Influence of the peeling process on pepper quality

Author: S. Arazuri ¹, C. Jarén ¹, P. C. Correa ² and I. Arana ^1*

Received 18 August 2009, accepted 3 January 2010.

Abstract

The peeling process for peppers (Capsicum annuum L.) can be done manually (by hand) or mechanically which affects the quality of canned peppers. The aim of this research was to evaluate the influence of the peeling process on the canned pepper quality and to accurately predict the piquancy of peppers using NIR spectroscopy. A sample of ‘Piquillo’ peppers was randomly divided into two groups. The first group was peeled by hand and the second one mechanically. For evaluating the quality of the peppers, colour, texture, sensorial and piquancy analyses were performed. The results showed that canned peppers peeled by hand had better quality than those peeled mechanically, since they showed a brighter and more intense red colour, a smoother flesh texture and a lower and more homogeneous piquancy. They showed the highest values for lightness and chroma, the lowest values of the maximum penetration force and the total penetration energy and the lowest and more homogeneous values for the sensory piquancy. The analysed parameters show that the mechanical peeling process diminishes the quality of peppers and the cost reduction provided by mechanical peeling is not justified. The studied characteristics related to pepper quality are common for most of the pepper varieties, and the results of this research indicate the general convenience of manual peeling for peppers. In order to analyse the piquancy of peppers, a calibration method based on NIR technology was developed. The model is able to accurately predict the sensory piquancy of peppers because the value of the Standard Error of Calibration (SEC) was 0.306 the value of the Standard Error of Cross Validation (SECV) was 0.309 and the value of the Residual Predictive Deviation was 1.76.

Key words: Colour, texture, piquancy, near infrared spectroscopy, food quality.