University of California

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Quality of Waterjet and Blade Cut Romaine Lettuce

Marita Cantwell (Dept. Plant Sciences, UC Davis, Davis, CA 95616 USA), Anderson Adriano Martins Melo (Universidade Federal de Viçosa, Viçosa, Brasil), Gyunghoon Hong (Dept. Plant Sciences, UC Davis, Davis, CA 95616) and Susanne Klose (R&D, Chiquita Brands NA/Fresh Express, Salinas CA 93901 USA)

Cutting fresh-cut produce is usually accomplished by stainless steel knives. Waterjet cutting employs a very small stream of high pressure water, with the type of nozzle, conveyor speed and water pressure being the main factors determining the quality of the cut. Two tests were conducted cutting romaine lettuce by an Urschel Translicer 2500 on a pilot process line using new or used and reconditioned (e.g., 3x used and sharpened) blades and by a KMT pilot waterjet system using standard or food grade nozzles. Cut romaine showed whitening dehydration and discoloration defects. In both tests, cut romaine had only minor differences in cut surface defects between blade and waterjet cutting when packaged in a modified atmosphere. However, large differences due to cutting treatments were observed in cut romaine stored in bags without modified atmosphere at 2.5 degrees C. In Test#1, pieces had very high quality with no differences between cutting method until after 15 days at 2.5 degrees C, when waterjet cut pieces had higher visual quality with less discoloration than blade cut pieces. New knife blades produced less damage on the cut surfaces than used and reconditioned blades. The food grade nozzle was superior to the standard waterjet nozzle and was the most important waterjet cutting parameter. In Test#2, discoloration appeared by day 8 in bags with no modified atmosphere at 2.5 degrees C and there were clear differences between the blade cutting and waterjet cutting. Potentially, improved cutting technology could reduce the need for extreme package atmospheres and/or ensure higher product quality with package leakers.

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