Salt and Soluble Solid Content Evaluation of Pickled Cucumbers Based on Inductive Methodology

• Published in: Food and bioprocess technology 2015-04, Vol.8 (4), p.749-757
• Main Authors: Jin, Yamei, Yang, Na, Ma, Qian, Wu, Fengfeng, Xu, Xueming, Tong, Qunyi
• Format: Article
• Language: English
• Subjects: Agriculture; bioprocessing; Biotechnology; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Coils; correlation; Cucumbers; Electric potential; electric power; Electrical properties; Electrical resistivity; Food Science; Frequency ranges; Impedance; Ions; juices; Magnetic flux; Magnetic properties; Organic compounds; Original Paper; Physicochemical properties; Pickling; prediction; regression analysis; Regression models; Room temperature; salt content; Sodium chloride; soluble solids; temperature; Transformers; Vegetables; Voltage
• ISSN: 1935-5130; 1935-5149
• DOI: 10.1007/s11947-014-1439-y

Salt content and soluble solid content are important test indicators of quality in pickled products according to commercial standards. Pickled cucumber contains many organic compounds and free ions, and its juice, acting as the secondary coil under alternating magnetic flux, shows specific electrical characteristics during pickling. This study applied a detection system based on the o-core transformer to determine the NaCl content (N c) and soluble solid content (SSC) of pickled cucumber in the extreme low-frequency range of 50 to 400 Hz at room temperature. It is interesting to note that the changes in electrical properties during pickling resulted in impedance changes in the coils of cucumber juice. Results showed that the terminal voltage (U ₛ) in the secondary circuit was positively correlated with NaCl content and SSC, due to the increase of conductivity in the coil. The inductive current was the ratio of the inductive voltage to the total impedance in the secondary circuit, which increased according to Ohm’s law, resulting in an increase of terminal voltages (U ₛ) related to the physicochemical properties of the samples, particularly the amount of free ions. The λ value was found to be more effective than U ₛ in evaluating the NaCl content (N c), while the most effective regression model for predicting SSC was obtained at a primary voltage of 30 V and a frequency of 120 Hz based on U ₛ value. The proposed method laid the foundation to investigate the response characteristics of food materials by combing magnetic flux with transformer properties.