No abstract

Two newly released cultivars of small watermelons [Citrullus lunatus (Thumb.) Matsum and Naki], `Mickylee' and `Minilee', plus two other cultivars, Baby Fun and Sugar Baby, were stored at various temperatures from 1 to 21C for up to 4 weeks plus 1 week at 21C over two seasons. All cultivars were susceptible to chilling injury (CI) when stored below 7C; however, `Minilee' was less susceptible than the other cultivars tested. Chilling injury increased with storage length. Conditioning at 26C for 3 days before storage at 1C reduced CI and increased the percentage of marketable watermelons after storage. Decay percentage increased with storage time and was highest on fruit held at 1C where CI led to decay. The flesh of `Mickylee' and `Minilee' was firmer than that of the other cultivars tested and `Mickylee' and Minilee' retained their firmness better during storage. Total soluble solids concentration decreased with increased storage temperature. `Minilee' watermelons were superior to the other three cultivars in postharvest storage potential and exhibited the least CI and decay.

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.

Quality changes of supersweet corn (Zea mays L.) were monitored during storage at 1, 4, or 10C, unwrapped or wrapped in stretch or shrink film. Film-wrapping maintained freshness and reduced moisture loss better than lack of wrapping. Wrapping in shrink film resulted in lower O2 and higher CO2 concentrations within packages than wrapping with stretch film. Film-wrapping in shrink film maintained total soluble solids content better than stretch-wrapping or no wrapping.

Comparisons were made of the major physical and chemical characteristics of seven cultivars of apples (Malus domestica Borkh.) produced and imported into Western Europe from 13 origins. During the 1990-91 marketing season, `Delicious', `Golden Delicious', `Granny Smith', `Elstar', `Jonagold', `Gala', and `Fuji' apples were included in the study. Physical characteristics evaluated were length-to-diameter ratio, shape, external defects, internal defects, water core, bruises, firmness, blush surface, and color. Chemical characteristics evaluated were starch, juice content, soluble solids, acids, and ascorbic acid. Significant differences in some of these quality characteristics were found between the different origins. Apples produced in the United States, particularly `Delicious', had some superior quality characteristics compared to fruit from other origins.