Abstract:
The objective of this work was to predict the shelf-life of unpacked and packed gluten-free rice-buckwheat cookies kept at ambient (23 ± 1 °C) and elevated (40 ± 1 °C) temperature during storage by measuring off-flavour volatile compounds (aldehydes), antioxidant capacity, total phenolic and rutin content and evaluating sensory properties. Analysis of variance and Tukey's HSD test at 95% confidence limit showed significant differences between the observed samples. Principal component analysis was used for assessing the effect of storage time, temperature and packaging condition on all investigated cookie parameters. Antioxidant capacity measured using DPPH test showed a decreasing tendency during storage in all investigated cookie samples. The obtained results correlated with a decrease in total phenolics and rutin content and an increase in total aldehydes content in cookies during storage. From the sensory evaluation, it could be concluded that the greatest loss of sensory quality resulted from hardness increase, fracturability decrease, and the raise of uncharacteristic odours and flavours. The end-point of cookie shelf-life obtained from sensory evaluation was lower compared to that obtained measuring total aldehydes content. Therefore, sensory properties might be the markers for gluten-free cookie shelf-life prediction rather than aldehydes content.
