Chopped `Salinas' crisphead lettuce (Lactuca sativa L.) was packaged in four types of polymeric films and stored at 1 or 5C for 14 days. Discoloration and off-flavors developed in lettuce stored in the two films in which the naturally produced CO2 rose above 20%. In the two films (oriented low-density polyethylene) with O2 transmission rates higher than 3000 ml·m-2· day-1·atm-1 at 22C, CO2 remained below 20%, O2 was between ≈ 2% and 15%, and the lettuce was acceptable after 14 days of storage at either 1 or 5C. Appearance and flavor were affected more by temperature than by length of storage.
Roy E. McDonald, Lawrence A. Risse and Charles R. Barmore
K.A. Sanford, P.D. Lidster, K.B. McRae, E.D. Jackson, R.A. Lawrence, R. Stark and R.K. Prange
Postharvest response of wild lowbush blueberry (Vaccinium angustifolium Ait. and V. myrtilloides Michx.) to mechanical damage and storage temperature was studied during 2 years. Fruit weight loss and the incidence of shriveled or split berries were major components that contributed to the loss of marketable yield resulting from mechanical damage and storage temperature. Decay of berries resulted in only 1% to 2% of the total marketable fruit loss. In general, the major quality attributes (firmness, microbial growth, hue, bloom, split, and unblemished berries) deteriorated with increasing damage levels and increasing storage temperature without significant interaction. Temperature had consistent effects in both years on moisture content, soluble solids concentration, titratable acids, weight loss, shriveled and decayed berries, Hunter L values, and anthocyanin leakage, while damage level had inconsistent or no significant effect.
P. Lawrence Pusey, David R. Rudell, Eric A. Curry and James P. Mattheis
The stigmatic secretions of pomaceous flowers serve as a natural medium not only for pollen, but also for the pathogen Erwinia amylovora (Burr.) Winslow et al. and other microorganisms. To understand the microecology on the stigma, exudates from cultivars of pear (Pyrus communis L.), apple (Malus pumila P. Mill.), and crab apple [Malus mandshurica (Maxim.) Kom.] were analyzed for free sugars and free amino acids as available carbon and nitrogen sources. Extracts were obtained at different stages of anthesis by submerging and sonicating stigmas in water. Certain free sugars (glucose and fructose) and free amino acids (proline, asparagine, glutamic acid, and glutamine) were consistently predominant and increased during anthesis. Apple stigma extracts were also analyzed for polysaccharides and proteins. Of major components identified for apple, free sugars made up 4.5% by mass; polysaccharides (composed of arabinose and galactose), 49.6%; and proteins, 45.9%. The two largest components are likely present as glycoproteins. This may be the first report on characteristics of rosaceous stigma exudates that includes the identity of specific free sugars, free amino acids, and polysaccharide subcomponents. Discussion includes the comparison of pomaceous stigma exudates to those of other plants and the microecological implications.