Robust prediction performance of inner quality attributes in intact cocoa beans using near infrared spectroscopy and multivariate analysis

Abstract

Fast and simultaneous determination of inner quality parameters, such as fat and moisture contents, need to be predicted in cocoa products processing. This study aimed to employ the near-infrared reflectance spectroscopy (NIRS) in predicting the quality mentioned above parameters in intact cocoa beans. Near-infrared spectral data, in a wavelength ranging from 1000 to 2500 nm, were acquired for a total of 110 bulk cocoa bean samples. Actual fat and moisture contents were measured with standard laboratory procedures using the Soxhlet and Gravimetry methods, respectively. Two regression approaches, namely principal component regression (PCR) and partial least square regression (PLSR), were used to develop the prediction models. Furthermore, four different spectra correction methods, namely multiple scatter correction (MSC), de-trending (DT), standard normal variate (SNV), and orthogonal signal correction (OSC), were employed to enhance prediction accuracy and robustness. The results showed that PLSR was better than PCR for both quality parameters prediction. Spectra corrections improved prediction accuracy and robustness, while OSC was the best correction method for fat and moisture content prediction. The maximum correlation of determination (R 2 ) and residual predictive deviation (RPD) index for fat content were 0.86 and 3.16, while for moisture content prediction, the R 2 coefficient and RPD index were 0.92 and 3.43, respectively. Therefore, NIRS combined with proper spectra correction method can be used to rapidly and simultaneously predict inner quality parameters of intact cocoa beans.

Agricultural products quality determination by means of near infrared spectroscopy

“…However, Indonesian cocoa bean products are generally not fermented, so the price is low in the market. Cocoa quality control such as moisture content and fat content has not been carried out intensively [1,2]. Quality assurance of cocoa beans through the development of fast and accurate quality estimation methods is the key word to increase the competitiveness of Indonesian cocoa beans exports at the world level [3,4].…”

“…Indonesia standard or known as SNI stipulates quality standards for cocoa beans physically, such as water content, contamination with insects, foreign objects and various aromas that can damage the distinctive aroma of cocoa. In particular, the quality of cocoa is determined by the yield of fat, aroma and taste, because these components usually determine the sensation of enjoying chocolate [2].…”

Identification of cocoa bean quality by near infrared spectroscopy and multivariate modeling

“…The data obtained with NIR were used to build the regression model, which used the information from the data matrix X (full spectrum) and the response matrix Y (pH and total acidity values) to obtain new variables, which were called latent variables, components or factors. The absorbance values from the full spectrum were used as variables (Anyidoho et al, 2021;Hayati et al, 2021;Santos et al, 2021).…”

Improving the sustainability of cocoa smallholders farming in Aceh, Indonesia

“…Olutegbe and Sanni [10] stated that farmers' compliance to the GAP was high. There was a high value of the economic and environmental benefits of cocoa farming due to the implementation of good practices on cocoa [11,12]. Certified farmers who applied a full package of good cocoa practices experienced a significant cocoa productivity and income increases [13].…”