PPI Spring Meeting 2001 - Abstract
Pilot System for Process-Ready Brined Cucumbers
Henry P. Fleming and Ervin G. Humphries
North Carolina State University
Procedures for the preservation of pickling cucumbers by brining
have changed significantly over the past 50 years due to increasing
environmental concerns with disposal of salt and organic wastes
and demands for higher, more uniform quality of the brined products.
However, waste control remains a serious concern for many companies,
and demands for higher product quality and uniformity are increasing
in the competitive food industry. The objective of the current
project is to develop a palletized system for temporarily storing
"process-ready" brined cucumbers. It is intended that the system
be applicable for use by growers and/or processors of brined cucumbers
and certain other vegetables. Potential advantages of the system
to growers include: (1) an increase in marketing flexibility,
and (2) value addition. Potential advantages to processors include:
(1) elimination or significant reduction in salt and organic wastes,
and (2) improved quality and uniformity of brined cucumbers.
Procedure. Cucumbers graded to size are washed, blanched,
and cooled (optional for non-fermented) and aseptically transferred
to the bag-in-box fermentation/storage container, along with brine
and starter culture (if to be fermented) or sulfite (if to be
non-fermented). The bag is filled and heat-sealed, and the container
then stored until needed for processing.
Equipment. The washer consists of a bank of six high pressure
flood nozzles, maintained at 90 psi for the initial four nozzles,
through which recycled washwater is sprayed, and at 40 psi for
the final two nozzles, through which fresh water is sprayed. The
blancher is a ferris wheel type with ten sections that forcibly
submerge cucumbers under the blanching water. Water temperature
is held at ca. 178EF, and blanching time can be varied between
18 and 200 seconds. The cooling and transfer conveyor functions
by circulating potable water through a reservoir of crushed ice
and onto the blanched cucumbers as they are being transferred
to the bag-in-box. The cucumbers are cooled sufficiently to equilibrate
with the brine at 80-90EF. Several combinations of bags and boxes
have been tested in the system with volumes of 264-330 gallons.
Bags tested were 3-ply (4 mil), ultra-low density polyethylene
(ULDPE), with or without one of the plies being nylon-coated to
retard oxygen transmission. Boxes tested included both rigid and
collapsible types constructed of plastic, wood, synthetic fibers,
or cardboard.
Brine composition. Brines (45% v) for fermented cucumbers
were composed to equalize with cucumbers (55% v) at 0.32% acetic
acid, 2 or 4% NaCl, 0.13% Ca(OH)2 and 0.13% CaCl2, and pH. 4.7.
Brines for non-fermented cucumbers were composed as described
by McFeeters in this symposium.
Culture. Cultures of Lactobacillus plantarum, grown fresh
in our laboratory or provided commercially in dehydrated form,
were added to the cover brine of cucumbers to be fermented at
a concentration of about 1 million per mL of total volume of the
bag.
Brine-stock quality. The firmness, bloater index, color,
and flavor of fermented and non-fermented sizes 1 and 2 cucumbers
were excellent. Bloater index and texture for size 3 cucumbers
were acceptable but less favorable.
Fermentation end-products. Fermentation of cucumbers was
complete within 1 month, and resulted in typical final concentrations
of 0.96% lactic acid, 0.28% acetic acid, and 0.04% sugar, and
pH 3.5.
Storage stability. Fermented cucumbers taken from the
bags and stored in glass jars were microbiologically stable for
up to 1 year when 4% salt was present, but stability was variable
at 2% salt. The ULDPE bag allowed sufficient oxygen transmission
to permit oxidative yeasts to grow at the brine/plastic interface
within about 2 months. The nylon-coated ULDPE retarded but did
not sufficiently restrict oxygen permeation. Alternative methods
to solve this problem are being investigated.
Finished pickle products. Strategies were developed to
utilize the entire bag contents of fermented cucumbers in finished
pickle products. The brine was filtered to remove bacterial cells
and used in partial acidification of the products. Products successfully
prepared included sweet chips, hamburger dill chips, process dill
whole pickles, and fresh-pack dill chips acidified with fermentation
brine. These products were subjected to taste panel evaluation
and received favorable ratings, compared to typical commercially
available products.
Conclusions. The bag-in-box concept offers the potential
for waste reduction/elimination and improved product quality and
uniformity based on these studies, but some technical concerns
should be addressed. Furthermore, economic feasibility of a commercial-scale
operation must be considered.
For further information, contact:
- Dr. H. P. Fleming, Professor
- Dr. E. G. Humphries, Professor Emeritus
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