Characterisation of the quality alterations in model fat-filled milk powders under inclement conditions and the prediction of the storage time using near infrared spectroscopy

Abstract

Fat-filled milk powders (FMP) are exported to tropical developing markets as inexpensive milk alternatives. Consequently, FMP are exposed to high temperature and humidity over long distribution and storage times, presenting challenges in preserving product quality and stability. Efficient and cost-effective methods for quality assurance under such conditions are needed. We utilised the changes in profile of the fatty acids, amino acids and near infrared spectra to investigate the quality alterations in 4 types of FMP produced onsite with 4 different vegetable oils (i.e., coconut, palm, soya-bean and sunflower) and stored for 7 weeks at 40 °C. Stearic acid decreased while the leucine content increased upon storage, but palm oil FMP appeared to be the most stable. Multiclass analyses offered substantive separation between fresh and aged samples. The models based on interval-PLS efficiently (NSE ≥ 0.90) predicted storage time with low errors (RSR ≤ 0.28), indicative of FMP freshness and stability.