Blanching Effect on the Quality and Shelf-Life Characteristics of Fresh Cowpea Grains [Vigna unguiculata (L.) Walp.]

Abstract

The high perishability of fresh cowpeas impairs its commercialization. Thus, this study aims to determine the temperature–time binomial for blanching fresh cowpea [Vigna unguiculata (L.) Walp] by evaluating the effects of heat treatment and kinetic behavior on the peroxidase (POD) activity and on the physical characteristics (firmness, color, mass gain). A factorial design (3 × 6) with temperature (70, 80, and 90 °C) and time (1, 2, 4, 6, 8, and 10 min) was implemented. Physicochemical, microbiological, and enzymatic (POD) changes, in addition to photographic monitoring, were evaluated throughout the storage period (4.90 °C). With regard to the effects of the independent variables and the first-order kinetic model, it was determined that 70 °C for 4 min of blanching maintained and/or improved the physical characteristics of the raw material. The pH and the acidity of the blanched fresh cowpea changed little during the storage period; the microbiological load and POD activity reduced with blanching and remained stable until the eighth day of storage, and provided an increase of 5 days in shelf-life under refrigeration when compared to non-blanched. Blanching is shown as an alternative for improving fresh cowpeas, favoring an economic increase in production with guaranteed quality and safety attributes.

New Approaches for Improving the Quality of Processed Fruits and Vegetables and Their By-Products

“…Pre-treatments have been widely used in different fruits and vegetables to improve their stability for consumption and commercialization and extend the product’s shelf-life. An example of this is the study of Tavares et al [ 1 ], where the blanching of fresh cowpeas contributed to enzymatic inactivation and microbiological control, promoting product conservation. The results showed that the ideal blanching conditions are 70 °C for 4 min, where significant quality losses are minimized, and the shelf-life of the samples is extended by 5 days.…”