A study was made to determine if induction of modified atmosphere at the time of packaging would be of a benefit to the quality of fresh-cut honeydew cubes because the desired gas levels are not attained immediately or at all during the short holding period in modified-atmosphere packages. Fresh-cut honeydew cubes (2-cm cube) were placed in a plastic container underlaid with a water absorbent packet and the container was sealed with a film. The film is coextruded polystyrene and polyethylene (Cryovac), which had oxygen transmission rates of 1448 and 1903ml/m2 per day per atm at 5 °C and 10 °C, respectively. The sealed packages were given one of the following three treatments: 1) the packages were allowed to form their own natural modified atmosphere (nMAP), 2) the internal atmosphere of the packages was flushed with a gas mixture of 5% O2 + 5% CO2 (iMAP), 3) the film was perforated with a needle to have ten 1.5-mm holes (PFP). The packages were stored at 5 °C, 2 days at 5 °C, and transferred to 10 °C or at 10 °C for 2, 4, 7, 9, or 11 days. Quality attributes and microbial population were analyzed after each holding period. The average gas mixture equilibrated to 7% O2 and 9.5% CO2 in nMAP, was unchanged from the induced atmosphere in iMAP, and was close to the ambient condition (air) in PFP. Honeydew cubes were marketable on days 11, 4, and 4 when held in nMAP; on days 11, 4, and 7 when held in iMAP; and unsalable on days 9, 4, and 7 when held in PFP at 5 °C, 10 °C or transferred to 10 °C, respectively. Development of water-soaked lesions and sour odor were the main factor affecting marketability of the cubes. The decreasing pH, chroma and `L' values and increasing hue angle, mesophilic aerobic microrganism, and yeast population was retarded in both of nMAP and iMAP.
Jin-He Bai and Alley E. Watada
Jin-He Bai, Robert A. Saftner, and Yuen S. Lee
The development of tissue translucency of fresh-cut honeydew cubes adversely affects product quality and primarily occurs in cubes that have been sanitized by dipping in chlorine water (sodium hypochlorite solution) following processing. Chlorine water dips containing calcium propionate as an antimicrobial salt were tested to decrease tissue translucency and extend the marketable shelf life of honeydew (2-cm cubes) sealed in a rigid container with a film overlap and stored at 10 °C for 7 days. Honeydew cubes not dipped following processing had higher respiration rates and microbial populations than cubes that had been dipped, and lost their marketability on day 5 due to off-odor development. Dipping in chlorine water decreased the initial population and growth of microorganisms on the cubes, compared to dipping in water or not dipping. However, translucency developed in cubes dipped in water, with or without chlorine, and became unsalable by day 5. Chlorine water dips containing calcium propionate were devised that maintained excellent antimicrobial characteristics and prevented translucency in honeydew cubes kept 7 days at 10 °C. Quality analyses revealed that calcium propionate treatments decreased respiration and ethylene production rates, maintained tissue firmness, the lightness and brightness of cube surfaces, melon aroma and overall visual quality through 7 days of storage. The calcium propionate dips did not impart or induce any detectable off-flavors or off-odors to the cubes.