Responses of minimally processed leeks to reduced O 2 and elevated CO 2 applied before processing and during storage

Abstract

To study the effects of storage atmosphere on the main quality attributes of minimally processed leeks, stalks were stored in air, 1, 3 or 5% O 2 in N 2, 6, 11 or 17% CO 2 in air, or 1% O 2 + 14% CO 2 in N 2 at 6.5 °C for 14 days. In addition, other leeks were subjected to a preprocessing treatment consisting of exposure to air or 1% O 2 + 14% CO 2 at 6.5 °C for 0, 12, or 24 h prior to minimal processing and storage in air or 1% O 2 + 14% CO 2 at 6.5 °C for 14 days. Leaf and root growth, number of newly formed roots, color changes at the basal cut surface as well as on the white and green leaf tissue, fresh weight loss, and enzymatically produced pyruvic acid content were determined. Storage of minimally processed leek stalks in 1% O 2 at 6.5 °C for 14 days minimized leaf and root growth as well as color changes at the center of the basal cut surface, but did not prevent peripheral discoloration of the basal cut surface; the other reduced O 2 and elevated CO 2 treatments were less effective than 1% O 2 in reducing leaf and root growth and cut surface discoloration. Storage in 1% O 2 + 14% CO 2, however, resulted in an additional beneficial effect compared with 1% O 2 alone by preventing the appearance of peripheral discoloration on the basal cut surface. Exposure to 1% O 2 + 14% CO 2 at 6.5 °C for 12 or 24 h prior to processing did not further contribute to quality maintenance of minimally processed leeks during storage in either air or 1% O 2 + 14% CO 2 at 6.5 °C for 14 days.