Post-effects of high hydrostatic pressure on green color retention and related properties of spinach puree during storage

Abstract

Abstract Based on related properties of green color retention, the effects of high hydrostatic pressure (HHP) (200, 400 and 600 MPa for 15 min) treatments on −a⁎ value, chlorophyll a and b contents, activities of chlorophyllase, Mg-dechelatase, peroxidase, polyphenol oxidase, total phenolic compounds content and pH of spinach puree were assessed during 43 days of storage at 4 °C/2000 lx and 4 °C/dark. Results showed that chlorophyll content changes followed a first-order reaction kinetics as a function of storage time at 4 °C. Samples treated by 600 MPa HHP showed higher −a⁎ value, chlorophyll a content and pH, lower chlorophyllase and polyphenol oxidase activity, and the post-effect existed at almost whole storage time, which could maintain better color of spinach puree during storage by inhibiting chlorophyll degradation and browning reaction effectively. The interesting result was −a⁎ value and Mg-dechelatase activity of samples were higher when stored at 2000 lx than dark storage ones. Another phenomenon was Mg-dechelatase activity of all samples increased greatly after HHP treatments, and the tendency was sustained during storage, especially for 400 and 600 MPa HHP-treated samples. Industrial relevance The yield of green vegetables in China is huge. However, the processing of green vegetable still faces many difficulties especially for color deterioration during processing and storage. As one novel non-thermal processing technique, high hydrostatic pressure (HHP) is likely to replace the traditional thermal processing. Many researchers have showed HHP can better keep color quality of green vegetables. However, the post-effects of HHP on green color retention and related properties during storage are still little. The aim of research is to analyze color related properties during storage in HHP-treated spinach, and provide theoretical basis of green vegetable non-thermal processing for commercial application of HHP-processed vegetable products. The research is important for HHP industrialization in China.