains controversial since subsequent studies (Clode and others 1987) have failed to support the Russian results. Canada as well as the European Union permits the use of FD & C Red nr 2 today. Regulations concerning permitted colorants vary from country to country and from time to time; exporters must be certain that colorants and their level of use are in compliance with their designated export market. FD & C Red nr 3 (erythrosine) is a di-sodium salt of carboxylic acid and phenol substituents (Figure 7). It is water soluble, but less than FD & C Red nr 4, 40, or 2. This limited water solubility is advantageous for brined cherries that are colored for use in canned fruit cocktail. FD & C Red nr 4 would diffuse from the colored cherries into the syrup and other fruit pieces, for example, peaches, pears. The “nonbleeding” property of FD & C Red nr 3 makes it the colorant of choice for canned fruit cocktail. FD & C Red nr 40 and 3 are classified by the FDA as certified colorants. This class of approved colorants is synthetic, and U.S. regulations require that samples from each manufactured batch of colorant be sent to FDA for analysis. This certification process ensures that the colorants are free from harmful impurities, and so on. Carmine (Figure 7), the major pigment of cochineal extract, is sparingly soluble in water and an alternative to FD & C Red nr 3 for use in cherries for canned fruit cocktail. Cochineal falls in the FDA classification of colorants exempt from certification. Most of the colorants in this class are natural, but not all. For example, β-carotene is chemically synthesized but included in this class of colorants. The colorant cochineal is manufactured by water extraction of the female cochineal insect, Dactylopus coccus costa, which lives on various species of cactus, principally Nopalea cochenillifera. Mexico and Peru are major producers of this colorant. While cochineal is an approved natural colorant, it cannot be used in Kosher designated products. Presently there is no suitable natural alternative to FD & C Red nr 40 for maraschino cherries. We have recently demonstrated that radish anthocyanin extract imparts a hue very close to that of FD & C Red nr 40 with acceptable stability for at least 6 mo (Giusti and Wrolstad 1996a, 1996b). The structure of the major pigments in radish is pelargonidin-3-sophoroside-5-glucoside with malonic acid and p-coumaric or ferulic acids as acylating substituents (Figure 7). Acylation with cinnamic acids is the key structural feature that imparts improved stability to the molecule.

Figure 7—.

Structures of those gorgeous reds, FD & C Red nr 4 (Ponceau SX; approved 1929, delisted 1976); FD & C Red nr 2 (Amaranth; approved 1907, delisted 1976); FD & C Red nr 3 (Erythrosine; approved, 1907); FD & C Red nr 40 (Allura Red; approved, 1971); Carmine (Cochineal extract); and pelargonidin-3-sophoroside-5-glucoside acylated with malonic and p-coumaric acids (source, red radish).

Flavoring is added after the sugar concentration of the cherries reach 40 °Brix. Most of the flavor volatiles originally present in the cherries are lost during the brining and leaching operations, leaving a product characterized principally by the sharp taste of residual SO2. Benzaldehyde is a naturally occurring compound that contributes significantly to the flavor of both sweet (Prunus avium) and sour cherries (Prunus cerasus) (Reineccius 1994). Since almonds (Prunus amygdalus) are an even richer source of benzaldehyde, almond extract was a logical choice for flavoring maraschino cherries. The distinctive strong, aromatic quality of benzaldehyde is associated with the flavor of maraschino cherries. Artificial flavorings for maraschino cherries will have benzaldehyde as a principal ingredient. If the processor prefers to use natural flavorings, almond and/or cherry extracts will be commonly used. With other natural flavors (WONF) flavorings are often used for maraschino cherries. With this regulatory classification, 50% or more of the flavoring material must be derived from the named flavoring, for example, cherry; the remainder can come from other natural sources, for example, almonds, peaches, and so on (Sinki and Schlegel 1990).

Bottling pasteurization and labeling The finished maraschino cherries are placed in glass jars along with the syrup medium, and after sealing the jars will be pasteurized. Heating at 85 °C for 20 min will be sufficient to ensure microbial stability. Maraschino cherries may remain on the bartender's shelf or in the home pantry for extended periods of time after opening. For this reason, the use of the preservatives sodium benzoate and potassium sorbate are necessary. The osmotic effects of the 40 °Brix sugar syrup helps in preventing microbial growth, as does the low level of residual SO2. Glazed cherries, which are, used in fruitcakes and other bakery applications, differ from maraschino cherries principally by having higher sugar content, for example, 74 °Brix. The reduced water activity at this sugar concentration will prevent microbial growth without the auxiliary use of preservatives.

The label must contain a listing of all ingredients, and they are to be given in decreasing order by weight. Thus, it is readily apparent which are major and minor ingredients, but the actual quantity does not need to be declared. Food additives are defined as substances that are added to foods during production, processing, packaging, and/or storage that are not basic foodstuffs or major ingredients (Branen 1990). There must be a valid reason for using a food additive such as improvement of nutritional and sensory (color, flavor, texture) quality and extension of shelf life (preservatives, antioxidants). Additives can be either natural or synthetic, the critical difference between classification as additive or ingredient being the amount that is used. Thus, for maraschino cherries, ingredients include cherries, water, sugar, and corn sweeteners while colorants, flavorings, and preservatives are additives. Acidulants such as citric acid would also be considered to be additives. It is not customary to make the distinction between additives and ingredients in label declarations. Food additives are subject to the Delaney Clause passed by Congress in 1958, which mandates that no substance shall be added to food that has been demonstrated to cause cancer in man or laboratory animals. Basic foodstuffs are not subject to this regulation; hence, a barbecued steak is not subject to this law even though it may contain trace amounts of benzopyrene, which is a known carcinogen. The statement “may contain pits” usually appears on the label. Mechanical cherry pitters are not 100% effective, and while this statement is not required by law, the warning offers some protection from litigation to processors whose customer may suffer a broken tooth as a result of biting on an unsuspected pit. The Nutrition Education Labeling Act of 1990 requires that nutritional information also be listed on the label in terms of serving size. The accepted serving size for maraschino cherries is 1 cherry; this is logical since most beverage and dessert applications would call for 1 cherry per serving. Nutritional information is presented as percent of daily value (DV) based on a 2000 calorie per day diet. One cherry (5 g) will provide 0 g of fat and protein; the sugars in 1 maraschino cherry will make a caloric contribution of approximately 10 calories, 0.5% of DV. The quantity of dietary fiber, vitamins, and minerals in 1 maraschino cherry will be insignificant. Maraschino cherries are not intended to be a significant contributor to our nutritional well-being. Their role is to make food more appealing, and by doing so, stimulate food consumption. Hospital dieticians are aware of this and will often place a maraschino cherry on a grapefruit or fruit salad to make the patient's meal more attractive and special.

Acknowledgments

The suggestions and information provided by Carl Payne of Oregon Cherry Growers Inc. in reviewing this chapter is much appreciated, as is the help of Robert W. Durst, M. Monica Giusti, and Ling Wen in preparing the figures.

Appendix

Study questions

True–False: If any part of a question is false, please correct so that the statement is true.

  • 1FDA's classification of certified food colorants is defined as “colorants that have been approved by FDA for use in foods.”
  • 2Certified food colorants are synthetic.
  • 3For all certified colorants, samples from each manufactured batch must be sent to FDA for analysis.
  • 4The corn syrup used in making maraschino cherries is classified as a food additive.
  • 5The major purpose for using sodium metabisulfite in cherry brine is to bleach the anthocyanin pigments.
  • 6All colorants classified as exempt from certification are natural.
  • 7Cherries used in manufacture of maraschino cherries are not natural, being synthesized from cellulose and other chemicals.

Answers to True and False

  • 1F: There are colorants exempt from certification that are also approved for use in foods.
  • 2T
  • 3T
  • 4F: Corn syrup is an ingredient.
  • 5F: The major purpose is to prevent microbial growth.
  • 6F: Some of the carotenoids in this classification are manufactured by chemical synthesis.
  • 7F: Real cherries preserved by brining are used.

Short Answer Questions:

  • 1What are the functions of the following substances that are used in processing maraschino cherries?
    •  a. citric acid
    •  b. sodium benzoate
    •  c. potassium sorbate
    •  d. sulfur dioxide
    •  e. calcium chloride
  • 2What pigments are responsible for the yellow color of cherries that have been bleached with sodium metabisulfite?
  • 3What color are cherries that have been subjected to the sodium chlorite based secondary bleaching process?
  • 4What pigments are responsible for the burgundy color of fresh Bing sweet cherries?
  • 5What would be the °Brix of the resulting solution if 30 pounds of 70 °Brix corn syrup were combined with 40 pounds of water?
  • 6FDA classifies FD&C Red nr 40 as a certified color additive while cochineal extract (carmine) is an approved color additive exempt from certification. Explain the distinction in this FDA classification system.
  • 7Why are the combination of sodium benzoate and potassium sorbate preservatives used in maraschino cherry manufacturer, rather than single usage exclusively one or the other?
  • 8What chemical compound is the principal flavor note in both artificial and natural flavorings used for maraschino cherries?
  • 9What structural feature imparts stability to radish anthocyanin pigments?
  • 10What structural feature accounts for the solubility properties of FD&C Red nr 40?
  • 11The ingredient listing for a commercial sample of maraschino cherries is as follows: cherries, water, corn syrup, sugar, citric acid, natural and artificial flavors, sodium benzoate, potassium sorbate, FD&C Red nr 40, sulfur dioxide. Which are basic ingredients and which would be classified as additives?

Answers to short answer questions:

  • 1citric acid: acidulant, pH control—effectiveness of preservatives, processing parameters, flavorant sodium benzoate: preservative effective against yeasts and bacteria potassium sorbate: preservative effective against molds sulfur dioxide: preservative (also bleaches anthocyanin pigments) calcium chloride: firming agent (Ca++ cross-links pectin)
  • 2carotenoids
  • 3white
  • 4anthocyanins
  • 530°
  • 6certified colorants: class of colorants requiring that sample from each manufactured batch be sent to FDA for analysis colorants exempt from certification: FDA colorants approved for food use not requiring certification
  • 7the combination is most effective since benzoates are most effective against yeasts and bacteria and sorbates are most effective against molds
  • 8benzaldehyde
  • 9acylation with cinnamic acids
  • 10sodium salt of sulfonic acid
  • 11ingredients: cherries, water, corn syrup, sugar additives: citric acid, natural and artificial flavors, sodium benzoate, potassium sorbate, FD&C Red nr 40, sulfur dioxide

Suggested student projects

  • 1Produce a gallon of maraschino cherries. If you are going to start with fresh sweet cherries and prepare your own brine solution, you will be restricted to the availability of fresh fruit. Alternatively, you may be able to purchase brined cherries from commercial companies. Two potential sources are listed in Materials and Methods:
  • 2Starting with the Food and Drug Act of 1906, outline the progression of USA food laws and regulations with respect to the colorants permitted for use in maraschino cherries.
  • 3Develop a flow-sheet of unit processing operations for manufacture of canned fruit cocktail; include a description of the process for making the cherries used as an ingredient.
  • 4Through library research, see if you can determine who deserves credit for inventing the Manhattan, Old Fashioned, and Shirley Temple cocktails; also, when did this occur? Did prohibition have any impact on the development of the maraschino cherry?
  • 5Review the safety and toxicological data for FD & C Red nr 2 and FD & C Red nr 40. Outline the regulatory decisions of the USA, Canada, the European Union, and Japan with regards to permitted use of these colorants.
  • 6Outline the roles of SO2 in manufacturing a maraschino cherry and review the safety and regulatory status of this food additive.

Ancillary