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ARS Home » Southeast Area » Raleigh, North Carolina » Food Science Research » Research » Publications at this Location » Publication #56616
Title: EFFECT OF SODIUM CHLORIDE CONCENTRATION ON CALCIUM UPTAKE INTO BRINED CUCUMBERS

Author
item WALTER W M JR - 6645-10-00
item FLEMING H P - 6645-10-00
item THOMPSON R L - 6645-10-00
item FINE T I - NCSU

Submitted to: Food Quality Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/8/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: Environmental concerns about chloride and organic waste disposal over the past 15 years have stimulated an interest in reducing the concentration of salt needed to preserve brined cucumbers. However, decreased salt concentrations can lead to rapid loss of firmness, a serious quality defect. To counteract this problem, calcium chloride is routinely added to ofermentation brines. For calcium to be most effective it should contact the tissue as soon after cucumbers are brined as possible. We wanted to find out how salt in the brine affected calcium movement into the fruit. Thus, we compared the uptake of calcium when it was the only component of a brine to uptake from a brine which contained the same amount of calcium but also contained 20 times as much NaCl. We found that calcium, which penetrated from the calcium-only brine, was localized mostly in the skin, while calcium which penetrated from the calcium plus sodium chloride brine was more evenly distributed in the fruit. These findings indicate that brines containing sodium chloride and calcium are needed to rapidly get calcium distributed throughout the tissue and will result in pickled cucumbers which will better maintain their firmness during long-term storage. Long-term firmness retention means a longer shelf life for the product.

Technical Abstract: Calcium from a brine approximately iso-osmotic with cucumber cell sap penetrated cucumber fruit much more slowly than did calcium ions from an Na brine supra-osmotic with cucumber cell sap. After 96 hr, calcium which penetrated from the iso-osmotic brine was localized mostly in the exocarp region, while calcium which penetrated from the supra-osmotic brine was mor revenly distributed among the exocarp, mesocarp, and endocarp sections. Calcium from supra-osmotic brine reached higher concentrations after 4 days oxygen-exchanged fruit more rapidly than in air-exchanged fruit, but this effect was not consistent after only 1 day. Our data indicate that both ma flow and diffusion may be operative for calcium movement into cucumbers fro the supra-osmotic brine. Also, calcium from the iso-osmotic brine seemed t be concentrated first in the exocarp tissue, and then more slowly move into the interior tissues.