Plant based natural mold inhibitors in baked goods and beyond
Summarize the pros and cons of plant-based natural mold inhibitors that can replace artificial preservatives in baked goods and other food applications.
3/4/20243 min read
The most effective and widely used preservative and mold inhibitor in baked goods is calcium propionate, an artificial ingredient. Other often-used include benzoic acid, sorbic acid and their salts. As the food industry is moving toward simple and better-for-you ingredients, many plant based natural mold inhibition ingredients emerged recently as clean label alternatives to artificial preservatives. Those natural alternatives can be split into two categories: individual ingredient and complex plant extract. Ingredients from animal resources are excluded from this discussion.
Individual ingredient: nisin and natamycin (pimaricin)
Complex plant extracts: prune juice concentrate (active ingredients: lactic acid), raisin juice concentrate (active ingredient: propionic acid and tartaric acid), cinnamon extract (eugenol and other active ingredients), oregano extract (carvacrol, thymol and other active ingredient), cloves extract (cinnamaldehyde and other active ingredients) or rosemary extract (caronsic acid and other active ingredients), and more.
In between: cultured dextrose and cultured wheat. Based on their purity of active ingredients (active ingredient: lactic acid and/or propionic acid), they can be categorized into individual ingredient or combination blends.
Although vinegar is cited as a mold inhibitor in various bakery-related materials, it is not included in this context due to its primary functionality as an anti-bacterial agent. It must be used at high dosage, which negatively impacts product’s flavor, to combat mold. It is evident by the fact that vinegar is barely employed as a standalone mold inhibitor in baked goods. As a result, cultured dextrose or wheat, if its key ingredient is acetic acid, is not regarded as an effective mold inhibitor (the active ingredient of cultured dextrose can be a lot of things, say alcohol).
Natamycin is known to be effective against nearly all mold and yeast at very low concentration (typically in low double-digit ppm), making it unsuitable for yeast-raised products. Nevertheless, it has been observed to be used in baked goods in combination with calcium propionate. Nisin, on the other hand, is effective against many bacteria and white mold and mostly used in cheese products. It has also been found to be blended with cultured dextrose for bakery applications. However, the "antibiotic" label associated with nisin and natamycin may not align well with consumer preference. A recent study found that consumption of nisin may have unexcepted, negative effect on the gut microbiome of human.
Prune and raisin juice concentrate contain natural propionate or lactate, however, their high cost-in-use and unpredictable variation occurred naturally may prevent their widespread adoption by the food industry.
While cinnamon, clove, oregano, and rosemary extracts are often touted for their mold inhibition properties in literature and by manufacturers, it’s important to note that they may actually serve as more potent antioxidants. The effectiveness of these extracts as standalone anti-mold agents remains to be validated by end users.
Now it comes down to cultured dextrose or wheat, a complex, difficult to define product due to lack of transparency (Ref). Abundant misinformation is available on the internet, complicating the decision-making process. Cultured dextrose/wheat produced by lactic acid bacteria (LAB) contain mainly lactic acid, while those produced by propionic acid bacteria (PAB) has propionic acid as major active ingredient. Both acids exhibit effectiveness against mold, although propionic acid is more potent. Due to its low pKa (~3.8), lactic acid or its salts are most effective at pH below 4.5. However, this pH range is not suitable for most baked goods, and meat products. On the other hand, propionic acid and its sales are effective at pH 5.5 and below, making it preferred ingredient to preserve baked goods and potentially benefit meat products as well.
Cultured dextrose can also be made from animal resources such as whey and milk, end-users should request disclosure from manufactures before making purchase decisions. For example, a prominent manufacture offers a long list of similar products under the same brand name, discerning the resource used in each product solely from the product name, functionality, and application area is mission impossible. This may be intentionally designed to obscure the true nature of the ingredients, making substitution challenging to deter competition. It is one of the factors contributing to the lack of transparency in the cultured dextrose industry.
In scientific literature, lactic acid bacteria (LAB) are considered promising bio-preservatives for food. Their mode of action is indirect and relies on antifungal compounds produced by LAB, including short-chain acids (typically lactic acid) and cyclic peptides (also found in cultured dextrose or wheat). However, this approach may not be suitable for large-scale commercial products that demand consistent quality; therefore, they are not included as a member of the natural mold inhibitor family in this scope.
References:
https://doi.org/10.1533/9780857090522.1.63
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8595390/
http://www.sunsweet.co.jp/ingredient/pdfs/Applications_Bakery-Using_Prune_Juice_Concentrate.pdf
https://link.springer.com/chapter/10.1007/978-1-4419-7880-6_9
