Maraschino Cherry: A Laboratory-Lecture Unit (an un-locked paper from the Wiley online library.
Apparently since 1994 Oregon State University has offered a 1-credit class about the making of maraschino cherries. The cherry is used to illustrate food chemistry, the fragmentation of processing unit operations, microbiology, food safety, food law, sensory analysis, and product development. The course seems like it would benefit culinary professionals working on next generation, modernist recipes.
Consider as you read the little bits I’ve extracted, just how different are Luxardo cherries? They are also gloppy pectin filled horrors but maybe just with better aroma added back after the leaching?
The course covers a lot of nitty gritty chemistry stuff: sulphur, calcium chloride, acidulants like citric acid & hydrochloric acid, sodium chloride, all for the cherry “brine” formulations.
How do they bleach the cherries?
*Cherries get a sulfite based primary bleaching brine in which they sit for three weeks
*Cherries follow up with a chlorite based secondary bleaching brine but only after the primary brine is carefully leached out with boiled water to reduce the sulphur content. “bleaching of brown discolorants will take from 5 to 10 days”
*The secondary brine gets leached out and they can return to the primary brine until they are ready for processing
“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. The divalent cation forms salt linkages between the galacturonic units of 2 adjacent pectin molecules.” …hardcore chemistry blah blah blah… “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.” [#Pectin<3Calcium #Luxardo!]
“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.”
“With the advent of mechanical harvesting of cherries in the 1960’s, 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. A secondary bleach process utilizing sodium chloride was developed by Oregon State Univ. researchers that bleaches the brown discoloration along with the carotenoids to produce a snowy white cherry.”
The brining process here is probably what I need to complete my project of embedding cocktails in fruit structures to illustrate how texture and haptic heft change thresholds of perception. I had previously been trying to wash the color out of golden raspberries by soaking them in vodka/sugar brines that I changed periodically. Brining plus reflux de-aeration will make this possible.
The cherries get sorted and supposedly only by size. When I make my alcoholic version, I sort cherries by density, but I guess when you can firm the texture with a calcium brine brix can more easily be augmented without swelling or shrinking so they can sort and just be concerned with size. They explain more of the leaching process and how it is an environmental problem because of BOD (biological oxygen demand).
“The optimum Brix of cherries for brining is from 12 to 15 degrees compared to 18 to 22 for fresh market or canning…”.
“Maraschino cherries commonly have a Brix of 40. The drained, brined cherries cannot be immediately introduced to the 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 equilibrium. The sugar content is increased in 3 to 4 Brix increments to gradually introduce sugar without tissue damage.” [#bigtradesecret]
“Since SO2 levels have been markedly reduced, preservatives such as potassium sorbate and sodium benzoate are included in the syrup to prevent microbial growth.” [#sadbuttrue]
[…]”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 […]
*The effectiveness of sodium benzoate and potassium sorbate as antimicrobial agents is dependent on pH. Un-dissociated benzoic acid is the form with antimicrobial activity, optimium 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. [why you need both!]
*[…#botulism blah blah boring]
They explain the pearson square for working with sugar.
The section on coloring is sort of painful.
“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 operation, 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 and sour cherries. Since almonds are an even richer source of benzaldehyde, almond extract was a logical choice for flavoring 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.”
The finish by explaining some labeling laws.
One cool reference ends up in the bibliography that I’d love to track down:
Searching for that book turns up a really interesting masters thesis on maraschino cherries.