Effect of calcium lactate and heat-shock on texture in fresh-cut lettuce during storage

Abstract

Textural and microstructural changes in fresh-cut lettuce were analysed over 12 days storage. The vegetable was treated with 120 ppm chlorine and with 15 g/L calcium lactate at room temperature ($18-20 °C) and at 50 °C (heat-shock). Texturometer analysis showed that samples washed with calcium lactate had significantly (p > 0.05) higher crispness values than samples washed with chlorine. However th e use of 50 °C treatment (heat-shock) gave better textural properties at the end of storage and significantly retarded the softening process, being in agreement with the sensorial results. Cryo-SEM micrographs showed a loss of turgor (shrinkage) of the tissue cells in the samples washed with chlorine, effect not so evident in calcium lactate treated samples. The use of heat-shock in combination with calcium lactate reduced this phenomenon better than the other two treatments. Pectin methyl esterase (PME), enzyme related to textural changes, showed higher activity in samples treated with calcium lactate at 50 °C. The combination of calcium lactate and 50 °C washing temperature maintained objective and sensorial textural properties of fresh-cut lettuce better than the calcium lactate or chlorine washing treatments at room temperature.

Development of rapid hygrothermal pasteurization using saturated water vapor

“…It was also reported that different types of heat treatments, such as hot air treatment increased the firmness of strawberry fruits immediately after treatment (Vicente et al, 2002(Vicente et al, , 2005. Martin-Diana et al (2006) also reported that heat treatment resulted in tissue firming in potatoes and tomatoes as well. Fig.…”

Physiological and physico-chemical changes in green papaya (Carica papayaL. ‘Kaek Noul’) shreds taken from the outer or inner mesocarp

“…Measurements were performed in triplicate (i.e. on three boxes per tissue layer) following the procedure of Martin-Diana et al (2006). DMC was calculated using the following equation:…”

Chlorophyll degradation and lignification of fresh-cut water fennel treated with a complex chemical solution and subsequent packaging

“…These treatments all inhibit enzyme activities involved in chlorophyll degradation. Ozone solution dipping (14), a calcium lactate treatment (15), and 6-BA can reportedly effectively inhibit lignification of fresh-cut green asparagus, lettuce, and Zizania latifolia, respectively. However, up to now, no additional methods have been applied for inhibition of chlorophyll degradation of freshcut water fennel.…”