Ascorbic Acid Retention in Fresh-Cut Broccoli Florets during Hyperbaric Storage

Abstract

We investigated the efficacy of hyperbaric storing for preserving ascorbic acid (AsA) in fresh-cut broccoli florets. The samples were stored in a container pressurized at 0.3 and 2.1 MPa of air at 8 ℃ for 14 d. Florets stored under atmospheric pressure (0.1 MPa) were used as a control. We assayed AsA content, enzyme activities involved in AsA degradation and recycling, including ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), and glutathione reductase (GR), as well as antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT). Changes in partial pressure of O 2 and CO 2 in the storage container were also determined. AsA content was successfully maintained for 14 d under both of our hyperbaric treatments and was approximately twice as high as the AsA content in the control treatment. Activities of CAT, APX, GR and SOD increased at 0.3 MPa, except DHAR, whereas florets stored at 2.1 MPa showed almost no enzymatic activity. The respiration was slowed down in florets stored under hyperbaric conditions. Our results suggest that the physiological response of fresh-cut broccoli florets to the hyperbaric condition varied with the magnitude of pressure applied, especially the enhancement of CAT enzyme activity leads to the AsA retention at 0.3 MPa.