Aguilar et al. 2013 : 2 (6) 2448-2451 2448 Journal of Microbiology, Biotechnology and Food Sciences ...International peer-reviewed scientific online journal... IMPROVEMENT OF SHELF LIFE QUALITY OF GREEN BELL PEPPERS USING EDIBLE COATING FORMULATIONS Emilio Ochoa-Reyes 1,2 , Gabriela Martínez-Vazquez 2 , Saul Saucedo-Pompa 3 , Julio Montañez 1 , Romeo Rojas-Molina 1 , Miguel A. de Leon-Zapata 1 , Raúl Rodríguez-Herrera 1 and Cristóbal N. Aguilar 1 * Address(es): Dr. Cristobal N. Aguilar, 1 Universidad Autónoma de Coahuila, School of Chemistry, Department of Food Science and Technology, Blvd. V. Carranza, 25280, Saltillo, Coahuila, México, +52 844 4161238. 2 CIAD-Unidad Cuauhtémoc, Río Conchos S/N, Parque Industrial, C.P. 31570, Cd. Cuauhtémoc, Chihuahua. 3 Universidad Autónoma Agraria “Antonio Narro“, Department of Food Science and Technology, 25000, Saltillo, Coahuila, México. 4 Fitokimica Industrial de Mexico S.A de C.V. Carretera Ramos Arizpe, Coahuila, México. *Corresponding author: cristobal.aguilar@uadec.edu.mx ABSTRACT Keywords: Candelilla wax, jojoba oil, polyphenols, tarbush, biopolymers INTRODUCTION Most of fruits are harvested at physiological maturity requiring specific post- harvest conditions for keeping commercial quality as long as possible, including market and sale periods. Traditionally, post-harvest losses can be minimized by controlling transpiration and respiration rate, reduction of microbial infection and modifying storing atmospheres thus extending fruit shelf life (Bisen and Pandey, 2008). But, these techniques should be easily available, economically viable and feasible (Pandey et al., 2010). Senescence process usually leads to yellowing of green vegetables, due to degradation of chlorophyll, this change is critical because influence preference of consumers during purchasing. Intense green color is a trait which gives a fresh look to many vegetables, green color changes to brown, due to formation of pheophytin (Artés et al., 2003). Modified atmospheres under refrigeration help to maintain fruit and vegetable quality and extend shelf life of vegetal products, mainly by inhibiting or decreasing the metabolic activity, development of biotic diseases, and enzymatic browning (Radziejewska-Kubzdela et al., 2007). Consumers demand less use of chemicals on minimally processed fruits and vegetables so more attention has been paid to the search of naturally occurring substances able to act as alternative antimicrobials and antioxidants ( Ponce et al., 2008; Ochoa et al., 2011). By this reason, in recent years, food packaging research has focused more on biodegradable layers, including those made from vegetal sources (Seydim and Sarikus, 2006) and natural extracts (Wijewardane and Guleria, 2011). Edible coatings can provide a suitable atmosphere (low O2 and high CO2) for fruit conservation (Baldwin, 2005). The capacity of edible layers to maintain moisture, oxygen, aromas and solute transport may be improved by including chemical or natural additives such as antioxidants, antimicrobials, colorants, flavors, fortifying nutrients, or spices (Pranoto et al., 2005). These additives have different active ingredients which diminish losses caused by microbial infections (Bhowmick and Choudhary, 1992; Wijewardane and Guleria, 2011). An edible coating must ensure stability of food and extend its shelf life. Under storage conditions of fruits and vegetables should therefore be considered mechanical and chemical factors that are involved in the coating edible design (Miranda et al., 2003). An edible coating is defined as a thin layer of material formed on a food as a coating, or placed (which implies that must be preformed) between food components (Krochta and De Mulder-Johnston, 1997). This coating must be from food grade materials mainly biopolymers commonly used in the food industry (Demirci et al., 2011) such as xanthan, Arabic, guar, carrageenan and locus bean gum, pectin, etc. Earlier our group reported that a edible coating of wax candelilla functionalized with ellagic acid extends and improves shelf life of Golden Delicious apples during 8 weeks of storage (Ochoa et al., 2011), without altering sensory quality of fruits. Similar results were obtained when edible coatings of candelilla wax were functionalized with a tar bush extract improving the physicochemical quality of apples (De León-Zapata, 2012). In this study, the objective was to extend and improve the shelf life quality of green bell pepper using an edible coating of candelilla wax. MATERIAL AND METHODS Raw materials Green bell peppers were purchased at a local market, 24 h before treatments application. Fruit selection criteria were: size, absence of skin damage, visible absence of microorganisms, physiological maturity and intense green color. Then, green bell peppers were taken and sorted in complete random groups, washed with detergent and disinfected with a chlorine solution (500 ppm) for five minutes, finally, the excess of water was removed at room temperature (Gonzalez-Aguilar et al., 2005). Grouping and classification of vegetables Green bell peppers were selected and assigned to a batch completely at random, Each group was analyzed in triplicates. Then each group was already In Latin-America, there are countries with high production levels of green bell peppers, which requires of new strategies of conservation for their international trade. Traditional techniques of preservations do not guarantee to prolong the shelf life of these kinds of fruits, for this reason, in the present study, the Influence of different edible coating formulations on shelf-life quality of green bell peppers was studied. Three different biopolymers (pectin, arabic, and xanthan gums) were evaluated in mixtures with candelilla wax as hydrophobic phase, jojoba oil as plasticizer and a crude extract of polyphenols as source of bioactive compounds. Green bell peppers were immersion-treated and then stored at room temperature. Response variables were: weight loss, color, appearance, pH, total soluble solids and firmness changes which were kinetically determined. All peppers treated with edible-coating showed a significant difference (Tukey, p≤0.05) in weight loss compared to control treatment (without edible coating), while a lower level of deterioration was observed in fruits treated with edible coating formulated with arabic gum, but appearance remained similar among fruits treated with different edible coatings. Use of mixtures of biopolymers, candelilla wax, jojoba oil and polyphenols to develop edible and functionalized coatings significantly extended shelf life of green bell pepper. ARTICLE INFO Received 9. 3. 2013 Revised 26. 4. 2013 Accepted 13. 5. 2013 Published 1. 6. 2013 Short communication