ABSTRACT
This study presents an innovative approach for estimating the proximate composition of diverse rice varieties using attenuated total reflectance fourier transform infrared (ATR-FTIR) spectroscopy and chemometric techniques. Principal component analysis (PCA) reveals distinct separations among the seven rice varieties based on their FTIR spectra. Robust partial least squares (PLS) regression models, developed with high calibration (R 2) values from 0.778 for protein up to 0.941 for moisture, demonstrate high accuracy in predicting proximate composition. The root mean squared error (RMSE) in percentage values, indicative of prediction accuracy, were low across all proximate components. To ensure the response variable of regression, proximate composition measurements were taken five times, while FTIR spectra were scanned tens of times, employing random numbers around the average with the same standard deviation as the measurement. Notably, the study emphasizes the pivotal role of the amide-III band in protein determination, alongside specific wavenumber regions associated with molecular changes in proximate components. This research underscores the potential of ATR-FTIR spectroscopy and chemometrics for rapid and accurate proximate assessment in food science and agriculture.
ABSTRACT
The chemical composition and sensory profile of cocoa beans are essential factors determining the quality of cocoa-based products. In this study, cocoa bean samples were collected from various regions of Indonesia, including Aceh, Banten, Bali, East Java, West Sumatra, West Sulawesi, East Kalimantan, and Yogyakarta. The cocoa beans were fermented and sun-dried according to the producers' protocols and local practices. The sensory profile, fat content, total phenolic content, and the composition of sugars, organic acids, and amino acids of the cocoa bean samples were analyzed. The results revealed that the chemical composition and sensory profiles of the samples were diverse. The sensory profiles of cocoa liquor samples were described by low intensities of cocoa notes with the occurrence of fruity, floral, spicy, and sweet notes. The concentration of acetic acid, lactic acid, and some amino acids (glutamic acid, proline, and methionine) was associated with fresh fruit, browned fruit, and roasted note of the cocoa liquor, respectively. The variation in the environmental conditions and postharvest practices contributed to the diversity of cocoa beans' chemical and sensory characteristics.
