IMBIV   05474
INSTITUTO MULTIDISCIPLINARIO DE BIOLOGIA VEGETAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Quality preservation of walnuts coated with different types of edible coatings
Autor/es:
GROSSO AL; ASENSIO CM; GROSSO NR; CAMILETTI BX; NEPOTE V
Lugar:
Cordoba
Reunión:
Jornada; I Jornada del ICTA; 2015
Institución organizadora:
FCEFyN-UNC
Resumen:
Walnuts are harvested once a year so it?s very important to preserve their quality throughout that time. The walnut seed is known because of its characteristic sensory attributes and health benefits. These benefits owe to the high content of polyunsaturated fatty acids, but these compounds make walnuts very susceptible to lipid oxidation. This process generates rancid tastes and toxic compounds that are not acceptable for the consumers. Edible coatings have advantages reducing oxidation process because they act like a barrier in the gas exchange. The objective of this study was to evaluate the preserving effect of different edible coating on chemical and sensory properties of walnuts during storage. These coatings are made of natural compounds and constitute an innocuous method to protect walnuts throughout a year until next harvest. In addition, edible coating application is an easy and economic process to perform by the food industry. Walnuts (var. Chandler) were acquired in La Rioja, Argentina. The walnuts were coated with edible coatings like polysacharids such as: carboxymethyl-cellulose (CMC) and methyl-cellulose (MC), and proteins such as whey protein (PS). Lipid oxidation indicators were measured: peroxide value (IP) and conjugated dienes (DC) and trienes (TC). Also, volatile compounds were measured by GC-MS and intensity ratings of sensory attributes were analyzed by descriptive analysis. The samples were stored for 210 days at room temperature (20 ºC). The samples were extracted every 35 days for the measuring of oxidation indicators. The results were statistically analyzed (ANOVA y Test LSD-Fisher). Lipid oxidation indicators increased in all the treatments during the storage period. These indicators in the last day of storage had higher values in walnuts without coating (NC) with 2.53 meqO2/kg IP, 2.75 DC, and 0.19 TC followed by walnuts coated with CMC, PS, and MC. At day 210, walnut with MC exhibited the lowest IP (1.20 meqO2/kg), DC (2.25), and TC (0.16). In descriptive analysis, MC showed the lowest oxidized flavor (13.50 in 150 mm line scale), and higher walnut flavor (75.83). Volatile compounds in MC also showed the lowest increase in the hexanal content (109880.2 counts). The methyl-cellulose coating on Walnuts shows better protection against lipid oxidation and preservation of sensory quality of this product during storage.