Analysis of Low Salt and Traditional Commercial Cucumber Fermentations Sean Whitfield1, Manmeet Cheema1, Matt Parks2, Katie Baker3, Rachel Stowe1

1Department of Food, Bioprocessing and Nutrition Sciences, 2Department of Mechanical and Aerospace Engineering, 3Department of Biological Sciences North Carolina State University, Raleigh, NC 27695

Organic acids were quantified

for each fermentation process and sample type.

Calcium chloride concentrations were monitored at different processing steps.

Polygalacturonase (PG) Activity Diffusion Plate Assay

Mt. Olive Pickle Company, Commercial Supplier Dr. Johanningsmeier, Instructor and Supervisor

Erin McMurtrie, Teaching Assistant

•  CaCl2 concentrations were lower than expected. This suggests that less CaCl2 was added commercially than what was designed, which may have contributed to the observed ineffectiveness of CaCl2.

•  There was no evidence to support polygalacturonase activity as the cause of reduced texture quality of Calcium Chloride fermented cucumbers.

•  Future studies should further explore why CaCl2 conditions might favor growth for other microbes. In these studies, CaCl2 concentrations should be carefully equilibrated, and a more quantitative PG assay could be implemented.

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Fermented Desalted Finished_product

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aCl 2

Processing Steps

Target %CaCl2 After Desalting

Target %CaCl2 During Fermentation

Figure 6. CaCl2 fermentations had higher pH values and greater variance than the NaCl fermentation values. It is suspected that the higher production of propionic acid and lower concentration of lactic acid in the CaCl2 fermentations increased the pH values.

Figure 5. Target %CaCl2 and measured %CaCl2 in low salt tanks.

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3 3.1 3.2 3.3 3.4 3.5 3.6

pH

Processing Steps

ACKNOWLEDGEMENTS

CONCLUSIONS

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1.1% Calcium Chloride 6.0% Sodium Chloride

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Processing Steps

Lactic Acid Acetic Acid

Figure 1. The firmness of the CaCl2 pickles was substantially lower than the cucumbers fermented in NaCl brine.

Figure 2. PG activity measured at various stages of pickle processing.

Figure 3. Concentrations of Lactic and Acetic Acids at Various Stages of Pickle Processing

Figure 4. CaCl2 fermentations showed a higher amount of propionic acid, indicating a secondary fermentation.

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Succinic Acid Propionic Acid

1.1% Calcium Chloride 6.0% Sodium Chloride

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1.1% Calcium Chloride 6.0% Sodium Chloride

RESULTS

1.1% Calcium Chloride 6.0% Sodium Chloride METHODS

Pickled cucumbers fermented in 1.1% calcium chloride (CaCl2) brines with a Lactobacillus plantarum starter culture have been developed to reduce chloride waste by 80%, but have also been observed in small scale trials to have a lower texture quality than pickles fermented with the traditional process which uses 6% or more sodium chloride (NaCl). The objective of this research was to determine what factors differ between the two fermentation processes that may cause changes in texture. Several chemical and physical characteristics were analyzed for CaCl2 (n = 38) and NaCl (n = 21) brined cucumbers in various stages of commercial fermentation and processing. pH, polygalacturonase (PG) activity, salt concentrations, and fermentation metabolites were measured using a pH meter, PG diffusion plate assay, titrations, and high performance liquid chromatography. NaCl brined cucumber samples from the fermentation and desalting steps had a lower pH on average than those fermented and stored in CaCl2 brines. Although NaCl brined, fermented cucumbers had a noticeably firmer texture than CaCl2 pickles, no connection with PG activity and texture degradation was made in either fermentation process. In future studies, it would be better to implement a more quantitative method to measure PG activity. Further research is needed in order to find the specific factors that may be influencing cucumber texture during low salt fermentation and processing.

•  Pickled cucumbers are normally fermented in a 5-8% sodium chloride (NaCl) brine which produces waste water high in chloride.

•  In order to reduce waste, pickles have been fermented in 1.1% calcium chloride (CaCl2) with an added starter culture of Lactobacillus plantarum strain MOP3. However, small scale trials have shown that CaCl2 pickles fermented on a commercial scale may have reduced texture quality (that can be detected by consumers) in some cases.

•  With the future goal of improving CaCl2 fermented pickles texture, the two fermentation processes were compared to find which factors cause texture differences.

6% NaCl, 0.3% CaCl2 & Potassium Sorbate

OR 1.1% CaCl2, Potassium Sorbate,

& L. plantarum starter culture

INTRODUCTION

OBJECTIVES

ABSTRACT

Traditional cucumber fermentations have a pH between 3.0 and 3.5.

pH Calcium Titration High Performance Liquid Chromatography

Sodium acetate, sodium

benzoate, ammonium

oxalate, glacial acetic acid and

DI water

PGA at 50°C and Agarose

Type II at 80°C Six wells were filled with brine

samples, and then incubated in a humidity chamber at 38°

C for 48 hrs.

Plates were then stained with ruthenium red for 30 min, rinsed, and soaked overnight with DI water.

Clear zones are measured using a ruler to the nearest

mm.

Raw Cucumbers Brine Fermented Cucumbers

Fermentation & Bulk Storage

Desalted Cucumbers

Packed and

Processed

Fermented Cucumbers

Water & alum 24-48 hours

Finished Product

RESULTS

1.1% Calcium Chloride 6.0% Sodium Chloride

•  To compare texture quality of low salt and traditionally fermented cucumbers.

•  To determine whether pH, organic acids, PG activity, and calcium concentrations relate to texture quality.