青椒论文啊.doc

Postharvest Biology and Technology 24 (2002) 271 – 278  HYPERLINK /locate/postharvbio /locate/postharvbio Quality changes in fresh-cut pear slices as affected by controlled atmospheres and chemical preservatives James R. Gorny a, Betty Hess-Pierce b, Rodrigo A. Cifuentes b, Adel A. Kader b,* a International Fresh -cut Produce Association, 1600 Duke St. Suite 440, Alexandria, VA 22314, USA b Department of Pomology, Uni ersity of California, One Shields A e, Da is, CA 95616, USA Received 7 November 2000; accepted 7 June 2001 Abstract Low O2 (0.25 or 0.5 kPa) elevated CO2 (air enriched with 5, 10 or 20 kPa CO2), or superatmospheric O2 (40, 60, or 80 kPa) atmospheres alone did not effectively prevent cut surface browning or softening of fresh-cut pear slices. A post-cutting dip of 2% (w/v) ascorbic acid, 1% (w/v) calcium lactate and 0.5% (w/v) cysteine adjusted to pH 7.0 did significantly extend shelf-life of ‘Bartlett’ pear slices, by inhibiting loss of slice flesh firmness and preventing cut surface browning. Participants in a quality evaluation could not distinguish between pear slices treated with this preservative solution and stored overnight at 0 °C and freshly prepared control pear slices. After 10 days storage in air at 0 °C, 82% of participants judged treated pear slices to be acceptable in appearance and 70% judged flavor to be acceptable. ? 2002 Elsevier Science B.V. All rights reserved. Keywords: Ascorbic acid; Browning; Calcium lactate; Controlled atmosphere; Cysteine; Minimal processing Pear 1. Introduction The greatest hurdles to the commercial market- ing of fresh-cut fruit products, including fresh-cut pear slices, are limited shelf-life due to excessive tissue softening and cut surface browning. Cut surface browning in sliced pears is caused by the action of polyphenol oxidase (PPO) on phenolic compounds released during the process of cutting (Am