Influence of Vacuum Impregnation with Different Substances on the Metabolic Heat Production and Sugar Metabolism of Spinach Leaves

Abstract

Vacuum impregnation (VI) has been widely used as pre-treatment prior to, e.g., minimal processing, freezing, or drying of fruit and vegetables. Most of the investigations have focused on the applicability of VI to modify physicochemical, sensory, and nutritive characteristics. However, little attention has been paid to the metabolic consequences of impregnating different substances into the plant tissue. This study explores short-and long-term metabolic responses of baby spinach leaves at 5°C after impregnation with several substances that are commonly used in food industry, e.g., sucrose, calcium lactate, citric acid, and ascorbic acid. Short-term metabolic response of impregnated spinach leaves was measured with isothermal calorimetry for 7 h. Results demonstrated that leaves impregnated with calcium lactate and sucrose showed a drastic increase in metabolic heat production, but no change was recorded in leaves impregnated with solutions of ascorbic acid or citric acid. Long-term metabolic responses were evaluated by measuring sugars and starch. The different impregnation solutes provoked specific changes in the carbohydrate composition during cold storage and the concentrations at each time point are likely to be the result of mobilization of starch, which sharply decreased during storage, and solute-specific differences in metabolization and interconversion of sugars.

Multi-Analytical Approach to Study Fresh-Cut Apples Vacuum Impregnated with Different Solutions

“…Similar behaviour was observed for the respiration rates measured in terms of oxygen consumed and carbon dioxide produced. Measurements of metabolic heat production by isothermal calorimetry as a consequence of VI have been carried out in various researches by the same group [54,55], mainly on leafy vegetables such as spinach. Results showed a sharp increase of the metabolic activity of the samples when impregnated with isotonic solution of both sucrose and trehalose.…”

Metabolic response of organic strawberries and kiwifruit subjected to PEF assisted-osmotic dehydration

“…Considering fruit to be a biologically active tissue, it is of extreme importance to evaluate the effect of different technologies on the tissue metabolic response and cell integrity and vitality. The metabolic response of the fruit tissue has been widely studied by application of isothermal calorimetry (Dellarosa et al, 2016;Dymek et al, 2016;Nowacka, Fijalkowska, et al, 2018;Panarese et al, 2014;Tappi et al, 2017;Yusof, Wadsö, Rasmusson, & Gómez Galindo, 2017). This technique is based on the measurements of heat production by the plant tissue, due to different physical, chemical and biological reactions (Rocculi et al, 2012).…”

Starch branching enzymes as putative determinants of postharvest quality in horticultural crops

“…Starch and sugar content decreased during the storage of harvested spinach leaves. The lower panel presents the respiratory activity, starch, and sugar content as TSS, i.e., total soluble solids, in postharvest packaged spinach [ 122 , 123 ]. Graphs were drawn in Microsoft® PowerPoint using the published data found in Table S1 …”