Respiration rate and shelf-life study of Crotalaria longirostrata (chipilín)

Abstract

The respiration rate and the shelf-life were studied on Crotalaria longirostrata, an edible leaf cultivated on the Central American region, locally known as chipilin. Besides being a native plant in El Salvador, chipilin is a commercialized food product. In order to obtain experimental data of respiration rates, a closed chamber approach was employed at temperatures of 6, 20 and 30 °C. The experimental data obtained was fit to a two-parameter non-exponential equation to obtain the respiration rates in terms of CO2 and O2 changes over time. The gas concentration results were also fit to an enzyme kinetics respiration model of the Michaelis–Menten type. Furthermore, the respiration rates from the enzyme kinetics model were used to determine the temperature effect on the respiration. This study also provides results of the shelf-life of the unpacked and packed chipilin with different materials, low density polyethylene (LDPE) and polypropylene (PP), by using a sensory panel and fitting data to the Weibull’s probabilistic distribution. Overall results show that the enzyme kinetics model, based on uncompetitive inhibition of CO2, applies very well to chipilin. The shelf life study results indicated that packaging in LDPE and PP bags increased chipilin shelf life by 3.7 and 2.5 times respectively, compared to storage without packaging.