Effect of high hydrostatic pressure (HHP) and supercooling storage in leaf mustard (Brassica juncea L.) kimchi: Modelling of microbial activity and preservation of physicochemical properties

Abstract

Kimchi products have a short shelf life due to continuous bacterial growth and fermentation. Herein, the microbiological and physicochemical properties of leaf mustard (Brassica juncea L.) kimchi were evaluated after high hydrostatic pressure (HHP) treatment (400 and 600 MPa for 5 min) and storage under supercooling (˗4.5 °C) or refrigeration (4 and 8 °C) conditions. Moreover, predictive models describing the growth kinetics of total lactic acid bacteria (TLAB) in leaf mustard kimchi were constructed. Treatment with 600 MPa reduced the total LAB and coliform counts in the samples before storage to 1.30 and > 1 log CFU/g, respectively. Supercooling storage prevented microbial growth for 30 days and allowed the maintenance of the titratable acidity, reducing sugar content, instrumental colour, total phenolic content, and antioxidant capacity of the samples. The Logistic and Gompertz models were relatively more acceptable to predict the growth behaviour of TLAB in leaf mustard kimchi treated/non-treated with 400 MPa during supercooled or refrigerated storage. Altogether, these findings suggest that HHP treatment combined with supercooling storage conditions that delay O2 and CO2 concentration changes in packaged kimchi's headspace could help maintain the initial microbiological and physicochemical qualities of leaf mustard kimchi.