Search

Abstract: The effect of murta (Ugni molinae Turcz) leaves extract on water vapor permeability (WVP) and gas permeability (GP) of carboxymethylcellulose (CMC)-based films was studied. Two ecotypes of murta leaves “Soloyo Grande” (SG) and “Soloyo Chico” (SC), were analyzed for their composition (HPLC-MS) and SC extract revealed a higher concentration of flavonols than the SG extract. The film forming solution was prepared with 2g of CMC, 0.4ml of glycerol and 0.5ml of sunflower oil in 100ml of water (Control), 50ml of water and 50ml of each exctract (SC50 or SG50) and 100ml of each extract (SC 100 or SG 100). The addition of murta leaves extract modified the WVP and GP of the films. The WVP decreased significantly (P⩽0.05) with the incorporation of SG extract in the film but not with the SC extract (P>0.05). The CO2 and O2 permeability of the films were influenced by the kind and concentration of murta leaves extract used. The CO2 permeability, with SG extract was higher than without extract (P⩽0.05) and with SC extract was not modified. The O2 permeability with murta leaves extract were lower than without extract. Therefore, it is possible to consider that films with SC acts only as barrier to the oxygen, but with SG the water vapor and gas barrier properties were modified, being more permeable to the CO2 and acting as barrier to O2 and water vapor. [Copyright &y& Elsevier]

Prior to detailed quality and physiology evaluations, different immersion solutions (SIs) were analysed by means of a nontrained sensory panel. Each SI (calcium chloride, pectin, potassium sorbate, garlic extract and citric acid) was analysed at three concentrations. Based on at least 70% acceptance, the best mixed SI (P<0.05) was determined to be 2 g/L citric acid, 1 g/L calcium chloride and 250 g/L garlic extract (SI). The control treatment was washed only with 0.05 g/L active chlorine. Treated lettuce was stored at 5°C in darkness in sealed polypropylene bags, for 9 days. Some senescence indicators (weight loss, colour), certain enzymes related to colour (chlorophyllase and polyphenoloxidase), and a nutrient (ascorbic acid), were measured during storage. SI showed a positive effect on shelf-life of minimally processed lettuce, controlling enzymatic browning, chlorophyllase activity and weight loss. The microorganisms growth was not significantly controlled, but the fact that the organoleptic results of SI-treated lettuce showed about 80% acceptability during 9 days of storage, suggests that some slight modifications on SI could be the basis of a promising formula for minimally processed lettuce. [Copyright &y& Elsevier]