2010 Annual Report
1a.Objectives (from AD-416)
Develop cutting methods to control wound signals as a means of preventing degradative actions that affect cut fruit sensory quality and shelf life. Develop methods to retard post-cutting biochemical and physiological actions that negatively affect fruit sensory quality and shelf life. Correlate cut fruit quality biochemically with sensory evaluations, and develop markers for rapidly assessing cut fruit quality.
1b.Approach (from AD-416)
The overall approach is to determine the effects of processing, handling, and storage of cut fruits on the generation and loss of sensory attributes. Methods will be developed to control wound signals by controlling turgor pressure loss during processing. One process will involve peeling and cutting of the fruit while submerged in solutions such as calcium, nicotinamide, naicinamide, and salicylic acid derivatives. Methods will also be developed to extend fresh-cut fruit shelf life by altering wound signals using ultraviolet radiation and by heat treatment. Additionally, methods will be developed to retard post-cutting biochemical and physiological actions that negatively affect fruit sensory quality and shelf life. The approach will be to identify processing aids that will improve product sensory quality and shelf life either in combination with established processing aids, such as, calcium and ascorbic acid, or when used individually. Assessment of fresh-cut fruit quality for all treatments will be conducted via physiological and biochemical measurements, and by sensory evaluations.
This is the final report for 6435-44000-068-00D which terminated 12/07/09 and was replaced with bridging project 6435-44000-073-00D. The following summarizes the progress/accomplishments over the 5-year life of the project:
Underwater Processing. Cantaloupe cut under water had increased plant cell enzyme activity and respired less. Calcium added to the water further increased peroxidase activity and reduced translucency development of fruit during storage.
Processing Under Ultraviolet (UV) Light. Sensory aroma evaluation indicated reduced rancidity and instrumental texture measurements suggested improved firmness retention in cantaloupe cut under UV radiation. Exposure to UV during cutting reduced the microbial load over post-cut UV treatment and no treatment for the 6 day storage duration.
Heat Treatment. Heat treatment in water reduced the rate of respiration and moisture loss during storage. It reduced the microbial count and controlled lactic acid bacteria during the 8 days of storage. Heat treatment increased fruity/melon and sweet/aromatic flavors; and reduced musty, sour, bitter, chemical, and fermented flavors. Heat-treated fruit had reduced respiration and increased hardness, chewiness, and cohesiveness. This method of improving fresh-cut melon sensory properties and shelf life is very feasible and can be accomplished by the in-store processor.
Storage Temperature. Fresh-cut melon samples that remained at 4°C or 10°C had more intense fruity/melon flavor than samples that were held at 4°C for two days followed by storing at 10°C. The development of musty flavor and rancid/painty flavor during storage was more of a problem in the samples that experienced a temperature change than in those that were held at a constant 4°C or 10°C.
Acetate and Non-acetate Ester Compounds. Fruit and sweet taste flavors and cut cube firmness and density were related to contents of acetate and non-acetate organic compounds in the cantaloupe.
Modified Atmoshpere Storage. Passive modified atmosphere storage retarded the loss of volatile compounds in stored (5°C) fresh-cut cantaloupe and honeydew melons, thus maintaining quality during storage. However, lower oxygen availability in fresh-cut fruit stored under controlled atmospheres suppressed some of the acetate esters relevant to the aroma of fresh-cut melon.
Cetylpyridinium Chloride (CPC) Dips. CPC dips were demonstrated to effectively reduce Shigella sonnei, Salmonella montevideo, and Escherichia coli 0157:H7 on fresh-cut cantaloupe and watermelon with very little change in flavor.