Abstract

Temperature is the key variable for the various biochemical reactions, because the Swedish Scientist Arrhenius demonstrated that any biochemical reaction is always temperature dependent and some components are extremely sensitive to temperature changes, while other components are relatively stable. Particularly bioactive compounds, for instance, purified anthocyanins are labile compounds and susceptible to thermal degradation. The high temperatures increase anthocyanin degradation due to the high sensitivity of these pigments to heat. Zorić et al. (2017) demonstrated this phenomenon on spray-dried sour cherry powder in which high storage temperature increased the degradation of phenolic compounds and decreased antioxidant activity during storage. Similar results were also found in the study performed by Galmarini et al. (2013) on spray-dried red wine powder in which phenolic composition, thereby antioxidant capacity also decreased as the storage temperature increased. Ferrari et al. (2013) have studied the effect of wall material and temperature on the stability of spray-dried blackberry powder. The study revealed that anthocyanin degradation can easily follow first-order kinetics model, and the stability of the anthocyanin was related to the type of wall material and temperature used in this study. It was also shown that the alteration of surface morphology throughout storage relies upon the storage temperature and the type of wall material used. Tonon et al. (2010) have determined the degradation kinetics of spray-dried açaí powder. It was found that anthocyanin degradation had two different first-order kinetics; the first one had with a higher reaction rate and the second one with a lower degradation rate. The higher degradation rate was attributed to the non-encapsulated material which has greater contact with oxygen that causes the degradation. Saénz et al. (2009) have studied the spray-dried bioactive compounds obtained from pulp or ethanolic extracts of cactus pear. The ethanolic extracts showed two different reaction rate constants; the first one was fast and the second one was slower. On the other hand, bioactive compounds obtained from the pulp powder demonstrated only a single degradation rate constant, which was independent of time.