Ring Characterization of Quality Indices in Butterhead Lettuce Cultivated Under Mulch and Bare Soil

Abstract

Butterhead lettuce was characterized by physical, microbiological and nutritional quality indices as a function of plant zoning and soil management (bare soil and mulch). Quality indices were measured in all the rings from the external toward the internal ratio. Assayed indices were: relative water content, water content, free and bound water, and the ratio between free water and total water, leaf area and color, total microbial counts (TMC) and ascorbic acid content (AA). The lettuce characterization by rings showed a remarkable plant zoning as a function of leaf age and development; also, some initial indices were affected by the soil management employed. Plastic mulches affect the microclimate around the plant, resulting in better plant water status. However, the use of black plastic covers could absorb sunlight therefore increasing soil temperature and causing lower AA and higher TMC in lettuce tissue. 4 Corresponding

Revalorization of spent coffee residues by a direct agronomic approach

“…Hence, Table 2 shows the mean values of the color parameters for all tested treatment groups. The results of color coordinates (L ⁎ , a ⁎ , b ⁎ and CI ⁎ ) for control plants are in accordance to those obtained by Goñi et al (2010). Statistically significant differences were found on all parameters.…”

“…The color coordinates were computed in the CIELAB scale in a CIE C/2°illuminant/observer condition and a 2.5 cm port/viewing area. Color results were expressed as tristimulus parameters: lightness (L ⁎ ), redness (a ⁎ ), yellowness (b ⁎ ), hue angle (h ab ), chroma (C ab ⁎ ), and color index (CI ⁎ ), determined as CI ⁎ = (a ⁎ × 1000) ÷ (L ⁎ × b ⁎ ) in accordance with Goñi, Agüero, Moreira, Ponce, and Roura (2010). Color evaluation was performed in 15 leaves from each composite sample, with the final results being the average of 75 measurements per treatment.…”

“…This color behavior was confirmed by total color intensity in the chroma value. The color index (CI ⁎ ) was within the "dark/ medium green" range (Goñi et al, 2010), but again more dark in the 20% and 30% samples and lighter in the 5% and 10%, in comparison to the Table 1 Soil analysis before and after lettuce cultivation with fresh spent coffee grounds (mean ± SD, dry weight basis). control.…”

Lactic acid as potential substitute of acetic acid for dissolution of chitosan: preharvest application to Butterhead lettuce

“…Although current techniques used by the fresh vegetable processing industry have improved the overall quality and extended the shelf-life of these products, but safety is still a concern (Olaimat and Holley 2012). Among fresh vegetables, Butterhead lettuce presents a particular challenge since the leaf arrangement in the head (concentric rings around the stem) favors the internalization of microorganisms, protecting them against subsequent disinfection procedures (Goñi et al 2010).…”

“…In Butterhead lettuce, when the plant reach maturity, the head is comprised of a closely pack of leaves that encircle the inner leaves with the outer ones (Goñi et al 2010). Any application of sanitizing solutions once the head is fully formed, will only reach the outer leaves, reducing its efficiency.…”