Cultured Dextrose and Calcium Propionate
As an effective antimicrobial as sorbate, calcium propionate is rarely used to preserve beverages. We will show you why and how cultured dextrose can be a game changer for preserving beverages naturally.
The global beverage market size was valued at over 2 trillion USD in 2022 and is expected to expand at a CAGR of 13.77% in the next five years (1). The industry is revolving around a growing focus on eco-friendly packaging and sustainable, clean-label ingredients. Most drinks, such as sodas and sports drinks, require good preservation because they are extensively distributed. Even after pasteurization, they still need preservatives to keep them fresh and last longer.
Benzoate and sorbate are the two predominant preservatives used in beverages, and often they are used in combination to maximize protection (for example, maximum 150 or 300ppm alone, 400ppm combined in non-alcoholic beverage). Another preservative, calcium propionate, most popular in bakery, shares the same effectiveness against bacteria and molds/fungi as sorbate, better than benzoate at stopping molds/fungi (see picture above). Although it has little effect on enzymes and not strong on some bacteria, they are not a big problem because most drinks like sodas, sports drinks, juice drinks, coffee and teas are very acidic, with a pH below 4. Pasteurization also kills enzymes, so they can’t grow in such an acidic environment after proper pasteurization. In fact, propionic acid is effective against Salmonella and yeast in combination with heating (2). Another unique advantage of calcium propionate is that it can suppress aflatoxin production. Despite it is allowed to be used in many beverages (3), having solubility and stability advantages and is cheaper than sorbate, calcium propionate is rarely found on the label of beverages. What are the reasons for this? We list some of them below.
Increasing concern of artificial preservatives
While all three are generally recognized as safe by regulatory authorities, concerns about synthetic additives have led to an interest in natural alternatives. Because calcium propionate is relatively new comparing to the other two, companies have no desire to replace one artificial ingredient with another. The perceived benefit may not justify the effort in formula and supply chain development.
Lack of legal limits
To our best knowledge, there are no legal limits set for calcium propionate in beverages while it’s upper limit in baked good is 3000 ppm (as propionic acid equivalence), much higher than sorbate or benzoate. It is reasonable to assume that calcium propionate can be used in higher dosage in beverages, therefore calcium propionate alone can replace the popular combination of benzoate and sorbate.
Adverse effect on taste
Calcium propionate has a mild, sweet taste and smell. Study found that calcium propionate solutions at concentrations at 50 mM (~0.9% w/w) had no detectable flavor or lip feel (4). Propionic acid is a flavor ingredient, its odor and taste description include pungent, acidic, vinegar, cheesy and dairy with a pronounced fruity lift.
Based on the above analysis, it is reasonable to believe that the increasing concern of artificial ingredients is behind the lack of calcium propionate use in beverages as new products focus on being green and natural.
Although all three preservatives occur in nature, propionate is the only compound that can be commercially produced by fermentation (or precision fermentation) technology, which is deemed “natural”. It is made by fermenting natural materials rich in simple carbohydrates by propionic acid bacteria (PAB) (the most important one is Propionibacterium freudenreichii), the final products containing propionate (or its acid) is preferably labelled as “cultured X”, where X refers to either the raw material (cultured wheat) or the main carbohydrate (cultured dextrose, fermented sugar). Some companies use " fermented" instead of " cultured". Be aware that some cultured dextrose products mainly have lactate or acetate, ask the manufacturer if the purpose is to replace the three artificial preservatives mentioned above.
However, it is easier said than done. Due to technical challenges, making high purity calcium propionate comparable to its synthetic counterpart (>96% pure) at commercial scale is very hard.
Cultured dextrose /wheat product containing around 50% or more calcium propionate can still work as a natural preservative for drinks. A study looked at how cultured dextrose affects the shelf-life of a sorghum malt based dairy drink and found that both cultured dextrose and potassium sorbate can keep the beverage fresh for about 3 weeks in the fridge (6 ± 1 °C)(5). Sadly, the study did not real the concentration of propionate in the cultured dextrose, so we cannot compare natural propionate and sorbate well without actuate dosage. At a usage level no more than 0.12% (<500ppm propionic acid equivalence), it can provide needed protection against molds and thermal-resistant bacteria without affecting product’s flavor and appearance as evident by a few fundamental case studies.
Interested in trying cultured dextrose? Please reach out to us at info@sunsonbiotech.com for free samples.
References
1: https://www.linkedin.com/pulse/global-beverage-market-insight-2023-2030-landscape-ot7lf/
2: L.D. Kagliwal, et al, in Encyclopedia of Food Microbiology (Second Edition), 2014
3:https://www.fao.org/gsfaonline/additives/details.html?id=306
4: R. A. Saftner, et al: Sanitary dips with calcium propionate, calcium chloride, or a calcium amino acid chelate maintain quality and shelf stability of fresh-cut honeydew chunks, Postharvest Biology and Technology, 2003, 29, 257-269
5: A. Hussain, et al: Effect of different preservative treatments on the shelf-life of sorghum malt based fermented milk beverage. Journal of Food Science and Technology. 2014, 51, 1582–1587.
