Physical properties of NaCl-free cucumber fermentation cover brine containing CaCl2and glycerin and apparent freezing injury of the brined fruits

Abstract

Use of glycerin and CaCl2 to reduce the freezing point and improve quality of bulk stored fermented cucumbers brined without NaCl, was explored. The incidence of pre-freezing injury on the fruits, caused by deposition in tanks containing cushion brine prepared with 2.5% CaCl2, was excluded by determining the liquid and fruits densities and buoyancy force. The NaCl-free cover brine thermal properties and freezing point, and the frozen fruits water loss were determined to estimate freezing damage. Cover brines supplemented with 14.5% glycerin, 18% CaCl2, or 14% glycerin and 5% CaCl2 were needed to match the freezing point of the 6% NaCl cover brine, typically used for fermentation. Thermal properties of the NaCl-free cover brine were insignificantly affected by temperature or composition. Water loss was the main freezing injury in brined cucumbers. Supplementation of CaCl2 and/or glycerin in fermentation cover brines helped minimize fermented cucumbers water loss associated with freezing. Practical applications This study presents an assessment of brine composition that can prolong processed pickle quality and bulk storage at temperatures below zero. Fermented cucumbers stored in cover brine containing 14.5 vol % glycerin, 18 wt % CaCl2, or 14 vol % glycerin and 5 wt % CaCl2 have a reduced freezing point, which theoretically extends the window for acceptable product quality. The use of 14% glycerin above the cover boards to reduce the freezing point and, consequently, ice formation on the surface of the open-top tanks is to enable the removal of fermented fruits during winter with minimal tissue injury.